Image Processing Apparatus Adaptive Dynamic Range Compression
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Solution Overview
Problem
Dynamic range compression in HDR image printing leads to image quality degradation due to differences in brightness compression curves between adjacent areas, causing issues like grayscale inversion and pseudo-contours.
Innovation Solution
An image processing apparatus that divides an image into areas, sets relationship information for each area, and calculates pixel brightness values based on environment-specific window settings to reduce image quality degradation by applying adaptive compression characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the image is divided into multiple areas and D range compression is performed with different curves for each area, then the contrast preservation in the D range compression is improved, but the image quality degrades due to curve changes at area boundaries
Solution Approach 1:
The patent applies different D range compression curves to different areas of the image based on local characteristics. Specifically, it divides the image into multiple areas and assigns appropriate compression curves to each area, allowing optimal contrast preservation in each region while maintaining overall image quality through boundary transition control.
Solution Approach 2:
The patent segments the image into multiple areas for processing. By dividing the image into distinct regions and applying area-specific D range compression curves, it achieves better local contrast preservation while managing the trade-off with boundary artifacts through proper segmentation strategies.
2Device complexity
If a fixed window size is used for calculating pixel brightness values, then the processing complexity is reduced, but the adaptability to different observation environments and image regions deteriorates
Solution Approach 1:
The patent implements dynamic window size adjustment based on local image characteristics and observation conditions. The window size is not fixed but adapts to the specific requirements of different image regions and viewing environments, improving processing adaptability while maintaining reasonable computational complexity through controlled variability.
Solution Approach 2:
The patent changes the window size parameter dynamically according to local image properties and observation conditions. By adjusting this key parameter based on actual processing needs, the system achieves better adaptability to different environments and image regions without excessive complexity increase.
Data Source
AI summary
An image processing apparatus divides a first image into a plurality of areas based on obtained image data of the first image and sets relationship information between input brightness values with output brightness values for each of the plurality of areas, and converts, based on the relationship information, a brightness value of pixels included in the first image into a brightness value of pixels of a second image whose brightness range is narrower than that of the first image. In the conversion, the apparatus sets, for at least some pixels of the first image, a size of a window for specifying pixels within a predetermined area including the pixels based on environment information in which the second image is observed, and calculates a brightness value in the second image for each of the at least some pixels based on the window.