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APPLICATION OF IMAGE PROCESSING IN THE DETECTION OF PRINTED CIRCUIT BOARD

Presented by:Jeevan B M

4KV11EC032VIII SEM E&C

KVGCE

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CONTENTS

• Introduction• Image Acquisition System• Image Enhancement• Edge Detection• Image Binarization• Defect Detection Of Subtraction Method• Conclusions• References

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INTRODUCTION

• Electronic equipments quality and performance depends on quality of printed circuit board[PCB].

• Defections appear in PCBo Solder mark is unevennesso Lines and pads damages productions in PCB

So detection is a necessary to ensure the quality of PCB

• defections appear in PCB due too Bad welding pointso Short circuit

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• Image processing has two purposeso Images suitable for human observation and detectionoRecognize and understand images automatically

• The system includeso Image acquisition system o Image enhancementoEdge detection oDefect detection

Continue..

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Image Acquisition system:

Figure: Acquisition system

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•System is composed of light source, conveyor belt, controlling board, circuit board and CCD camera.

•Light sources that improve the capabilities of vision systems.

•Conveyor belt is used to automatically transmit detected circuit boards.

•According to the requirements, we fix the CCD camera on the position is fixed.

•The speed of the belt should match the CCD acquisition rate.

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•The hole procedure consists of 3 steps1) Detected board should be placed.2) Setting the CCD camera resolution and exposure time.3) The circuit board images collected by CCD are saved to

PC.

• Then image processing and feature extraction is going to be undertaken.

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Image Enhancement

•Image gray transformation and image smoothing are the two methods of image enhancement.

•Image smoothing also called blurring of an image and image smoothing is mainly used to reduce the noise.

•Gray scale image refereed as monochrome or one color image contains only brightness information no color information.

•Gray level correction is a simple and effective way to enhance image in spatial domain.

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Continue..

• In this paper two dimensional gray equalization is achieved

• Gray transformation increase the dynamic range, expand the image contrast and make the image clearer.

a) Original Image b) Enhancement Image Figure. Gray Enhancement Image

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Edge Detection

•In this edge of the object is reflected by the discontinuity of gray level.

•It can be divided into step edges and roof edges according to the characteristics.

•the purpose of edge detection is to obtain external contour features of the image.

•Edge detection is the name for which identifying points in a digital image.

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Image binariztion

•Binary image is a simplest type of image can take on two values typically black or white and 0 or 1.

•It is a important technology to get the image contour.

•Mathematical morphological opening operation can be usedto eliminate small objects, separating objects, smooth largerobject boundaries without obvious area changes.

•Morphological opening operation is firstly proposed to the original image in solder joint

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a) Background image b) Image Enhancement Figure .Morphological image enhancement

Figure . Binarization of solder joints

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Defect detection of subtraction method

•Background subtraction can provide the difference between images. •And can be used to oGuide the dynamic monitoringo Moving target detection and trackingo Image background elimination and image recognition .

•In this process difference corresponding to missing components in a target PCB is identified.

• In the processing noise will be extracted and leaving only defect characteristics .

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a) Detect Image b)Template image (c)Defect detection

Figure . Image detection of Subtraction Method

Figure shows is the defect detection image by subtraction method, and a) is the board image to be detected.b) is the template image.c) is the defect detection image by subtraction.

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CONCLUSION

•This paper analysis the Binarization and defects detectingsystem of the printed circuit board based on imageprocessing technology.

•The system is composed of image acquisition, image enacement, edge détection , image binariztion and defects detection by subtraction method.

•This method can perform high effective, fast speed and accurate measurement by the powerful digital image processing ability

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REFERENCES

[1] Xiong Zhenjiao. Research on the Detection Method Based on Image for Defect in Circuit Board. [Mj. School of Information Engineering Nanchang Hangkong University, 2012.

[2] N.G.Shankar, Z.W. Zhong. Defect detection on semiconductorwafersurfaces[I].Microelectronic Engineering , 2005: 337-346.

[3] JIANG Ke-wan, WU Qi. Application of Image RecognitionTechnology in PCB Precision.

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• Xiong Bangshu, Xiong Zhenjiao, Mo Van. Detection Method ofPrinted Circuit Board Defect

•S-J Ko, Lee Y H. Center Weighted Median Filter and theirApplication to Image Enhancement

•Liu He. Digital image processing and application [ Mj. ChinaElectric Power Press, 2005

• Zhao Chunhui. Modern Image Processing Technology and Matlab Realization[M]. Beijing People' Posts And Telecommunications press, 200 I.

•K.RCastleman. Digital Image Processing. Newyork PrenticeHall,1998.

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•Bin He. Digital Image Processing [Mj. Beijing People' Posts And Telecommunications Press, 2001

• Zhou Iinping.MATLAB6.5 Image Processing and Application Examples[Mj. Beijing: Science

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THANK YOU