Online AOI (Automatic Optical Inspection) image retrieval method based on double-threshold binaryzation

Abstract

The invention provides an online AOI (Automatic Optical Inspection) image retrieval method based on double-threshold binaryzation. The online AOI image retrieval method comprises the following steps: S1, acquiring a position image of a standard PCB (Printed Circuit Board); S2, carrying out grey processing on the position image to acquire a grey template image; S3, carrying out double-threshold binaryzation treatment on the grey template image to acquire a template image; S4, acquiring a position image of a PCB to be detected, and acquiring a search region image corresponding to the template image according to the double thresholds set in the step S3; and S5, matching the search region image with the template image to search out a position point which is has the biggest matching degree with the template image. The double-threshold binaryzation treatment is adopted to reduce a grey level of the position image, so that the target area of an electronic component is more protruded; moreover, calculation can be effectively reduced, and calculation speed can be improved, so that a rate of missing report and a misstatement rate are reduced when the AOI software identifies an image.

Description

technical field [0001] The invention relates to the technical field of SMT, in particular to an online AOI image retrieval method based on double-threshold binarization. Background technique [0002] Automatic Optical Inspection (AOI) is a method based on optical principles to detect common defects encountered in PCB board welding production. It is an SMT inspection technology that has emerged in recent years. [0003] With the rapid development of the SMT industry, the size of components is developing in the direction of miniaturization and density, which makes it difficult to detect the defects of components on the PCB by manual visual inspection. The efficiency of manual detection is low, and it is time-consuming and laborious. Some traditional detection technologies, such as online testers, can no longer meet the requirements of SMT development. Therefore, AOI technology is produced to meet the requirements of SMT development. [0004] At present, the existing AOI sof...

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Problems solved by technology

[0004] At present, the existing AOI software has the problem of false negatives and false negatives when detecting target components. The reason for this involves two problems: the light source used when collecting images and the detection algorithm used in the software

[0006] The second problem is the AOI software detection algorithm. Since the algorithms used by various manufacturers are not the same, the detection effect is also different.

No matter which algorithm is used, false positives and false positives will occur during component detection. In order to reduce the rate of false negatives and false negatives, only more accurate positioning and image recognition methods are sought in the algorithm.

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