Abstract:
A system and method that determines the direction of an edge in a video image using a gradient of the edge in a first direction and a gradient of the edge in a second direction. The system uses the sign of the product of the gradient in the first direction and the gradient in the second direction along with a ratio of multiples of the two gradients to determine the direction of the edge. The direction may correspond to an angle range, where the ratio of the gradients corresponds to a trigonometric function of the angle of the edge.

Description:
RELATED APPLICATIONS  
       [0001]     This patent application makes reference to, claims priority to and claims benefit from U.S. Provisional Patent Application Ser. No. 60/540,826, entitled “Method and System for Motion Adaptive Deinterlacer with Integrated Directional Filter,” filed on Jan. 30, 2004, the complete subject matter of which is hereby incorporated herein by reference, in its entirety.  
         [0002]     This application makes reference to: 
    U.S. patent application Ser. No. 10/314,525 filed Dec. 9, 2002;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15439US02) filed Sep. 21, 2004;     U.S. patent application Ser. No. 10/875,422 (Attorney Docket No. 15443US02) filed Jun. 24, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15444US02) filed Sep. 21, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15448US02) filed Sep. 21, 2004;     U.S. patent application Ser. No. 10/871,758 (Attorney Docket No. 15449US02) filed Jun. 17, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15450US02) filed Sep. 21, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15451US02 filed Sep. 21, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15452US02 filed Sep. 21, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15453US02) filed Sep. 21, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15459US02) filed Sep. 21, 2004;     U.S. patent application Ser. No. ______ (Attorney Docket No. 15632US02 filed Sep. 21, 2004; and     U.S. patent application Ser. No. 10/871,649 (Attorney Docket No. 15503US03) filed Jun. 17, 2004.    
 
         [0016]     The above stated applications are hereby incorporated herein by reference in their entirety. 
     
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0017]     [Not Applicable] 
       MICROFICHE/COPYRIGHT REFERENCE  
       [0018]     [Not Applicable] 
       BACKGROUND OF THE INVENTION  
       [0019]     In the field of video compression, communication, decompression, and display, there has been for many years problems associated with supporting both interlaced content and interlaced displays, along with progressive content and progressive displays. Many advanced video systems support either one or the other format. As a result such devices as deinterlacers have become important components in many video systems. Deinterlacers convert interlaced video format into progressive video format.  
         [0020]     Deinterlacing takes interlaced video fields and coverts them into progressive frames, at double the display rate. Certain problems may arise concerning the motion of objects from image to image. Objects that are in motion are encoded differently in interlaced fields from progressive frames. Video images, encoded in deinterlaced format, containing little motion from one image to another may be deinterlaced into progressive format with virtually no problems or visual artifacts. However, problems arise with video images containing a lot of motion and change from one image to another, when converted from interlaced to progressive format. As a result, some video systems were designed with motion adaptive deinterlacers.  
         [0021]     Today, motion adaptive deinterlace video systems rely on multiple fields of data to extract the highest picture quality from a video signal. When motion is detected between fields, it may be very difficult to use temporal information for deinterlacing. Instead, a deinterlacing circuit must utilize a spatial filter (usually a vertical filter of the field of interest). However, often the source material has diagonal lines, or curved edges, and using a spatial filter may not yield satisfactory results. For example, diagonal or curved edges will be represented with stair-step or jaggies that are visible in the image.  
         [0022]     Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.  
       BRIEF SUMMARY OF THE INVENTION  
       [0023]     Aspects of the present invention may be seen in a system and method that determines the direction of an edge in a video image using a gradient of the edge in a first direction and a gradient of the edge in a second direction. The method comprises determining the sign of the product of the gradient in the first direction and the gradient in the second direction; comparing a multiple of the gradient in the first direction to a multiple of the gradient in the second direction; and determining the direction of the edge based on the result of the comparison.  
         [0024]     The direction of the edge corresponds to one of a plurality of angle ranges. Additionally, the ratio of the gradient in the first direction and the gradient in the second direction corresponds to a trigonometric function of an angle in the angle range.  
         [0025]     The system comprises circuitry capable of performing the method as described hereinabove that determines the direction of an edge in a video image.  
         [0026]     These and other features and advantages of the present invention may be appreciated from a review of the following detailed description of the present invention, along with the accompanying figures in which like reference numerals refer to like parts throughout.  
     
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS  
       [0027]      FIG. 1A  illustrates a block diagram of an exemplary architecture for positioning of a MAD-3:2, in accordance with an embodiment of the invention.  
         [0028]      FIG. 1B  illustrates a block diagram of exemplary interfaces for the MAD-3:2 shown in  FIG. 1A , in accordance with an embodiment of the invention.  
         [0029]      FIG. 1C  illustrates a block diagram of an exemplary flow of the algorithm, which may be utilized by the MAD-3:2 of  FIG. 1A  and  FIG. 1B , in accordance with an embodiment of the invention.  
         [0030]      FIG. 2  illustrates a block diagram of an exemplary directional filter that may be integrated into a motion adaptive de-interlacer and utilized for motion adaptive deinterlacing with integrated directional filtering, in accordance with an embodiment of the present invention.  
         [0031]      FIG. 3  illustrates a block diagram of an exemplary angle detection block that may be integrated in a directional filter and utilized for motion adaptive deinterlacing with integrated directional filtering, in accordance with an embodiment of the present invention.  
         [0032]      FIG. 4  illustrates a block diagram of an exemplary diagonal filter block that may be integrated in a directional filter, in accordance with an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     Aspects of the present invention relate to processing of video signals. More specifically, certain embodiments of the invention relate to a method and system for simpler determination of the direction of an edge in a video image. Although the following discusses an embodiment of the invention with respect to video processing and tangent function, it should be understood that the present invention may be modified for use in systems requiring determination of other trigonometric functions.  
         [0034]     Certain aspects of the invention may comprise methods and systems for a motion adaptive deinterlacer (MAD) capable of reverse 3:2 pull-down and 3:2 pull-down with cadence detection, which may be referred to as MAD-3:2 or MAD32, that may be utilized in a video network (VN). The algorithms and architectures for the motion adaptive deinterlacer may be adapted to acquire interlaced video fields from one of a plurality of video sources in the video network and convert the acquired interlaced video fields into progressive frames, at double the display rate, in a visually pleasing manner.  
         [0035]     The motion adaptive deinterlacer (MAD-3:2) may be adapted to accept interlaced video input from a video bus (VB) and output deinterlaced, progressive video to the video bus (BUS) utilized by the video network. The motion adaptive deinterlacer may accept, for example, 720×480i and produce, for example, 720×480p in the case of NTSC. For PAL, the motion adaptive deinterlacer (MAD) may accept, for example, 720×576i and produce, for example, 720×576p. Horizontal resolution may be allowed to change on a field-by-field basis up to, for example, a width of 720. The motion adaptive algorithm utilized by the motion adaptive deinterlacer (MAD-3:2) may be adapted to smoothly blend various approximations for the missing pixels to prevent visible contours produced by changing decisions.  
         [0036]     A plurality of fields of video may be utilized to determine motion. For example, in an embodiment of the invention, five fields of video may be utilized to determine motion. The motion adaptive deinterlacer (MAD) may produce stable non-jittery video with reduced risk of visual artifacts due to motion being misinterpreted while also providing improved still frame performance. The motion adaptive deinterlacer (MAD-3:2) may also provide additional fields per field type of quantized motion information, which may be selectable in order to reduce the risk of misinterpretation. For example, up to three (3) additional fields or more, per field type, of quantized low-cost motion information may optionally be selected in order to reduce risk of misinterpreted motion even further. This may provide a total historical motion window of up to, for example, 10 fields in a cost effective manner. Integrated cross-chrominance removal functionality may be provided, which may aid in mitigating or eliminating NTSC comb artifacts. A directional compass filtering may also be provided in order to reduce or eliminate jaggies in moving diagonal edges. The MAD-3:2 may provide reverse 3:2 pull-down for improved quality from film-based sources.  
         [0037]     In accordance with another aspect of the invention, the algorithms and architectures for the motion adaptive deinterlacer (MAD) may also be adapted to provide bad-edit detection in order to ensure a visually pleasing transition to new cadence in situations where editing may have been carelessly performed. Furthermore, per-pixel correction may also be provided to improve the quality of subject matter containing both film and video at the same time. For example, per-pixel correction may be utilized for interlaced titles, which have been overlaid on film-based content. The motion adaptive deinterlacer (MAD-3:2) may also provide optional CPU control over, for example, 3:2 and/or 2:2 cadence detection and correction.  
         [0038]      FIG. 1   a  is a block diagram of an exemplary architecture illustrating the positioning of a MAD-3:2  100 , in accordance with an embodiment of the present invention. Referring to  FIG. 1   a , the MAD-3:2  100  along with a plurality of scalers ( 102 ,  104 ,  106 , and  108 ), for example, may be positioned between a first crossbar  110  and a second crossbar  112 . The first crossbar  110  may be referred to as an input crossbar and the second crossbar  112  may be referred to as an output crossbar.  
         [0039]     The MAD-3:2  100  may comprise at least one video network input and at least one video network output and may be configured to maintain its own additional field stores. A feedback path may be provided from the output of the second crossbar  112  to the input of the first crossbar  110 . This may allow any of the standard definition (SD) video sources such as the MPEG feeders  103  and  105 , video feeders  107 ,  109 ,  111 ,  113  and  115 , and/or VDEC  117 , and so on, to function as an input to the MAD32  100  and/or one of the scalers  102 ,  104 ,  106 , and  108 . The VDEC  117  may be an analog video decoder that may process NTSC signals to separate color from luma. The MPEG feeders  103  and  105  may accept 4:2:0 and 4:2:2 video data and supply 4:2:2 video data. The video feeders  107 ,  109 ,  111 ,  113  and  115 , may accept 4:2:2 video data and supply 4:2:2 video data. The output of the second crossbar  112  may be passed back to the first crossbar  110  via the feedback path  114 .  
         [0040]     U.S. patent application Ser. No. 10/314,525 filed Dec. 9, 2002 entitled “Network Environment for Video Processing Modules” discloses an exemplary crossbar network module and associated system, which is representative of the video network crossbar that may be utilized in connection with the present invention. Accordingly, U.S. patent application Ser. No. 10/314,525 filed Dec. 9, 2002 is hereby incorporated herein by reference in its entirety.  
         [0041]      FIG. 1   b  is a block diagram illustrating exemplary interfaces for the MAD-3:2  100  shown in  FIG. 1   a , in accordance with an embodiment of the present invention. Referring to  FIG. 1   b , the MAD-3:2  100  may comprise a plurality of bus interfaces and may include the capability to generate one or more system CPU interrupts. The MAD-3:2  100  may run on, for example, a single system clock. However, the invention may not be so limited and more than one clock may be utilized. In one embodiment of the invention, the MAD-3:2  100  may include a video bus (VB) input  120 , a video bus output  122 , and, for example, two independent bidirectional read/write SCB client connections, SCBO  124  and SCBI  126 . The SCB may be an internal bus utilized to access frames/fields stored in the memory. The video bus (VB) input  120  may be utilized for supplying fields to the MAD-3:2  100 . The video bus output  122  may allow the deinterlaced output frames to be transferred throughout the video network and pass through a scaler before reaching a composite or capture block. An RBUS interface  128  may be utilized to configure the MAD-3:2  100  or to access its status via one or more interface signals and/or registers. The RBUS may be a general-purpose bus utilized for programming registers for control and configuration of the CPU. At least a portion of the interfaces of the MAD-3:2  100  may be synchronous to a clock input of the scaler. A video network receiver input error interrupt  130  may be generated on an input field size, which may differ from a programmed field size, which is expected. An inverse telecine ready interrupt  132  may be generated for every field, or at least some fields, at the point in time when the statistics gathered in the previous field are ready to be read by a CPU or other processor.  
         [0042]      FIG. 1   c  is a block diagram illustrating an exemplary flow of the algorithm which may be utilized by the MAD-3:2  100  of  FIG. 1   a  and  FIG. 1   b , in accordance with an embodiment of the present invention. Referring to  FIG. 1   c , there is shown a data flow corresponding to the algorithm utilized for deinterlacing the luma component of video. The algorithm may effectively be divided into two sub-blocks. For example, diagrammed on the left of  FIG. 1   c  is the motion adaptive deinterlacer (MAD) method of deinterlacing  150  and on the right, there is shown the reverse 3:2 pulldown method  180 . For every output pixel, motion adaptive deinterlacing  150 , reverse 3:2 pulldown  180 , or a blend  160  of motion adaptive deinterlacing and reverse 3:2 deinterlacing may be utilized to determine a motion-adapted value of the output pixel under consideration.  
         [0043]     The motion adaptive deinterlacer (MAD)  150  may comprise a directional filter  154 , a temporal average  156 , and a blender  158 . The MAD  150  may comprise suitable logic, code, and/or circuitry and may be adapted for performing the MAD method of deinterlacing. A processor may be adapted to perform the operation of the MAD  150 . The MAD  150  may comprise local memory for storage of data and/or instructions. The directional filter  154  may comprise suitable logic, code, and/or circuitry and may be adapted for spatially approximating the value of the output pixel. The temporal average  156  may comprise suitable logic, code, and/or circuitry and may be adapted for temporal approximation of the value of the output pixel. The blender  158  may comprise suitable logic, code, and/or circuitry and may be adapted to combine the temporal and spatial approximations of the value of the output pixel.  
         [0044]     In operation, the MAD  150  may receive input field pixels from an interlaced video field and convert them into output frame fields in a progressive frame, at double the display rate. The horizontal resolution of the input to the MAD  150  may change on a field-by-field basis. The MAD  150  may utilize a motion adaptive algorithm that may smoothly blend various approximations for the output pixels to prevent visible contours, which may be produced by changing decisions. In an embodiment of the present invention, it may be necessary to determine the amount of motion around each output pixel, to use an appropriate approximation for the output pixel. The MAD  150  may utilize the directional filter  154 , the temporal average  156 , and the blender  158  to obtain a motion-adapted value for the output pixel that is visually pleasing.  
         [0045]      FIG. 2  illustrates a block diagram of an exemplary directional filter  200  that may be integrated into a motion adaptive de-interlacer and utilized for motion adaptive deinterlacing with integrated directional filtering, in accordance with an embodiment of the present invention. The directional filter  200  may be, for example, the directional filter  154  of the MAD  150  of  FIG. 1   c . A plurality of pixels may be read from line buffers every cycle and processed at the clock rate. For example, four pixels  201 ,  203 ,  205  and  207  may be read from the line buffers every cycle and processed at the clock rate. The pixels may be arranged in, for example, a vertical order H, E, F, J from top to bottom. The current pixel O, which is missing, or part of an absent line in the interlaced field. Pixels E and F may be directly above and below pixel O, in the present lines in the interlaced field, and pixels H and J may be the pixels directly above pixel E and below pixel F in present lines in the interlaced field. U.S. patent application Ser. No. 10/______ (Attorney Docket No. 15450US02) filed Sep. 21, 2004 entitled “Pixel Constellation for Motion Detection in Motion Adaptive Deinterlacer” discloses an exemplary pixel constellation that may be utilized in connection with the present invention for pixels H, E, F, and J. Accordingly, U.S. patent application Ser. No. 10/______ (Attorney Docket No. 15450US02) filed Sep. 21, 2004 is hereby incorporated herein by reference in its entirety.  
         [0046]     The directional filter  200  may receive the pixels  201 ,  203 ,  205  and  207  from the line buffers, and produce a spatial average using a process of adaptive diagonal filtering. The directional filter  200  may comprise an angle detection block  209  and a diagonal filter block  211 . The angle detection block  209  may examine an array of pixels to determine the angle and strength of gradients in the source picture. The diagonal filter block  211  may utilize an array of pixels and the angle information  215  outputted by the angle detection block  209  to select one of a plurality of filter kernels and blend the resulting diagonal filter with a vertical FIR based on the strength of the diagonal information  217  outputted by the angle detection block  209 . The resulting output  213  may be used as a spatial average in the motion adaptive de-interlacer (MAD).  
         [0047]     Filtering in the directional filter  200  may be performed on field data entirely within a field. As a result the directional filter  200  may be immune from motion artifacts. Additionally, there may be no motion in the MAD, in which case the output spatial average  213  may not be used elsewhere in the MAD. As a result the diagonal filter  200  may only affect images with motion.  
         [0048]      FIG. 3  illustrates a block diagram of an exemplary angle detection block  300  that may be integrated in a directional filter and utilized for motion adaptive deinterlacing with integrated directional filtering, in accordance with an embodiment of the invention. The angle detection block  300  may be, for example, the angle detection block  209  of the directional filter  200  of  FIG. 2 . The angle detection block  300  may output an angle select signal  317  and a diagonal strength signal  315  per clock cycle. The angle detection block  300  may comprise a delta x (dx) kernel and a delta y (dy) kernel, comparison block  305  for angle selection; and distance approximation block  307  with a threshold block  309  for diagonal strength determination.  
         [0049]     Delta x (dx) kernel and delta y (dy) kernel may be computed using a vertical and horizontal edge detectors  301  and  303  respectively on, for example, a 3×2 array of pixels from lines E and F. Ultimately, the vertical edge detector  301  may determine the gradient in the y-direction, which may indicate whether there is a change in the vertical direction in a field. Similarly, the horizontal edge detector  303  may determine the gradient in the x-direction, which may indicate whether there is a change in the horizontal direction in the field. The dx kernel may be represented as: 
        [½, 0, −½]    [½, 0, −½]
 
 The dy kernel may be represented as: 
    [¼, ½, ¼]    [−  1 / 4 , −  1 / 2 , −¼]
 
 A partial crossbar may be utilized to repeat pixels at the boundaries before they are multiplied. A gradient in both the x- and y-directions may indicate the presence of a diagonal edge. A gradient in only the x-direction may indicate the presence of a vertical edge, and a gradient in only the y-direction may indicate the presence of a horizontal edge. 
       
 
         [0054]     The comparison block  305  may receive scaled values  321  and  323  of abs |dx| and abs |dy| respectively, as well as a sign value  319  to determine the angle of the gradient in the source image. The case selection using comparisons of |dx| and |dy| may be accurate to within, for example, at 0.001 radians of a true arc-tangent (arctan) function, but may be considerably cheaper. A modification to a true absolute value may be made to prevent overflow. When the delta x kernel dx=(−256), the absolute value |dx|=255. Similar absolute value operation for |dy| may be used.  
         [0055]     Theoretically, the angle “a” may be determined using the arctan function as follows:  
       a   =     {             tan     -   1       ⁡     (            ⅆ   y                 ⅆ   x            )               when   ⁢           ⁢        dx          &gt;   0               π   2               when   ⁢           ⁢        dx          =   0     ,          dy        &gt;   0               0             when   ⁢           ⁢        dx          =   0     ,          dy        =   0                   
 
 However, computing the arctan function may be complicated to realize using hardware. Rather, a look up table may be used to determine the angle of an edge in a field using |dx|  321  and |dy|  323  and a sign value  319 . The possible values of an angle a may be in the range  
       [     0   ,     π   2       }       
 
 radians, which may be divided into ranges such as  
         {       a   &lt;     π   16       ,       π   16     ≤   a   &lt;       3   ⁢   π     16       ,         3   ⁢   π     16     ≤   a   &lt;       5   ⁢   π     16       ,         5   ⁢   π     16     ≤   a   &lt;     π   2       ,     a   =     π   2         }     .       
 
 More ranges may be used, but experimentally these 5 ranges may be sufficient for determining the direction of an edge. The values for the tangent corresponding to each range may be used to determine the range of the angle, and the tangent is simply  
                ⅆ   y                 ⅆ   x            .       
 
 For example, to determine that an angle is in the range  
         a   &lt;     π   16       ,       then   ⁢           ⁢            ⅆ   y                 ⅆ   x              &lt;   0.2     ,       
 
 where  
           tan   ⁡     (     π   16     )       ~   0.2     ,       
 
 and so on. If an edge is in the first range of angle, which may indicate that the edge is at a small angle, and may be treated like a horizontal line. The values for |dx| and |dy| may be directly compared instead of divided them compared to a number to determine the angle. For example, |dx| may be compared to 5|dy|, if 5|dy|&lt;|dx|, that&#39;s equivalent to  
                  ⅆ   y                 ⅆ   x            &lt;   0.2     ,       
 
 which may indicate that the angle “a” is small enough that the direction may be chosen to be north. 
 
         [0056]     The sign value  319  may be determined using: 
 
 s=sign ( dx )× sign ( dy ) 
 
         [0057]     The following table may be utilized to select a direction of an edge based on the angle, the direction of an edge, and the strength of the diagonal:  
                                           Measured   Measured   Measured   Interpolator       strength d   angle a   sign s   Selection                   d &lt; TH   X   X   Int N             X   X   Int N                 d ≧ TH           a   &lt;     π   16             Positive Negative   Int N Int N                               π   16     ≤   a   &lt;       3   ⁢   π     16             Positive Negative   Int NNE Int NNW                                 3   ⁢   π     16     ≤   a   &lt;       5   ⁢   π     16             Positive Negative   Int NE Int NW                                 5   ⁢   π     16     ≤   a   &lt;     π   2             Positive Negative   Int NEE Int NWW                             a   =     π   2             Positive Negative   Int E Int E                    
 
         [0058]     Generally, the angle “a” may provide the angle of the edge relative to horizontal, and the sign s may provide information regarding the quadrant in which the edge may be. For example, the angle “a” for an edge in the NW direction may be the same as that for a NE direction, and based on the sign s a correct determination may be made to distinguish whether the edge is in NW or NE. The determination of the measured strength d is explained hereinafter.  
         [0059]     The resulting angle selection value  317  may result in a selection of one of, for example, 7 filter kernels comprising {NWW, NW, NNW, N, NNE, NE, NEE} each indicating a direction corresponding to the resulting angle. An additional filter kernel HOR may be utilized for horizontal filtering when |dy|&gt;5|dx|. Similar results may be achieved using the N filter in this condition. The comparison block  305  may produce one angle selection per cycle.  
         [0060]     The distance approximation block  307  may determine the strength of the diagonal, which may be determined using the Cartesian distance: 
 
 d={square root}{square root over (dx     2     +dy     2     )} 
 
         [0061]     The ideal distance equation may be complicated to realize with simple hardware because of the squares and square root. Instead, an approximation may be implemented utilizing simpler methods to determine the distance value. U.S. patent application Ser. No. 10/______ (Attorney Docket No. 15632US02) filed Sep. 21, 2004 entitled “Method and System for Detecting Diagonal Strength of an Edge for an Image” discloses a method for determining the distance using an approximation. Accordingly, U.S. patent application Ser. No. 10/______(Attorney Docket No. 15632US02) filed Sep. 21, 2004 is hereby incorporated herein by reference in its entirety.  
         [0062]     Following the distance approximation block  307 , there may be the threshold block  309 . In the threshold block  309 , if 
        (d&lt;TH) then Diagonal Strength=0     (d&gt;=TH) then Diagonal Strength=d 
 
 As a result, depending on the threshold, weak edges in an image may get forced to zero and get treated as if there is no edge at all. The value of the threshold TH may be programmable. If the diagonal strength is 0, the vertical FIR may be utilized by default. 
       
 
         [0065]     The threshold block  309  may be adapted to force the follow-on diagonal filter blend circuit to default to a simple 4-tap vertical filter in images where the diagonal content may not be particularly strong. The output signal diagonal strength  315  may be a value in the range { 0 - 150 }.  
         [0066]      FIG. 4  illustrates a block diagram of an exemplary diagonal filter block  400  that may be integrated in a directional filter, in accordance with an embodiment of the invention. The diagonal filter block  400  may be, for example, the diagonal filter block  211  of the directional filter  200  of  FIG. 2 . The diagonal filter block  400  may utilize the input pixel values in addition to the angle selection signal  215  and diagonal strength signal  217  outputted by the angle detection block  209  to implement a 2-D x-y filter kernel, and blend with a vertical 4-tap FIR. The diagonal filter  400  may be adapted to output a single luma value as the spatial average  411  every clock cycle. The diagonal filter  400  may comprise a 2-D x-y filter  401 , and a blend function  403 .  
         [0067]     The 2-D x-y kernel of diagonal filter  400  may be implemented with, for example, a 5-pixel horizontal filter by 4-line vertical filter. The 4-line vertical filter may be utilized to compute the N (north) FIR filter; the remaining diagonal kernels may utilize a 5-pixel horizontal by 2-line vertical filter. The x-y kernel may output every cycle both a value  405  for N (north) and a diagonal value  407  for one of the other directional filters {NWW, NW, NNW, NNE, NE, NEE} depending upon the selected coefficients for {E− 2  E− 1  E 0  E 1  E 2 } and {F −2  F −1  F 0  F 1  F 2 } based on the direction determined by the angle detection block  209 . The selection of the filters may be determined using the angle selection signal  215  and may, for example, consist of the following choices:  
       P   =     [         ∘       ∘       H       ∘       ∘             E     -   2             E     -   1             E   0           E   1           E   2               F     -   2             F     -   1             F   0           F   1           F   2             ∘       ∘       J       ∘       ∘         ]         
 
         [0068]     The table below illustrates exemplary directional interpolators that may be utilized by the motion adaptive de-interlacer with integrated directional filter  200  based on the direction of the diagonal, in accordance with an embodiment of the invention.  
                                                               Int   N     =     [         0       0         -   0.046875         0       0           0       0       0.546875       0       0           0       0       0.546875       0       0           0       0         -   0.046875         0       0         ]                               Int   E     =     [         0       0       0       0       0           0       0       0.5       0       0           0       0       0.5       0       0           0       0       0       0       0         ]                                           Int   NE     =     [         0       0       0       0       0           0       0       0       0.5       0           0       0.5       0       0       0           0       0       0       0       0         ]                               Int   NW     =     [         0       0       0       0       0           0       0.5       0       0       0           0       0       0       0.5       0           0       0       0       0       0         ]                                           Int   NNE     =     [         0       0       0       0       0           0       0       0.25       0.25       0           0       0.25       0.25       0       0           0       0       0       0       0         ]                               Int   NNW     =     [         0       0       0       0       0           0       0.25       0.25       0       0           0       0       0.25       0.25       0           0       0       0       0       0         ]                                           Int   NEE     =     [         0       0       0       0       0           0       0       0       0.25       0.25           0.25       0.25       0       0       0           0       0       0       0       0         ]                               Int   NWW     =     [         0       0       0       0       0           0.25       0.25       0       0       0           0       0       0       0.25       0.25           0       0       0       0       0         ]                                  
 
         [0069]     The coefficients in the diagonal filter  400  may be implemented with, for example, a simple shift and inversion in order to reduce hardware cost. A partial crossbar may be utilized to repeat pixels at the boundaries of the picture. This may apply to both the vertical N (north) filter and/or the diagonal filter kernel selected for diagonal filtering.  
         [0070]     The blend control parameter DS  409  may be derived from a select north signal and the diagonal strength signal  217  from the angle detection block  209 . The DS signal  409  may be driven to 0 when select north is active, thus forcing the blend to select pure north (N) for the spatial average output  411 . In other conditions, the DS signal  409  may be used to merge midway between north (N) and diagonal filter (diag) depending upon the diagonal strength. The spatial average output  411  may be determined in one of several ways using the blend control parameter along with the diagonal filter and north signals.  
         [0071]     Combining the directional filter  200  adaptively with de-interlacing technology may provide high quality stills with weave function, and produce high quality motion with compass filter. Additionally, the directional filter may have unique angle detection capabilities, and may blend multiple directions for smooth transitions in the source material. Accordingly, a method and system for motion adaptive de-interlacer with an integrated directional filter  200  may provide a better quality video signal and a good complement to de-interlace processing for motion, while utilizing a low cost implementation.  
         [0072]     Accordingly, the present invention may be realized in hardware, software, or a combination thereof. The present invention may be realized in a centralized fashion in at least one computer system, or in a distributed fashion where different elements may be spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein may be suited. A typical combination of hardware and software may be a general-purpose computer system with a computer program that, when being loaded and executed, may control the computer system such that it carries out the methods described herein.  
         [0073]     The present invention may also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.  
         [0074]     While the present invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from its scope. Therefore, it is intended that the present invention not be limited to the particular embodiment disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims.