Display Management for High Dynamic Range Video Tone Mapping
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Solution Overview
Problem
Current display technologies face challenges in efficiently managing high or enhanced dynamic range images, particularly in converting and displaying them on devices with different dynamic ranges, leading to suboptimal visual experience and compatibility issues.
Innovation Solution
The proposed solution involves transforming input images into a perceptually-quantized color space (LMS-PQ), applying non-linear tone-mapping functions, and adjusting intensity and saturation to match the target display's characteristics, using pre-computed look-up tables for efficient display management, which reduces computational complexity while improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EDR content is displayed on LDR displays using conventional tone mapping, then compatibility is maintained, but visual quality and immersive experience deteriorate
Solution Approach 1:
The patent applies perceptual quantization (PQ) transfer function parameters to transform EDR content into a format suitable for LDR displays. By changing the luminance encoding parameters from linear to perceptually-based PQ scaling, the system maintains compatibility with LDR displays while preserving visual quality through human visual system-aligned intensity mapping.
Solution Approach 2:
The patent introduces an intermediate processing stage that converts EDR content through PQ color space transformation before display. This intermediary transformation layer acts as a bridge between EDR source material and LDR display capabilities, enabling quality preservation without requiring hardware changes.
2Manufacturing precision
If EDR content is processed with complex tone mapping algorithms, then visual quality improves, but computational complexity increases
Solution Approach 1:
The patent performs perceptual quantization transformation and tone mapping operations during the content encoding and distribution stage, before delivery to the display device. By pre-processing EDR content into PQ-formatted streams, the computational complexity is shifted from the display device to the content preparation stage, enabling simple playback on consumer devices.
Solution Approach 2:
The patent replaces complex real-time tone mapping computations with pre-computed lookup tables and simplified PQ transfer function applications. This substitution transforms the processing from intensive algorithmic operations to efficient table-driven transformations, reducing device complexity while maintaining visual quality.
Data Source
AI summary
A display management processor receives an input image with enhanced dynamic range to be displayed on a target display which has a different dynamic range than a reference display. The input image is first transformed into a perceptually-quantized (PQ) color space. A non-linear mapping function generates a tone-mapped intensity image in response to the characteristics of the source and target display and a measure of the intensity of the PQ image. After a detail-preservation step which may generate a filtered tone-mapped intensity image, an image-adaptive intensity and saturation adjustment step generates an intensity adjustment factor and a saturation adjustment factor as functions of the measure of intensity and saturation of the PQ image, which together with the filtered tone-mapped intensity image are used to generate the output image. Examples of the functions to compute the intensity and saturation adjustment factors are provided.