HDR Image Gamut Conversion With BT.2020 and Luminance Mapping
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Solution Overview
Problem
Conventional image processing technologies limit images to the sRGB color gamut, resulting in loss of dynamic range and color information, leading to poor user experience and inability to display high dynamic range (HDR) images accurately.
Innovation Solution
Convert RGB images captured by a photographing apparatus to meet the BT2020 color gamut range, determine a maximum luminance value, and adjust the dynamic range accordingly, followed by gamut mapping on a display apparatus to enhance luminance and color remapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the photographing apparatus directly limits the color gamut range to sRGB, then the image data can be transmitted to the display apparatus, but color information is lost and the display apparatus cannot display the lost color of the image
Solution Approach 1:
The photographing apparatus performs preliminary color gamut conversion before transmission, converting the captured image from sRGB color space to BT.2020 color space. This preliminary action preserves the full color information during capture and storage, allowing the display apparatus to later adapt the colors according to its specific display capabilities without losing original color data
Solution Approach 2:
The patent changes the color gamut parameter from sRGB to BT.2020 in the photographing apparatus. By using the broader BT.2020 color space for image representation and transmission, the system maintains higher color fidelity and allows display apparatuses with different color gamut capabilities to adaptively display images with accurate color reproduction
2Productivity
If the RGB data is quantized relative data without maximum luminance information, then the image can be captured and transmitted, but the absolute luminance of the image is lost and the display apparatus cannot accurately display the real luminance
Solution Approach 1:
The photographing apparatus incorporates a luminance sensor that provides feedback about the actual luminance of the captured image. This feedback mechanism allows the system to determine the maximum luminance value and use it for accurate tone mapping and luminance reproduction, enabling the display apparatus to display the real luminance of the image accurately
Solution Approach 2:
The system performs preliminary luminance measurement and maximum luminance determination during the image capture process. By obtaining the maximum luminance value in advance, the photographing apparatus can embed this information in the image data, allowing the display apparatus to accurately reproduce the absolute luminance without needing to rely on relative quantized data alone
3Device complexity
If conventional technologies are limited to sRGB color gamut, then the processing is simple, but display of HDR image cannot be supported and no more dynamic ranges or image details can be displayed
Solution Approach 1:
The patent changes the color gamut parameter from sRGB to BT.2020 and enables HDR by determining maximum luminance values. This parameter change allows the system to support wide color gamut and high dynamic range imaging while maintaining compatibility with standard display apparatuses through adaptive gamut mapping and tone mapping algorithms
Solution Approach 2:
The photographing apparatus performs preliminary processing to convert images to BT.2020 color space and determine maximum luminance values before transmission. This preliminary preparation enables HDR and wide color gamut display capabilities without requiring complex real-time processing at the display apparatus, balancing processing complexity with enhanced display capabilities
Data Source
AI summary
An image processing method and a related apparatus are provided, to support display of an HDR image, display more dynamic ranges and image details, provide richer colors, and improve user experience. The image processing method includes: obtaining a first RGB image sensed by a photographing apparatus; converting the first RGB image into a second RGB image meeting a BT2020 color gamut range; determining a first luminance value corresponding to the second RGB image, where the first luminance value indicates a maximum luminance of each frame of image in the second RGB image; determining a target image based on the first luminance value and the second RGB image; and sending the target image to a display apparatus for display.