Real-Time HDR Exposure Control via Block Luminance Analysis
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Solution Overview
Problem
Conventional exposure control methods for image processing, particularly in real-time sequential image capture like video recording, face delays and inefficiencies due to reliance on preview images, making them unsuitable for dynamic changes in brightness conditions.
Innovation Solution
An automatic exposure control method that receives source images from multiple image sources with different exposure settings, generates composite images, adjusts exposure settings based on luminance information, and fine-tunes these settings on a block-by-block basis to achieve high dynamic range (HDR) images in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional exposure control methods use preview images for analysis, then exposure settings can be determined, but significant delay occurs between image capture operations
Solution Approach 1:
The patent applies preliminary action by using the most recently captured sequential image for exposure analysis instead of preview images. This allows the system to determine exposure settings based on actual captured image data that reflects current lighting conditions, eliminating the time delay inherent in using preview images while maintaining accurate exposure control.
Solution Approach 2:
The patent implements feedback by continuously analyzing the most recent sequential image and using its luminance information to adjust exposure settings for subsequent images. This closed-loop feedback mechanism ensures that exposure control adapts to changing lighting conditions in real-time without introducing significant delays.
2Ease of operation
If exposure settings are adjusted based on overall luminance, then simple control is achieved, but local brightness variations in different regions are not optimized
Solution Approach 1:
The patent applies segmentation by dividing the image into multiple regions and calculating luminance values for each region separately. This allows the system to perform simple regional luminance analysis while achieving local brightness optimization, as each region's exposure can be independently evaluated and adjusted based on its specific lighting conditions.
Solution Approach 2:
The patent implements local quality by applying different exposure adjustments to different regions of the image based on their specific luminance characteristics. This allows the system to maintain simple overall control while optimizing local brightness in each region, ensuring that areas with varying light conditions receive appropriate exposure treatment.
3Manufacturing precision
If multiple image sources with different exposure settings are used, then HDR image quality is improved, but processing complexity increases
Solution Approach 1:
The patent applies dynamics by dynamically selecting which image sources to combine based on current lighting conditions and scene requirements. Rather than always processing multiple exposure sources, the system adapts its processing complexity by choosing the most appropriate combination, maintaining HDR quality when needed while reducing unnecessary processing complexity.
Solution Approach 2:
The patent implements parameter changes by adjusting exposure settings and combining image sources based on luminance analysis. The system changes processing parameters dynamically according to scene characteristics, achieving HDR image quality by combining images only when the luminance distribution indicates it is beneficial, thereby managing processing complexity effectively.
Data Source
AI summary
An exposure control method and an image processing system are provided. The image processing system comprises: an image sensor module, configured to provide at least two types of source images in parallel, each type of the source images has different exposure setting; a pre-processing unit, configured to determine luminance distribution of the source images on block basis, perform a first exposure control according to the luminance distribution of the two types of source images, and generate output images according to the source images in RAW image domain, and a post-processing unit, configured to determine luminance distribution of the output images, and perform a second exposure control according to the luminance distribution of the output images in normal image domain; wherein exposure settings of the image sensor module is adjusted according to the first exposure control and the second exposure control.