Image Processing Device Region Exposure Correction
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Solution Overview
Problem
Existing camera technologies face challenges in accurately correcting exposure setting errors across regions of an imaging sensor, leading to potential mismatches and gradation steps at boundaries, which affect image quality.
Innovation Solution
An image processing device that acquires and corrects pixel values by deriving a correction amount based on boundary pixel values from adjacent regions, using a derivation unit and correction unit to ensure accurate exposure settings across the imaging sensor's divided regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If exposure settings are adjusted for each region to widen dynamic range, then dynamic range is improved, but exposure mismatch and gradation steps occur at region boundaries
Solution Approach 1:
The patent applies local quality by setting different exposure conditions (exposure time and analog gain) for different regions of the imaging sensor based on local luminance characteristics. This allows each region to be optimized for its specific lighting conditions, widening the overall dynamic range while maintaining appropriate exposure for each local area.
Solution Approach 2:
The patent implements feedback by calculating correction gains based on the ratio of target exposure conditions to actual exposure conditions, then applying these correction gains to pixel values. This feedback mechanism compensates for exposure mismatches at region boundaries, preventing gradation steps and ensuring smooth transitions between regions with different exposure settings.
2Measurement precision
If correction gain is calculated from exposure setting to correct digital signal, then exposure variance is reduced, but exposure errors from imaging sensor cause mismatch and gradation steps
Solution Approach 1:
The patent applies preliminary action by setting target exposure conditions in advance for each region before actual image capture. These target exposure conditions serve as reference values for calculating correction gains, allowing the system to proactively compensate for expected exposure variations rather than reacting to them after capture.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting exposure time and analog gain parameters for different regions based on measured luminance values. The system changes these parameters to achieve target exposure conditions, then uses correction gains to further adjust pixel values, effectively compensating for imaging sensor errors and ensuring reliable exposure matching across regions.
Data Source
AI summary
An image processing device that corrects an image captured by an imaging sensor is capable of setting an exposure condition for each of a plurality of regions and includes an acquisition unit configured to acquire the image by setting the exposure condition for each region in the imaging sensor, a derivation unit configured, regarding a boundary between a region of interest and at least one adjacent region adjacent to the region of interest in the image, to derive a correction amount in the region of interest based on pixel values of a boundary pixel group in contact with the boundary included in the region of interest and pixel values of a boundary pixel group in contact with the boundary included in the adjacent region, and a correction unit configured to correct pixel values of pixels in the region of interest based on the derived correction amount.