Backwards Compatible Extended Image Format Encoding
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Solution Overview
Problem
Existing image file formats are limited in terms of dynamic range and color gamut, failing to represent the full range of human-perceivable colors and brightness levels, and are not compatible with new display technologies that can produce wider color gamuts and increased dynamic ranges.
Innovation Solution
The method involves encoding an extended image format that uses channel primaries matching an existing format, allowing additional image information to be extracted through computationally inexpensive operations, with the extended format referencing the same primaries as the base format but extending the range of reference values to include wider gamuts and dynamic ranges, using negative values and over unity values to represent colors and brightness outside the base format's capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If image file formats use extended reference value ranges to represent wider color gamuts and dynamic ranges, then color representation capability is improved, but compatibility with existing devices deteriorates
Solution Approach 1:
The image data is segmented into two parts: a base image encoded in the standard sRGB format that ensures compatibility with existing devices, and an extended image component that contains the additional color information. This segmentation allows existing devices to process the base image while advanced devices can utilize both components for extended color gamut representation.
Solution Approach 2:
The patent extends the reference value range beyond the traditional 0-1 sRGB bounds by introducing negative values and values greater than 1.0, effectively adding dimensional extension to the color space. This allows representation of colors outside the standard gamut while maintaining the original sRGB coordinate system for backward compatibility.
2Adaptability or versatility
If image file formats extend the reference value range beyond standard bounds, then dynamic range is improved, but compatibility with existing devices deteriorates
Solution Approach 1:
The image data is segmented into two parts: a base image encoded in the standard sRGB format that ensures compatibility with existing devices, and an extended image component that contains the additional color information. This segmentation allows existing devices to process the base image while advanced devices can utilize both components for extended color gamut representation.
Solution Approach 2:
The patent changes the parameter range of reference values from the standard 0-1 bounds to an extended range that includes negative values and values greater than 1.0. This parameter extension enables representation of a wider dynamic range and colors outside the standard gamut while maintaining compatibility through the base image component.
3Measurement precision
If image formats use higher precision reference values, then color precision is improved, but data size increases
Solution Approach 1:
The patent applies partial precision extension by providing higher precision reference values only for the extended image component that represents colors outside the standard gamut. The base image maintains standard precision, so existing devices process data at normal size while advanced devices can utilize the additional precision where needed without processing the entire image at extended precision.
Data Source
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AI summary
Techniques are provided for encoding an extended image such that it is backwards compatible with existing decoding devices. An extended image format is defined such that the extended image format is consistent with an existing image format over the full range of the existing image format. Because the extended image format is consistent with the existing image format over the full range of the existing image format, additional image information that is included in an extended image can be extracted from the extended image. A base version of an image (expressed using the existing image format) may be encoded in a payload portion and the extracted additional information may be stored in a metadata portion of a widely supported image file format.