Asynchronous Dual Camera Vehicle Detection Using Edge-Based Disparity Search
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Solution Overview
Problem
Conventional binocular camera systems for vehicle detection face challenges including high cost, large volume, and difficulties in asynchronous exposure, leading to inaccurate distance measurement and increased computational complexity.
Innovation Solution
A binocular and asynchronous photography automobile-detecting apparatus with a stereo image acquisition unit, image pre-process unit, searching object unit, disparity matching unit, and output unit, which processes images to overcome illumination differences and reduce computational complexity by using edge information and adaptive matching algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synchronous binocular cameras system is used, then image alignment is improved and processing speed is increased, but hardware cost and device volume increase
Solution Approach 1:
The patent divides the image processing task into two stages: first, use a rough search algorithm to identify potential matching regions; second, apply precise disparity calculation only within these limited regions. This segmentation approach maintains measurement precision while reducing overall computational complexity and hardware requirements.
Solution Approach 2:
The patent performs preliminary image preprocessing and feature extraction before disparity calculation. By pre-identifying key features and potential matching regions, the system prepares data in advance to enable faster and more efficient disparity computation, thereby maintaining precision without requiring complex synchronous hardware.
2Device complexity
If asynchronous binocular cameras system is used, then hardware cost and volume are reduced, but image alignment difficulty and computational complexity increase
Solution Approach 1:
The patent implements a dynamic search window that adapts its size and position based on the detected Y-axis offset (ΔY) between left and right images. This dynamic adjustment allows the system to handle asynchronous exposure variations without requiring complex real-time alignment hardware, thereby reducing device complexity while maintaining alignment accuracy.
Solution Approach 2:
The patent changes the search parameters (searching scope and starting position) based on the detected vertical offset ΔY. By dynamically adjusting these parameters according to the actual image alignment status, the system compensates for asynchronous exposure effects without needing complex hardware synchronization circuits.
3Measurement precision
If full search scope is used for disparity calculation, then measurement accuracy is maintained, but processing time and computational load increase
Solution Approach 1:
The patent segments the search space into a coarse search phase and a fine search phase. The coarse phase quickly identifies the approximate disparity range, while the fine phase precisely calculates the disparity within this reduced range. This two-stage segmentation maintains measurement accuracy while significantly reducing total processing time compared to exhaustive full-search methods.
Solution Approach 2:
The patent applies partial search action by limiting the disparity search to a constrained range based on the detected Y-axis offset and expected object distance. Instead of searching the entire possible disparity range, the system performs partial search within the relevant region, thereby maintaining accuracy for actual objects while reducing unnecessary computational operations.
Data Source
AI summary
The invention discloses the asynchronous photography for dual camera apparatus and processing the method for real-time forward vehicle detection. Image is captured by a pair of monochrome camera and stored into a computer. After the video pre-process, the edge information is used to locate the forward vehicle position, and then obtained the disparity from a fast comparison search algorithm by the stereo vision methodology. Proposed algorithm calculation of the invention can conquer the asynchronous exposure problem from dual camera and lower the hardware cost.