Research on Non-contact Measurement Technology of Geometric Dimension Based on Virtual Instrument

The traditional measurement methods, with shortcomings such as the low precision, the high cost, the survey not convenient, the deficient flexibility, cannot support the online detection, can't meet the need of modern manufacturing. Therefore, a non-contact visual measurement system based on VI was designed in this paper to avoid above problems to some extent. In this system, each step of the whole system-image preprocessing, image segmentation, edge detection,-was analyzed and realized. Then, the size data were analyzed using the statistics process control and appraisal technology (SPC). Finally, the read, write, storage and display of the measurement data were realized by use of the LabVIEW database package - LabSQL based on ADO technology. Results show that the measurement error is less than 0.07%. And the performances of the non-contact visual measurement system can meet the requirements for factory applications and the demands of on-line and real time measurement with high accuracy in the production line.