Image Processing Apparatus Optimizing Dynamic Range via Exposure Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing methods struggle to generate high dynamic range images effectively, especially when the camera is out of focus or the subject is moving during bracket imaging, leading to poor image quality due to difficulties in determining exposure conditions and combining images correctly.
Innovation Solution
An image processing apparatus that includes an exposure-correction-value acquiring unit, an illumination-component generating unit, and a gain-amount calculating unit to optimize the luminance range by adjusting exposure correction values and applying gain amounts to input image data, allowing for the generation of high dynamic range images in one exposure and optimizing gradation ranges without compromising image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bracket imaging is performed to capture wide luminance range scenes, then the dynamic range of the image is improved, but the image quality deteriorates when the camera is out of focus or the subject is moving
Solution Approach 1:
The patent applies low-pass filter processing to the input image before determining exposure correction values. This preliminary action creates a version of the image with reduced high-frequency components, allowing accurate exposure determination even when the original image is out of focus or contains moving subjects. The low-pass filtered image serves as a reliable basis for calculating exposure correction values without being affected by focus issues or motion blur.
2Adaptability or versatility
If multiple images are combined through bracket imaging to generate high dynamic range images, then the luminance range is expanded, but the processing time and complexity increase
Solution Approach 1:
The patent extracts only the necessary information (exposure correction values) from the low-pass filtered image, rather than processing and combining multiple full-resolution images. By determining exposure correction values from the down-sampled low-pass filtered image, the system significantly reduces processing time and computational complexity while still achieving high dynamic range image generation.
3Device complexity
If exposure correction values are determined from the original image, then the processing is simpler, but the accuracy deteriorates when the image is out of focus or contains moving subjects
Solution Approach 1:
The patent introduces a low-pass filtered image as an intermediary between the original image and the exposure correction value determination process. This intermediary image removes high-frequency components that cause inaccuracies in out-of-focus or moving subject scenarios, while preserving the overall luminance distribution needed for accurate exposure correction. The low-pass filtered image acts as a mediator that enables accurate measurement without the distortions present in the original image.
Data Source
AI summary
An image processing apparatus that processes input image data includes an exposure-correction-value acquiring unit that acquires exposure correction values at plural stages with respect to an exposure control value during imaging of the input image data, an illumination-component generating unit that generates illumination components on the basis of the input image data, a gain-amount calculating unit that multiplies each of plural weighting coefficients with a multiplication coefficient corresponding to the exposure correction value corresponding to the weighting coefficient and adds up multiplied values to calculate a gain amount, and a gain applying unit that applies, for each of pixels, the gain amount calculated by the gain-amount calculating unit to the input image data.