text: /*====================================================================*
   -  Copyright (C) 2001 Leptonica.  All rights reserved.
   -
   -  Redistribution and use in source and binary forms, with or without
   -  modification, are permitted provided that the following conditions
   -  are met:
   -  1. Redistributions of source code must retain the above copyright
   -     notice, this list of conditions and the following disclaimer.
   -  2. Redistributions in binary form must reproduce the above
   -     copyright notice, this list of conditions and the following
   -     disclaimer in the documentation and/or other materials
   -     provided with the distribution.
   -
   -  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   -  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   -  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   -  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL ANY
   -  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   -  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   -  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   -  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   -  OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   -  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   -  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *====================================================================*/
  
  /*!
   * \file recogident.c
   * <pre>
   *
   *      Top-level identification
   *         l_int32             recogIdentifyMultiple()
   *
   *      Segmentation and noise removal
   *         l_int32             recogSplitIntoCharacters()
   *
   *      Greedy character splitting
   *         l_int32             recogCorrelationBestRow()
   *         l_int32             recogCorrelationBestChar()
   *         static l_int32      pixCorrelationBestShift()
   *
   *      Low-level identification of single characters
   *         l_int32             recogIdentifyPixa()
   *         l_int32             recogIdentifyPix()
   *         l_int32             recogSkipIdentify()
   *
   *      Operations for handling identification results
   *         static L_RCHA      *rchaCreate()
   *         l_int32            *rchaDestroy()
   *         static L_RCH       *rchCreate()
   *         l_int32            *rchDestroy()
   *         l_int32             rchaExtract()
   *         l_int32             rchExtract()
   *         static l_int32      transferRchToRcha()
   *
   *      Preprocessing and filtering
   *         l_int32             recogProcessToIdentify()
   *         static PIX         *recogPreSplittingFilter()
   *         static PIX         *recogSplittingFilter()
   *
   *      Postprocessing
   *         SARRAY             *recogExtractNumbers()
   *         PIX                *showExtractNumbers()
   *
   *      Static debug helper
   *         static void         l_showIndicatorSplitValues()
   *
   *  See recogbasic.c for examples of training a recognizer, which is
   *  required before it can be used for identification.
   *
   *  The character splitter repeatedly does a greedy correlation with each
   *  averaged unscaled template, at all pixel locations along the text to
   *  be identified.  The vertical alignment is between the template
   *  centroid and the (moving) windowed centroid, including a delta of
   *  1 pixel above and below.  The best match then removes part of the
   *  input image, leaving 1 or 2 pieces, which, after filtering,
   *  are put in a queue.  The process ends when the queue is empty.
   *  The filtering is based on the size and aspect ratio of the
   *  remaining pieces; the intent is to remove anything that is
   *  unlikely to be text, such as small pieces and line graphics.
   *
   *  After splitting, the selected segments are identified using
   *  the input parameters that were initially specified for the
   *  recognizer.  Unlike the splitter, which uses the averaged
   *  templates from the unscaled input, the recognizer can use
   *  either all training examples or averaged templates, and these
   *  can be either scaled or unscaled.  These choices are specified
   *  when the recognizer is constructed.
   * </pre>
   */
  
  #include <string.h>
  #include "allheaders.h"
  
      /* There are two methods for splitting characters: DID and greedy.
       * The default method is DID.  */
  #define  SPLIT_WITH_DID   1
  
      /* Padding on pix1: added before correlations and removed from result */
  static const l_int32    LeftRightPadding = 32;
  
      /* Parameters for filtering and sorting connected components in splitter */
  static const l_float32  MinFillFactor = 0.10;
  static const l_int32  DefaultMinHeight = 15;  /* min unscaled height */
  static const l_int32  MinOverlap1 = 6;  /* in pass 1 of boxaSort2d() */
  static const l_int32  MinOverlap2 = 6;  /* in pass 2 of boxaSort2d() */
  static const l_int32  MinHeightPass1 = 5;  /* min height to start pass 1 */
  
  
  static l_int32 pixCorrelationBestShift(PIX *pix1, PIX *pix2, NUMA *nasum1,
                                         NUMA *namoment1, l_int32 area2,
                                         l_int32 ycent2, l_int32 maxyshift,
                                         l_int32 *tab8, l_int32 *pdelx,
                                         l_int32 *pdely, l_float32 *pscore,
                                         l_int32 debugflag );
  static L_RCH *rchCreate(l_int32 index, l_float32 score, char *text,
                          l_int32 sample, l_int32 xloc, l_int32 yloc,
                          l_int32 width);
  static L_RCHA *rchaCreate();
  static l_int32 transferRchToRcha(L_RCH *rch, L_RCHA *rcha);
  static PIX *recogPreSplittingFilter(L_RECOG *recog, PIX *pixs, l_int32 minh,
                                      l_float32 minaf, l_int32 debug);
  static l_int32 recogSplittingFilter(L_RECOG *recog, PIX *pixs, l_int32 min,
                                      l_float32 minaf, l_int32 *premove,
                                      l_int32 debug);
  static void l_showIndicatorSplitValues(NUMA *na1, NUMA *na2, NUMA *na3,
                                         NUMA *na4, NUMA *na5, NUMA *na6);
  
  /*------------------------------------------------------------------------*
   *                             Identification
   *------------------------------------------------------------------------*/
  /*!
   * \brief   recogIdentifyMultiple()
   *
   * \param[in]    recog       with training finished
   * \param[in]    pixs        containing typically a small number of characters
   * \param[in]    minh        remove shorter components; use 0 for default
   * \param[in]    skipsplit   1 to skip the splitting step
   * \param[out]   pboxa       [optional] locations of identified components
   * \param[out]   ppixa       [optional] images of identified components
   * \param[out]   ppixdb      [optional] debug pix: inputs and best fits
   * \param[in]    debugsplit  1 returns pix split debugging images
   * \return  0 if OK; 1 if nothing is found; 2 for other errors.
   *
   * <pre>
   * Notes:
   *      (1) This filters the input pixa and calls recogIdentifyPixa()
   *      (2) Splitting is relatively slow, because it tries to match all
   *          character templates to all locations.  This step can be skipped.
   *      (3) An attempt is made to order the (optionally) returned images
   *          and boxes in 2-dimensional sorted order.  These can then
   *          be used to aggregate identified characters into numbers or words.
   *          One typically wants the pixa, which contains a boxa of the
   *          extracted subimages.
   * </pre>
   */
  l_ok
  recogIdentifyMultiple(L_RECOG  *recog,
                        PIX      *pixs,
                        l_int32   minh,
                        l_int32   skipsplit,
                        BOXA    **pboxa,
                        PIXA    **ppixa,
                        PIX     **ppixdb,
                        l_int32   debugsplit)
  {
  l_int32  n;
  BOXA    *boxa;
  PIX     *pixb;
  PIXA    *pixa;
  
      PROCNAME("recogIdentifyMultiple");
  
      if (pboxa) *pboxa = NULL;
      if (ppixa) *ppixa = NULL;
      if (ppixdb) *ppixdb = NULL;
      if (!recog)
          return ERROR_INT("recog not defined", procName, 2);
      if (!recog->train_done)
          return ERROR_INT("training not finished", procName, 2);
      if (!pixs)
          return ERROR_INT("pixs not defined", procName, 2);
  
          /* Binarize if necessary */
      if (pixGetDepth(pixs) > 1)
          pixb = pixConvertTo1(pixs, recog->threshold);
      else
          pixb = pixClone(pixs);
  
          /* Noise removal and splitting of touching characters */
      recogSplitIntoCharacters(recog, pixb, minh, skipsplit, &boxa, &pixa,
                               debugsplit);
      pixDestroy(&pixb);
      if (!pixa || (n = pixaGetCount(pixa)) == 0) {
          pixaDestroy(&pixa);
          boxaDestroy(&boxa);
          L_WARNING("nothing found\n", procName);
          return 1;
      }
  
      recogIdentifyPixa(recog, pixa, ppixdb);
      if (pboxa)
          *pboxa = boxa;
      else
          boxaDestroy(&boxa);
      if (ppixa)
          *ppixa = pixa;
      else
          pixaDestroy(&pixa);
      return 0;
  }
  
  
  /*------------------------------------------------------------------------*
   *                     Segmentation and noise removal                     *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   recogSplitIntoCharacters()
   *
   * \param[in]    recog
   * \param[in]    pixs        1 bpp, contains only mostly deskewed text
   * \param[in]    minh        remove shorter components; use 0 for default
   * \param[in]    skipsplit   1 to skip the splitting step
   * \param[out]   pboxa       character bounding boxes
   * \param[out]   ppixa       character images
   * \param[in]    debug       1 for results written to pixadb_split
   * \return  0 if OK, 1 on error or if no components are returned
   *
   * <pre>
   * Notes:
   *      (1) This can be given an image that has an arbitrary number
   *          of text characters.  It optionally splits connected
   *          components based on document image decoding in recogDecode().
   *          The returned pixa includes the boxes from which the
   *          (possibly split) components are extracted.
   *      (2) After noise filtering, the resulting components are put in
   *          row-major (2D) order, and the smaller of overlapping
   *          components are removed if they satisfy conditions of
   *          relative size and fractional overlap.
   *      (3) Note that the splitting function uses unscaled templates
   *          and does not bother returning the class results and scores.
   *          These are more accurately found later using the scaled templates.
   * </pre>
   */
  l_ok
  recogSplitIntoCharacters(L_RECOG  *recog,
                           PIX      *pixs,
                           l_int32   minh,
                           l_int32   skipsplit,
                           BOXA    **pboxa,
                           PIXA    **ppixa,
                           l_int32   debug)
  {
  static l_int32  ind = 0;
  char     buf[32];
  l_int32  i, xoff, yoff, empty, maxw, bw, ncomp, scaling;
  BOX     *box;
  BOXA    *boxa1, *boxa2, *boxa3, *boxa4, *boxad;
  BOXAA   *baa;
  PIX     *pix, *pix1, *pix2, *pix3;
  PIXA    *pixa;
  
      PROCNAME("recogSplitIntoCharacters");
  
      lept_mkdir("lept/recog");
  
      if (pboxa) *pboxa = NULL;
      if (ppixa) *ppixa = NULL;
      if (!pboxa || !ppixa)
          return ERROR_INT("&boxa and &pixa not defined", procName, 1);
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
      if (!recog->train_done)
          return ERROR_INT("training not finished", procName, 1);
      if (!pixs || pixGetDepth(pixs) != 1)
          return ERROR_INT("pixs not defined or not 1 bpp", procName, 1);
      if (minh <= 0) minh = DefaultMinHeight;
      pixZero(pixs, &empty);
      if (empty) return 1;
  
          /* Small vertical close for consolidation.  Don't do a horizontal
           * closing, because it might join separate characters. */
      pix1 = pixMorphSequence(pixs, "c1.3", 0);
  
          /* Carefully filter out noise */
      pix2 = recogPreSplittingFilter(recog, pix1, minh, MinFillFactor, debug);
      pixDestroy(&pix1);
  
          /* Get the 8-connected components to be split/identified */
      boxa1 = pixConnComp(pix2, NULL, 8);
      pixDestroy(&pix2);
      ncomp = boxaGetCount(boxa1);
      if (ncomp == 0) {
          boxaDestroy(&boxa1);
          L_WARNING("all components removed\n", procName);
          return 1;
      }
  
          /* Save everything and split the large components */
      boxa2 = boxaCreate(ncomp);
      maxw = recog->maxwidth_u + 5;
      scaling = (recog->scalew > 0 || recog->scaleh > 0) ? TRUE : FALSE;
      pixa = (debug) ? pixaCreate(ncomp) : NULL;
      for (i = 0; i < ncomp; i++) {
          box = boxaGetBox(boxa1, i, L_CLONE);
          boxGetGeometry(box, &xoff, &yoff, &bw, NULL);
              /* Treat as one character if it is small, if the images
               * have been scaled, or if splitting is not to be run. */
          if (bw <= maxw || scaling || skipsplit) {
              boxaAddBox(boxa2, box, L_INSERT);
          } else {
              pix = pixClipRectangle(pixs, box, NULL);
  #if SPLIT_WITH_DID
              if (!debug) {
                  boxa3 = recogDecode(recog, pix, 2, NULL);
              } else {
                  boxa3 = recogDecode(recog, pix, 2, &pix2);
                  pixaAddPix(pixa, pix2, L_INSERT);
              }
  #else  /* use greedy splitting */
              recogCorrelationBestRow(recog, pix, &boxa3, NULL, NULL,
                                      NULL, debug);
              if (debug) {
                  pix2 = pixConvertTo32(pix);
                  pixRenderBoxaArb(pix2, boxa3, 2, 255, 0, 0);
                  pixaAddPix(pixa, pix2, L_INSERT);
              }
  #endif  /* SPLIT_WITH_DID */
              pixDestroy(&pix);
              boxDestroy(&box);
              if (!boxa3) {
                  L_ERROR("boxa3 not found for component %d\n", procName, i);
              } else {
                  boxa4 = boxaTransform(boxa3, xoff, yoff, 1.0, 1.0);
                  boxaJoin(boxa2, boxa4, 0, -1);
                  boxaDestroy(&boxa3);
                  boxaDestroy(&boxa4);
              }
          }
      }
      boxaDestroy(&boxa1);
      if (pixa) {  /* debug */
          pix3 = pixaDisplayTiledInColumns(pixa, 1, 1.0, 20, 2);
          snprintf(buf, sizeof(buf), "/tmp/lept/recog/decode-%d.png", ind++);
          pixWrite(buf, pix3, IFF_PNG);
          pixaDestroy(&pixa);
          pixDestroy(&pix3);
      }
  
          /* Do a 2D sort on the bounding boxes, and flatten the result to 1D.
           * For the 2D sort, to add a box to an existing boxa, we require
           * specified minimum vertical overlaps for the first two passes
           * of the 2D sort.  In pass 1, only components with sufficient
           * height can start a new boxa. */
      baa = boxaSort2d(boxa2, NULL, MinOverlap1, MinOverlap2, MinHeightPass1);
      boxa3 = boxaaFlattenToBoxa(baa, NULL, L_CLONE);
      boxaaDestroy(&baa);
      boxaDestroy(&boxa2);
  
          /* Remove smaller components of overlapping pairs.
           * We only remove the small component if the overlap is
           * at least half its area and if its area is no more
           * than 30% of the area of the large component.  Because the
           * components are in a flattened 2D sort, we don't need to
           * look far ahead in the array to find all overlapping boxes;
           * 10 boxes is plenty. */
      boxad = boxaHandleOverlaps(boxa3, L_COMBINE, 10, 0.5, 0.3, NULL);
      boxaDestroy(&boxa3);
  
          /* Extract and save the image pieces from the input image. */
      *ppixa = pixClipRectangles(pixs, boxad);
      *pboxa = boxad;
      return 0;
  }
  
  
  /*------------------------------------------------------------------------*
   *                       Greedy character splitting                       *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   recogCorrelationBestRow()
   *
   * \param[in]    recog       with LUT's pre-computed
   * \param[in]    pixs        typically of multiple touching characters, 1 bpp
   * \param[out]   pboxa       bounding boxs of best fit character
   * \param[out]   pnascore    [optional] correlation scores
   * \param[out]   pnaindex    [optional] indices of classes
   * \param[out]   psachar     [optional] array of character strings
   * \param[in]    debug       1 for results written to pixadb_split
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) Supervises character matching for (in general) a c.c with
   *          multiple touching characters.  Finds the best match greedily.
   *          Rejects small parts that are left over after splitting.
   *      (2) Matching is to the average, and without character scaling.
   * </pre>
   */
  l_ok
  recogCorrelationBestRow(L_RECOG  *recog,
                          PIX      *pixs,
                          BOXA    **pboxa,
                          NUMA    **pnascore,
                          NUMA    **pnaindex,
                          SARRAY  **psachar,
                          l_int32   debug)
  {
  char      *charstr;
  l_int32    index, remove, w, h, bx, bw, bxc, bwc, w1, w2, w3;
  l_float32  score;
  BOX       *box, *boxc, *boxtrans, *boxl, *boxr, *boxlt, *boxrt;
  BOXA      *boxat;
  NUMA      *nascoret, *naindext, *nasort;
  PIX       *pixb, *pixc, *pixl, *pixr, *pixdb, *pixd;
  PIXA      *pixar, *pixadb;
  SARRAY    *sachart;
  
  l_int32    iter;
  
      PROCNAME("recogCorrelationBestRow");
  
      if (pnascore) *pnascore = NULL;
      if (pnaindex) *pnaindex = NULL;
      if (psachar) *psachar = NULL;
      if (!pboxa)
          return ERROR_INT("&boxa not defined", procName, 1);
      *pboxa = NULL;
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
      if (!pixs || pixGetDepth(pixs) != 1)
          return ERROR_INT("pixs not defined or not 1 bpp", procName, 1);
      if (pixGetWidth(pixs) < recog->minwidth_u - 4)
          return ERROR_INT("pixs too narrow", procName, 1);
      if (!recog->train_done)
          return ERROR_INT("training not finished", procName, 1);
  
          /* Binarize and crop to foreground if necessary */
      pixb = recogProcessToIdentify(recog, pixs, 0);
  
          /* Initialize the arrays */
      boxat = boxaCreate(4);
      nascoret = numaCreate(4);
      naindext = numaCreate(4);
      sachart = sarrayCreate(4);
      pixadb = (debug) ? pixaCreate(4) : NULL;
  
          /* Initialize the images remaining to be processed with the input.
           * These are stored in pixar, which is used here as a queue,
           * on which we only put image fragments that are large enough to
           * contain at least one character.  */
      pixar = pixaCreate(1);
      pixGetDimensions(pixb, &w, &h, NULL);
      box = boxCreate(0, 0, w, h);
      pixaAddPix(pixar, pixb, L_INSERT);
      pixaAddBox(pixar, box, L_INSERT);
  
          /* Successively split on the best match until nothing is left.
           * To be safe, we limit the search to 10 characters. */
      for (iter = 0; iter < 11; iter++) {
          if (pixaGetCount(pixar) == 0)
              break;
          if (iter == 10) {
              L_WARNING("more than 10 chars; ending search\n", procName);
              break;
          }
  
              /* Pop one from the queue */
          pixaRemovePixAndSave(pixar, 0, &pixc, &boxc);
          boxGetGeometry(boxc, &bxc, NULL, &bwc, NULL);
  
              /* This is a single component; if noise, remove it */
          recogSplittingFilter(recog, pixc, 0, MinFillFactor, &remove, debug);
          if (debug)
              fprintf(stderr, "iter = %d, removed = %d\n", iter, remove);
          if (remove) {
              pixDestroy(&pixc);
              boxDestroy(&boxc);
              continue;
          }
  
              /* Find the best character match */
          if (debug) {
              recogCorrelationBestChar(recog, pixc, &box, &score,
                                       &index, &charstr, &pixdb);
              pixaAddPix(pixadb, pixdb, L_INSERT);
          } else {
              recogCorrelationBestChar(recog, pixc, &box, &score,
                                       &index, &charstr, NULL);
          }
  
              /* Find the box in original coordinates, and append
               * the results to the arrays. */
          boxtrans = boxTransform(box, bxc, 0, 1.0, 1.0);
          boxaAddBox(boxat, boxtrans, L_INSERT);
          numaAddNumber(nascoret, score);
          numaAddNumber(naindext, index);
          sarrayAddString(sachart, charstr, L_INSERT);
  
              /* Split the current pixc into three regions and save
               * each region if it is large enough. */
          boxGetGeometry(box, &bx, NULL, &bw, NULL);
          w1 = bx;
          w2 = bw;
          w3 = bwc - bx - bw;
          if (debug)
              fprintf(stderr, " w1 = %d, w2 = %d, w3 = %d\n", w1, w2, w3);
          if (w1 < recog->minwidth_u - 4) {
              if (debug) L_INFO("discarding width %d on left\n", procName, w1);
          } else {  /* extract and save left region */
              boxl = boxCreate(0, 0, bx + 1, h);
              pixl = pixClipRectangle(pixc, boxl, NULL);
              boxlt = boxTransform(boxl, bxc, 0, 1.0, 1.0);
              pixaAddPix(pixar, pixl, L_INSERT);
              pixaAddBox(pixar, boxlt, L_INSERT);
              boxDestroy(&boxl);
          }
          if (w3 < recog->minwidth_u - 4) {
              if (debug) L_INFO("discarding width %d on right\n", procName, w3);
          } else {  /* extract and save left region */
              boxr = boxCreate(bx + bw - 1, 0, w3 + 1, h);
              pixr = pixClipRectangle(pixc, boxr, NULL);
              boxrt = boxTransform(boxr, bxc, 0, 1.0, 1.0);
              pixaAddPix(pixar, pixr, L_INSERT);
              pixaAddBox(pixar, boxrt, L_INSERT);
              boxDestroy(&boxr);
          }
          pixDestroy(&pixc);
          boxDestroy(&box);
          boxDestroy(&boxc);
      }
      pixaDestroy(&pixar);
  
  
          /* Sort the output results by left-to-right in the boxa */
      *pboxa = boxaSort(boxat, L_SORT_BY_X, L_SORT_INCREASING, &nasort);
      if (pnascore)
          *pnascore = numaSortByIndex(nascoret, nasort);
      if (pnaindex)
          *pnaindex = numaSortByIndex(naindext, nasort);
      if (psachar)
          *psachar = sarraySortByIndex(sachart, nasort);
      numaDestroy(&nasort);
      boxaDestroy(&boxat);
      numaDestroy(&nascoret);
      numaDestroy(&naindext);
      sarrayDestroy(&sachart);
  
          /* Final debug output */
      if (debug) {
          pixd = pixaDisplayTiledInRows(pixadb, 32, 2000, 1.0, 0, 15, 2);
          pixDisplay(pixd, 400, 400);
          pixaAddPix(recog->pixadb_split, pixd, L_INSERT);
          pixaDestroy(&pixadb);
      }
      return 0;
  }
  
  
  /*!
   * \brief   recogCorrelationBestChar()
   *
   * \param[in]    recog       with LUT's pre-computed
   * \param[in]    pixs        can be of multiple touching characters, 1 bpp
   * \param[out]   pbox        bounding box of best fit character
   * \param[out]   pscore      correlation score
   * \param[out]   pindex      [optional] index of class
   * \param[out]   pcharstr    [optional] character string of class
   * \param[out]   ppixdb      [optional] debug pix showing input and best fit
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) Basic matching character splitter.  Finds the best match among
   *          all templates to some region of the image.  This can result
   *          in splitting the image into two parts.  This is "image decoding"
   *          without dynamic programming, because we don't use a setwidth
   *          and compute the best matching score for the entire image.
   *      (2) Matching is to the average templates, without character scaling.
   * </pre>
   */
  l_ok
  recogCorrelationBestChar(L_RECOG    *recog,
                           PIX        *pixs,
                           BOX       **pbox,
                           l_float32  *pscore,
                           l_int32    *pindex,
                           char      **pcharstr,
                           PIX       **ppixdb)
  {
  l_int32    i, n, w1, h1, w2, area2, ycent2, delx, dely;
  l_int32    bestdelx, bestdely, bestindex;
  l_float32  score, bestscore;
  BOX       *box;
  BOXA      *boxa;
  NUMA      *nasum, *namoment;
  PIX       *pix1, *pix2;
  
      PROCNAME("recogCorrelationBestChar");
  
      if (pindex) *pindex = 0;
      if (pcharstr) *pcharstr = NULL;
      if (ppixdb) *ppixdb = NULL;
      if (pbox) *pbox = NULL;
      if (pscore) *pscore = 0.0;
      if (!pbox || !pscore)
          return ERROR_INT("&box and &score not both defined", procName, 1);
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
      if (!pixs || pixGetDepth(pixs) != 1)
          return ERROR_INT("pixs not defined or not 1 bpp", procName, 1);
      if (!recog->train_done)
          return ERROR_INT("training not finished", procName, 1);
  
          /* Binarize and crop to foreground if necessary.  Add padding
           * to both the left and right side; this is compensated for
           * when reporting the bounding box of the best matched character. */
      pix1 = recogProcessToIdentify(recog, pixs, LeftRightPadding);
      pixGetDimensions(pix1, &w1, &h1, NULL);
  
          /* Compute vertical sum and moment arrays */
      nasum = pixCountPixelsByColumn(pix1);
      namoment = pixGetMomentByColumn(pix1, 1);
  
          /* Do shifted correlation against all averaged templates. */
      n = recog->setsize;
      boxa = boxaCreate(n);  /* location of best fits for each character */
      bestscore = 0.0;
      bestindex = bestdelx = bestdely = 0;
      for (i = 0; i < n; i++) {
          pix2 = pixaGetPix(recog->pixa_u, i, L_CLONE);
          w2 = pixGetWidth(pix2);
              /* Note that the slightly expended w1 is typically larger
               * than w2 (the template). */
          if (w1 >= w2) {
              numaGetIValue(recog->nasum_u, i, &area2);
              ptaGetIPt(recog->pta_u, i, NULL, &ycent2);
              pixCorrelationBestShift(pix1, pix2, nasum, namoment, area2, ycent2,
                                      recog->maxyshift, recog->sumtab, &delx,
                                      &dely, &score, 1);
              if (ppixdb) {
                  fprintf(stderr,
                      "Best match template %d: (x,y) = (%d,%d), score = %5.3f\n",
                      i, delx, dely, score);
              }
                    /* Compensate for padding */
              box = boxCreate(delx - LeftRightPadding, 0, w2, h1);
              if (score > bestscore) {
                  bestscore = score;
                  bestdelx = delx - LeftRightPadding;
                  bestdely = dely;
                  bestindex = i;
              }
          } else {
              box = boxCreate(0, 0, 1, 1);  /* placeholder */
              if (ppixdb)
                  fprintf(stderr, "Component too thin: w1 = %d, w2 = %d\n",
                          w1, w2);
          }
          boxaAddBox(boxa, box, L_INSERT);
          pixDestroy(&pix2);
      }
  
      *pscore = bestscore;
      *pbox = boxaGetBox(boxa, bestindex, L_COPY);
      if (pindex) *pindex = bestindex;
      if (pcharstr)
          recogGetClassString(recog, bestindex, pcharstr);
  
      if (ppixdb) {
          L_INFO("Best match: class %d; shifts (%d, %d)\n",
                 procName, bestindex, bestdelx, bestdely);
          pix2 = pixaGetPix(recog->pixa_u, bestindex, L_CLONE);
          *ppixdb = recogShowMatch(recog, pix1, pix2, NULL, -1, 0.0);
          pixDestroy(&pix2);
      }
  
      pixDestroy(&pix1);
      boxaDestroy(&boxa);
      numaDestroy(&nasum);
      numaDestroy(&namoment);
      return 0;
  }
  
  
  /*!
   * \brief   pixCorrelationBestShift()
   *
   * \param[in]    pix1        1 bpp, the unknown image; typically larger
   * \param[in]    pix2        1 bpp, the matching template image)
   * \param[in]    nasum1      vertical column pixel sums for pix1
   * \param[in]    namoment1   vertical column first moment of pixels for pix1
   * \param[in]    area2       number of on pixels in pix2
   * \param[in]    ycent2      y component of centroid of pix2
   * \param[in]    maxyshift   max y shift of pix2 around the location where
   *                           the centroids of pix2 and a windowed part of pix1
   *                           are vertically aligned
   * \param[in]    tab8        [optional] sum tab for ON pixels in byte;
   *                           can be NULL
   * \param[out]   pdelx       [optional] best x shift of pix2 relative to pix1
   * \param[out]   pdely       [optional] best y shift of pix2 relative to pix1
   * \param[out]   pscore      [optional] maximum score found; can be NULL
   * \param[in]    debugflag   <= 0 to skip; positive to generate output;
   *                           the integer is used to label the debug image.
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) This maximizes the correlation score between two 1 bpp images,
   *          one of which is typically wider.  In a typical example,
   *          pix1 is a bitmap of 2 or more touching characters and pix2 is
   *          a single character template.  This finds the location of pix2
   *          that gives the largest correlation.
   *      (2) The windowed area of fg pixels and windowed first moment
   *          in the y direction are computed from the input sum and moment
   *          column arrays, %nasum1 and %namoment1
   *      (3) This is a brute force operation.  We compute the correlation
   *          at every x shift for which pix2 fits entirely within pix1,
   *          and where the centroid of pix2 is aligned, within +-maxyshift,
   *          with the centroid of a window of pix1 of the same width.
   *          The correlation is taken over the full height of pix1.
   *          This can be made more efficient.
   * </pre>
   */
  static l_int32
  pixCorrelationBestShift(PIX        *pix1,
                          PIX        *pix2,
                          NUMA       *nasum1,
                          NUMA       *namoment1,
                          l_int32     area2,
                          l_int32     ycent2,
                          l_int32     maxyshift,
                          l_int32    *tab8,
                          l_int32    *pdelx,
                          l_int32    *pdely,
                          l_float32  *pscore,
                          l_int32     debugflag)
  {
  l_int32     w1, w2, h1, h2, i, j, nx, shifty, delx, dely;
  l_int32     sum, moment, count;
  l_int32    *tab, *area1, *arraysum, *arraymoment;
  l_float32   maxscore, score;
  l_float32  *ycent1;
  FPIX       *fpix;
  PIX        *pixt, *pixt1, *pixt2;
  
      PROCNAME("pixCorrelationBestShift");
  
      if (pdelx) *pdelx = 0;
      if (pdely) *pdely = 0;
      if (pscore) *pscore = 0.0;
      if (!pix1 || pixGetDepth(pix1) != 1)
          return ERROR_INT("pix1 not defined or not 1 bpp", procName, 1);
      if (!pix2 || pixGetDepth(pix2) != 1)
          return ERROR_INT("pix2 not defined or not 1 bpp", procName, 1);
      if (!nasum1 || !namoment1)
          return ERROR_INT("nasum1 and namoment1 not both defined", procName, 1);
      if (area2 <= 0 || ycent2 <= 0)
          return ERROR_INT("area2 and ycent2 must be > 0", procName, 1);
  
         /* If pix1 (the unknown image) is narrower than pix2,
          * don't bother to try the match.  pix1 is already padded with
          * 2 pixels on each side. */
      pixGetDimensions(pix1, &w1, &h1, NULL);
      pixGetDimensions(pix2, &w2, &h2, NULL);
      if (w1 < w2) {
          if (debugflag > 0) {
              L_INFO("skipping match with w1 = %d and w2 = %d\n",
                     procName, w1, w2);
          }
          return 0;
      }
      nx = w1 - w2 + 1;
  
      if (debugflag > 0)
          fpix = fpixCreate(nx, 2 * maxyshift + 1);
      if (!tab8)
          tab = makePixelSumTab8();
      else
          tab = tab8;
  
          /* Set up the arrays for area1 and ycent1.  We have to do this
           * for each template (pix2) because the window width is w2. */
      area1 = (l_int32 *)LEPT_CALLOC(nx, sizeof(l_int32));
      ycent1 = (l_float32 *)LEPT_CALLOC(nx, sizeof(l_int32));
      arraysum = numaGetIArray(nasum1);
      arraymoment = numaGetIArray(namoment1);
      for (i = 0, sum = 0, moment = 0; i < w2; i++) {
          sum += arraysum[i];
          moment += arraymoment[i];
      }
      for (i = 0; i < nx - 1; i++) {
          area1[i] = sum;
          ycent1[i] = (sum == 0) ? ycent2 : (l_float32)moment / (l_float32)sum;
          sum += arraysum[w2 + i] - arraysum[i];
          moment += arraymoment[w2 + i] - arraymoment[i];
      }
      area1[nx - 1] = sum;
      ycent1[nx - 1] = (sum == 0) ? ycent2 : (l_float32)moment / (l_float32)sum;
  
          /* Find the best match location for pix2.  At each location,
           * to insure that pixels are ON only within the intersection of
           * pix and the shifted pix2:
           *  (1) Start with pixt cleared and equal in size to pix1.
           *  (2) Blit the shifted pix2 onto pixt.  Then all ON pixels
           *      are within the intersection of pix1 and the shifted pix2.
           *  (3) AND pix1 with pixt. */
      pixt = pixCreate(w2, h1, 1);
      maxscore = 0;
      delx = 0;
      dely = 0;  /* amount to shift pix2 relative to pix1 to get alignment */
      for (i = 0; i < nx; i++) {
          shifty = (l_int32)(ycent1[i] - ycent2 + 0.5);
          for (j = -maxyshift; j <= maxyshift; j++) {
              pixClearAll(pixt);
              pixRasterop(pixt, 0, shifty + j, w2, h2, PIX_SRC, pix2, 0, 0);
              pixRasterop(pixt, 0, 0, w2, h1, PIX_SRC & PIX_DST, pix1, i, 0);
              pixCountPixels(pixt, &count, tab);
              score = (l_float32)count * (l_float32)count /
                      ((l_float32)area1[i] * (l_float32)area2);
              if (score > maxscore) {
                  maxscore = score;
                  delx = i;
                  dely = shifty + j;
              }
  
              if (debugflag > 0)
                  fpixSetPixel(fpix, i, maxyshift + j, 1000.0 * score);
          }
      }
  
      if (debugflag > 0) {
          lept_mkdir("lept/recog");
          char  buf[128];
          pixt1 = fpixDisplayMaxDynamicRange(fpix);
          pixt2 = pixExpandReplicate(pixt1, 5);
          snprintf(buf, sizeof(buf), "/tmp/lept/recog/junkbs_%d.png", debugflag);
          pixWrite(buf, pixt2, IFF_PNG);
          pixDestroy(&pixt1);
          pixDestroy(&pixt2);
          fpixDestroy(&fpix);
      }
  
      if (pdelx) *pdelx = delx;
      if (pdely) *pdely = dely;
      if (pscore) *pscore = maxscore;
      if (!tab8) LEPT_FREE(tab);
      LEPT_FREE(area1);
      LEPT_FREE(ycent1);
      LEPT_FREE(arraysum);
      LEPT_FREE(arraymoment);
      pixDestroy(&pixt);
      return 0;
  }
  
  
  /*------------------------------------------------------------------------*
   *                          Low-level identification                      *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   recogIdentifyPixa()
   *
   * \param[in]    recog
   * \param[in]    pixa     of 1 bpp images to match
   * \param[out]   ppixdb   [optional] pix showing inputs and best fits
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) This should be called by recogIdentifyMuliple(), which
   *          binarizes and splits characters before sending %pixa here.
   *      (2) This calls recogIdentifyPix(), which does the same operation
   *          on each pix in %pixa, and optionally returns the arrays
   *          of results (scores, class index and character string)
   *          for the best correlation match.
   * </pre>
   */
  l_ok
  recogIdentifyPixa(L_RECOG  *recog,
                    PIXA     *pixa,
                    PIX     **ppixdb)
  {
  char      *text;
  l_int32    i, n, fail, index, depth;
  l_float32  score;
  PIX       *pix1, *pix2, *pix3;
  PIXA      *pixa1;
  L_RCH     *rch;
  
      PROCNAME("recogIdentifyPixa");
  
      if (ppixdb) *ppixdb = NULL;
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
      if (!pixa)
          return ERROR_INT("pixa not defined", procName, 1);
  
          /* Run the recognizer on the set of images.  This writes
           * the text string into each pix in pixa. */
      n = pixaGetCount(pixa);
      rchaDestroy(&recog->rcha);
      recog->rcha = rchaCreate();
      pixa1 = (ppixdb) ? pixaCreate(n) : NULL;
      depth = 1;
      for (i = 0; i < n; i++) {
          pix1 = pixaGetPix(pixa, i, L_CLONE);
          pix2 = NULL;
          fail = FALSE;
          if (!ppixdb)
              fail = recogIdentifyPix(recog, pix1, NULL);
          else
              fail = recogIdentifyPix(recog, pix1, &pix2);
          if (fail)
              recogSkipIdentify(recog);
          if ((rch = recog->rch) == NULL) {
              L_ERROR("rch not found for char %d\n", procName, i);
              pixDestroy(&pix1);
              pixDestroy(&pix2);
              continue;
          }
          rchExtract(rch, NULL, NULL, &text, NULL, NULL, NULL, NULL);
          pixSetText(pix1, text);
          LEPT_FREE(text);
          if (ppixdb) {
              rchExtract(rch, &index, &score, NULL, NULL, NULL, NULL, NULL);
              pix3 = recogShowMatch(recog, pix2, NULL, NULL, index, score);
              if (i == 0) depth = pixGetDepth(pix3);
              pixaAddPix(pixa1, pix3, L_INSERT);
              pixDestroy(&pix2);
          }
          transferRchToRcha(rch, recog->rcha);
          pixDestroy(&pix1);
      }
  
          /* Package the images for debug */
      if (ppixdb) {
          *ppixdb = pixaDisplayTiledInRows(pixa1, depth, 2500, 1.0, 0, 20, 1);
          pixaDestroy(&pixa1);
      }
  
      return 0;
  }
  
  
  /*!
   * \brief   recogIdentifyPix()
   *
   * \param[in]    recog     with LUT's pre-computed
   * \param[in]    pixs      of a single character, 1 bpp
   * \param[out]   ppixdb    [optional] debug pix showing input and best fit
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) Basic recognition function for a single character.
   *      (2) If templ_use == L_USE_ALL_TEMPLATES, which is the default
   *          situation, matching is attempted to every bitmap in the recog,
   *          and the identify of the best match is returned.
   *      (3) For finding outliers, templ_use == L_USE_AVERAGE_TEMPLATES, and
   *          matching is only attemplted to the averaged bitmaps.  For this
   *          case, the index of the bestsample is meaningless (0 is returned
   *          if requested).
   *      (4) The score is related to the confidence (probability of correct
   *          identification), in that a higher score is correlated with
   *          a higher probability.  However, the actual relation between
   *          the correlation (score) and the probability is not known;
   *          we call this a "score" because "confidence" can be misinterpreted
   *          as an actual probability.
   * </pre>
   */
  l_ok
  recogIdentifyPix(L_RECOG  *recog,
                   PIX      *pixs,
                   PIX     **ppixdb)
  {
  char      *text;
  l_int32    i, j, n, bestindex, bestsample, area1, area2;
  l_int32    shiftx, shifty, bestdelx, bestdely, bestwidth, maxyshift;
  l_float32  x1, y1, x2, y2, delx, dely, score, maxscore;
  NUMA      *numa;
  PIX       *pix0, *pix1, *pix2;
  PIXA      *pixa;
  PTA       *pta;
  
      PROCNAME("recogIdentifyPix");
  
      if (ppixdb) *ppixdb = NULL;
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
      if (!pixs || pixGetDepth(pixs) != 1)
          return ERROR_INT("pixs not defined or not 1 bpp", procName, 1);
  
          /* Do the averaging if required and not yet done. */
      if (recog->templ_use == L_USE_AVERAGE_TEMPLATES && !recog->ave_done) {
          recogAverageSamples(&recog, 0);
          if (!recog)
              return ERROR_INT("averaging failed", procName, 1);
      }
  
          /* Binarize and crop to foreground if necessary */
      if ((pix0 = recogProcessToIdentify(recog, pixs, 0)) == NULL)
          return ERROR_INT("no fg pixels in pix0", procName, 1);
  
          /* Optionally scale and/or convert to fixed stroke width */
      pix1 = recogModifyTemplate(recog, pix0);
      pixDestroy(&pix0);
      if (!pix1)
          return ERROR_INT("no fg pixels in pix1", procName, 1);
  
          /* Do correlation at all positions within +-maxyshift of
           * the nominal centroid alignment. */
      pixCountPixels(pix1, &area1, recog->sumtab);
      pixCentroid(pix1, recog->centtab, recog->sumtab, &x1, &y1);
      bestindex = bestsample = bestdelx = bestdely = bestwidth = 0;
      maxscore = 0.0;
      maxyshift = recog->maxyshift;
      if (recog->templ_use == L_USE_AVERAGE_TEMPLATES) {
          for (i = 0; i < recog->setsize; i++) {
              numaGetIValue(recog->nasum, i, &area2);
              if (area2 == 0) continue;  /* no template available */
              pix2 = pixaGetPix(recog->pixa, i, L_CLONE);
              ptaGetPt(recog->pta, i, &x2, &y2);
              delx = x1 - x2;
              dely = y1 - y2;
              for (shifty = -maxyshift; shifty <= maxyshift; shifty++) {
                  for (shiftx = -maxyshift; shiftx <= maxyshift; shiftx++) {
                      pixCorrelationScoreSimple(pix1, pix2, area1, area2,
                                                delx + shiftx, dely + shifty,
                                                5, 5, recog->sumtab, &score);
                      if (score > maxscore) {
                          bestindex = i;
                          bestdelx = delx + shiftx;
                          bestdely = dely + shifty;
                          maxscore = score;
                      }
                  }
              }
              pixDestroy(&pix2);
          }
      } else {  /* use all the samples */
          for (i = 0; i < recog->setsize; i++) {
              pixa = pixaaGetPixa(recog->pixaa, i, L_CLONE);
              n = pixaGetCount(pixa);
              if (n == 0) {
                  pixaDestroy(&pixa);
                  continue;
              }
              numa = numaaGetNuma(recog->naasum, i, L_CLONE);
              pta = ptaaGetPta(recog->ptaa, i, L_CLONE);
              for (j = 0; j < n; j++) {
                  pix2 = pixaGetPix(pixa, j, L_CLONE);
                  numaGetIValue(numa, j, &area2);
                  ptaGetPt(pta, j, &x2, &y2);
                  delx = x1 - x2;
                  dely = y1 - y2;
                  for (shifty = -maxyshift; shifty <= maxyshift; shifty++) {
                      for (shiftx = -maxyshift; shiftx <= maxyshift; shiftx++) {
                          pixCorrelationScoreSimple(pix1, pix2, area1, area2,
                                                    delx + shiftx, dely + shifty,
                                                    5, 5, recog->sumtab, &score);
                          if (score > maxscore) {
                              bestindex = i;
                              bestsample = j;
                              bestdelx = delx + shiftx;
                              bestdely = dely + shifty;
                              maxscore = score;
                              bestwidth = pixGetWidth(pix2);
                          }
                      }
                  }
                  pixDestroy(&pix2);
              }
              pixaDestroy(&pixa);
              numaDestroy(&numa);
              ptaDestroy(&pta);
          }
      }
  
          /* Package up the results */
      recogGetClassString(recog, bestindex, &text);
      rchDestroy(&recog->rch);
      recog->rch = rchCreate(bestindex, maxscore, text, bestsample,
                             bestdelx, bestdely, bestwidth);
  
      if (ppixdb) {
          if (recog->templ_use == L_USE_AVERAGE_TEMPLATES) {
              L_INFO("Best match: str %s; class %d; sh (%d, %d); score %5.3f\n",
                     procName, text, bestindex, bestdelx, bestdely, maxscore);
              pix2 = pixaGetPix(recog->pixa, bestindex, L_CLONE);
          } else {  /* L_USE_ALL_TEMPLATES */
              L_INFO("Best match: str %s; sample %d in class %d; score %5.3f\n",
                     procName, text, bestsample, bestindex, maxscore);
              if (maxyshift > 0 && (L_ABS(bestdelx) > 0 || L_ABS(bestdely) > 0)) {
                  L_INFO("  Best shift: (%d, %d)\n",
                         procName, bestdelx, bestdely);
              }
              pix2 = pixaaGetPix(recog->pixaa, bestindex, bestsample, L_CLONE);
          }
          *ppixdb = recogShowMatch(recog, pix1, pix2, NULL, -1, 0.0);
          pixDestroy(&pix2);
      }
  
      pixDestroy(&pix1);
      return 0;
  }
  
  
  /*!
   * \brief   recogSkipIdentify()
   *
   * \param[in]    recog
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) This just writes a "dummy" result with 0 score and empty
   *          string id into the rch.
   * </pre>
   */
  l_ok
  recogSkipIdentify(L_RECOG  *recog)
  {
      PROCNAME("recogSkipIdentify");
  
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
  
          /* Package up placeholder results */
      rchDestroy(&recog->rch);
      recog->rch = rchCreate(0, 0.0, stringNew(""), 0, 0, 0, 0);
      return 0;
  }
  
  
  /*------------------------------------------------------------------------*
   *             Operations for handling identification results             *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   rchaCreate()
   *
   *      Return: 0 if OK, 1 on error
   *
   *  Notes:
   *      (1) Be sure to destroy any existing rcha before assigning this.
   */
  static L_RCHA *
  rchaCreate()
  {
  L_RCHA  *rcha;
  
      rcha = (L_RCHA *)LEPT_CALLOC(1, sizeof(L_RCHA));
      rcha->naindex = numaCreate(0);
      rcha->nascore = numaCreate(0);
      rcha->satext = sarrayCreate(0);
      rcha->nasample = numaCreate(0);
      rcha->naxloc = numaCreate(0);
      rcha->nayloc = numaCreate(0);
      rcha->nawidth = numaCreate(0);
      return rcha;
  }
  
  
  /*!
   * \brief   rchaDestroy()
   *
   * \param[in,out]   prcha     to be nulled
   */
  void
  rchaDestroy(L_RCHA  **prcha)
  {
  L_RCHA  *rcha;
  
      PROCNAME("rchaDestroy");
  
      if (prcha == NULL) {
          L_WARNING("&rcha is null!\n", procName);
          return;
      }
      if ((rcha = *prcha) == NULL)
          return;
  
      numaDestroy(&rcha->naindex);
      numaDestroy(&rcha->nascore);
      sarrayDestroy(&rcha->satext);
      numaDestroy(&rcha->nasample);
      numaDestroy(&rcha->naxloc);
      numaDestroy(&rcha->nayloc);
      numaDestroy(&rcha->nawidth);
      LEPT_FREE(rcha);
      *prcha = NULL;
      return;
  }
  
  
  /*!
   * \brief   rchCreate()
   *
   * \param[in]    index    index of best template
   * \param[in]    score    correlation score of best template
   * \param[in]    text     character string of best template
   * \param[in]    sample   index of best sample; -1 if averages are used
   * \param[in]    xloc     x-location of template: delx + shiftx
   * \param[in]    yloc     y-location of template: dely + shifty
   * \param[in]    width    width of best template
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) Be sure to destroy any existing rch before assigning this.
   *      (2) This stores the text string, not a copy of it, so the
   *          caller must not destroy the string.
   * </pre>
   */
  static L_RCH *
  rchCreate(l_int32    index,
            l_float32  score,
            char      *text,
            l_int32    sample,
            l_int32    xloc,
            l_int32    yloc,
            l_int32    width)
  {
  L_RCH  *rch;
  
      rch = (L_RCH *)LEPT_CALLOC(1, sizeof(L_RCH));
      rch->index = index;
      rch->score = score;
      rch->text = text;
      rch->sample = sample;
      rch->xloc = xloc;
      rch->yloc = yloc;
      rch->width = width;
      return rch;
  }
  
  
  /*!
   * \brief   rchDestroy()
   *
   * \param[in,out] prch to be nulled
   */
  void
  rchDestroy(L_RCH  **prch)
  {
  L_RCH  *rch;
  
      PROCNAME("rchDestroy");
  
      if (prch == NULL) {
          L_WARNING("&rch is null!\n", procName);
          return;
      }
      if ((rch = *prch) == NULL)
          return;
      LEPT_FREE(rch->text);
      LEPT_FREE(rch);
      *prch = NULL;
      return;
  }
  
  
  /*!
   * \brief   rchaExtract()
   *
   * \param[in]    rcha
   * \param[out]   pnaindex    [optional] indices of best templates
   * \param[out]   pnascore    [optional] correl scores of best templates
   * \param[out]   psatext     [optional] character strings of best templates
   * \param[out]   pnasample   [optional] indices of best samples
   * \param[out]   pnaxloc     [optional] x-locations of templates
   * \param[out]   pnayloc     [optional] y-locations of templates
   * \param[out]   pnawidth    [optional] widths of best templates
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) This returns clones of the number and string arrays.  They must
   *          be destroyed by the caller.
   * </pre>
   */
  l_ok
  rchaExtract(L_RCHA   *rcha,
              NUMA    **pnaindex,
              NUMA    **pnascore,
              SARRAY  **psatext,
              NUMA    **pnasample,
              NUMA    **pnaxloc,
              NUMA    **pnayloc,
              NUMA    **pnawidth)
  {
      PROCNAME("rchaExtract");
  
      if (pnaindex) *pnaindex = NULL;
      if (pnascore) *pnascore = NULL;
      if (psatext) *psatext = NULL;
      if (pnasample) *pnasample = NULL;
      if (pnaxloc) *pnaxloc = NULL;
      if (pnayloc) *pnayloc = NULL;
      if (pnawidth) *pnawidth = NULL;
      if (!rcha)
          return ERROR_INT("rcha not defined", procName, 1);
  
      if (pnaindex) *pnaindex = numaClone(rcha->naindex);
      if (pnascore) *pnascore = numaClone(rcha->nascore);
      if (psatext) *psatext = sarrayClone(rcha->satext);
      if (pnasample) *pnasample = numaClone(rcha->nasample);
      if (pnaxloc) *pnaxloc = numaClone(rcha->naxloc);
      if (pnayloc) *pnayloc = numaClone(rcha->nayloc);
      if (pnawidth) *pnawidth = numaClone(rcha->nawidth);
      return 0;
  }
  
  
  /*!
   * \brief   rchExtract()
   *
   * \param[in]    rch
   * \param[out]   pindex    [optional] index of best template
   * \param[out]   pscore    [optional] correlation score of best template
   * \param[out]   ptext     [optional] character string of best template
   * \param[out]   psample   [optional] index of best sample
   * \param[out]   pxloc     [optional] x-location of template
   * \param[out]   pyloc     [optional] y-location of template
   * \param[out]   pwidth    [optional] width of best template
   * \return  0 if OK, 1 on error
   */
  l_ok
  rchExtract(L_RCH      *rch,
             l_int32    *pindex,
             l_float32  *pscore,
             char      **ptext,
             l_int32    *psample,
             l_int32    *pxloc,
             l_int32    *pyloc,
             l_int32    *pwidth)
  {
      PROCNAME("rchExtract");
  
      if (pindex) *pindex = 0;
      if (pscore) *pscore = 0.0;
      if (ptext) *ptext = NULL;
      if (psample) *psample = 0;
      if (pxloc) *pxloc = 0;
      if (pyloc) *pyloc = 0;
      if (pwidth) *pwidth = 0;
      if (!rch)
          return ERROR_INT("rch not defined", procName, 1);
  
      if (pindex) *pindex = rch->index;
      if (pscore) *pscore = rch->score;
      if (ptext) *ptext = stringNew(rch->text);  /* new string: owned by caller */
      if (psample) *psample = rch->sample;
      if (pxloc) *pxloc = rch->xloc;
      if (pyloc) *pyloc = rch->yloc;
      if (pwidth) *pwidth = rch->width;
      return 0;
  }
  
  
  /*!
   * \brief   transferRchToRcha()
   *
   * \param[in]    rch     source of data
   * \param[in]    rcha    append to arrays in this destination
   * \return  0 if OK, 1 on error
   *
   * <pre>
   * Notes:
   *      (1) This is used to transfer the results of a single character
   *          identification to an rcha array for the array of characters.
   * </pre>
   */
  static l_int32
  transferRchToRcha(L_RCH   *rch,
                    L_RCHA  *rcha)
  {
  
      PROCNAME("transferRchToRcha");
  
      if (!rch)
          return ERROR_INT("rch not defined", procName, 1);
      if (!rcha)
          return ERROR_INT("rcha not defined", procName, 1);
  
      numaAddNumber(rcha->naindex, rch->index);
      numaAddNumber(rcha->nascore, rch->score);
      sarrayAddString(rcha->satext, rch->text, L_COPY);
      numaAddNumber(rcha->nasample, rch->sample);
      numaAddNumber(rcha->naxloc, rch->xloc);
      numaAddNumber(rcha->nayloc, rch->yloc);
      numaAddNumber(rcha->nawidth, rch->width);
      return 0;
  }
  
  
  /*------------------------------------------------------------------------*
   *                        Preprocessing and filtering                     *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   recogProcessToIdentify()
   *
   * \param[in]    recog     with LUT's pre-computed
   * \param[in]    pixs      typ. single character, possibly d > 1 and uncropped
   * \param[in]    pad       extra pixels added to left and right sides
   * \return  pixd 1 bpp, clipped to foreground, or NULL if there
   *                    are no fg pixels or on error.
   *
   * <pre>
   * Notes:
   *      (1) This is a lightweight operation to insure that the input
   *          image is 1 bpp, properly cropped, and padded on each side.
   *          If bpp > 1, the image is thresholded.
   * </pre>
   */
  PIX *
  recogProcessToIdentify(L_RECOG  *recog,
                         PIX      *pixs,
                         l_int32   pad)
  {
  l_int32  canclip;
  PIX     *pix1, *pix2, *pixd;
  
      PROCNAME("recogProcessToIdentify");
  
      if (!recog)
          return (PIX *)ERROR_PTR("recog not defined", procName, NULL);
      if (!pixs)
          return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
  
      if (pixGetDepth(pixs) != 1)
          pix1 = pixThresholdToBinary(pixs, recog->threshold);
      else
          pix1 = pixClone(pixs);
      pixTestClipToForeground(pix1, &canclip);
      if (canclip)
          pixClipToForeground(pix1, &pix2, NULL);
      else
          pix2 = pixClone(pix1);
      pixDestroy(&pix1);
      if (!pix2)
          return (PIX *)ERROR_PTR("no foreground pixels", procName, NULL);
  
      pixd = pixAddBorderGeneral(pix2, pad, pad, 0, 0, 0);
      pixDestroy(&pix2);
      return pixd;
  }
  
  
  /*!
   * \brief   recogPreSplittingFilter()
   *
   * \param[in]    recog
   * \param[in]    pixs     1 bpp, many connected components
   * \param[in]    minh     minimum height of components to be retained
   * \param[in]    minaf    minimum area fraction (|fg|/(w*h)) to be retained
   * \param[in]    debug    1 to output indicator arrays
   * \return  pixd with filtered components removed or NULL on error
   */
  static PIX *
  recogPreSplittingFilter(L_RECOG   *recog,
                          PIX       *pixs,
                          l_int32    minh,
                          l_float32  minaf,
                          l_int32    debug)
  {
  l_int32  scaling, minsplitw, maxsplith, maxasp;
  BOXA    *boxas;
  NUMA    *naw, *nah, *na1, *na1c, *na2, *na3, *na4, *na5, *na6, *na7;
  PIX     *pixd;
  PIXA    *pixas;
  
      PROCNAME("recogPreSplittingFilter");
  
      if (!recog)
          return (PIX *)ERROR_PTR("recog not defined", procName, NULL);
      if (!pixs)
          return (PIX *)ERROR_PTR("pixs not defined", procName, NULL);
  
          /* If there is scaling, do not remove components based on the
           * values of min_splitw and max_splith. */
      scaling = (recog->scalew > 0 || recog->scaleh > 0) ? TRUE : FALSE;
      minsplitw = (scaling) ? 1 : recog->min_splitw - 3;
      maxsplith = (scaling) ? 150 : recog->max_splith;
      maxasp = recog->max_wh_ratio;
  
          /* Generate an indicator array of connected components to remove:
           *    short stuff
           *    tall stuff
           *    components with large width/height ratio
           *    components with small area fill fraction  */
      boxas = pixConnComp(pixs, &pixas, 8);
      pixaFindDimensions(pixas, &naw, &nah);
      na1 = numaMakeThresholdIndicator(naw, minsplitw, L_SELECT_IF_LT);
      na1c = numaCopy(na1);
      na2 = numaMakeThresholdIndicator(nah, minh, L_SELECT_IF_LT);
      na3 = numaMakeThresholdIndicator(nah, maxsplith, L_SELECT_IF_GT);
      na4 = pixaFindWidthHeightRatio(pixas);
      na5 = numaMakeThresholdIndicator(na4, maxasp, L_SELECT_IF_GT);
      na6 = pixaFindAreaFraction(pixas);
      na7 = numaMakeThresholdIndicator(na6, minaf, L_SELECT_IF_LT);
      numaLogicalOp(na1, na1, na2, L_UNION);
      numaLogicalOp(na1, na1, na3, L_UNION);
      numaLogicalOp(na1, na1, na5, L_UNION);
      numaLogicalOp(na1, na1, na7, L_UNION);
      pixd = pixCopy(NULL, pixs);
      pixRemoveWithIndicator(pixd, pixas, na1);
      if (debug)
          l_showIndicatorSplitValues(na1c, na2, na3, na5, na7, na1);
      numaDestroy(&naw);
      numaDestroy(&nah);
      numaDestroy(&na1);
      numaDestroy(&na1c);
      numaDestroy(&na2);
      numaDestroy(&na3);
      numaDestroy(&na4);
      numaDestroy(&na5);
      numaDestroy(&na6);
      numaDestroy(&na7);
      boxaDestroy(&boxas);
      pixaDestroy(&pixas);
      return pixd;
  }
  
  
  /*!
   * \brief   recogSplittingFilter()
   *
   * \param[in]    recog
   * \param[in]    pixs     1 bpp, single connected component
   * \param[in]    minh     minimum height of component; 0 for default
   * \param[in]    minaf    minimum area fraction (|fg|/(w*h)) to be retained
   * \param[out]   premove  0 to save, 1 to remove
   * \param[in]    debug    1 to output indicator arrays
   * \return  0 if OK, 1 on error
   */
  static l_int32
  recogSplittingFilter(L_RECOG   *recog,
                       PIX       *pixs,
                       l_int32    minh,
                       l_float32  minaf,
                       l_int32   *premove,
                       l_int32    debug)
  {
  l_int32    w, h;
  l_float32  aspratio, fract;
  
      PROCNAME("recogSplittingFilter");
  
      if (!premove)
          return ERROR_INT("&remove not defined", procName, 1);
      *premove = 0;
      if (!recog)
          return ERROR_INT("recog not defined", procName, 1);
      if (!pixs)
          return ERROR_INT("pixs not defined", procName, 1);
      if (minh <= 0) minh = DefaultMinHeight;
  
          /* Remove from further consideration:
           *    small stuff
           *    components with large width/height ratio
           *    components with small area fill fraction */
      pixGetDimensions(pixs, &w, &h, NULL);
      if (w < recog->min_splitw) {
          if (debug) L_INFO("w = %d < %d\n", procName, w, recog->min_splitw);
          *premove = 1;
          return 0;
      }
      if (h < minh) {
          if (debug) L_INFO("h = %d < %d\n", procName, h, minh);
          *premove = 1;
          return 0;
      }
      aspratio = (l_float32)w / (l_float32)h;
      if (aspratio > recog->max_wh_ratio) {
          if (debug) L_INFO("w/h = %5.3f too large\n", procName, aspratio);
          *premove = 1;
          return 0;
      }
      pixFindAreaFraction(pixs, recog->sumtab, &fract);
      if (fract < minaf) {
          if (debug) L_INFO("area fill fract %5.3f < %5.3f\n",
                            procName, fract, minaf);
          *premove = 1;
          return 0;
      }
  
      return 0;
  }
  
  
  /*------------------------------------------------------------------------*
   *                              Postprocessing                            *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   recogExtractNumbers()
   *
   * \param[in]    recog
   * \param[in]    boxas         location of components
   * \param[in]    scorethresh   min score for which we accept a component
   * \param[in]    spacethresh   max horizontal distance allowed between digits;
   *                             use -1 for default
   * \param[out]   pbaa          [optional] bounding boxes of identified numbers
   * \param[out]   pnaa          [optional] scores of identified digits
   * \return  sa of identified numbers, or NULL on error
   *
   * <pre>
   * Notes:
   *      (1) This extracts digit data after recogaIdentifyMultiple() or
   *          lower-level identification has taken place.
   *      (2) Each string in the returned sa contains a sequence of ascii
   *          digits in a number.
   *      (3) The horizontal distance between boxes (limited by %spacethresh)
   *          is the negative of the horizontal overlap.
   *      (4) Components with a score less than %scorethresh, which may
   *          be hyphens or other small characters, will signal the
   *          end of the current sequence of digits in the number.  A typical
   *          value for %scorethresh is 0.60.
   *      (5) We allow two digits to be combined if these conditions apply:
   *            (a) the first is to the left of the second
   *            (b) the second has a horizontal separation less than %spacethresh
   *            (c) the vertical overlap >= 0 (vertical separation < 0)
   *            (d) both have a score that exceeds %scorethresh
   *      (6) Each numa in the optionally returned naa contains the digit
   *          scores of a number.  Each boxa in the optionally returned baa
   *          contains the bounding boxes of the digits in the number.
   * </pre>
   */
  SARRAY *
  recogExtractNumbers(L_RECOG   *recog,
                      BOXA      *boxas,
                      l_float32  scorethresh,
                      l_int32    spacethresh,
                      BOXAA    **pbaa,
                      NUMAA    **pnaa)
  {
  char      *str, *text;
  l_int32    i, n, x1, x2, h_ovl, v_ovl, h_sep, v_sep;
  l_float32  score;
  BOX       *box, *prebox;
  BOXA      *ba;
  BOXAA     *baa;
  NUMA      *nascore, *na;
  NUMAA     *naa;
  SARRAY    *satext, *sa, *saout;
  
      PROCNAME("recogExtractNumbers");
  
      if (pbaa) *pbaa = NULL;
      if (pnaa) *pnaa = NULL;
      if (!recog || !recog->rcha)
          return (SARRAY *)ERROR_PTR("recog and rcha not both defined",
                                     procName, NULL);
      if (!boxas)
          return (SARRAY *)ERROR_PTR("boxas not defined", procName, NULL);
  
      if (spacethresh < 0)
          spacethresh = L_MAX(recog->maxheight_u, 20);
      rchaExtract(recog->rcha, NULL, &nascore, &satext, NULL, NULL, NULL, NULL);
      if (!nascore || !satext) {
          numaDestroy(&nascore);
          sarrayDestroy(&satext);
          return (SARRAY *)ERROR_PTR("nascore and satext not both returned",
                                     procName, NULL);
      }
  
      saout = sarrayCreate(0);
      naa = numaaCreate(0);
      baa = boxaaCreate(0);
      prebox = NULL;
      n = numaGetCount(nascore);
      for (i = 0; i < n; i++) {
          numaGetFValue(nascore, i, &score);
          text = sarrayGetString(satext, i, L_NOCOPY);
          if (prebox == NULL) {  /* no current run */
              if (score < scorethresh) {
                  continue;
              } else {  /* start a number run */
                  sa = sarrayCreate(0);
                  ba = boxaCreate(0);
                  na = numaCreate(0);
                  sarrayAddString(sa, text, L_COPY);
                  prebox = boxaGetBox(boxas, i, L_CLONE);
                  boxaAddBox(ba, prebox, L_COPY);
                  numaAddNumber(na, score);
              }
          } else {  /* in a current number run */
              box = boxaGetBox(boxas, i, L_CLONE);
              boxGetGeometry(prebox, &x1, NULL, NULL, NULL);
              boxGetGeometry(box, &x2, NULL, NULL, NULL);
              boxOverlapDistance(box, prebox, &h_ovl, &v_ovl);
              h_sep = -h_ovl;
              v_sep = -v_ovl;
              boxDestroy(&prebox);
              if (x1 < x2 && h_sep <= spacethresh &&
                  v_sep < 0 && score >= scorethresh) {  /* add to number */
                  sarrayAddString(sa, text, L_COPY);
                  boxaAddBox(ba, box, L_COPY);
                  numaAddNumber(na, score);
                  prebox = box;
              } else {  /* save the completed number */
                  str = sarrayToString(sa, 0);
                  sarrayAddString(saout, str, L_INSERT);
                  sarrayDestroy(&sa);
                  boxaaAddBoxa(baa, ba, L_INSERT);
                  numaaAddNuma(naa, na, L_INSERT);
                  boxDestroy(&box);
                  if (score >= scorethresh) {  /* start a new number */
                      i--;
                      continue;
                  }
              }
          }
      }
  
      if (prebox) {  /* save the last number */
          str = sarrayToString(sa, 0);
          sarrayAddString(saout, str, L_INSERT);
          boxaaAddBoxa(baa, ba, L_INSERT);
          numaaAddNuma(naa, na, L_INSERT);
          sarrayDestroy(&sa);
          boxDestroy(&prebox);
      }
  
      numaDestroy(&nascore);
      sarrayDestroy(&satext);
      if (sarrayGetCount(saout) == 0) {
          sarrayDestroy(&saout);
          boxaaDestroy(&baa);
          numaaDestroy(&naa);
          L_INFO("saout has no identified text\n", procName);
          return NULL;
      }
  
      if (pbaa)
          *pbaa = baa;
      else
          boxaaDestroy(&baa);
      if (pnaa)
          *pnaa = naa;
      else
          numaaDestroy(&naa);
      return saout;
  }
  
  /*!
   * \brief   showExtractNumbers()
   *
   * \param[in]    pixs     input 1 bpp image
   * \param[in]    sa       recognized text strings
   * \param[in]    baa      boxa array for location of characters in each string
   * \param[in]    naa      numa array for scores of characters in each string
   * \param[out]   ppixdb   [optional] input pixs with identified chars outlined
   * \return  pixa   of identified strings with text and scores, or NULL on error
   *
   * <pre>
   * Notes:
   *      (1) This is a debugging routine on digit identification; e.g.:
   *            recogIdentifyMultiple(recog, pixs, 0, 1, &boxa, NULL, NULL, 0);
   *            sa = recogExtractNumbers(recog, boxa, 0.8, -1, &baa, &naa);
   *            pixa = showExtractNumbers(pixs, sa, baa, naa, NULL);
   * </pre>
   */
  PIXA *
  showExtractNumbers(PIX     *pixs,
                     SARRAY  *sa,
                     BOXAA   *baa,
                     NUMAA   *naa,
                     PIX    **ppixdb)
  {
  char       buf[128];
  char      *textstr, *scorestr;
  l_int32    i, j, n, nchar, len;
  l_float32  score;
  L_BMF     *bmf;
  BOX       *box1, *box2;
  BOXA      *ba;
  NUMA      *na;
  PIX       *pix1, *pix2, *pix3, *pix4;
  PIXA      *pixa;
  
      PROCNAME("showExtractNumbers");
  
      if (ppixdb) *ppixdb = NULL;
      if (!pixs)
          return (PIXA *)ERROR_PTR("pixs not defined", procName, NULL);
      if (!sa)
          return (PIXA *)ERROR_PTR("sa not defined", procName, NULL);
      if (!baa)
          return (PIXA *)ERROR_PTR("baa not defined", procName, NULL);
      if (!naa)
          return (PIXA *)ERROR_PTR("naa not defined", procName, NULL);
  
      n = sarrayGetCount(sa);
      pixa = pixaCreate(n);
      bmf = bmfCreate(NULL, 6);
      if (ppixdb) *ppixdb = pixConvertTo8(pixs, 1);
      for (i = 0; i < n; i++) {
          textstr = sarrayGetString(sa, i, L_NOCOPY);
          ba = boxaaGetBoxa(baa, i, L_CLONE);
          na = numaaGetNuma(naa, i, L_CLONE);
          boxaGetExtent(ba, NULL, NULL, &box1);
          box2 = boxAdjustSides(NULL, box1, -5, 5, -5, 5);
          if (ppixdb) pixRenderBoxArb(*ppixdb, box2, 3, 255, 0, 0);
          pix1 = pixClipRectangle(pixs, box1, NULL);
          len = strlen(textstr) + 1;
          pix2 = pixAddBlackOrWhiteBorder(pix1, 14 * len, 14 * len,
                                          5, 3, L_SET_WHITE);
          pix3 = pixConvertTo8(pix2, 1);
          nchar = numaGetCount(na);
          scorestr = NULL;
          for (j = 0; j < nchar; j++) {
               numaGetFValue(na, j, &score);
               snprintf(buf, sizeof(buf), "%d", (l_int32)(100 * score));
               stringJoinIP(&scorestr, buf);
               if (j < nchar - 1) stringJoinIP(&scorestr, ",");
          }
          snprintf(buf, sizeof(buf), "%s: %s\n", textstr, scorestr);
          pix4 = pixAddTextlines(pix3, bmf, buf, 0xff000000, L_ADD_BELOW);
          pixaAddPix(pixa, pix4, L_INSERT);
          boxDestroy(&box1);
          boxDestroy(&box2);
          pixDestroy(&pix1);
          pixDestroy(&pix2);
          pixDestroy(&pix3);
          boxaDestroy(&ba);
          numaDestroy(&na);
          LEPT_FREE(scorestr);
      }
  
      bmfDestroy(&bmf);
      return pixa;
  }
  
  
  /*------------------------------------------------------------------------*
   *                        Static debug helper                             *
   *------------------------------------------------------------------------*/
  /*!
   * \brief   l_showIndicatorSplitValues()
   *
   * \param[in]   na1, na2, na3, na4, na5, na6      6 indicator array
   *
   * <pre>
   * Notes:
   *      (1) The values indicate that specific criteria has been met
   *          for component removal by pre-splitting filter..
   *          The 'result' line shows which components have been removed.
   * </pre>
   */
  static void
  l_showIndicatorSplitValues(NUMA  *na1,
                             NUMA  *na2,
                             NUMA  *na3,
                             NUMA  *na4,
                             NUMA  *na5,
                             NUMA  *na6)
  {
  l_int32  i, n;
  
      n = numaGetCount(na1);
      fprintf(stderr, "================================================\n");
      fprintf(stderr, "lt minw:    ");
      for (i = 0; i < n; i++)
          fprintf(stderr, "%4d ", (l_int32)na1->array[i]);
      fprintf(stderr, "\nlt minh:    ");
      for (i = 0; i < n; i++)
          fprintf(stderr, "%4d ", (l_int32)na2->array[i]);
      fprintf(stderr, "\ngt maxh:    ");
      for (i = 0; i < n; i++)
          fprintf(stderr, "%4d ", (l_int32)na3->array[i]);
      fprintf(stderr, "\ngt maxasp:  ");
      for (i = 0; i < n; i++)
          fprintf(stderr, "%4d ", (l_int32)na4->array[i]);
      fprintf(stderr, "\nlt minaf:   ");
      for (i = 0; i < n; i++)
          fprintf(stderr, "%4d ", (l_int32)na5->array[i]);
      fprintf(stderr, "\n------------------------------------------------");
      fprintf(stderr, "\nresult:     ");
      for (i = 0; i < n; i++)
          fprintf(stderr, "%4d ", (l_int32)na6->array[i]);
      fprintf(stderr, "\n================================================\n");
  }
  