System and method for a multi-primary wide gamut color system
Inventors
Mandle, Gary B. • DeFilippis, James M.
Assignees
Publication Number
US-11436967-B2
Publication Date
2022-09-06
Expiration Date
2039-10-21
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Abstract
Systems and methods for a multi-primary color system for display. A multi-primary color system increases the number of primary colors available in a color system and color system equipment. Increasing the number of primary colors reduces metameric errors from viewer to viewer. One embodiment of the multi-primary color system includes Red, Green, Blue, Cyan, Yellow, and Magenta primaries. The systems of the present invention maintain compatibility with existing color systems and equipment and provide systems for backwards compatibility with older color systems.
Core Innovation
The present invention discloses a multi-primary color system for image display and processing, expanding conventional color systems by introducing additional primary colors beyond the standard red, green, and blue. The multi-primary color system supports at least four primaries with preferred embodiments detailing six primaries: red, green, blue, cyan, magenta, and yellow. This expanded color primary approach is achieved through methods of encoding, transporting, and decoding image data that are compatible with existing and legacy display standards, enabling use without requiring entirely new infrastructure.
A fundamental aspect of the invention is the use of an encoding and decoding system that converts image data into a format using two colorimetric coordinates (x and y) and a luminance or luma (Y or Y′), supporting accurate color reproduction for displays utilizing multiple primary colors. The system applies a gamma or ½ gamma function only to the luminance component, leaving the colorimetric coordinates unmodified, thereby preserving the chromaticity information through processing and transport. Furthermore, the encoder may include a watermark engine to encode digital watermarks, and the decoder may be equipped with watermark detection and subtraction engines, supporting secure handling of image data.
The invention addresses problems in the prior art relating to limited color gamut, metameric errors between viewers, and incompatibility of multi-primary workflows with existing infrastructure. Through the described systems and methods, the invention enables display devices to support and utilize six primaries, reduces color perception inconsistencies among viewers, and maintains backward compatibility with systems designed for RGB or other color standards, allowing wider color representation with minimal system overhaul.
Claims Coverage
The patent claims center around three principal inventive features describing the encoding and decoding of image signals using multi-primary color systems with colorimetric coordinate encoding, selective gamma application, and watermark features.
Encoding and decoding image signals with xyY colorimetric data
A system that includes both an encoder and a decoder, each with specific hardware components (processors, memories, inputs, outputs), wherein the encoder converts image data into xyY format consisting of two colorimetric coordinates (x and y) and a luma (Y′). The encoder applies a gamma function to the luminance (Y), creating the luma (Y′), but does not apply it to the colorimetric coordinates. The xyY-formatted data is then transmitted to the decoder, which processes it to produce output for further use.
Selective watermark integration and management in the image signal pipeline
Integration of a watermark engine within the encoder, which is operable to modify input image data to include a digital watermark. Correspondingly, the decoder incorporates a watermark detection engine to detect digital watermarks and a watermark subtraction engine to remove them. This pipeline enables secure and traceable handling of image content.
1/2 gamma function application to luminance in multi-primary color encoding and decoding
A system wherein the encoder applies a ½ gamma function specifically to the luminance (Y) component of input image data when producing xyY output, without affecting the colorimetric coordinates (x and y). The decoder includes a ½ gamma to linear converter to remove the ½ gamma function during processing, allowing the accurate restoration of original luminance values.
The inventive features define methods and systems for encoding and decoding multi-primary color image signals by employing colorimetric coordinate-based data, selective application of gamma functions, and integrated watermark control throughout the encoding and decoding process.
Stated Advantages
Expands the number of primary colors in display systems, reducing metameric errors from viewer to viewer.
Maintains compatibility and provides backward compatibility with existing and legacy color systems and equipment.
Enables the transport and display of wide-gamut, multi-primary image data without major modifications to established data formats or infrastructures.
Improves color representation and viewer experience by allowing a broader range of visible surface colors to be reproduced.
Documented Applications
Display devices implementing six-primary (RGBCYM) color systems for increased color gamut, including LCD, OLED, DLP, quantum dot, and direct-emissive assembled displays.
Encoding and decoding of image signals for use in television, digital cinema, and video transport standards such as SDI, HDMI, SMPTE, and Ethernet-based video systems.
Image processing systems and workflows for professional video, broadcast, and content production environments supporting standard and high dynamic range imaging.
Secure image distribution using embedded digital watermarking in conjunction with multi-primary encoding.
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