Multi-least significant bit (LSB) dithering systems and methods
AssigneeApple Inc.
InventorsJongyup Lim, David S Zalatimo, Hyunwoo Nho, Jie Won Ryu, Koorosh Aflatooni, Myungjoon Choi, Wei Xiong
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Abstract
An electronic device may include an electronic display having multiple display pixels that display an image based on dithered image data. The electronic device may also include image processing circuitry that generates the dithered image data based on input image data and a threshold gray level that is greater than one. Generating the dithered image data may include replacing each gray level of the input image data that is less than the threshold gray level with either a zero gray level or the threshold gray level according to a dither pattern.
Claims20
An electronic device comprising:
- an electronic display comprising a plurality of display pixels configured to display an image based on dithered image data;
- and
- image processing circuitry configured to generate the dithered image data based on input image data and a threshold gray level, wherein generating the dithered image data comprises replacing each gray level of the input image data that is less than the threshold gray level with either a zero gray level or the threshold gray level according to a dither pattern, wherein the threshold gray level is greater than one, and wherein the threshold gray level is greater than a range of gray levels that cause display pixel non-uniformity when programmed into the plurality of display pixels.
A method comprising:
- receiving, via a dither block of image processing circuitry, input image data;
- determining whether a set of values of the input image data comprises values less than a threshold value;
- and
- in response to determining that the input image data does comprise the values less the threshold value:
- separating the set of values into a high gray sub-image and a low gray sub-image, wherein the high gray sub-image comprises values greater than the threshold value and the low gray sub-image comprises the values less than the threshold value;
- dividing the values less than the threshold value of the low gray sub-image by the threshold value to generate fractional values;
- dithering the fractional values to generate a single dithered bit for each fractional value;
- and
- generating a processed low gray sub-image based on the single dithered bit for each fractional value;
- and
- combine the processed low gray sub-image with the high gray sub-image or a processed high gray sub-image to generate dithered image data.
Image processing circuitry comprising:
- least-significant-bit dither circuitry configured to dither a high gray sub-image, wherein the high gray sub-image comprises gray level values greater than a threshold gray level and zero gray values in place of gray level values less than the threshold gray level;
- and
- multi-least-significant-bit dither circuitry configured to:
- dither a low gray sub-image, wherein the low gray sub-image comprises the gray level values less than the threshold gray level and the zero gray values in place of the gray level values greater than the threshold gray level;
- and
- combine the dithered high gray sub-image and the dithered low gray sub-image to generate dithered image data that does not include gray levels less than threshold gray level.
Dependencies are inferred from the claim text.