Video signal extracting method and related apparatus

Abstract

A method and for extracting a chrominance signal of a video signal is disclosed. The method includes the following steps: generating a target video signal, a first delayed video signal, a second delayed video signal and a plurality of reference video signals; generating a HCS according to the target video signal; generating a VCS according to the target video signal and the plurality of reference video signals; generating a temporal chrominance signal; generating a SLFD according to the target video signal and the plurality of reference video signals; generating a weighting factor according to the target video signal, the second delayed video signal and the plurality of reference video signals; generating a spatial chrominance signal; and generating the chrominance signal of the video signal by determining the spatial chrominance signal, the temporal chrominance signal and the weighting factor.

1 . A method for extracting a chrominance signal from a video signal, the method comprising the following steps: 
 (a) generating a target video signal, a first delayed video signal, a second delayed video signal and a plurality of reference video signals by delaying the video signal;    (b) generating a horizontal chrominance signal (HCS) according to the target video signal;    (c) generating a vertical chrominance signal (VCS) according to the target video signal and the plurality of reference video signals;    (d) generating a temporal chrominance signal according to the target video signal and the first delayed video signal;    (e) generating a horizontal/vertical fading factor (SLFD) according to the target video signal and the plurality of reference video signals;    (f) generating a weighting factor according to the target video signal, the second delayed video signal and the plurality of reference video signals;    (g) generating a spatial chrominance signal by determining the HCS, the VCS, and the SLFD; and    (h) generating the chrominance signal of the video signal by determining the spatial chrominance signal, the temporal chrominance signal and the weighting factor.    
   
   
       2 . The method of  claim 1 , wherein the step (c) comprises: 
 (c1) generating an UDFD and a plurality of VRVSs according to the target video signal and the plurality of reference video signals; and    (c2) generating the VCS according to the UDFD and the plurality of VRVSs.    
   
   
       3 . The method of  claim 2 , wherein the plurality of reference video signals generated in step (a) comprises a first upward reference video signal (URVS), a second URVS, a first downward reference video signal (DRVS), and a second DRVS, the video signal being the second DRVS, the first DRVS lagged the video signal by a first predetermined numbers of scan lines, the target video signal lagged the first DRVS by the first predetermined numbers of scan lines, the first URVS lagged the target video signal by the first predetermined numbers of scan lines, and the second DRVS lagged the first URVS by the first predetermined numbers of scan lines, and step (c1) comprises the following steps: 
 (h) generating a first upward video signal (UVS) according to the target video signal and the first URVS;    (i) generating a second UVS according to the first URVS and the second URVS;    (j) generating a first downward video signal (DVS) according to the target video signal and the first DRVS;    (k) generating a second DVS according to the first DRVS and the second DRVS;    (l) generating a Diff up  according to the first UVS and the second UVS;    (m) generating a Diff dn  according to the first DVS and the second DVS; and    (n) generating the UDFD according to the Diff up  and the Diff dn .    
   
   
       4 . The method of  claim 3 , wherein the UDFD is equal to Lim(Diff dn −Diff up ), Lim( ) being a Sigmoid-like curve.  
   
   
       5 . The method of  claim 1 , wherein the first delayed video signal is generated from delaying the target video signal by a second predetermined numbers of video frames, the second delayed video signal is generating from delaying the first delayed video signal by the second predetermined numbers of video frames, and step (f) comprises the following steps: 
 generating a horizontal chrominance interfering factor (Dhc) and a horizontal luminance interfering factor (Dhy) according to the target signal and the reference signals;    generating a horizontal difference (Hdiff) according to the Dhc and the Dhy;    generating a vertical chrominance interfering factor (Dvc) and a vertical luminance interfering factor (Dvy) according to the target signal and the reference signals;    generating a vertical difference (Vdiff) according to the Dvc and the Dvy; and    generating the weighting factor according to the Hdiff, the Vdiff, the target signal, and the second delayed video signal.    
   
   
       6 . The method of  claim 1 , wherein step (e) comprises the following steps: 
 generating a horizontal chrominance interfering factor (Dhc) and a horizontal luminance interfering factor (Dhy) according to the target signal and the reference signals;    generating a horizontal difference (Hdiff) according to the Dhc and the Dhy;    generating a vertical chrominance interfering factor (Dvc) and a vertical luminance interfering factor (Dvy) according to the target signal and the reference signals;    generating a vertical difference (Vdiff) according to the Dvc and the Dvy; and    generating the SLFD according to the H diff  and the V diff , wherein the SLFD is equal to Lim(k*V diff −H diff ), Lim( ) being a Sigmoid-like curve, and k a weighting constant.    
   
   
       7 . A method for extracting a chrominance signal from a video signal, the method comprising the following steps: 
 (a) generating a target video signal, a first delayed video signal, a second delayed video signal and a plurality of reference video signals by delaying the video signal;    (b) generating a horizontal chrominance signal (HCS) according to the target video signal;    (c) generating a vertical chrominance signal (VCS) according to the target video signal and the plurality of reference video signals;    (d) generating a horizontal/vertical fading factor (SLFD) according to the target video signal and the plurality of reference video signals; and    (e) generating the chrominance signal by determining the HCS, the VCS, and the SLFD.    
   
   
       8 . The method of  claim 7 , wherein step (d) comprises the following steps: 
 generating a horizontal chrominance interfering factor (Dhc) and a horizontal luminance interfering factor (Dhy) according to the target signal and the reference signals;    generating a horizontal difference (Hdiff) according to the Dhc and the Dhy;    generating a vertical chrominance interfering factor (Dvc) and a vertical luminance interfering factor (Dvy) according to the target signal and the reference signals;    generating a vertical difference (Vdiff) according to the Dvc and the Dvy; and    generating the SLFD according to the H diff  and the V diff , wherein the SLFD is equal to Lim(k*V diff −H diff ), Lim( ) being a Sigmoid-like curve, and k a weighting constant.    
   
   
       9 . The method of  claim 7 , wherein the plurality of reference video signals generated in step (a) comprises a first upward reference video signal (URVS), a second URVS, a first downward reference video signal (DRVS), and a second DRVS, the video signal being the second DRVS, the first DRVS lagged the video signal by a first predetermined numbers of scan lines, the target video signal lagged the first DRVS by the first predetermined numbers of scan lines, the first URVS lagged the target video signal by the first predetermined numbers of scan lines, and the second DRVS lagged the first URVS by the first predetermined numbers of scan lines.  
   
   
       10 . A video signal processor for extracting a chrominance signal from a video signal comprising: 
 a delay unit for generating a target video signal, a first delayed video signal, a second delayed video signal, and a plurality of reference video signals by delaying the video signal;    a horizontal chrominance signal generator for generating a horizontal chrominance signal (HCS) according to the target video signal;    a vertical chrominance signal generator for generating a vertical chrominance signal (VCS) according to the target video signal and the plurality of reference video signal;    a temporal chrominance signal generator for generating a temporal chrominance signal according to the target video signal and the first delayed video signal;    a horizontal/vertical fading factor generator for generating a horizontal/vertical fading factor (SLFD) according to the target video signal and the plurality of reference video signals;    a weighting factor generator for generating a weighting factor according to the target video signal, the second delayed video signal and the plurality of reference video signals;    a spatial chrominance signal generator for generating a spatial chrominance signal according to the HCS, the VCS, and the SLFD; and    a chrominance signal generator for generating the chrominance signal of the video signal according to the temporal chrominance signal, the spatial chrominance signal and the weighting factor.    
   
   
       11 . The video signal processor of  claim 10 , wherein the vertical chrominance signal generator comprises: 
 a intermediate video signal generator (IVS generator) for generating an upward chrominance signal, a downward chrominance signal and a plurality of intermediate video signals according to the target video signal and the references,    an UDFD generator, for generating a UDFD according to the plurality of intermediate video signals; and    a VRVS generator, for generating the VCS according to the upward chrominance signal, the downward chrominance signal and the UDFD.    
   
   
       12 . The video signal processor of  claim 11 , wherein the plurality of intermediate video signals comprises a first upward video signal (UVS), a second UVS, a first downward video signal (DVS) and a second DVS, the IVS generator comprising: 
 a first UVS generator for generating the first UVS according to the target video signal and the first URVS;    a second UVS generator for generating the second UVS according to the first URVS and the second URVS;    a first DVS generator for generating the first DVS according to the target video signal and the first DRVS;    a second DVS generator for generating the second DVS according to the first DRVS and the second DRVS;    an upward chrominance signal generator for generating the upward chrominance signal according to the target video signal and the first URVS; and    a downward chrominance signal generator for generating the downward chrominance signal according to the target video signal and the first DRVS; and    the UDFD generator comprising:    a Diff up  generator for generating a upward difference (Diff up ) according to the first UVS and the second UVS;    a Diff dn  generator for generating a downward difference (Diff dn ) according to the first DVS and the second DVS; and    a UDDM generator for generating the UDFD according to the Diff up  and the Diff dn .    
   
   
       13 . The video signal processor of  claim 12 , wherein the UDFD is equal to Lim(Diff dn −Diff up ), Lim( ) being a Sigmoid-like curve.  
   
   
       14 . The video signal processor of  claim 12 , wherein the first UVS comprises a Y cu , a U cu  heading to a first direction and a V cu  heading to a second direction, which is not parallel to the first direction, and the second UVS comprises a Y u , a U u  heading to the first direction and a V u  heading to the second direction, wherein Diff up  is equal to ABS(Y u −Y cu )+SQRT((U u −U cu ) 2 +(V u −V cu ) 2 ), ABS(x) being an absolute value of x, and SQRT(y) being a square root of y.  
   
   
       15 . The video signal processor of  claim 12 , wherein the first DVS comprises a Y cd , a U cd  heading to a first direction and a V cd  heading to a second direction, which is not parallel to the first direction, and the second DVS comprises a Y d , a U d  heading to the first direction and a V d  heading to the second direction, wherein Diff dn  is equal to ABS(Y d −Y cd )+SQRT((U d −U cd ) 2 +(V d −V cd ) 2 ), ABS(x) being an absolute value of x, and SQRT(y) being a square root of y.  
   
   
       16 . The video signal processor of  claim 10 , wherein the plurality of reference video signals comprises a first upward reference video signal (URVS), a second URVS, a first downward reference video signal (DRVS), and a second DRVS, the video signal being the second DRVS, the delay unit comprising: 
 a first delay device for generating the first DRVS by delaying the video signal by a first predetermined numbers of scan lines;    a second delay device for generating the target video signal by delaying the first DRVS by the first predetermined numbers of scan lines;    a third delay device for generating the first URVS by delaying the target video signal by the first predetermined numbers of scan lines;    a fourth delay device for generating the second DRVS by delaying the first URVS by the first predetermined numbers of scan lines;    a first frame delay device for generating the first delayed video signal by delaying the target video signal by a second predetermined numbers of video frames; and    a second frame delay device for generating the second delayed video signal by delaying the first delayed video signal by the second predetermined numbers of video frames.    
   
   
       17 . The video signal processor of  claim 16 , wherein the horizontal/vertical fading factor generator comprises: 
 a horizontal interference calculator for calculating a horizontal chrominance interfering factor (D hc ) and a horizontal luminance interfering factor (D hy ) according to the target video signal and the plurality of reference video signals;    a vertical interference calculator for calculating a vertical chrominance interfering factor (D vc ) and a vertical luminance interfering factor (D vy ) according to the target video signal and the plurality of reference video signals;    a horizontal difference generator for generating a horizontal difference (H diff ) according to the D hc  and the D hy ;    a vertical difference generator for generating a vertical difference (V diff ) according to the D vc  and the D vy ; and    a SLFD module for generating the SLFD according to the H diff  and the V diff ;    wherein the SLFD is equal to Lim(k*V diff −H diff ), Lim( ) being a Sigmoid-like curve, and k a weighing factor.    
   
   
       18 . The video signal processor of  claim 17 , wherein the horizontal interference calculator comprises: 
 a first adder for generating a first vertical luminance interfering signal by adding the URVS to the target video signal;    a first 1-D comb filter for transferring the vertical luminance interfering signal into a first vertical luminance filtered signal;    a second adder for generating a second vertical luminance interfering signal by adding the DRVS to the target video signal;    a second 1-D comb filter for transferring the second vertical luminance interfering signal into a second vertical luminance filtered signal;    a third adder for generating a vertical luminance signal by adding the first vertical luminance filtered signal to the second vertical luminance filtered signal;    a first absoluter for transferring the vertical luminance signal into a positive vertical luminance signal;    a first low pass filter for transferring the positive vertical luminance signal into the D hy ;    a sample point delay circuit for generating a rightward reference video signal by delaying the target video signal by two sampling points;    a subtractor for generating a horizontal chrominance interfering signal by subtracting the rightward reference video signal from the target video signal;    a 2-D comb filter for transferring the horizontal chrominance interfering signal into a horizontal chrominance filtered signal;    a second absoluter for transferring the horizontal chrominance filtered signal into a positive horizontal chrominance signal; and    a second low pass filter for transferring the positive horizontal chrominance signal into the D hc .    
   
   
       19 . The video signal processor of  claim 17 , wherein the vertical interference calculator comprises: 
 a first subtractor for generating a first vertical chrominance interfering signal by subtracting the URVS from the target video signal;    a second subtractor for generating a second vertical chrominance interfering signal by subtracting the DRVS from the target video signal;    a third subtractor for generating a vertical chrominance signal by subtracting the first vertical chrominance interfering signal from the second vertical chrominance interfering signal;    a third absoluter for transferring the vertical chrominance signal into a positive vertical chrominance signal;    a third low pass filter for transferring the positive vertical chrominance signal into the D vc ;    a fourth adder for generating a first luminance interfering signal by adding a first rightward reference video signal to the URVS, the first rightward reference video signal lagging the URVS by twice an inverse of the sampling frequency;    a fifth adder for generating a second horizontal luminance interfering signal by adding a second rightward reference video signal to the downward reference video signal, the second rightward reference video signal leading the DRVS by twice an inverse of the sampling frequency;    a fourth subtractor for generating a horizontal luminance signal by subtracting the first horizontal luminance interfering signal from the second horizontal luminance interfering signal;    a fourth absoluter for transferring the horizontal luminance signal into a positive horizontal luminance signal; and    a fourth low pass filter for transferring the positive horizontal luminance signal into the D vy .    
   
   
       20 . The video signal processor of  claim 17 , wherein the weighting factor generator comprises: 
 a second operator for processing the target video signal and the second delayed video signal to generate a temporal chrominance difference (T diff ) between the target video signal and the second delayed video signal;    a selecting module for selecting one of the H diff  and the V diff  to generate a SP diff ; and    a third operator for generating the weighting factor according to the T diff  and the SP diff .    
   
   
       21 . The video signal processor of  claim 16 , wherein the temporal chrominance signal generator comprises: 
 a first operator for processing the target video signal and the first delayed video signal to generate the temporal chrominance signal.    
   
   
       22 . A video signal processor for extracting a chrominance signal from a video signal comprising: 
 a delay unit for generating a target video signal and a plurality of reference video signals by delaying the video signal;    a horizontal chrominance signal generator for generating a horizontal chrominance signal (HCS) according to the target video signal;    a vertical chrominance signal generator for generating a vertical chrominance signal (VCS) according to the target video signal and the plurality of reference video signal;    a horizontal/vertical fading factor generator for generating a horizontal/vertical fading factor (SLFD) according to the target video signal and the plurality of reference video signals; and    a chrominance signal generator for generating a spatial chrominance signal according to the HCS, the VCS, and the SLFD.    
   
   
       23 . The video signal processor of  claim 22 , wherein the VCS generator comprises: 
 a intermediate video signal generator (IVS generator) for generating an upward chrominance signal, a downward chrominance signal and a plurality of intermediate video signals according to the target video signal and the references,    a UDFD generator, for generating a UDFD according to the plurality of intermediate video signals; and    a VRVS generator, for generating the VCS according to the upward chrominance signal, the downward chrominance signal and the UDFD.    
   
   
       24 . The video signal processor of  claim 23 , wherein the plurality of intermediate video signals comprising a first upward video signal (UVS), a second UVS, a first downward video signal (DVS) and a second DVS, the IVS generator comprising: 
 a first UVS generator for generating the first UVS according to the target video signal and the first URVS;    a second UVS generator for generating the second UVS according to the first URVS and the second URVS;    a first DVS generator for generating the first DVS according to the target video signal and the first DRVS;    a second DVS generator for generating the second DVS according to the first DRVS and the second DRVS;    an upward chrominance signal generator for generating the upward chrominance signal according to the target video signal and the first URVS; and    a downward chrominance signal generator for generating the downward chrominance signal according to the target video signal and the first DRVS; and    the UDFD generator comprising:    a Diff up  generator for generating a upward difference (Diff up ) according to the first UVS and the second UVS;    a Diff dn  generator for generating a downward difference (Diff dn ) according to the first DVS and the second DVS; and    a UDDM generator for generating the UDFD according to the Diff up  and the Diff dn .    
   
   
       25 . The video signal processor of  claim 23 , wherein the UDFD is equal to Lim(Diff dn −Diff up ), Lim( ) being a Sigmoid-like curve.  
   
   
       26 . The video signal processor of  claim 23 , wherein the first UVS comprises a Y cu , a U cu  heading to a first direction and a V cu  heading to a second direction, which is not parallel to the first direction, and the second UVS comprises a Y u , a U u  heading to the first direction and a V u  heading to the second direction, wherein Diff up  is equal to ABS(Y u −Y cu )+SQRT((U u −U cu ) 2 +(V u −V cu ) 2 ), ABS(x) being an absolute value of x, and SQRT(y) being a square root of y.  
   
   
       27 . The video signal processor of  claim 23 , wherein the first DVS comprises a Y cd , a U cd  heading to a first direction and a V cd  heading to a second direction, which is not parallel to the first direction, and the second DVS comprises a Y d , a U d  heading to the first direction and a V d  heading to the second direction, wherein Diff dn  is equal to ABS(Y d −Y cd )+SQRT((U d −U cd ) 2 +(V d −V cd ) 2 ), ABS(x) being an absolute value of x, and SQRT(y) being a square root of y.  
   
   
       28 . The video signal processor of  claim 22 , wherein the plurality of reference video signals comprises a first upward reference video signal (URVS), a second URVS, a first downward reference video signal (DRVS), and a second DRVS, the video signal being the second DRVS, the delay unit comprising: 
 a first delay device for generating the first DRVS by delaying the video signal by a first predetermined numbers of scan lines;    a second delay device for generating the target video signal by delaying the first DRVS by the first predetermined numbers of scan lines;    a third delay device for generating the first URVS by delaying the target video signal by the first predetermined numbers of scan lines; and    a fourth delay device for generating the second DRVS by delaying the first URVS by the first predetermined numbers of scan lines;    a first frame delay device for generating the first delayed video signal by delaying the target video signal by a second predetermined numbers of video frames; and    a second frame delay device for generating the second delayed video signal by delaying the first delayed video signal by the second predetermined numbers of video frames.    
   
   
       29 . The video signal processor of  claim 28 , wherein the horizontal/vertical fading factor generator comprises: 
 a horizontal interference calculator for calculating a horizontal chrominance interfering factor (D hc ) and a horizontal luminance interfering factor (D hy ) according to the target video signal and the plurality of reference video signals;    a vertical interference calculator for calculating a vertical chrominance interfering factor (D vc ) and a vertical luminance interfering factor (D hy ) according to the target video signal and the plurality of reference video signals;    a horizontal difference generator for generating a horizontal difference (H diff ) according to the D hc  and the D hy ;    an vertical difference generator for generating a vertical difference (V diff ) according to the D vc  and the D vy ; and    a SLFD module for generating the SLFD according to the H diff  and the V diff ;    wherein the SLFD is equal to Lim(k*V diff −H diff ), Lim( ) being a Sigmoid-like curve, and k a weighing factor.    
   
   
       30 . The video signal processor of  claim 29 , wherein the horizontal interference calculator comprises: 
 a first adder for generating a first vertical luminance interfering signal by adding the URVS to the target video signal;    a first 1-D comb filter for transferring the vertical luminance interfering signal into a first vertical luminance filtered signal;    a second adder for generating a second vertical luminance interfering signal by adding the DRVS to the target video signal;    a second 1-D comb filter for transferring the second vertical luminance interfering signal into a second vertical luminance filtered signal;    a third adder for generating a vertical luminance signal by adding the first vertical luminance filtered signal to the second vertical luminance filtered signal;    a first absoluter for transferring the vertical luminance signal into a positive vertical luminance signal;    a first low pass filter for transferring the positive vertical luminance signal into the D hy ;    a sample point delay circuit for generating a rightward reference video signal by delaying the target video signal by two sampling points;    a subtractor for generating a horizontal chrominance interfering signal by subtracting the rightward reference video signal from the target video signal;    a 2-D comb filter for transferring the horizontal chrominance interfering signal into a horizontal chrominance filtered signal;    a second absoluter for transferring the horizontal chrominance filtered signal into a positive horizontal chrominance signal; and    a second low pass filter for transferring the positive horizontal chrominance signal into the D hc .    
   
   
       31 . The video signal processor of  claim 29 , wherein the vertical interference calculator comprises: 
 a first subtractor for generating a first vertical chrominance interfering signal by subtracting the URVS from the target video signal;    a second subtractor for generating a second vertical chrominance interfering signal by subtracting the DRVS from the target video signal;    a third subtractor for generating a vertical chrominance signal by subtracting the first vertical chrominance interfering signal from the second vertical chrominance interfering signal;    a third absoluter for transferring the vertical chrominance signal into a positive vertical chrominance signal;    a third low pass filter for transferring the positive vertical chrominance signal into the D vc ;    a fourth adder for generating a first luminance interfering signal by adding a first rightward reference video signal to the URVS, the first rightward reference video signal lagging the URVS by twice an inverse of the sampling frequency;    a fifth adder for generating a second horizontal luminance interfering signal by adding a second rightward reference video signal to the downward reference video signal, the second rightward reference video signal leading the DRVS by twice an inverse of the sampling frequency;    a fourth subtractor for generating a horizontal luminance signal by subtracting the first horizontal luminance interfering signal from the second horizontal luminance interfering signal;    a fourth absoluter for transferring the horizontal luminance signal into a positive horizontal luminance signal; and    a fourth low pass filter for transferring the positive horizontal luminance signal into the D vy .