Google patents image compression using extended palettes
Google describes a method for decoding images by using a list of specific colors, or a palette, to reconstruct picture blocks. When a pixel's color is not in that list, the system estimates its value by blending it with nearby known colors. This process helps create a more accurate image from compressed data.
In the filing’s own words
A current block of an image is reconstructed using extended palette coding. A residual block corresponding to the current block is decoded from an encoded bitstream. For pixels of the current block, a color index is identified, and a determination is made whether the color index identifies a defined pixel value in a palette that includes multiple defined pixel values and an indicator of an undefined pixel value. The prediction block is generated by, for respective pixels, populating a pixel position of the pixel within the prediction block with the defined pixel value when the color index indicates the defined pixel value, and otherwise populating the pixel position with a pixel value interpolated using a defined pixel value of the multiple defined pixel values and another pixel value within the prediction block. The current block is reconstructed using the residual block and the prediction block.
What exactly they claim (claim 1)
1. A method for reconstructing a current block of an image, comprising: decoding, from an encoded bitstream, a residual block corresponding to the current block; for each pixel of multiple pixels of a prediction block for the current block: identifying a color index for the pixel; and determining whether the color index identifies a defined pixel value in a palette, wherein the palette includes multiple defined pixel values and an indicator of an undefined pixel value; generating a prediction block by, for each pixel of the multiple pixels: populating a pixel position of the pixel within the prediction block with the defined pixel value when the color index indicates the defined pixel value, and otherwise populating the pixel position with a pixel value interpolated using a defined pixel value of the multiple defined pixel values and another pixel value within the prediction block; and reconstructing the current block using the residual block and the prediction block.
Facts
- Company
- Google (GOOGLE LLC)
- Official title
- EXTENDED PALETTE CODING
- Publication number
- US20260323057A1
- Application number
- 19485417
- Filed
- May 20, 2024
- Published
- Oct 15, 2026
- Inventors
- 3
- Claims
- 22
Classified under
H04N 19/44 Electricity & electronicsH04N 19/176 Electricity & electronicsH04N 19/182 Electricity & electronicsH04N 19/186 Electricity & electronicsH04N 19/70 Electricity & electronicsMore from Google in AI & software
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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.