BACKGROUND 
     De-interlacing capability is a common feature of today&#39;s televisions, Digital Video Disc (DVD) players and set-top boxes (STBs). Video format conversion such as converting standard definition (SD) video content into high definition (HD) content requires de-interlacing of the interlaced content. In addition, de-interlacing functionality is needed to convert interlaced video content into a form suitable for modern progressive scan displays. 
     De-interlacing techniques can be classified as intra-field, inter-field, motion adaptive or motion compensation. Intra-field de-interlacing is the process of interpolating missing pixel values from an existing field of interlaced video pixel values to generate a full frame image. Intra-field de-interlacing is an attractive technique because it maximizes de-interlacing speed while minimizing computational complexity. However, conventional intra-field de-interlacing techniques may cause visible artifacts when de-interlacing video content that includes shallow angle edges. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more implementations consistent with the principles of the invention and, together with the description, explain such implementations. The drawings are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the invention. In the drawings, 
         FIG. 1  illustrates an example video processing system; 
         FIG. 2  illustrates a representative video pixel labeling scheme; 
         FIG. 3  is a flow chart illustrating an example process for edge directed de-interlacing; 
         FIG. 4  is a flow chart illustrating respective portions of the process of  FIG. 3  in greater detail; 
         FIGS. 5A-C  illustrate representative video data quantities; 
         FIG. 6  is a flow chart illustrating respective portions of the process of  FIG. 3  in greater detail; and 
         FIG. 7  illustrates another representative video pixel labeling scheme. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the following description specific details may be set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of the claimed invention. However, such details are provided for purposes of explanation and should not be viewed as limiting with respect to the claimed invention. With benefit of the present disclosure it will be apparent to those skilled in the art that the various aspects of the invention claimed may be practiced in other examples that depart from these specific details. Moreover, in certain instances, descriptions of well known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. 
       FIG. 1  illustrates an example system  100  according to one implementation of the invention. System  100  may include one or more video processors  102 , memory  104 , and one or more image data output devices  108 . In addition, in one implementation, processor  102  may communicate over a shared bus or other communications pathway  110  with a host processor  112 , one or more input/output (I/O) interfaces  114  (e.g., universal synchronous bus (USB) interfaces, parallel ports, serial ports, telephone ports, and/or other I/O interfaces), and/or one or more network interfaces  116  (e.g., wired and/or wireless local area network (LAN) and/or wide area network (WAN) and/or personal area network (PAN), and/or other wired and/or wireless network interfaces). Host processor  112  may also communicate with one or more memory devices  118 . 
     System  100  may assume a variety of physical implementations suitable for edge directed de-interlacing of video data. For example, image output device  108  may be implemented in a single device such as a digital television; while video processor  102 , memory  104 , host processor  112 , interfaces  114 / 116 , and memory  118  may be implemented in a device such as a set-top box (STB) coupled to output device  108  through communications pathway  110  (e.g., a digital transmission cable, a wireless network, etc.). Alternatively, all or most of the components of system  100  may be implemented in a single device such as a personal computer (PC), a networked PC, a server computing system, a handheld computing platform (e.g., a personal digital assistant (PDA)), cell phone, etc. Moreover, while components of system  100  may be implemented within a single device, such as a system-on-a-chip (SOC) integrated circuit (IC), components of system  100  may also be distributed across multiple ICs or devices. 
     Video processor  102  may constitute any video processing logic including one or more devices and/or logic modules capable of performing one or more video processing functions. For example, although the invention is not limited in this regard, processor  102  may comprise a collection of coupled video processing logic elements, each processing element capable of undertaking video processing functions. In one implementation, video processor  102  may receive interlaced video data (e.g., in the form of video field data comprising rows of individual pixel values) from memory  104  and/or from processor  112  or other video data sources coupled to system  100  through interfaces  114 / 116 . In one implementation, video processor  102  may be used for implementing methods for edge directed de-interlacing of video data in accordance with the invention. Video processor  102  may output resulting de-interlaced video data to memory  104  and/or image output device  108 . 
     Memory  104  and/or memory  118  may be any device and/or mechanism capable of storing and/or holding video data, color pixel data and/or component values, to name a few examples. For example, although the invention is not limited in this regard, memory  104  may be volatile memory such as static random access memory (SRAM) or dynamic random access memory (DRAM). For example, although the invention is not limited in this regard, memory  118  may be non-volatile memory such as flash memory. 
     Image data output device(s)  108  may include any of a number of mechanisms and/or device(s) that consume and/or display video data. For example, although the invention is not limited in this regard, image output device  108  may comprise a television display such as a cathode ray tube (CRT), liquid crystal display (LCD), plasma display panel (PDP) etc. Those of skill in the art will recognize that certain image processing components (e.g., display processor) that would be necessary to implement the displaying of de-interlaced video data by device  108  but that are not particularly germane to the claimed invention have been omitted from system  100  in the interest of clarity. 
     Host processor  112  may be, in various implementations, a special purpose or a general purpose processor. Further, host processor  112  may comprise a single device (e.g., a microprocessor or ASIC) or multiple devices. In one implementation, host processor  112  may be capable of performing any of a number of tasks that support methods for edge directed de-interlacing of video data. These tasks may include, for example, although the invention is not limited in this regard, downloading microcode to processor  102 , initializing and/or configuring registers within processor  102 , interrupt servicing, and providing a bus interface for uploading and/or downloading video data. In alternate implementations, some or all of these functions may be performed by processor  102 . 
       FIG. 2  illustrates a representative labeling scheme  200  that may be used to describe implementations of edge directed de-interlacing in accordance with implementations of the invention. When de-interlacing input video data in accordance with an implementation of the invention, an output pixel value  202  to be generated by interpolation to form part of a new line of video data J may be interpolated using the average of one or more pairs of pixels of existing lines of video data J−1 and J+1 from a field of input interlaced video data. Thus, a value for pixel  202  may be generated by interpolation between any one of the pixel pairs (−W, W), . . . , (−2, 2), (−1, 1), (0, 0), (1, −1), (2, −2), . . . , (W, −W); where W may be described as a horizontal distance over which candidate directions and/or de-interlacing orientations may be assessed. For example, if a horizontal distance W=3 is selected then a total of 2W+1=7 candidate directions may be evaluated where those directions are delineated by the pixel pairs (−3, 3), (−2, 2), (−1, 1), (0, 0), (1, −1), (2,−2), and (3, −3). In one implementation of the invention, a value of W=5 may provide satisfactory results as will be explained in more detail below. However, the invention is not limited in this regard and other values of W may be implemented in accordance with the invention. 
     In accordance with an implementation of the invention, each one of the 2W+1 candidate directions and/or de-interlacing orientations may be assigned a score based on an assessment of neighboring pixel values associated with the pixel pairs delineating those directions as will be described in greater detail below. The pixel pair delineating the candidate direction having the best score of the 2W+1 candidate directions may then be selected as the pair to be interpolated to generate a value for the output pixel  202 . 
       FIG. 3  is a flow diagram illustrating a process  300  for edge directed de-interlacing in accordance with an implementation of the claimed invention. While, for ease of explanation, process  300 , and associated processes, may be described with regard to system  100  of  FIG. 1 , the claimed invention is not limited in this regard and other processes or schemes supported and/or performed by appropriate devices and/or combinations of devices in accordance with the claimed invention are possible. 
     Process  300  may begin with obtaining of interlaced video data [act  302 ]. In one implementation, processor  102  may obtain a portion of a field of interlaced video data stored in memory  104 . For example, processor  102  may obtain input video data in the form of a portion of an odd field of a single frame of luma pixels having 8-bit intensity values. The invention is not limited in this regard however and processor  102  may obtain input video data in act  302  from many sources and in many forms. For example, processor  102  may obtain input video data from other devices coupled to pathway  110  or, for that matter, from a source external to system  100  via interfaces  112  and/or  116 . 
     Process  300  may continue in act  304  with detection of the edge direction.  FIG. 4  is a flow chart illustrating a process  400  for determining artifact strength in accordance with one implementation of act  304 . Process  400  may begin with selection of the horizontal distance [act  402 ] over which to undertake detecting edge directions. For example, as discussed above with respect to  FIG. 2 , in one implementation, a horizontal distance value of W=5 may be selected. When 5 is selected as the horizontal distance a total of 2W+1=11 candidate edge directions may be evaluated where those directions are delineated by the pixel pairs (−5, 5), (−4, 4), (−3,3), (−2, 2), (−1, 1), (0, 0), (1, −1), (2,−2), (3, −3), (4, −4) and (5,−5) defined with reference to the pixel  202  to be interpolated as shown in  FIG. 2 . 
     In one implementation, the horizontal distance value W may be selected by processor  102  in response to control data provided by host processor  112  although the invention is not limited in this regard and act  402  may, for example, be undertaken by processor  102  in response to other devices coupled to system  100  via interfaces  114  and/or  116 . Alternatively, act  402  may, for example, be undertaken by processor  102  in response to control data and/or indicators associated with the portion of input video data obtained in act  302 . 
     Process  400  may continue with the determination of the variation of pixel values for specific data windows [acts  404 - 408 ].  FIGS. 5A-C  illustrate a representative labeling scheme  500  that may be used to describe implementations of edge directed de-interlacing with respect to acts  404 - 408  in accordance with implementations of the invention. When de-interlacing interlaced input video data in accordance with an implementation of the invention, scores for the 2W+1 candidate directions may be generated by determining a score value S for each candidate direction according to the following relationship of sum of absolute difference (SAD) values:
 
 S=SAD ( w 1 , w 2)+ SAD ( w 3 , w 4)+2 [SAD ( w 5 , w 6)]  (1)
 
     In the implementation of  FIGS. 5A-C  an example candidate edge direction is shown delineated by the pixel pair (−3,3).  FIG. 5A  illustrates a representative labeling scheme for an implementation of determining SAD(w 1 ,w 2 ) [act  404 ] for the example (−3,3) candidate direction for a pixel  501  to be interpolated in the current line J of pixels being processed for interpolation. Referring to this figure, the quantity w 1  of equation (1) represents a 7×3 data window  502  in a current field  503  of the input interlaced video data (represented, in part, in  FIG. 5A  by portions of video lines J−3, J−1, J+1, and J+3) centered on a terminal edge pixel  505  (P′) of the candidate edge direction being assessed (where, in this case, P′ is a pixel in line J−1). Likewise, the quantity w 2  represents a 7×3 data window  506  in the current field  503  centered on the other terminal edge pixel  507  (P″) of the (3,−3) candidate edge direction. 
     In one implementation of the invention, act  404  may be performed by processor  102  of  FIG. 1 . In such case, processor  102  may ascertain the contents (pixel values) of windows  502  and  506 , and undertake determination of the quantity SAD(w 1 ,w 2 ). For example, processor  102  may undertake determination of the quantity SAD(w 1 ,w 2 )
 
 SAD ( w 1 ,w 2)=[ ABS[p 1( w 1)− p 1( w 2)]+ . . . + ABS[p 21( w 1)− p 21( w 2)]  (2)
 
where p 1 (w 1 ) refers to the pixel in the upper left-hand corner of window  502 , p 1 (w 2 ) refers to the pixel in the upper left-hand corner of window  506 , p 21 (w 1 ) refers to the pixel in the lower right-hand corner of window  502 , p 21 (w 2 ) refers to the pixel in the lower right-hand corner of window  506 , and ABS refers to the absolute value of the bracketed quantities.
 
       FIG. 5B  illustrates a representative labeling scheme for an implementation of determining SAD(w 3 ,w 4 ) [act  406 ] for the example (3,−3) candidate direction. Referring to this figure, the quantity w 3  of equation 1 represents a 5×1 data window  508  associated with pixel P′ in the current frame  509  of partially de-interlaced video data. The quantity w 4  represents a 5×1 data window  510  centered on pixel P, the pixel currently being processed. 
     It should be noted that the portion of the current frame  509  shown in  FIG. 5B  includes portions of input video data lines J−1 and J+1 (as also shown in  FIG. 5A ) in addition to portions of a line J of video data that includes previously interpolated pixels  511  to the left in  FIG. 5B  of the current pixel being processed  512  (P) in line J and included in data window  510 . In the implementation of  FIG. 5B  the value of pixel  512  may be represented by a line average of the vertically adjacent pixels in lines J−1 and J+1. Likewise, the value of each of the pixels  513  in line J to the right of pixel  512  in  FIG. 5B  included in data window  510  may also be represented by a line average of the respective vertically adjacent pixels in lines J−1 and J+1. 
     In one implementation of the invention, act  406  may be performed by processor  102  of  FIG. 1 . In such case, processor  102  may ascertain the contents (pixel values) of window  508  and, after determining the line averages for pixel P ( 512 ) and pixels  513 , ascertain the contents of window  510 , and undertake determination of the quantity SAD(w 3 ,w 4 ). 
       FIG. 5C  illustrates a representative labeling scheme for an implementation of determining SAD(w 5 ,w 6 ) [act  408 ] for the example (3,−3) candidate direction. Referring to this figure, the quantity w 5  of equation 1 represents a 7×1 data window  514  in line J−2 centered above pixel P′ (line J−1) in the current frame  509  of partially de-interlaced video data. In the implementation of  FIG. 5C , window  514  includes previously interpolated pixel values in line J−2. In addition, the quantity w 6  represents a 7×1 data window  516 , comprising pixels in line J−1 including the pixel P′ (pixel  505 ), centered above the pixel to be interpolated (pixel P  512 ). 
     In one implementation of the invention, act  408  may be performed by processor  102  of  FIG. 1 . In such case, processor  102  may ascertain the contents (pixel values) of windows  514  and  516  and undertake determination of the quantity SAD(w 5 ,w 6 ). 
     It should be noted that while  FIGS. 5A-C  illustrate respective data windows w 1 -w 6  for the example of the (−3,3) candidate direction and/or de-interlacing orientation, similar data windows may be defined with respect to the pixel pairs delineating all other candidate directions. Such data windows for candidate directions other than (−3,3) may bear the same spatial orientation with respect to those other direction&#39;s pixel pairs as the spatial orientations shown for windows  502 ,  506 ,  508 ,  510 ,  514 , and  516  with respect to the (P′,P″) pixel pair in  FIGS. 5A-C . Moreover, as those skilled in the art will recognize, de-interlacing video in a top-down and right-to-left manner or orientation is conventional and  FIGS. 5A-C  assume this convention. However, the invention is not limited in this regard and other orientations may be implemented. For example, acts  404 - 408  may also be undertaken in a right-to-left processing orientation (describable with attendant modification to the labeling scheme of  FIGS. 5A-C ) without departing from the scope and spirit of the invention. 
     Furthermore, with respect to equation 1, the weight value of 2 applied to the quantity SAD(w 5 , w 6 ) represents only one possible choice of weight value and other weight values are possible in accordance with other implementations of the invention. In addition, the locations and sizes of data windows w 1 -w 6  in the scheme  300  as shown and describe herein are representative of only one implementation of invention and other data window locations and sizes are possible in accordance with the scope and spirit of the invention. 
     Returning again the  FIG. 4 , process  400  may continue with a determination of a score for each candidate direction [act  410 ]. In one implementation, this may be done by determining S (equation 1) for each candidate edge direction processed through acts  404 - 408 . For example, processor  102  of  FIG. 1  may be employed to determine the score S for each candidate edge direction. 
     Upon determination of candidate edge direction scores in act  410 , process  400  may conclude with selection of an edge direction based on those scores [act  412 ]. In one implementation, the candidate edge direction having the lowest score S may be selected as the edge direction in act  412 . One way to do this is to have processor  102  of  FIG. 1  select the edge direction having the lowest score in act  412  after having determined all the candidate scores in act  410 . 
     Referring again to  FIG. 3 , once act  304  of detecting the edge direction has been performed as discussed above with respect to the implementations shown in  FIG. 4  and  FIGS. 5A-C , process  300  may continue with performance of edge directed interpolation [act  306 ] in accordance with the invention. One way to do this is to have processor  102  of  FIG. 1  determine the value for the pixel being interpolated (for example, pixel  512  of  FIGS. 5B-C ) by averaging the two pixel values of the pair of pixels that delineates the edge direction detected in act  304 . For instance, referring again to the example illustrated in  FIGS. 5A-C , were direction (−3,3) determined to be the edge direction in act  304  having the lowest score S (as described above with respect to acts  404 - 412  of process  400 ) then processor  102  may average the values of the pixels P′  505  and P″  507  to obtain the edge directed interpolated value for pixel  512 . 
     Having performed edge directed interpolation in act  306 , process  300  may, in accordance with the invention, continue with error protection [act  308 ] of the interpolated pixel.  FIG. 6  is a flow chart illustrating a process  600  for performing error protection in accordance with one implementation of act  308 , while  FIG. 7  illustrates a representative labeling scheme  700  that may be used to describe implementations of error protection with respect to process  600  in accordance with implementations of the invention. Any and/or all of the acts of process  600  may be performed by processor  102  of  FIG. 1 . However, the invention is not limited in this regard and other components of system  100 , such as host processor  112  may perform one or more of the acts of process  600 . 
     Referring to  FIG. 7 , scheme  700  defines several quantities (D 1 , D 2 , D 3 , D 4  and D 5 ) with respect to a directionally interpolated pixel  702  (in line J), where pixel  702  may represent the pixel value most recently obtained through the edge directed interpolation performed in act  306 . The value of pixel  702  obtained through the edge directed interpolation is represented in scheme  700  as the quantity (af). Pixels  704 ,  706 , and  708  (having the respective values m 1 , p 1 , and p 3 ) represent pixels in the current field of input video data (e.g., field  503  of  FIG. 5A ) located in lines J−1, J+1, and J+3 respectively and found in the same data column I as the directionally interpolated pixel  702 . Pixel  710  (having value m 2 ) represents a previously directionally interpolated pixel of line J−2 also occupying the same column I as pixel  702 . Pixel  712  (having value m 2 ) represents a temporary pixel value of row J+2 also occupying the same column I as pixel  702  and obtained by averaging the values of pixels  706  (p 1 ) and  708  (p 3 ). Finally, pixel  714  (having value n1) represents the value of the previously directionally interpolated pixel in line J. 
     Along with the values for pixels  702 - 714  (af, m 1 , p 1 , p 3 , m 2 , p 2 , and n 1  respectively), scheme  700  also defines the following quantities:
 
 D 1 =[af−m 1]  (3)
 
 D 2 =[af−m 2]  (4)
 
 D 3 =ABS[af−p 1]  (5)
 
 D 4 =ABS[af−p 2]  (6)
 
 D 5 =ABS[af−n 1]  (7)
 
where ABS is the absolute value of the bracketed quantities.
 
     Referring to both  FIGS. 6 and 7 , process  600  may begin with the determination of values for the quantities D 1  [act  602 ], D 2  [act  604 ], D 3  [act  606 ], D 4  [act  608 ], and D 5  [act  610 ]. One way to implement acts  602 - 610  is to have processor  102  of  FIG. 2  undertake the respective determinations in keeping with the relationships set out in equations (3)-(7) above. 
     Process  600  may continue with an assessment in act  612  of the quantities D 1 , D 2 , D 3 , D 4 , and D 5  determined or generated in acts  602 - 610 . Specifically, in the implementation of the invention set forth in process  600 , act  612  may constitute determining whether the value of D 5  is less than  60 , whether the absolute value of D 1  is less than or equal to the absolute value of D 2 , whether D 1  and D 2  have the same sign, and whether the value of D 3  is less than or equal to the value of D 4 . If the answer to all four queries is yes then process  600  may conclude in act  614  with the selection of the value af as the output pixel value (i.e., with the selection of the value of the directionally interpolated pixel  702  as the interpolated output pixel value). In other words, if the result of act  612  is a positive determination then no error correction may be applied and the output pixel value may be the directionally interpolated pixel value af obtained in act  306  of  FIG. 3 . 
     If, however, the result of act  612  is negative (i.e., if any one of the conditions described above with respect to act  612  is not met) then process  600  may continue with a determination of whether the horizontal distance factor W is less than two [act  616 ]. If the result of act  616  is positive then process  600  may conclude in act  618  with the selection of the value of the output pixel as the median of the values (af, p 1 , m 1 ). In other words, if the value of W is less than two then the output pixel value may not be the directionally interpolated value as determined in  306  but, rather, may be the error corrected value corresponding to the median of the values (af, p 1 , m 1 ). 
     If, however, the result of act  616  is negative (i.e., if the value of W is equal to or greater than two) then process  600  may continue in act  620  with a determination of whether (p 1 ≦af≦m 1 ) or whether (m 1 ≦af≦p 1 ). If either condition in act  620  is met then af may be selected as the output pixel value [act  622 ] and process  600  may complete. In other words, if the result of act  620  is a positive determination then no error correction may be applied and the output pixel value may be the directionally interpolated pixel value af obtained in act  306  of  FIG. 3 . 
     Alternatively, if the result of act  620  is negative (i.e., if both conditions in act  620  fail) then process  600  may continue in act  624  with a determination of the best direction within horizontal distance W=1. In other words, the minimum score from the scores for directions (−1,1), (0,0), and (1,−1) as determined in  410  of  FIG. 4  may be determined in act  624 . Subsequently, the average of the pixel pair delineating that direction having the minimal score determined in act  624  may be used to generate an interpolated value af 1  [act  626 ]. Process  600  may then conclude with the determination in act  628  of the output pixel value as the median of the values (af, af 1 , p 1 , m 1 , n 1 ). In other words, if the result of act  620  is negative then the output pixel value may not be the directionally interpolated value as determined in  306  but, rather, may be the error corrected value corresponding to the median of the values (af, af 1 , p 1 , m 1 , n 1 ). 
     The acts shown in  FIGS. 3 ,  4  and  6  need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. For example, selection of the horizontal distance in act  402  may be undertaken at any juncture prior to acts  404 - 408 . Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. For example, acts  404 - 408  of process  400  may be undertaken in parallel. Likewise, acts  602 - 610  of process  600  may be undertaken in parallel. Moreover, some acts of processes  300 ,  400  or  600  may be implemented in and/or undertaken using hardware and/or firmware and/or software. For example, the acts in process  600  of determining D 1 -D 5  (acts  602 - 610 ) may be implemented using hardware and/or firmware, while other acts may be implemented in software (e.g., decisions  612 ,  616  and/or  620 ). However, the invention is not limited in this regard and acts that may be implemented in hardware and/or firmware may, alternatively, be implemented in software. For example, acts  602 - 610  may be implemented in software. Clearly, many such combinations of software and/or hardware and/or firmware implementation of processes  300 ,  400  and/or  600  may be contemplated consistent with the scope and spirit of the invention. Further, at least some of the acts in processes  300 ,  400  and/or  600  may be implemented as instructions, or groups of instructions, implemented in a machine-readable medium. 
     The foregoing description of one or more implementations consistent with the principles of the invention provides illustration and description, but is not intended to be exhaustive or to limit the scope of the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various implementations of the invention. Clearly, many implementations may be employed to provide a method, apparatus and/or system to implement edge directed de-interlacing consistent with the claimed invention. 
     No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. In addition, some terms used to describe implementations of the invention, such as “data” and “value,” may be used interchangeably in some circumstances. For example, those skilled in the art will recognize that the terms “pixel value” and “pixel data” may be used interchangeably without departing from the scope and spirit of the invention. Moreover, when terms such as “coupled” or “responsive” are used herein or in the claims that follow, these terms are meant to be interpreted broadly. For example, the phrase “coupled to” may refer to being communicatively, electrically and/or operatively coupled as appropriate for the context in which the phrase is used. Variations and modifications may be made to the above-described implementation(s) of the claimed invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.
One implementation of a method for edge directed video de-interlacing in accordance with the disclosed invention includes obtaining at least a portion of a field of input video data including at least portions of four consecutive rows of field pixels including first, second, third, and fourth rows of field pixels. The method further includes selecting an orientation over which to de-interlace the input video data based, at least in part, on a measure of the deviation in pixel values among the four consecutive rows of field pixels and a fifth row of pixels located between the second and third rows of field pixels, the fifth row of pixels including previously interpolated pixel values and pixel values obtained by line averaging between pixel values in the second and third rows of field pixels. The method further includes interpolating along the selected orientation to determine a value for a pixel to be interpolated.