Automatic Calibration of the Optical System in Passive Component Inspection Sungho Suh and Moonjoo Kim Samsung Electro-Mechanics, 150 Maeyoung-ro, Suwon, Korea {sh86.suh, moonjoo.kim}@samsung.com Keywords: Automatic Calibration of the Optical System, Passive Component Inspection, Gain, White Balance Ratio. Abstract: A passive component inspection machine is to obtain a image of a passive component by using a speciﬁc lighting and camera, and to detect defects on the image of the component. It inspects all the aspects of the component based on the image which is captured by using the lightings and cameras. The number of the lightings and cameras are proportional to the number of the component aspects. To detect the defects of the component effectively, the difference between the image quality by each camera should be minimized. Even if the light conditions are calibrated automatically, the average intensities of the images are different because of inﬂuence of Bayer ﬁlter which is used in CCD camera in the passive component inspection machine. More- over, there is one more problem that the range of the light intensity cannot cover the range of the component reﬂectance. Sometimes, it is needed to calibrate a gain value and white balance ratios of the camera manually. In order to solve the problems, we propose an automatic calibration method of the optical system in passive component inspection machine. The proposed method minimizes the inﬂuence of Bayer ﬁlter, does not use any initial camera calibration, and ﬁnd the optimal values for the overall gain and white balance ratios of red, green, blue colors automatically. To reduce the inﬂuence of Bayer ﬁlter, we perform to ﬁnd the optimal values of all colors balance ratio iteratively and formulate a relation between the overall gain and the white balance ratios to control all the parameters automatically. The proposed method is simple and the experimental results show that the proposed method provides faster and more precise than the previous method. 1 INTRODUCTION A passive component is a component that con- sumes, accumulates, and emits electric power sup- plied from the outside. It means that the part is in- capable of an active function. It includes various types of chips: MLCC (Multi-Layer Ceramic Capac- itor), BLCC (Boundary Layer Ceramic Capacitor), VLC (Vertically Laminated Capacitor), EMC (Elec- tro Magnetic Compatibility), etc. One of the pro- duction processes for the passive components is a visual inspection that inspect a chip visually. Prior to visual inspection, electrical properties inspection ﬁnishes to ship the chip without any visual defects. A passive component inspection machine (Liu et al., 2007) (Kim et al., 2013) (chieh Tseng et al., 2006) (chieh Tseng et al., 2009) is to capture an image of the passive component by using a speciﬁc lighting and camera, and to judge whether the chip has defects. The passive component inspection machine is shown in Figure 1 and the ﬂow of the machine is shown in Figure 2. It inspects all the aspects of the compo- nent based on the image captured by the lightings and cameras. The number of the lightings and cameras are proportional to the number of the component aspects. For effective detection, the difference in image quality by each camera should be minimized. More and more different image quality between cameras can cause higher false-positive and false-negative. Therefore, it is important that the inspection machine should se- cure uniformity of the image quality and calibrate its optical system to minimize the difference of the im- age quality between each camera. The number of the lighting for inspection is 12 based on two lanes six sides machine which is shown in Figure 2, and the number of the lighting channel is 128. And the num- ber of the used cameras is also twelve and it is nec- essary to calibrate the overall gain value, red, green, blue balance ratios. Previously, those are calibrated by operators manually. Thus, obtained image qual- ities vary as shown in Figure 3 because the calibra- tion by each operator is different. Moreover, it takes around 240 minutes averagely per a machine to set the optical system manually. In order to improve the 230 Suh S. and Kim M. Automatic Calibration of the Optical System in Passive Component Inspection. DOI: 10.5220/0006165402300237 In Proceedings of the 12th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2017), pages 230-237 ISBN: 978-989-758-225-7 Copyright c  2017 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved