Dynamic Exposure Time Setting for High Dynamic Range Imaging
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Solution Overview
Problem
Conventional image sensors in digital cameras and camera phones have a limited dynamic range, leading to deficient color and picture quality, as they struggle to capture images with the same sensitivity as human vision, and existing methods to increase dynamic range either require costly hardware modifications or complex software-based image synthesis with varying exposure times.
Innovation Solution
A method and apparatus that divide an input image into regions based on luminance distribution, classify these regions, and set exposure times for each region using a target luminance value, allowing for the synthesis of high-dynamic range images without the need for hardware modifications, by capturing images with different exposure times and compensating for luminance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardware modifications are made to increase image sensor sensitivity, then the dynamic range is improved, but the manufacturing cost and device size increase
Solution Approach 1:
The patent changes the exposure time parameter dynamically based on region classification. By adjusting the exposure time parameter for different image regions (short exposure for bright regions, long exposure for dark regions), the system achieves extended dynamic range without modifying the physical image sensor, thereby avoiding increased manufacturing costs and device size.
2Reliability
If hardware modifications are made to increase image sensor sensitivity, then the dynamic range is improved, but the device size increases
Solution Approach 1:
The patent achieves extended dynamic range by dynamically changing the exposure time parameter through software processing rather than through hardware modifications. This approach maintains the original device size while achieving the desired performance improvement in dynamic range.
3Reliability
If multiple images are captured with different exposure times, then the dynamic range is improved, but the complexity of the system increases
Solution Approach 1:
The patent divides the image into multiple regions based on luminance distribution and applies different exposure times to each region. This segmentation approach simplifies the system by processing regions independently rather than requiring complex full-image processing, thereby reducing system complexity while achieving extended dynamic range.
Solution Approach 2:
The patent applies different exposure characteristics to different regions of the image based on their local luminance properties. By classifying regions into bright and dark areas and applying appropriate exposure times locally, the system achieves high dynamic range without requiring complex global processing, thus reducing overall system complexity.
4Reliability
If exposure time is extended to capture more light, then the sensitivity is improved, but the occurrence of blur increases
Solution Approach 1:
The patent dynamically adjusts the exposure time parameter based on region luminance classification. For bright regions, a short exposure time is applied to prevent blur, while for dark regions, a long exposure time is applied to capture sufficient light. This selective parameter adjustment maintains image quality while improving sensitivity where needed.
Solution Approach 2:
The patent applies different exposure time settings to different regions of the image based on their local luminance characteristics. By giving each region its optimal exposure time, the system prevents blur in bright areas while capturing adequate light in dark areas, thus maintaining overall image quality while improving sensitivity.
Data Source
AI summary
A method, medium, and apparatus for setting an exposure time is provided. The apparatus includes a section setting module which sets one or more luminance sections based on a luminance distribution of an input image, an image division module which divides the input image into two or more regions, a region classification module which classifies the regions into the luminance sections, and an exposure-time setting module which sets an exposure time for each of the regions with reference to a target luminance value, the target luminance value being set based on the results of the classification performed by the region classification module.