Area-Based Exposure Control for HDR Image Noise Reduction
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Solution Overview
Problem
Conventional methods of generating high dynamic range images (HDR) using different exposure conditions for each pixel can result in image blur or noise due to varying exposure times, especially when capturing scenes with diverse brightness levels.
Innovation Solution
An image capturing device that controls exposure conditions, such as shutter speed and ISO sensitivity, for each area of the image, using an exposure value map to adjust and correct these settings to minimize differences between areas, thereby reducing blur and noise in HDR images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If different exposure times are set for each pixel to capture dark objects, then the dynamic range is improved, but image blur occurs due to long exposure times
Solution Approach 1:
The patent applies local quality by setting different exposure conditions for different areas of the image based on brightness levels. Dark areas use longer exposure times to capture sufficient light, while bright areas use shorter exposure times to avoid overexposure. This area-based approach maintains image clarity while expanding dynamic range coverage.
Solution Approach 2:
The patent segments the image into multiple areas with different exposure requirements. By dividing the image capture into distinct exposure zones and processing them separately with appropriate exposure times, the system achieves high dynamic range without the blur that would result from uniformly long exposure across the entire image.
2Illumination intensity
If different exposure conditions are set for each pixel, then the dynamic range is improved, but noise increases in the acquired HDR image
Solution Approach 1:
The patent reduces noise by applying local quality control where exposure conditions are optimized for each area's brightness characteristics. Dark areas receive longer exposure to improve signal-to-noise ratio, while bright areas use shorter exposure to avoid saturation noise, thereby reducing overall noise in the HDR image.
3Manufacturing precision
If exposure conditions are controlled for each area, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent implements self-service by enabling the image capturing element to automatically determine and adjust exposure conditions for each area based on the captured image data. The system autonomously calculates optimal exposure parameters without requiring complex external control mechanisms, thereby maintaining image quality while reducing control complexity.
Data Source
AI summary
A control method for generating a high quality HDR image is provided. A control device of the technique of this disclosure is a control device configured to control an image capturing element capable of controlling an exposure condition for each of areas, the device including: an acquisition unit configured to acquire an exposure value map obtained by preliminary exposure using the image capturing element; and a setting unit configured to set the exposure condition including a shutter speed and an ISO sensitivity for each of the areas based on the exposure value map.