HDR Image Format Using Recovery Maps for LDR Compatibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image formats struggle to efficiently display high dynamic range (HDR) images on both low dynamic range (LDR) and HDR display devices without loss of visual quality or requiring specialized hardware.
Innovation Solution
A backward-compatible HDR image format is created using a recovery map that encodes luminance differences between HDR and LDR images, allowing devices to adapt the dynamic range of the image to match their display capabilities by applying luminance gains based on a range scaling factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HDR image format is used to provide greater dynamic range and true-to-life picture quality, then image quality is improved, but compatibility with LDR display devices is lost
Solution Approach 1:
The patent segments the HDR image data into two components: an LDR base image and a recovery map. The LDR base image ensures compatibility with legacy display devices, while the recovery map contains the luminance difference information needed to reconstruct HDR images on HDR-capable devices. This segmentation allows the same image file to be displayed appropriately on both LDR and HDR displays without requiring separate files or formats.
2Adaptability or versatility
If separate HDR and LDR image files are maintained to ensure compatibility across all devices, then display compatibility is improved, but storage and processing resources are increased
Solution Approach 1:
The patent merges the LDR base image and the recovery map into a single unified image file format. Instead of storing separate HDR and LDR files, the format combines both representations in one file, allowing the same file to serve both LDR and HDR display devices. This merging reduces storage requirements and simplifies image distribution while maintaining full compatibility across device types.
3Adaptability or versatility
If HDR images are displayed on LDR display devices, then compatibility is maintained, but visual quality and dynamic range are reduced
Solution Approach 1:
The recovery map acts as an intermediary that enables HDR-capable devices to recover the full dynamic range information from the LDR base image. When displayed on HDR devices, the recovery map is applied to the LDR base image to reconstruct the original HDR luminance values, thereby restoring the full visual quality and dynamic range that would otherwise be lost in LDR display.
4Adaptability or versatility
If a unified image format supports both LDR and HDR representations, then adaptability is improved, but format complexity is increased
Solution Approach 1:
The patent applies local quality by making the recovery map spatially varying rather than a uniform scaling factor. The recovery map contains per-pixel or per-region luminance correction values that are applied locally to the LDR base image. This allows different regions of the image to have different recovery characteristics, preserving local contrast and detail while maintaining overall HDR reconstruction accuracy.
Data Source
AI summary
Implementations relate to providing an HDR image format with low dynamic range compatibility. In some implementations, a computer-implemented method includes obtaining a first image depicting a scene and having a first dynamic range, obtaining a second image depicting the scene and having a second dynamic range that is different than the first dynamic range, and generating a recovery map based on the first and second images. The recovery map encodes differences in luminances between corresponding portions of the first and second images, the differences scaled by a range scaling factor including a ratio of maximum luminances of the second image and the first image. The first image and recovery map are provided in an image container that is readable to display a derived image that is based on applying the recovery map to the first image and has a dynamic range that is different than the first dynamic range.