Stereo Camera Point Association Using Phase Only Correlation
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Solution Overview
Problem
Existing stereo camera systems face challenges in associating coordinate points between images at high speed and high precision, particularly when camera positions deviate from parallel alignment, leading to decreased precision and increased processing time.
Innovation Solution
The system specifies corresponding points on the second image by searching along specific basis directions, using a combination of first, second, and third specifying parts to align points accurately, employing Phase Only Correlation (POC) method for high precision and frequency decomposition to suppress amplitude components, thereby enhancing processing speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Phase Only Correlation (POC) method is used to eliminate amplitude components and perform correlation calculation with only phase components, then measurement precision is improved and robustness against brightness fluctuations and noise is enhanced, but processing time increases significantly
Solution Approach 1:
The patent segments the image into multiple blocks and performs POC calculation independently for each block. This division allows parallel processing of different blocks, reducing the total processing time while maintaining the high precision benefits of POC method for corresponding point association.
Solution Approach 2:
The patent applies POC method selectively only to regions where corresponding point association is needed, rather than processing the entire image with POC. This partial application reduces the overall computation load and processing time while maintaining precision in the critical association regions.
2Productivity
If two cameras are mechanically disposed almost parallel with each other to enable high-speed processing using SAD method, then processing speed is improved, but precision deteriorates when cameras deviate from parallel position due to changes over time
Solution Approach 1:
The patent replaces the mechanical requirement for parallel camera disposal with a computational approach using POC method. Instead of relying on precise mechanical alignment, the system uses phase-only correlation calculations that are insensitive to camera angle deviations, thereby maintaining precision without strict mechanical constraints.
Solution Approach 2:
The patent changes the correlation calculation parameter from intensity-based (SAD method) to phase-based (POC method). This parameter change makes the corresponding point association robust against camera position and angle variations, maintaining precision even when cameras are not perfectly parallel.
3Device complexity
If only one window is set in a distance measurement target portion, then processing is simple, but the system cannot handle multiple corresponding points simultaneously
Solution Approach 1:
The patent divides the image into multiple blocks and sets multiple windows (one per block) to perform corresponding point association simultaneously for multiple regions. This segmentation approach enables multi-point association while keeping the processing complexity manageable through independent block processing.
Solution Approach 2:
The patent creates a universal processing framework that can handle both single-point and multi-point corresponding point association using the same POC-based methodology. The system is designed to process multiple blocks and windows simultaneously, providing versatile functionality for various measurement scenarios.
Data Source
AI summary
An information processing system for performing processes on first image and second image captured from different viewpoints, comprising: a first specifying part for specifying a first corresponding point on the second image, corresponding to a designation point designated on the first image, by searching on a line along a first basis direction corresponding to a predetermined direction and passing through a position corresponding to the designation point in the second image; a second specifying part for specifying a second corresponding point on the second image, corresponding to the designation point, by searching on a line passing through the first corresponding point in the second image and along a second basis direction almost perpendicular to the first basis direction; and a third specifying part for specifying a third corresponding point on the second image, corresponding to the designation point, by searching on a line passing through the second corresponding point in the second image and along the first basis direction.