Battery Shell Weld Inspection with Datum-Plane Depth Correction
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Solution Overview
Problem
Existing depth image-based welding inspection of battery shell assemblies is affected by camera deviations and environmental changes, leading to inaccuracies in defect detection.
Innovation Solution
A correction method and apparatus that fits a datum plane parallel to the intersecting line between adjacent surfaces, projecting and mapping points to correct the depth image, using a simple algorithm to reduce computation and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If depth image is used for welding inspection, then defect detection is enabled, but measurement precision deteriorates due to camera deviations and environmental changes
Solution Approach 1:
The patent applies preliminary action by establishing a datum plane before depth image acquisition. The datum plane is fitted to the intersecting line between adjacent surfaces in advance, creating a reference framework that compensates for camera deviations. This preliminary setup ensures that subsequent depth measurements are referenced against a stable geometric model, improving measurement precision despite environmental changes or camera mounting errors.
Solution Approach 2:
The patent employs parameter changes by transforming the depth image data through coordinate transformation. Points from the depth image are projected onto the datum plane, changing the coordinate system from camera-relative to datum-plane-relative. This parameter transformation corrects depth information by removing systematic errors, thereby improving both measurement precision and inspection reliability.
2Measurement precision
If complex correction algorithms are used to improve depth image accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the correction process into distinct modular steps: extracting the intersecting line, fitting the datum plane, projecting depth points, and calculating corrected coordinates. Each step handles a specific aspect of the correction, making the overall complex task manageable and computationally efficient. This segmented approach maintains measurement precision while avoiding unnecessary algorithmic complexity.
Solution Approach 2:
The datum plane serves as an intermediary between the raw depth image and the corrected measurement data. Instead of directly correcting depth values, the patent introduces the datum plane as a intermediate reference surface. Points from the depth image are first projected onto this intermediary datum plane, which then provides the basis for accurate measurements. This intermediary approach simplifies the correction algorithm while maintaining high precision.
Data Source
AI summary
A correction method for a depth image of a battery includes obtaining the depth image of the battery. The depth image includes two adjacent surfaces of a shell assembly of the battery and an intersecting line between the two adjacent surfaces. The method further includes extracting the intersecting line from the depth image, determining planes in the depth image in which the two adjacent surfaces are located, and obtaining a datum plane based on the intersecting line and the planes in which the two adjacent surfaces are located. The datum plane is parallel to the intersecting line, and included angles between the datum plane and the planes in which the two adjacent surfaces are located are equal to each other. The method also includes projecting and mapping points in the depth image to the datum plane, to obtain depth information of points in a corrected depth image.