Research On The Inspection Methods Of SMT Chip Based On Machine Vision

Electronic products are increasingly sophisticated, chip test is inportent in thesemiconductor industry. This paper mainly studies the detection methods of the SMTchip using machine vision, to achieve locating pins and dimensions detection for SOPchip.The paper designs hardware and software system of machine vision matching withdetection methods, including light, camera, lens and the interface of software.Achieving the pin positioning method based on morphology, firstly solve the “pinmissing” problem of image due to uneven illumination using the top-hat transform;and then locate pins of chip using pixel labeled algorithm of connecting area,countingthe number and geometric parameters of pins. Achieving the method of inspection fordimension of chip based on edge detection, firstly using histogram equalization; andthen compare the effect of classic edge detection operator; optimizing the filteringalgorithm to solve the problem that median, mean filtering algorithm can notcompletely eliminate background noise; lastly calculate the width and pitch of pinsusing vertical gray projection and analyse defect of pins.Achieving the testing methods above mentioned using vc6.0software developmentplatform. According to the experimental data, the methods mentioned in the articlecould meet the needs of the actual test...