Research On Detection Method Of Abnormal Frequency Point Of High-density Board

High-density circuit boards with high density, high frequency, high reliabilityfeatures, making it more difficult assembly, resulting in lower quality assembly, and thetraditional detection methods can not adapt to high-density circuit board assemblyquality of the testing requirements. This paper attempts to detect the use ofelectromagnetic scanning high-density circuit board assembly quality, the mostimportant problem is the frequency of its spectrum detection of abnormal, so thisresearch has important practical significance and a good value.This paper detailed study of the electromagnetic spectrum scan edge detectionmethod, proposed a multi-window adaptive threshold Canny edge detection algorithm,that is, the window through the spectrum by, in a window using the improved method ofcalculating the gradient magnitude and adaptive threshold detection algorithm Cannyedge detection on the spectrum; under the edge of the spectrum, we proposed to thesemi-regional5-direction chain-code concept, design semi-regional5-directionchain-code tracking mechanism, proposed coding method; By analyzing the spectralcharacteristics of the curve, constructed spectrum curve extreme points of the costfunction using simulated annealing algorithm with memory frequency spectrum curveof the extreme point of detection, combined with extreme points on both sides of theedge vector similarity, detection of high-density circuit abnormal frequency board.Theoretical analysis and experimental results show that the proposed algorithm hasaccurate and comprehensive features, can automatically detect the abnormalhigh-density circuit boards frequency, electromagnetic scanning technology for the useof the specific location of the fault detection circuit board laid a good foundation.In the follow-up research work will be abnormal in high-density circuit boardsbased on the frequency of detection, continue to study the cloud of electromagneticscanning documents with the combination of circuit design the specific fault locationdetection circuit board approach.