Tone Mapping Messaging for Extended Dynamic Range Video
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Solution Overview
Problem
Current video coding technologies are limited by the dynamic range capabilities of display devices, which cannot reproduce the full range of the human visual system, hindering applications that require capturing and processing larger dynamic ranges for surveillance, film-making, and archival purposes.
Innovation Solution
The implementation of a Supplemental Enhancement Information (SEI) message within the bit-stream to signal higher bit-depth profiles for representing larger dynamic range sequences, along with sophisticated tone mapping algorithms to convert high bit-depth images to traditional low bit-depth representations, using models such as linear, sigmoidal, user-defined lookup tables, and piece-wise linear mappings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If video coding techniques discard information to reduce bit-rate, then transmission efficiency is improved, but dynamic range representation is degraded
Solution Approach 1:
The patent applies preliminary action by performing tone mapping processing before video encoding. The high dynamic range image is pre-processed to generate a tone mapped image that preserves essential dynamic range information while adapting to display device capabilities. This preliminary transformation allows subsequent encoding to achieve compression without losing critical dynamic range characteristics.
Solution Approach 2:
The patent utilizes parameter changes by transforming the dynamic range parameters of the image data. Different tone mapping curves (linear, sigmoidal, piece-wise linear) are applied to map high dynamic range values to lower dynamic range suitable for standard displays. This parameter transformation enables the video stream to carry extended dynamic range information that can be appropriately rendered on various display devices.
2Adaptability or versatility
If tone mapping is applied to convert high bit-depth images to low bit-depth representations, then compatibility with current display devices is improved, but dynamic range fidelity is degraded
Solution Approach 1:
The patent applies dynamics by making the tone mapping process adaptive rather than static. Multiple tone mapping curves are provided and selected based on the specific display device characteristics and content requirements. The system dynamically adjusts the tone mapping parameters to optimize both compatibility and fidelity for different viewing conditions and device capabilities.
Solution Approach 2:
The patent implements local quality by applying different tone mapping strategies to different regions or portions of the image. Piece-wise linear tone mapping curves allow different dynamic range mappings for different intensity regions, preserving local details in both highlights and shadows while maintaining overall compatibility with standard display devices.
3Adaptability or versatility
If multiple tone mapping models are supported for different display devices, then adaptability is improved, but system complexity is degraded
Solution Approach 1:
The patent applies segmentation by dividing the tone mapping function into multiple discrete models (linear, sigmoidal, piece-wise linear). Each model is optimized for specific display device types or dynamic range requirements. The system segments the problem into manageable model options, allowing selection of the appropriate model based on device characteristics without requiring a single complex universal solution.
Data Source
AI summary
Embodiments of the present invention comprise methods and systems for signaling tone map data to an image recipient.