HDR Image Encoding with Metadata-Guided Tone Mapping
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Solution Overview
Problem
Existing systems fail to correctly process and display high dynamic range (HDR) data due to independent modules and lack of metadata transmission, leading to inadequate image processing and display effects.
Innovation Solution
A method involving a double-layer bitstream is used to combine decoded images in two buffers, with tone mapping based on metadata for correct HDR display, and a fallback to baseline images for compatibility with different systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If independent modules (decoding, graphics processing, display) are used with a single image buffer, then device complexity is reduced and ease of operation is improved, but HDR data processing accuracy deteriorates and display quality worsens
Solution Approach 1:
The patent segments the image processing pipeline into two distinct buffers: a first buffer for baseline image data and a second buffer for HDR image data. This segmentation allows each buffer to handle specific types of data with appropriate processing, resolving the contradiction by maintaining simple independent modules while enabling accurate HDR processing through structured data separation.
Solution Approach 2:
The patent introduces metadata as an intermediary element that carries transfer function information between the decoding module, graphics processing module, and display module. This metadata acts as a mediator that enables accurate HDR data transmission and processing across the independent modules, solving the precision problem without increasing structural complexity.
2Ease of operation
If metadata is not transmitted and ignored, then ease of operation is improved and device complexity is reduced, but HDR display accuracy deteriorates
Solution Approach 1:
The patent implements a self-service mechanism where the system automatically generates, transmits, and processes metadata containing transfer function information without requiring manual intervention. The display module automatically applies the transfer function from metadata to process HDR data, maintaining ease of operation while achieving accurate HDR display through automated metadata utilization.
3Manufacturing precision
If a double-layer bitstream with two image buffers is used, then HDR data processing accuracy is improved, but device complexity and file size increase
Solution Approach 1:
The patent applies local quality by assigning different characteristics to different buffers: the first buffer handles baseline image data with standard processing, while the second buffer handles HDR image data with specialized transfer function processing. This local differentiation enables accurate HDR processing in the second buffer while maintaining simplicity in the first buffer, resolving the complexity-precision contradiction.
4Manufacturing precision
If tone mapping is performed based on metadata, then HDR display accuracy is improved, but processing time and complexity increase
Solution Approach 1:
The patent performs preliminary action by pre-calculating and embedding the transfer function information in the metadata during the encoding stage. This allows the display module to directly apply the pre-prepared transfer function without performing complex real-time calculations, achieving accurate tone mapping while minimizing processing time during playback.
Data Source
AI summary
A signal processing method provided in this application includes: obtaining a first baseline image, a first gain map, and metadata, where the first baseline image corresponds to a first dynamic range; processing the first baseline image based on the metadata to obtain a second baseline image; and obtaining a target image based on the second baseline image and the first gain map, where the target image corresponds to a second dynamic range, and the second dynamic range is different from the first dynamic range. The solutions provided in this application are compatible with image encoding and processing in a plurality of formats, and comparatively good image quality can be achieved on systems with different support capabilities.