Enhancing Accuracy of Line-Structured Light Sensor for Narrow Weld Gap Measurement

Line-structured light sensors (LLSs) are widely used in measurement of multi-section bevels in thick plate weldments to ensure the structural integrity in shipbuilding and high-pressure vessels. However, in some engineering scenarios, it is necessary to select a large range LLS, which usually has poor resolution, making it difficult for traditional algorithms to obtain an accurate weld gap. This article introduces a novel narrow weld gap measurement method utilizing key points identification and alignment. The method extracts key points by analyzing data from an LLS with large range, and aligns them with theoretical model for gap calculation. Experimental results demonstrate remarkable accuracy with 2-D measurement errors as low as 0.0122 mm for weld gaps as narrow as 0.75 mm. The average 3-D measurement error for 0.8 mm weld gaps is also remarkably precise at 0.0301 mm. This method offers a significant improvement for reliable and efficient narrow weld gap measurement in critical applications.