An Automated Template Making Method for Visual Measurement of Microwave Probes

Microwave probes typically have two or more pins, and planarization is crucial in wafer testing. This study examines the planarization of microwave probes and determines the probe’s rotation angle based on planarization conditions. Given that automatic probe holders are not yet widely adopted, this article proposes a method to measure the rotation angle. Our research indicates a correlation between the actual angle of the microwave probe and its lateral displacement in the image. Therefore, we employed vision-based measurement techniques to determine and control the rotation angle. The quality of the template significantly impacts the recognition resolution in template matching. To mitigate errors caused by templates, we propose an intelligent template-making algorithm based on the frame difference method. The template generated by our method can achieve a resolution of 0.0041° without using subpixel techniques. This method provides real-time angle measurement capabilities, which are particularly useful before the widespread adoption of automatic probes.