HDR Image Processing Gain and Development Before Composition
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Solution Overview
Problem
Conventional high dynamic range (HDR) image processing techniques face challenges in generating images with high contrast and favorable quality due to tone compression and brightness adjustments, which lead to reduced contrast and increased noise, as well as difficulties in applying optimal noise reduction and edge enhancement processing after image alignment.
Innovation Solution
An image processing device that includes an input unit for multiple images with different exposures, a generation unit for generating gain information, a gain processing unit for applying gain processing based on the generated information, and a development processing unit for applying development processing, followed by composition to produce an HDR image with high contrast and improved quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tone compression and brightness adjustment using tone curves are applied to composite images with different exposures, then the tone jump becomes unnoticeable, but the contrast is reduced
Solution Approach 1:
The patent applies tone compression and brightness adjustment to individual images before composition rather than after. This preliminary processing ensures that each image contributes optimally to the final composite, maintaining contrast while preventing tone jumps at boundaries between differently exposed images.
Solution Approach 2:
The patent applies different gain characteristics to different regions of the image based on luminance distribution. By determining separate gain characteristics for highlight and shadow regions, the system maintains local contrast while ensuring smooth tone transitions across the entire image.
2Illumination intensity
If gain processing is applied after composition to achieve high contrast, then the contrast improves, but the noise amount increases
Solution Approach 1:
The patent applies gain processing to individual images before composition rather than to the final composite. This preliminary application of gain characteristics based on pre-composition luminance distribution achieves the desired contrast enhancement while avoiding the amplification of noise that would occur if gain processing were applied after composition.
3Object-affected harmful factors
If noise reduction processing is applied after composition, then the noise amount is suppressed, but the optimal noise reduction cannot be applied due to image deformation and band degradation
Solution Approach 1:
The patent performs noise reduction processing on individual images before composition rather than on the final composite. This timing allows optimal noise reduction parameters to be applied to each image independently, avoiding the image deformation and band artifacts that would prevent effective noise reduction if applied after composition.
4Illumination intensity
If edge enhancement processing is applied after composition, then the image sharpness improves, but the optimal edge enhancement cannot be applied due to image deformation and band degradation
Solution Approach 1:
The patent applies edge enhancement processing to individual images before composition rather than to the final composite. This preliminary application allows optimal edge enhancement parameters to be determined and applied to each image independently, achieving maximum sharpness enhancement while avoiding the degradation caused by applying such processing after position alignment and composition.
Data Source
AI summary
An image processing device includes an input unit, a generation unit, a gain processing unit, a development processing unit, and a composition unit. The input unit receives input of a plurality of images having different exposures from one another. The generation unit generates gain information according to each of the plurality of images input through the input unit. The gain processing unit applies gain processing to each of the plurality of images based on the gain information generated by the generation unit. The development processing unit applies development processing to each of the plurality of images to which the gain processing has been applied by the gain processing unit. The composition unit composites the plurality of images to which the development processing has been applied by the development processing unit.