Region-Based Auto Gain Control for Image Sensor Oscillation
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Solution Overview
Problem
Automatic exposure and gain control algorithms for image sensors often result in oscillations, adversely impacting image quality, especially when dealing with varying light conditions, as they fail to converge desired and actual settings in a timely manner.
Innovation Solution
A region-based approach that focuses on a weighted area of interest within an image, using a grid system to define tiles with programmable coordinates, allowing for real-time feedback and adjustment of exposure and gain settings, thereby prioritizing the correct exposure of the object of interest even if it becomes backlit or shaded, while minimizing oscillations and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic exposure and gain control algorithms are applied to the entire image, then overall image quality is maintained, but oscillations occur and convergence is delayed
Solution Approach 1:
The patent divides the image into multiple tiles arranged in a grid pattern, where each tile can be independently processed for exposure and gain control. This segmentation allows the system to focus computational resources on specific regions rather than processing the entire image, thereby reducing convergence time and minimizing oscillations while maintaining overall image quality.
Solution Approach 2:
The patent applies different exposure and gain control settings to different tiles based on their local characteristics and importance. By identifying and prioritizing tiles containing objects of interest, the system optimizes local image quality without compromising the entire image, enabling faster convergence and reduced oscillations in critical regions.
2Device complexity
If exposure and gain control is applied to the entire image uniformly, then processing is simplified, but the object of interest cannot be correctly exposed when backlit or shaded
Solution Approach 1:
The patent segments the image into multiple tiles, allowing differential exposure and gain control for each tile. This enables the system to identify tiles containing objects of interest and apply optimized exposure settings to those specific regions, ensuring correct exposure even when objects are backlit or shaded, while maintaining manageable algorithm complexity through systematic grid-based organization.
Solution Approach 2:
The patent dynamically adjusts exposure and gain settings based on the content and characteristics of each tile. By continuously monitoring and adapting settings per tile rather than using uniform static settings, the system achieves accurate exposure for objects of interest while keeping the control mechanism manageable through automated tile-based processing.
3Manufacturing precision
If region-based exposure and gain control is applied, then the object of interest is correctly exposed, but the remainder of the image may be compromised
Solution Approach 1:
The patent divides the image into tiles and applies exposure and gain control independently to each tile. By segmenting the image, the system can optimize exposure for tiles containing objects of interest without unnecessarily degrading the quality of tiles containing background or less important content, thus balancing exposure accuracy with overall image quality.
Solution Approach 2:
The patent applies local quality control by adjusting exposure and gain settings specifically for tiles containing objects of interest while maintaining appropriate settings for other tiles. This localized optimization ensures accurate exposure for critical objects without compromising the overall image quality through excessive processing of the entire image.
Data Source
AI summary
An apparatus and method for performing automatic exposure and gain control while minimizing oscillations as well as providing a good response time, for example, a lag time or a settling time of about one frame. The automatic exposure and gain controls are performed not only on the image as a whole but on a weighted region of interest. If the contrast in the image exceeds the dynamic range of the sensor array, then the image in the region of interest will improve at the expense of the remainder of the image. A region of interest is a selected subset of tiles upon which automatic exposure and gain control will be based. The tiles are defined by a grid system having grid coordinates, which are programmable. Image sensors have to receive feedback with regular updates of exposure and gain settings based on ever changing light conditions.