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US 9,177,509 B2Granted
Methods and systems for backlight modulation with scene-cut detection
AssigneeSharp Laboratories of America, Inc.
InventorsLouis J. Kerofsky, Jin Zhou
Life of this patent
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Abstract
Elements of the present invention relate to systems and methods for filtering a display source light illumination level with an adaptive filter based on the presence of a scene cut proximate to the current frame.
Claims7
A method for selectively filtering a source light illumination level signal based on scene cut detection, said method comprising:
- a) detecting the presence or absence of a scene cut in a video sequence;
- b) determining a source light illumination level value for a current frame of said video sequence based on image characteristics of said current frame;
- c) selectively filtering said source light illumination level value with a first filter only if a scene cut was detected proximate to said current frame, said first filter comprising an infinite impulse response filter having a first pole value;
- and
- d) selectively filtering said source light illumination level value with a second filter only if a scene cut was not detected proximate to said current frame, said second filter more aggressive than said first filter and comprising an infinite impulse response filter having a second pole value different than said first pole value;
- (e) said light source illumination level value is not filtered with said first filter if a scene cut is not detected, and said light source illumination level value is not filtered with said second filter if a scene cut is detected;
- where
- (f) said first filter and said second filter are described with the following equation:
- S(i)=α·S(i−1)+(1−α)·BL(i) 0≦α≦1
- where BL(i) is the backlight value based on image content, S(i) is a smoothed backlight value based on a current value and history and a defines the location of the filter pole.
7 more elements
A method for selectively filtering a source light illumination level signal based on scene cut detection, said method comprising:
- a) detecting the presence or absence of a scene cut in a video by measuring a histogram distance between said current frame and a frame proximate to said current frame, using the following equations:
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- wherein i and j are bin indices, N is the number of bins and H1(i) is the value of the i-th bin of the histogram of said frame proximate to said current frame and H2(i) is the i-th bin of the histogram of said current frame, and aij is the correlation weight which is equal to the square of the distance between bin indices;
- b) determining a source light illumination level value for a current frame of said video sequence based on image characteristics of said current frame;
- c) selectively filtering said source light illumination level value with a first filter only if a scene cut was detected proximate to said current frame, said first filter comprising an infinite impulse response filter having a first pole value;
- and
- d) selectively filtering said source light illumination level value with a second filter only if a scene cut was not detected proximate to said current frame, said second filter more aggressive than said first filter and comprising an infinite impulse response filter having a second pole value different than said first pole value;
- (e) said light source illumination level value is not filtered with said first filter if a scene cut is not detected, and said light source illumination level value is not filtered with said second filter if a scene cut is detected;
- where
- (f) said first filter and said second filter are described with the following equation:
- S(i)=α·S(i−1)+(1−α)·BL(i) 0≦α≦1
- where BL(i) is the backlight value based on image content, S(i) is a smoothed backlight value based on a current value and history and a defines the location of the filter pole.
102 more elements
Dependencies are inferred from the claim text.