MELF (Metal Electrode Leadless Face) component positioning and detecting method based on match template

Abstract

The invention discloses a MELF (Metal Electrode Leadless Face) component positioning and detecting method based on match template which belongs to the technical field of component positioning and detecting. Under a traditional match template algorithm, it takes great amount of computing to detect a component with a rotation angle, and the process is also very slow to perform. For these reasons, the positioning and detecting speed for the component is also rather slow. In light of these shortcomings, the invention provides a MELF (Metal Electrode Leadless Face) component positioning and detecting method. The method creates a template image with angle to obtain a distance transformation image of a narrowed image of the component and a distance transformation image of the original image of the component and to obtain a final best match template image and a best match position. Key edge points are extracted from an edge image with interference points to form a minimum external rectangle. According to the number of the non-zero pixels in the minimum external rectangle with added offset value, the method determines that the positioning of the component is correct and that the length and the width of the component are in the bearable range. After that, the positioning and detecting process is complete and positioning information of the component is then transmitted out. The method provided by the invention is capable of reducing the number of positions searched during the computing of a match template value. With the method, the computing efficiency of a match template can be increased and the accurate rate for positioning and detecting reaches 95% to 98%.

Description

technical field [0001] The invention relates to a method for locating and detecting MELF elements based on template matching. Background technique [0002] The application of machine vision in surface mount technology (SMT) has become more and more mature. During the placement process, the precise positioning and detection of components has an important impact on the efficiency of the entire SMT production line. [0003] MELF is a cylindrical packaging form with metal cap electrodes at both ends, usually wafer resistors, bonded inductors, and bonded diodes. The existing detection methods are mainly for chip components, spherical lead components and rectangular lead components, and there are few researches for cylindrical components. Under specific lighting conditions, the image geometry features of MELF components are relatively regular rectangular areas. The goal of the detection algorithm is to extract a rectangle that can describe the component pose from the acquired ima...

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