Methods and systems for area adaptive backlight management
First Claim
Patent Images
1. A method for modifying display backlight target values, said method comprising:
- a) receiving an initial backlight target value image, BL0;
b) establishing an initial LED driving value (led0) image comprising on-grid LED points and off-grid virtual points located between said on-grid LED points of said initial backlight target value image by convolving said BL0 image with an LED mask comprising said virtual point off-grid locations;
c) determining an approximated backlight image (bl1) by convolving said led0 image with a truncated point spread function (psf2) kernel;
d) determining a backlight deficiency image (bl2), based on a difference between said BL0 image and said bl1 image;
e) creating a compensated backlight image (bl3) by convolving said bl2image with a diffusion kernel; and
f) determining a modified LED target value image (BL1) by adding said bl3image to said BL0 image.
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Abstract
Elements of the present invention relate to systems and methods for generating, modifying and applying backlight array driving values.
26 Citations
20 Claims
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1. A method for modifying display backlight target values, said method comprising:
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a) receiving an initial backlight target value image, BL0; b) establishing an initial LED driving value (led0) image comprising on-grid LED points and off-grid virtual points located between said on-grid LED points of said initial backlight target value image by convolving said BL0 image with an LED mask comprising said virtual point off-grid locations; c) determining an approximated backlight image (bl1) by convolving said led0 image with a truncated point spread function (psf2) kernel; d) determining a backlight deficiency image (bl2), based on a difference between said BL0 image and said bl1 image; e) creating a compensated backlight image (bl3) by convolving said bl2image with a diffusion kernel; and f) determining a modified LED target value image (BL1) by adding said bl3image to said BL0 image. - View Dependent Claims (2, 3)
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4. A method for generating a modified LED target value image for a display backlight array, said method comprising:
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a) receiving a target backlight image (BL1); b) combining said BL1 image with an LED mask, comprising off-grid virtual points interspersed between actual image points, to create an led1 image; c) convolving said led1 image with a point spread function (PSF) to create an approximated backlight image, BL 2; d) determining a difference image representing the difference between said target backlight image, BL1, and said approximated backlight image, BL2; e) determining a scaling factor, β
;f) scaling said difference image with said scaling factor thereby creating a scaled difference image; g) adding said led1 image to said scaled difference image to create a revised LED image, ledi+1; and h) setting values in said revised, ledi+1, image to zero when said values are less than zero. - View Dependent Claims (5, 6)
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7. A method for post-processing backlight image driving values for a display backlight array, said method comprising:
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a) receiving a backlight image comprising backlight image driving values in display hardware; b) finding a backlight image driving value, ledi,j, in said backlight image, that is greater than one; c) calculating coefficients for neighbors of said driving value, ledi,j, with said display hardware using the following equations;
Ci−
1,j=max(0,1−
ledi−
1,j)
Ci+1,j=max(0,1−
ledi+1,j)
Ci,j−
1=max(0,1−
ledi,j−
1)
Ci,j+1=max(0,1−
ledi,j+1)d) updating said backlight image driving values and the values of said neighbors, with said processor using the following equations;
ledi,j=1
ledi−
1,j=ledi−
1,j+k(ledi,j−
1)*Ci−
1,j/Σ
(Ci,j)
ledi+1,j=ledi+1,j+k(ledi,j−
1)*Ci−
1,j/Σ
(Ci,j)
ledi,j−
1=ledi,j−
1+k(ledi,j−
1)*Ci−
1,j/Σ
(Ci,j)
ledi,j+1=ledi,j+1+k(ledi,j−
1)*Ci−
1,j/Σ
(Ci,j);wherein k is a constant used to compensate for a reduced contribution from neighboring LEDs.
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8. A method for generating a backlight image for a display backlight array, said method comprising:
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a) receiving an input image comprising an array of pixel values representing an image at an LCD image pixel resolution; b) low-pass filtering said input image with a point spread function of a display diffusion screen to create a low-pass-filtered (LPF) image; c) subsampling said LPF image to an intermediate resolution thereby creating a LED 1p image; d) low-pass filtering said input image with a kernel that is smaller than the kernel used to create said LPF image thereby creating a second low-pass-filtered (SLPF) image; e) dividing said SLPF image into blocks wherein each block corresponds to a display backlight LED element in said display backlight array with some overlap between array elements; f) determining a maximum value in each of said blocks of said SLPF image thereby creating LEDmax values in an LEDmax image; and g) creating an LED1 image comprising values based on one of a corresponding LEDmax image value and a corresponding LED 1p image value. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method for generating a backlight image for a display backlight array, said method comprising:
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a) receiving an input image comprising an array of pixel values representing an image at an LCD image pixel resolution; b) low-pass filtering said input image with a point spread function of a display diffusion screen to create a low-pass-filtered (LPF) image; c) subsampling said LPF image to an intermediate resolution thereby creating a LED 1p image; d) low-pass filtering said input image with a kernel that is smaller than the kernel used to create said LPF image thereby creating a second low-pass-filtered (SLPF) image; e) dividing said SLPF image into blocks wherein each block corresponds to a display backlight LED element in said display backlight array with some overlap between array elements; f) determining a maximum value in each of said blocks of said SLPF image thereby creating LEDmax values in an LEDmax image; g) creating an LED1image comprising values based on one of a corresponding LEDmax image value and a corresponding LED 1p image value; h) establishing a target LED driving value (led0) image comprising virtual off-grid points located between on-grid LED elements of said input image by convolving a target backlight image, BL0, with an LED mask comprising said virtual point locations; i) determining an approximated backlight image (bl1) by convolving said led0 image with a truncated point spread function (psf2) kernel; j) determining a backlight deficiency image (bl2), which represents a difference between said BL0 image and said bl1 image; k) creating a compensated LED driving value image (bl3) by convolving said bl2 image with a diffusion kernel; and l) determining a modified LED target value image (BL1) by adding said BL0 image to said bl3image. - View Dependent Claims (17, 18, 19, 20)
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Specification