Regional HDR Conversion for Bokeh Contrast and Subject Tonality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing methods fail to effectively convert HDR image data to a lower dynamic range without degrading image quality, particularly in regions deviating from the focal plane, leading to loss of detail and contrast in bokeh areas.
Innovation Solution
An image processing apparatus that divides image data into regions, determines conversion characteristics based on distance from the focal plane, and applies different conversion characteristics to maintain tone and contrast, ensuring high contrast in bokeh regions while preserving the main subject's tonality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If highlight restoration processing is applied to restore the main subject's tonality, then the reproduction of details is improved, but the bokeh region loses sparkle and becomes dull
Solution Approach 1:
The image is divided into multiple regions based on distance from the focal plane. The in-focus region (main subject) and out-of-focus region (bokeh) are processed separately with different conversion characteristics, allowing detail restoration in the main subject while preserving sparkle in the bokeh region.
Solution Approach 2:
Different conversion characteristics are applied to different regions of the image. The in-focus region uses a conversion characteristic optimized for detail reproduction, while the out-of-focus region uses a different characteristic that preserves bokeh sparkle, making each region have the quality most suitable for its purpose.
2Device complexity
If a single conversion characteristic is used for the entire image, then the processing is simple, but image quality degrades in regions deviating from the focal plane
Solution Approach 1:
The image processing is segmented into region division, distance information calculation, and selective conversion characteristic application. This segmentation allows quality optimization for different regions while keeping the overall processing framework manageable and systematic.
3Adaptability or versatility
If HDR image data is converted to D range, then the image can be reproduced by standard devices, but tonality is lost in high luminance regions
Solution Approach 1:
Different conversion characteristics are selected for different regions based on their distance from the focal plane. This allows the conversion process to maintain tonality in the in-focus region while still achieving compatibility with standard D range display devices.
Data Source
AI summary
An image processing apparatus including a determining unit configured to determine, based on at least one of a first conversion characteristic or a second conversion characteristic, a conversion characteristic of each of a plurality of regions in a first image having a first dynamic range, and a conversion unit configured to convert an image of each of the plurality of regions into a second image having a second dynamic range less than the first dynamic range by using the conversion characteristic determined by the determining unit. In relation to input luminance and output luminance, the first conversion characteristic has a higher characteristic of maintaining tone than the second conversion characteristic, and has a lower characteristic of maintaining contrast than the second conversion characteristic.