Abstract:
Aspects of the invention are directed towards an apparatus and method for detecting local video pixels in mixed cadence video. The local video detector comprises a comb detector that is adaptive to the contour of moving objects and local contrast, a motion detector that is robust to false motion due to vertical details, and a fader value estimator that provides a video confidence value to a fader that combines film mode and video mode processing results. The coupling of the local video detector to a film mode detector increases the robustness, accuracy, and efficiency of local film/video mode processing as compared to the prior art.

Description:
RELATED APPLICATIONS 
       [0001]    The present application relates to co-pending U.S. patent application Ser. No. 12/978,154, filed on Dec. 23, 2010, and assigned Attorney Docket No. 10-SIN-058, and U.S. patent application Ser. No. ______, filed concurrently, and assigned Attorney Docket No. 10-SIN-1148. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention generally relates to an apparatus and method for local video detection for mixed cadence sequence, and more particularly to a pixel-based Local Video Detection (LVD) method and system used as part of the Local Film Mode Detector (LFMD), or part of the de-interlacer, or part of the picture quality enhancement in TV and Set-Top-Box products. 
         [0004]    2. Relevant Background. 
         [0005]    Interlaced video was used for cathode ray tube (CRT) displays and is found throughout a number of broadcasting formats. Modern video displays, e.g., liquid crystal displays (LCD) and plasma displays, do not operate in interlaced mode. Therefore, de-interlacing circuitry is needed in set-top-box (STB)/TV to de-interlace video into progressive video that can be played on modern video displays. 
         [0006]    Currently, there are a number of different source formats. Video formats usually display at 50 or 60 frames per second; film formats are commonly captured at 24 or 25 frames per second. Because of the difference is frame rate, telecine is applied to a film source video in order to properly display the film source video on a video display. Reverse telecine may be applied to the telecined film source video to recover a higher quality non-interlaced video to display on a compatible device, such as a modern video display. 
         [0007]    U.S. patent application Ser. No. 12/978,154, “Apparatus and Method for Exotic Cadence Detection,” discusses an apparatus and method for exotic cadence detection. Cadence detection finds the source format of a sequence of video fields or detects the absence of motion between frames (still pictures) and determines whether a video is originally from a video or film source that had interlacing or telecine applied. After that, de-interlacing or inverse telecine can be appropriately applied to the video. 
         [0008]    Cadence detection systems in the related art have limited applicability to broadcasted videos. Broadcasted videos commonly consist of mixed video and film sources, for example, graphics overlay on a video source, or scrolling text on a film source. Applying either de-interlacing or inverse telecine to mixed cadence sources is suboptimal because de-interlacing compromises vertical resolution on the telecined parts and inverse telecine leaves unhandled feathering or combing artifacts on the interlaced parts. 
         [0009]    U.S. Patent Publication No. 2007/0291169, “Region-Based Cadence Detector,” discusses blocked based film/video decision and switching. A frame is segmented into a pre-set number of regions (or clusters of blocks) for cadence and phase tracking. Region-based cadence detection suffers in picture quality and robustness due to artifacts from the switching. 
         [0010]    Accordingly, there is a need in the art for an accurate, robust, and efficient mixed film/video mode cadence detection system. 
       SUMMARY OF THE INVENTION 
       [0011]    Accordingly, the invention is directed to an apparatus and method for local film/video mode processing system that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
         [0012]    An advantage of the invention is to provide an apparatus and method to increase detection accuracy and to prevent feathering/comb artifacts on moving video object areas. 
         [0013]    Another advantage of the invention is to increase the robustness of local film mode detection to improve picture quality of mixed cadence sources. 
         [0014]    Yet another advantage of the invention is to avoid global, block, or region-of-block based decisions on mixed film and video sequences to prevent switch artifacts. 
         [0015]    Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0016]    To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, an apparatus for local video detection is provided. The apparatus includes a contour and contrast adjusted comb detector, a false motion excluded motion detector, and a video fader value estimator. 
         [0017]    In one embodiment of the invention, the contour and contrast adjusted comb detector includes a field to frame coupling unit, a directional support pixel extraction unit, a comb detection unit, a comb post-processing unit, a comb value estimation unit, and a contrast adjustment unit. The false motion excluded motion detector includes an inter-frame motion detection unit, an inter-field motion detection unit, a false motion exclusion unit, and a motion post-processing unit. The video fader value estimator includes a pixel classification unit, a video value calculator, and a video value post-processing unit. 
         [0018]    Another aspect of the invention is directed towards a mixed film/video mode detection apparatus. The mixed film/video mode detection apparatus includes a film mode detector, a local video detector, a film mode processing unit, and a video mode processing unit and a fader. 
         [0019]    Yet another aspect of the invention is directed towards a method for local film/video mode processing. The method includes the steps of detecting a cadence and phase information from an input video, calculating pixel-based video confidence values of the input video based on the cadence and phase information, performing film mode processing on the input video, performing video mode processing on the input video, and fading between the film mode and video mode processing according to the pixel-based video confidence values. 
         [0020]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. In addition, various aspects of the invention may be generated with software or hardware as known in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  illustrates an exemplary diagram of a video processing system that makes use of a local video detector for optimally displaying a mixed cadence video sequence according to an embodiment of the invention; 
           [0022]      FIG. 2  is an exemplary diagram of a local video detector according to an embodiment of the invention; 
           [0023]      FIG. 3  is an exemplary diagram of a contour and contrast adjusted comb detector according to an embodiment of the invention; 
           [0024]      FIG. 4  is a diagram illustrating examples of contour adjusted support pixel extraction; 
           [0025]      FIG. 5  is a diagram illustrating a pixel window used by a comb detection unit, a comb value estimation unit, and a contrast adjustment unit; 
           [0026]      FIG. 6  is a diagram of an example processing window of a comb post-processing unit; 
           [0027]      FIG. 7  is an exemplary diagram of a false motion excluded motion detector according to an embodiment of the invention; 
           [0028]      FIG. 8  is an exemplary diagram of an inter-frame motion detector according to an embodiment of the invention; 
           [0029]      FIG. 9  is an exemplary diagram of an inter-field motion detector according to an embodiment of the invention; 
           [0030]      FIG. 10  is an exemplary diagram of a false motion exclusion unit according to an embodiment of the invention; 
           [0031]      FIG. 11  is a diagram of an example processing window of a motion post-processing unit; 
           [0032]      FIG. 12  is an exemplary diagram of a video fader value estimator according to an embodiment of the invention; 
           [0033]      FIG. 13  is a diagram of an example processing window of a video value post-processing unit. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    Embodiments of the present invention are hereafter described in detail with reference to the accompanying figures. Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the combination and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention. 
         [0035]    The following description with reference to the accompanying figures is provided to assist in a comprehensive understanding of exemplary embodiments of the present invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. 
         [0036]    The terms and words used in the following description and claims are not limited to the bibliographical meanings, but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for purposes of illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
         [0037]    Reference will now be made in detail to an embodiment of the present invention, an example of which is illustrated in the accompanying drawings. 
         [0038]      FIG. 1  illustrates a video processing system that makes use of a local video detector for optimally displaying a mixed cadence video sequence according to an embodiment of the invention. 
         [0039]    The video processing system receives an input video signal  10 , which could contain film or video source, or a mix of both, and outputs the processed video  90  for displaying on modern LCD/LED TVs. The video processing system comprises a film mode detector  20 , a local video detector  50 , a film mode processing unit  30 , also known as “inverse telecine”, a video mode processing unit  40 , also referred to as “de-interlacer”, and a fader unit  60 . 
         [0040]    The film mode detector  20 , such as one disclosed U.S. patent application Ser. No. 12/978,154, detects the cadence and the phase of the film source, if there is any, and provides such cadence and phase information  70  to the local video detector  50  and the film mode processing unit  30 . The local video detector  50  receives the input video signal  10 , the cadence and phase information  70 , and provides a pixel-based video fader value  80  to the fader  60 . The film mode processing unit  30  receives the input video signal  10 , interweaves the coupling of two fields according to the cadence and phase information  70  from the film mode detector  20 , and outputs the merged video frame  35  to the fader  60 . The video mode processing unit  40  receives the input video signal  10 , interpolates it spatially and/or temporally, and outputs an interpolated frame  45  to the fader  60 . Finally, the fader  60  receives the outputs from the film mode processing unit  30  and the video mode processing unit  40 , then fades between them based on the video fader value  80  estimated by the local video detector  50 , and outputs the final video output  90  for display. 
         [0041]    Referring now to  FIG. 2 , there is illustrated in diagram an embodiment of a local video detector  200  according to an embodiment of the invention. 
         [0042]    The local video detector receives the input video signal  10  and the cadence and phase information  70 , and outputs the video fader value  80 . The local video detector apparatus comprises a contour and contrast adjusted comb detector  100 , a false motion excluded motion detector  200 , and a video fader value estimator  300 . 
         [0043]    Referring now to  FIG. 3 , there is illustrated in diagram an embodiment of a contour and contrast adjusted comb detector  100 . 
         [0044]    Contour and contrast adjusted comb detector  100  receives the input video signal  10 , the cadence and phase information  70 , a contour angle α  101  from an external contour detector, and a recursive motion m  102  from an external motion detector, and provides the detected comb signals  180  and a comb value  190 . Contour and contrast adjusted comb detector  100  further comprises a field to frame coupling unit  110 , a directional support pixel extraction unit  120 , a comb detection unit  130 , an optional post-processing unit  140 , a comb value estimation unit  150 , and an optional contrast adjustment unit  160 . 
         [0045]    The field to frame coupling unit  110  receives three fields of the input video signal  10  at times t−1, t, and t+1, and merges two fields belonging to the same frame (either t−1 &amp; t, or t &amp; t+1) according to the cadence and phase information received from an external film mode detector to generate a complete frame. 
         [0046]    The directional support pixel extraction unit  120 , receives a complete frame from the field to frame coupling unit  110  and a contour angle signal  101  estimated on the field at time t from an external contour detector, which could be part of a video mode processing unit in many cases, and provides a seven-pixel window  125 . An example of the external contour detector providing contour angle α  101  is disclosed in U.S. Pat. No. 7,773,151. As combing artifacts appear along the contours of a moving object, a directional support pixel extraction unit could greatly improve the accuracy of a comb detector, as can be appreciated by the skilled addressee. Some examples of the directional support pixel extraction based on the estimated contour angle α  101  are shown in  FIG. 4 . 
         [0047]    The comb detection unit  130  then receives the seven-pixel window  125  as shown in  FIG. 5 , including even-numbered pixels from the current field and odd-numbered pixels from the coupling field. It also receives the recursive motion m  102  from an external motion detector, and provides a moving comb signal  135 . An example of the external motion detector providing recursive motion m  102  is disclosed in U.S. Pat. No. 7,193,655. 
         [0048]    An example method of moving comb detection processed by comb detection unit  130  is illustrated with reference to Equation 1, 2, and 3. 
         [0000]    
       
         
           
             
               
                 
                   
                       
                   
                    
                   
                     
                       vfreq 
                       k 
                     
                     = 
                     
                       { 
                       
                         
                           
                             
                               
                                 
                                   
                                     
                                       freq 
                                       
                                         k 
                                         , 
                                         1 
                                       
                                     
                                     - 
                                     
                                       freq 
                                       
                                         k 
                                         , 
                                         2 
                                       
                                     
                                   
                                 
                                 
                                   
                                     
                                       fielddiff 
                                       k 
                                     
                                     ≥ 
                                     MonotoneTh 
                                   
                                 
                               
                               
                                 
                                   0 
                                 
                                 
                                   otherwise 
                                 
                               
                             
                              
                             
                               
 
                             
                              
                             
                                 
                             
                              
                             k 
                           
                           = 
                           0 
                         
                         , 
                         1 
                         , 
                         2 
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   1 
                    
                   
                     ( 
                     a 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   where 
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     
                       freq 
                       
                         k 
                         , 
                         1 
                       
                     
                     = 
                     
                       
                         ∑ 
                         
                           i 
                           = 
                           0 
                         
                         3 
                       
                        
                       
                         ( 
                         
                           
                             
                               ( 
                               
                                 
                                   y 
                                   
                                     k 
                                     + 
                                     i 
                                   
                                 
                                 - 
                                 
                                   mean 
                                   k 
                                 
                               
                               ) 
                             
                             · 
                             
                               ( 
                               
                                 
                                   y 
                                   
                                     k 
                                     + 
                                     i 
                                     + 
                                     1 
                                   
                                 
                                 - 
                                 
                                   mean 
                                   k 
                                 
                               
                               ) 
                             
                           
                           &lt; 
                           0 
                         
                         ) 
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   1 
                    
                   
                     ( 
                     b 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     
                       freq 
                       
                         k 
                         , 
                         2 
                       
                     
                     = 
                     
                       
                         ∑ 
                         
                           i 
                           = 
                           0 
                         
                         2 
                       
                        
                       
                         ( 
                         
                           
                             
                               ( 
                               
                                 
                                   y 
                                   
                                     k 
                                     + 
                                     i 
                                   
                                 
                                 - 
                                 
                                   mean 
                                   k 
                                 
                               
                               ) 
                             
                             · 
                             
                               ( 
                               
                                 
                                   y 
                                   
                                     k 
                                     + 
                                     i 
                                     + 
                                     2 
                                   
                                 
                                 - 
                                 
                                   mean 
                                   k 
                                 
                               
                               ) 
                             
                           
                           &lt; 
                           0 
                         
                         ) 
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   1 
                    
                   
                     ( 
                     c 
                     ) 
                   
                 
               
             
             
               
                 
                   
                     mean 
                     k 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             ( 
                             
                               
                                 y 
                                 k 
                               
                               + 
                               
                                 y 
                                 
                                   k 
                                   + 
                                   2 
                                 
                               
                               + 
                               
                                 y 
                                 
                                   k 
                                   + 
                                   4 
                                 
                               
                             
                             ) 
                           
                           × 
                           2 
                         
                         + 
                         
                           
                             ( 
                             
                               
                                 y 
                                 
                                   k 
                                   + 
                                   1 
                                 
                               
                               + 
                               
                                 y 
                                 
                                   k 
                                   + 
                                   3 
                                 
                               
                             
                             ) 
                           
                           × 
                           3 
                         
                         + 
                         6 
                       
                       ) 
                     
                     / 
                     12 
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   1 
                    
                   
                     ( 
                     d 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   and 
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     fielddiff 
                     k 
                   
                   = 
                   
                     
                        
                       
                         
                           
                             ( 
                             
                               
                                 y 
                                 k 
                               
                               + 
                               
                                 y 
                                 
                                   k 
                                   + 
                                   2 
                                 
                               
                               + 
                               
                                 y 
                                 
                                   k 
                                   + 
                                   4 
                                 
                               
                             
                             ) 
                           
                           × 
                           2 
                         
                         - 
                         
                           
                             ( 
                             
                               
                                 y 
                                 
                                   k 
                                   + 
                                   1 
                                 
                               
                               + 
                               
                                 y 
                                 
                                   k 
                                   + 
                                   3 
                                 
                               
                             
                             ) 
                           
                           × 
                           3 
                         
                       
                        
                     
                     / 
                     12 
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   1 
                    
                   
                     ( 
                     e 
                     ) 
                   
                 
               
             
           
         
       
     
         [0049]    In Equation 1, comb pixels are detected by evaluating the local vertical frequency. One should note that ‘vertical frequency’ referenced here actually means ‘directional frequency’ as a directional support pixel extraction unit has been used previously. The vertical frequency, represented by vfreq k , is calculated by the vertical frequency of consecutive pixels in a frame (freq k,1 ), subtracted by the vertical frequency of pixels in a field (freq k,2 ). To calculate the vertical frequency freq k,1  and freq k,2 , the number of pixels having different signs when they are subtracted by the local mean value would be summed, as in Equation 1(b) and (c). The local mean value mean k , calculated as in Equation 1(d), represents the mean value of two coupling fields at the center pixel. One of ordinary skill in the art would understand that by subtracting the vertical frequency of pixels in a field from the vertical frequency of pixels in a frame, the comb effect could be detected with less interference from high frequency details of the picture content. Finally, for immunity to noise at monotone area, the vertical frequency vfreq k  is set to zero if the average difference of two fields fielddiff k  calculated in Equation 1(e) is lower than a monotone threshold MonotoneTh, as in Equation 1(a). 
         [0000]    
       
         
           
             
               
                 
                   C 
                   = 
                   
                     { 
                     
                       
                         
                           
                             max 
                              
                             
                               ( 
                               
                                 
                                   vfreq 
                                   0 
                                 
                                 , 
                                 
                                   vfreq 
                                   1 
                                 
                               
                               ) 
                             
                           
                         
                         
                           topfield 
                         
                       
                       
                         
                           
                             max 
                              
                             
                               ( 
                               
                                 
                                   vfreq 
                                   1 
                                 
                                 , 
                                 
                                   vfreq 
                                   2 
                                 
                               
                               ) 
                             
                           
                         
                         
                           bottomfield 
                         
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   2 
                 
               
             
             
               
                 
                   
                     C 
                     ′ 
                   
                   = 
                   
                     { 
                     
                       
                         
                           C 
                         
                         
                           
                             m 
                             ≥ 
                             MotionTh 
                           
                         
                       
                       
                         
                           0 
                         
                         
                           otherwise 
                         
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   3 
                 
               
             
             
               
                 
                   where 
                    
                   
                       
                   
                    
                   m 
                    
                   
                       
                   
                    
                   is 
                    
                   
                       
                   
                    
                   the 
                    
                   
                       
                   
                    
                   recursive 
                    
                   
                       
                   
                    
                   motion 
                 
               
               
                 
                     
                 
               
             
           
         
       
     
         [0050]    Equation 2 is optional to take the comb pixels of the neighboring field into account. Equation 3 is to exclude the stationary ‘comb’ pixels from the final moving comb signal C′ to improve the comb detection accuracy, since stationary ‘comb’ pixels could only be false alarms. 
         [0051]    The optional comb detection post-processing unit  140  is configured to receive a plurality of the detected comb signals C′ from comb detection unit  130 , and provides a post-processed comb signal  180  to the video fader value estimator  300  for more robust comb detection. An example embodiment of the comb detection post-processing is illustrated in Equation 4 (a) to (f) with its local processing window shown in  FIG. 6 . 
         [0000]    
       
         
           
             
               
                 
                   c_mid1 
                   = 
                   
                     
                       
                         ( 
                         
                           
                             
                               ∑ 
                               
                                 i 
                                 = 
                                 
                                   - 
                                   1 
                                 
                               
                               1 
                             
                              
                             
                               l 
                               i 
                             
                           
                           ≥ 
                           DirCombCntThM 
                         
                         ) 
                       
                       &amp; 
                     
                      
                     
                       ( 
                       
                         
                           
                             ∑ 
                             
                               i 
                               = 
                               
                                 - 
                                 1 
                               
                             
                             1 
                           
                            
                           
                             ( 
                             
                               
                                 h 
                                 i 
                               
                               &gt; 
                               0 
                             
                             ) 
                           
                         
                         ≥ 
                         DirCombCntInRowTh 
                       
                       ) 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   4 
                    
                   
                     ( 
                     a 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     c_mid2 
                     = 
                     
                       ( 
                       
                         
                           min 
                            
                           
                             ( 
                             
                               
                                 
                                   
                                     C 
                                     
                                       
                                         i 
                                         - 
                                         1 
                                       
                                       , 
                                       j 
                                     
                                     ′ 
                                   
                                 
                                 
                                   
                                     C 
                                     
                                       i 
                                       , 
                                       j 
                                     
                                     ′ 
                                   
                                 
                                 
                                   
                                     C 
                                     
                                       
                                         i 
                                         + 
                                         1 
                                       
                                       , 
                                       j 
                                     
                                     ′ 
                                   
                                 
                               
                             
                             ) 
                           
                         
                         ≥ 
                         DirCombThH 
                       
                       ) 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   4 
                    
                   
                     ( 
                     b 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     c_mid 
                     = 
                     
                       c_mid1 
                       | 
                       c_mid2 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   4 
                    
                   
                     ( 
                     c 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     c_low 
                     = 
                     
                       ( 
                       
                         
                           
                             ∑ 
                             
                               i 
                               = 
                               
                                 - 
                                 1 
                               
                             
                             1 
                           
                            
                           
                             l 
                             i 
                           
                         
                         ≥ 
                         DirCombCntThL 
                       
                       ) 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   4 
                    
                   
                     ( 
                     d 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   where 
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     
                       h 
                       i 
                     
                     = 
                     
                       
                         
                           ∑ 
                           
                             j 
                             = 
                             
                               - 
                               4 
                             
                           
                           4 
                         
                          
                         
                           
                             ( 
                             
                               
                                 C 
                                 
                                   i 
                                   , 
                                   j 
                                 
                                 ′ 
                               
                               &gt; 
                               DirCombThH 
                             
                             ) 
                           
                            
                           
                               
                           
                            
                           i 
                         
                       
                       ∈ 
                       
                         [ 
                         
                           
                             - 
                             1 
                           
                           , 
                           1 
                         
                         ] 
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   4 
                    
                   
                     ( 
                     e 
                     ) 
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     
                       l 
                       i 
                     
                     = 
                     
                       
                         
                           ∑ 
                           
                             j 
                             = 
                             
                               - 
                               4 
                             
                           
                           4 
                         
                          
                         
                           
                             ( 
                             
                               
                                 C 
                                 
                                   i 
                                   , 
                                   j 
                                 
                                 ′ 
                               
                               &gt; 
                               DirCombThL 
                             
                             ) 
                           
                            
                           
                               
                           
                            
                           i 
                         
                       
                       ∈ 
                       
                         [ 
                         
                           
                             - 
                             1 
                           
                           , 
                           1 
                         
                         ] 
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   4 
                    
                   
                     ( 
                     f 
                     ) 
                   
                 
               
             
           
         
       
     
         [0052]    According to the embodiment, comb detection post-processing  140  selects a bigger window within the locale of a target comb pixel to determine how densely combing pixels are located near the target comb pixel. As a result, comb detection accuracy is further improved as the target comb pixel can be confirmed and higher confidence is obtained. Comb detection post-processing according to the embodiment calculates and outputs c_mid and c_low as the detected comb signals  180 . 
         [0053]    The comb value estimation unit  150  is configured to receive the seven-pixel window  125  as in  FIG. 5 , and provides the calculated comb value  155 . An example comb value estimation method is illustrated in Equation 5 (a) to (c), and Equation 6 is optional to take the comb values of the neighboring field into account. 
         [0000]    
       
         
           
             
               
                 
                   
                     f 
                     k 
                   
                   = 
                   
                     
                       
                         
                           ( 
                           
                             
                               3 
                               × 
                               
                                 a 
                                 
                                   k 
                                   , 
                                   1 
                                 
                               
                             
                             - 
                             
                               4 
                               × 
                               
                                 a 
                                 
                                   k 
                                   , 
                                   2 
                                 
                               
                             
                           
                           ) 
                         
                         / 
                         12 
                       
                        
                       
                           
                       
                        
                       k 
                     
                     ∈ 
                     
                       [ 
                       
                         0 
                         , 
                         2 
                       
                       ] 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   5 
                    
                   
                     ( 
                     a 
                     ) 
                   
                 
               
             
             
               
                 where 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     a 
                     
                       k 
                       , 
                       1 
                     
                   
                   = 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         k 
                       
                       
                         k 
                         + 
                         3 
                       
                     
                      
                     
                        
                       
                         
                           y 
                           i 
                         
                         - 
                         
                           y 
                           
                             i 
                             + 
                             1 
                           
                         
                       
                        
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   5 
                    
                   
                     ( 
                     b 
                     ) 
                   
                 
               
             
             
               
                 
                   
                     a 
                     
                       k 
                       , 
                       2 
                     
                   
                   = 
                   
                     
                       ∑ 
                       
                         i 
                         = 
                         k 
                       
                       
                         k 
                         + 
                         2 
                       
                     
                      
                     
                        
                       
                         
                           y 
                           i 
                         
                         - 
                         
                           y 
                           
                             i 
                             + 
                             2 
                           
                         
                       
                        
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   5 
                    
                   
                     ( 
                     c 
                     ) 
                   
                 
               
             
             
               
                 
                   f 
                   = 
                   
                     max 
                      
                     
                       ( 
                       
                         
                           f 
                           0 
                         
                         , 
                         
                           f 
                           1 
                         
                         , 
                         
                           f 
                           2 
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   6 
                 
               
             
           
         
       
     
         [0054]    Equation 5(a) calculates f k , the detail compensated comb value, where the comb value in frame is α k,1  in Equation 5(b) and the details in field is α k,2  in Equation 5(c). Equation 6 further takes into account the maximum comb value of the two fields at three vertically adjacent center positions as the actual comb value. 
         [0055]    The optional contrast adjustment unit  160  then receives the same seven-pixel window  125  and the calculated comb value  155 , and provides a contrast adjusted comb value  190  for the low contrasted but highly confident comb pixels. Contrast adjustment is needed to enhance certain low contrast pixels for better result. An example contrast adjustment method is illustrated in Equation 7 (a) to (c). 
         [0000]    
       
         
           
             
               
                 
                   F 
                   = 
                   
                     { 
                     
                       
                         
                           
                             max 
                              
                             
                               ( 
                               
                                 
                                   MinContras 
                                    
                                   
                                       
                                   
                                    
                                   t 
                                 
                                 , 
                                 f 
                               
                               ) 
                             
                           
                         
                         
                           
                             
                               max 
                                
                               
                                 ( 
                                 
                                   
                                      
                                     
                                       b 
                                       0 
                                     
                                      
                                   
                                   , 
                                   
                                      
                                     
                                       b 
                                       1 
                                     
                                      
                                   
                                   , 
                                   
                                      
                                     
                                       b 
                                       2 
                                     
                                      
                                   
                                 
                                 ) 
                               
                             
                             ≥ 
                             4 
                           
                         
                       
                       
                         
                           f 
                         
                         
                           otherwise 
                         
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   7 
                    
                   
                     ( 
                     a 
                     ) 
                   
                 
               
             
             
               
                 where 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     b 
                     k 
                   
                   = 
                   
                     
                       
                         ∑ 
                         
                           i 
                           = 
                           k 
                         
                         
                           k 
                           + 
                           3 
                         
                       
                        
                       
                         
                           sign 
                            
                           
                             ( 
                             
                               
                                 y 
                                 i 
                               
                               , 
                               
                                 y 
                                 
                                   i 
                                   + 
                                   1 
                                 
                               
                               , 
                               DTh 
                             
                             ) 
                           
                         
                          
                         
                             
                         
                          
                         k 
                       
                     
                     ∈ 
                     
                       [ 
                       
                         0 
                         , 
                         2 
                       
                       ] 
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   7 
                    
                   
                     ( 
                     b 
                     ) 
                   
                 
               
             
             
               
                 and 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                     sign 
                      
                     
                       ( 
                       
                         
                           y 
                           i 
                         
                         , 
                         
                           y 
                           
                             i 
                             + 
                             1 
                           
                         
                         , 
                         DTh 
                       
                       ) 
                     
                   
                   = 
                   
                     { 
                     
                       
                         
                           1 
                         
                         
                           
                             
                               y 
                               odd 
                             
                             &gt; 
                             
                               
                                 y 
                                 even 
                               
                               + 
                               DTh 
                             
                           
                         
                       
                       
                         
                           
                             - 
                             1 
                           
                         
                         
                           
                             
                               y 
                               even 
                             
                             &gt; 
                             
                               
                                 y 
                                 odd 
                               
                               + 
                               DTh 
                             
                           
                         
                       
                       
                         
                           0 
                         
                         
                           otherwise 
                         
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   7 
                    
                   
                     ( 
                     c 
                     ) 
                   
                 
               
             
           
         
       
     
         [0056]    Equation 7(a) enhances a low-contrasted comb value if the confidence of combing is high. Equation 7(b) and (c) calculates the confidence that a pixel is combing. 
         [0057]    Referring now to  FIG. 7 , there is illustrated in diagram an embodiment of a false motion excluded motion detector  200 . 
         [0058]    The false motion excluded motion detector  200  receives three fields of the input video signal  10  at time t−1, t, and t+1, the cadence and phase information  70 , and provides detected motion signals  285  and a motion value  275 . The false motion excluded motion detector  200  further comprises optional pre-filters  210 ,  220 , and  230  applied on the three input fields respectively, a multiplexer  240 , an inter-frame motion detector  250 , an inter-field motion detector  260 , a false motion exclusion unit  270 , and an optional motion post-processing unit  280 . 
         [0059]    Each of the optional pre-filters  210 ,  220 , and  230  is configured to receive an input video field with its respective top/bottom parity signal, and provide a phase-adjusted output field with noise immunity. An example pre-filter is disclosed in U.S. patent application Ser. No. 12/978,154. 
         [0060]    The multiplexer  240  receives the previous and the next field at t−1 and t+1, and selects one of them as the coupling field  245  to form a complete frame with the current field  235  at time t in accordance with the cadence and phase information  70  provided by an external film mode detector. 
         [0061]    The inter-frame motion detection  250  is configured to receive the previous and the next field at time t−1 and t+1, and provides the inter-frame motion signal  255 . An example embodiment of the inter-frame motion detection  250  is illustrated in  FIG. 8 . 
         [0062]    Similarly, an example embodiment of the inter-field motion detection  260  is illustrated in  FIG. 9 . The inter-field motion detection  260  is configured to receive the two coupling fields  245  and  235  and provide the inter-field motion  265 . 
         [0063]    Based on the detected inter-frame and inter-field motion, the false alarms of the inter-field motion could be excluded by the false motion exclusion unit  270 , with an example embodiment of the implementation shown in  FIG. 10 . In this example embodiment, the false motion exclusion unit  270  compares the inter-frame motion signal  255  with a pre-determined motion threshold  271 , selects the received inter-field motion  265  or ‘0’ according to the result of comparison, and provides the motion value  275 . Other embodiments of the false motion exclusion unit  270  based on the inter-frame and inter-field motion signals could be easily derived by those of ordinary skilled in the art. 
         [0064]    The optional motion post-processing unit  280  is configured to receive a plurality of the motion value  275 , and provides a post-processed motion detection signal  285  to the video fader value estimator  300  for more robust in-frame motion detection. An example motion post-processing method is illustrated in Equation 8 (a) and (b) with its local processing window shown in  FIG. 11 . 
         [0000]    
       
         
           
             
               
                 
                   m_mid 
                   = 
                   
                     
                       
                         ( 
                         
                           
                             
                               ∑ 
                               
                                 i 
                                 = 
                                 
                                   - 
                                   1 
                                 
                               
                               1 
                             
                              
                             
                               m 
                               i 
                             
                           
                           ≥ 
                           IFMotCntTh 
                         
                         ) 
                       
                       &amp; 
                     
                      
                     
                       ( 
                       
                         
                           
                             ∑ 
                             
                               i 
                               = 
                               
                                 - 
                                 1 
                               
                             
                             1 
                           
                            
                           
                             ( 
                             
                               
                                 m 
                                 i 
                               
                               &gt; 
                               0 
                             
                             ) 
                           
                         
                         ≥ 
                         IFMotCntInRowTh 
                       
                       ) 
                     
                   
                 
               
               
                 
                   
                     Eqn 
                      
                     
                         
                     
                      
                     8 
                      
                     
                       ( 
                       a 
                       ) 
                     
                   
                    
                   
                       
                   
                 
               
             
             
               
                 
                   
                       
                   
                    
                   where 
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   
                       
                   
                    
                   
                     
                       m 
                       i 
                     
                     = 
                     
                       
                         
                           ∑ 
                           
                             j 
                             = 
                             
                               - 
                               4 
                             
                           
                           4 
                         
                          
                         
                           
                             ( 
                             
                               
                                 P 
                                 
                                   i 
                                   , 
                                   j 
                                 
                               
                               &gt; 
                               IFMotTh 
                             
                             ) 
                           
                            
                           
                               
                           
                            
                           i 
                         
                       
                       ∈ 
                       
                         [ 
                         
                           
                             - 
                             1 
                           
                           , 
                           1 
                         
                         ] 
                       
                     
                   
                 
               
               
                 
                   Eqn 
                    
                   
                       
                   
                    
                   8 
                    
                   
                     ( 
                     b 
                     ) 
                   
                 
               
             
           
         
       
     
         [0065]    According to the embodiment, motion post-processing uses motions in neighboring pixels to reinforce the detection of a motion pixel. As a result, motion detection accuracy is further improved as the target motion pixel can be confirmed and higher confidence is obtained. Motion post-processing according to the embodiment calculates and outputs m_mid as the detected motion signal  285 . 
         [0066]    Referring now to  FIG. 12 , there is illustrated an embodiment of a video fader value estimator  300 . 
         [0067]    The video fader value estimator  300  receives the detected comb signal  180 , the detected motion signal  285 , the estimated comb value  190 , and the motion value  275 , and provides a video fader value  80 . It further comprises a pixel classification unit  310 , a video value calculator  320 , and a video value post-processing unit  330 . 
         [0068]    The pixel classification unit  310  receives the detected comb signal  180  and the detected motion signal  285 , and provides the classification result  315  of the video pixel to the video value calculator  320 . 
         [0069]    The video value calculator  320  then receives the comb value  190 , the motion value  275 , and the classification result  315 , and provides a better represented video value  325  based on the comb or in-frame motion classification. 
         [0070]    The optional video value post-processing unit  330  receives a plurality of the video values  325 , and provides the video fader value  80  for better coverage of video pixels. An example video value post-processing method is illustrated in Equation 9 with its processing window shown in  FIG. 13 . 
         [0000]        R ′=max i=0   26 ( R   i )  Eqn 9
 
         [0071]    In an alternative embodiment, the present invention can be implemented in software as executed by a central processing unit. Software programming code, which can embody the present invention is typically accessed by a microprocessor from long-term, persistent storage media of some type, such as a flash drive or hard drive. The software programming code may be embodied in any of a variety of known media for use with a data processing system, such as a diskette, hard drive, or CD-ROM. The code may be distributed on such media, or may be distributed from the memory or storage of one computer system over a network of some type to other computer systems for use by such other systems. Alternatively, the programming code may be embodied in the memory of the device and accessed by a microprocessor using an internal bus. The techniques and methods for embodying software programming code in memory, on physical media, and/or distributing software code via networks are well known and will not be further discussed herein. 
         [0072]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.