title: Why do I get such poor results from Tesseract for simple single character recognizing?
body: <p>I am trying to use Tesseract  for single character recognizing and the results are awful.
  "h" is recognized as "n",  "4" as "/i",  "O" as "()";</p>
  
  <p><img src="https://i.stack.imgur.com/R2a51.png" alt="h_char"></p>
  
  <p><img src="https://i.stack.imgur.com/IltbT.png" alt="4_char"> </p>
  
  <p><img src="https://i.stack.imgur.com/ssDol.png" alt="O_char"></p>
  
  <p>Single character mode seems not to act, as many characters are recognized as two characters,
  not  just one. My images are  simple bilevel black and white TIFF images,
  latin characters.  This is bitmap font, not scanned images, they are absolutely clean and
  need no improvement.
  Оnly about half of the characters are correctly recognized, which seems to be
  a very low percent for such a simple task.</p>
  
  <p>The Tesseract  library version I am using is  "4.0.0-beta.3".
  This is how I call Tesseract.</p>
  
  <pre><code> int CharRecognizer::recognizeTIFFData(char* data, int datalength){
              char *outText;
              TessBaseAPI* api = new TessBaseAPI();
  
              if (api-&gt;Init(NULL, "eng")) {
                      fprintf(stderr, "Could not initialize tesseract.\n");
                      exit(1);
              }
              api-&gt;SetPageSegMode(tesseract::PSM_SINGLE_CHAR);
              Pix *image = pixReadMem(data,datalength);
              api-&gt;SetImage(image);
              // Get OCR result
              outText = api-&gt;GetUTF8Text();
              printf("\nOCR output:\n%s", outText);
              // Destroy used object and release memory
              int utf8 = outText[0];
              api-&gt;End();
              delete[] outText;
              pixDestroy(&amp;image);
              return utf8;
   }
  </code></pre>
  
  <p>I am new to Tesseract, so probably I am missing something.  Do I have to somehow train
   the library first?  May be I should set another  OcrEngineMode?  I have expected no
   problems  with simple  bitmap font recognizing and am quite at lost now.
  Thank you very much in advance,
  Yuliana </p>