Browsing by Author "Perng, Der-Baau"

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A novel internal thread defect auto-inspection system
(2010-03-01)
Perng, Der-Baau
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Chen, Ssu-Han
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Chang, Yuan-Shuo
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工業工程與管理學系
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Department of Industrial Engineering and Management
This paper describes a novel optical thread plug gauge (OTPG) for internal thread inspection using machine vision. The OTPG is composed of a rigid industrial endoscope, a charge-coupled device camera, and a two degree-of-freedom motion control unit. A sequence of partial wall images of an internal thread are retrieved and reconstructed into a 2D unwrapped image. Then, a digital image processing and classification procedure is used to normalize, segment, and determine the quality of the internal thread. The proposed OTPG provides an orientation-free and convenient method for detecting defects such as scratches, collapses, and flaws in an internal thread.
A Study of Using Smart Digital Content Technology in Retail Stores
(2013)
Sha, D. Y.
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Perng, Der-Baau
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Lai, Guo-Liang
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交大名義發表
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National Chiao Tung University
The main purpose of this study is to identify the critical factors that affect shopping intention of consumers while using smart digital content technology at a retail store. Through verifying the factors in the test model proposed by this study based on the technology acceptance model, we performed structural equation modeling method to test the model and collected data from 209 customers to evaluate the proposed model. The results of this study strongly support that the simplification of user interface and proper information feedback are the important factors to affect the customer\'s intention to use smart digital content information technology.
Advanced automated optical inspection system for fishtail collapse of microrouter
(2008)
Perng, Der-Baau
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Chen, Yen-Chung
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工業工程與管理學系
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Department of Industrial Engineering and Management
In this paper, an innovative automated optical inspection (AOI) system is proposed to detect fishtail collapse of various fishtail images. Up to the present, there is no report on the inspection of fishtail collapse by using an AOI system. The proposed AOI system is the first system that can inspect the fishtail collapse of microrouter. The fishtail image of the microrouter was extracted first by a newly developed lighting device. We use the end gash to identify one of the blades as the reference blade, in order to provide an orientation-invariant method to solve the fishtail image rotation problem. Three invariant features of the blade are used as indicators of quality control. The blade with collapse, whose area is as small as 0.02mm x 0.02mm, could be identified based on the constructed quality control charts. Twenty-five fishtail images are used to validate the proposed AOI system. The successful detection rate of the implemented AOI system is up to 99.2%, and it demonstrates that this system detects the collapse accurately and robustly.
An Advanced Auto-Inspection System for Fishtail Collapse of Micro-router
(2008)
Perng, Der-Baau
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Chen, Yen-Chung
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工業工程與管理學系
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Department of Industrial Engineering and Management
In this paper, an auto-optical inspection system for fishtail collapse of router was proposed. The proposed AOI system first extracts the fishtail image of router by developed mechanism. A method for identifying the center of fishtail was proposed. The I D profile formed by the boundary and center of fishtail is used to segment the fishtail into several blades. We used the end gash to identify one of the blades as the reference blade, so as to provide an orientation-invariant method to solve fishtail image rotation problem. Three invariant features of blade were used as indicators of quality control. The blade with collapse, which area is as small as 0.02 mm x 0.02 mm, could be identified based on the constructed quality control charts. Twenty-five fishtails were used to validate the proposed AOI system. The successful detection rate of the implemented AOI system is up to 99.2% that demonstrated this system achieves the collapse detection accurately and robustly.
An advanced auto-inspection system for micro-router collapse
(2010-10-01)
Perng, Der-Baau
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Chen, Yen-Chung
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工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, we propose an auto-optical inspection (AOI) system that can inspect micro-router (router) collapse automatically. The router is a tool used to cut a printed circuit board (PCB). A few types of defects could occur in the routers and cause unexpected damage to the PCBs. Among these defects, collapse is the most critical defect that must be detected. Currently, router manufacturing companies rely on human inspectors to control the router quality. We first extract the silhouette edges and associated features (peaks and valleys) of a router's silhouette image by computer vision technique. Then, these silhouette edges and associated features are used to reconstruct a set of 2D isograms that correspond to the router surface. Finally, a pattern recognition method is devised to identify and classify some features of the pattern in the 2D isograms. In this study, two types of routers with different diameters are used for inspection experiments. There are 15 routers of each type. The experimental results reveal that the proposed AOI system can robustly and successfully detect the collapse of diamond-patterned routers with different sizes. The successful detection rate is above 96%. The proposed AOI system can assist in determining the quality of the routers.
An AOI Approach for IC Lead Index Auto-verification
(2010)
Perng, Der-Baau
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Chang, Guei-Ci
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Lee, Shu-Ming
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Chen, Ssu-Han
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工業工程與管理學系
To wire-bond automatically, the IC lead positions on the CAD drawing and the corresponding ones on the extracted substrate image should be pre-verified. This paper proposed an AOI approach for IC lead index auto-verification which conquered the lead shape distortion, golden exposed, shifting, rotation, and scaling difficulties of extracted substrate image. Experimentations revealed that the proposed AOI approach can accurately verify the corresponding leads between a CAD drawing and the extracted substrate image with high repeatability.
Analysis of changes to the anterior chest wall after the Nuss procedure-an objective measurement of pectus excavatum
(2009-12-01)
Chang, Pei-Yeh
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Chang, Chaur-Hsiang
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Lai, Jin-Yao
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Chen, Jeng-Chang
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Perng, Der-Baau
Introduction: We report a noninvasive method for recording the deviation of the anterior chest wall (ACW) in patients with pectus excavatum before and after the insertion and removal of a Nuss bar. Patients and Method: All patients undergoing the Nuss procedure at our institutions between June 2008 and February 2009 were enrolled in this study. A thermal plastic strip was used to cast the ACW at the skin level along the area corresponding to the tract of the inserted bar. The height of the ACW was defined as the perpendicular length from the xiphoid process to the transverse line drawn between the 2 midaxillary points. Results: Bar insertion caused a significant increase in ACW height and width. Bar removal reduced the corrective effects in terms of a significant decrease in ACW height; at the same time, an increase in ACW width was noted. Conclusion: Feature extraction and analyses of permanent contour casts of the ACW help to understand immediate changes in the ACW after the Nuss procedure and may assist in the design of the bar at insertion. The Nuss bar in situ helped to maintain cosmetic benefits to the ACW. (C) 2009 Elsevier Inc. All rights reserved.
Automated bonding position inspection on multi-layered wire IC using machine vision
(2010)
Perng, Der-Baau
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Lee, Shu-Ming
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Chou, Cheng-Chuan
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
No available method can automatically verify the correctness of the wire bonding positions on a multi-layered wire IC. This paper presents a novel method that integrates image processing and wire bonding simulation techniques. The proposed method first takes the IC leadframe image and calculates the lead information before actual wire bonding begins. The wire bonding position information is then generated to simulate the actual wire bonding process. The generated pseudo bonding information is then compared with that from a referential machine. This approach can check the wire bonding position correctness before any actual wire bonding is executed. This approach can fully solve the mal-detection and lost detection problems that may occur in other available methods. The experimental results show that the proposed bonding position check (BPC) method is robust and fast enough for applied multi-layered wire IC inspection synchronously with the wire bonding process.
Automated SMD LED inspection using machine vision
(2011-12-01)
Perng, Der-Baau
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Liu, Hsiao-Wei
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Chang, Ching-Ching
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工業工程與管理學系
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Department of Industrial Engineering and Management
Light-emitting diodes (LED) are used in many different applications. However, some LED defects are unavoidable in large-volume fabrication and taping processes. These defects may include missing components, incorrect orientations, inverse polarity, mouse bites, missing gold wires, and surface stains. Human visual inspection has traditionally been used in LED-packaging factories. However, it is subjective, time consuming, and lacking consistent inspection results. This paper proposes a machine vision system combining an automatic system-generated inspection regions (IR) method to inspect two types of LED surface-mounted devices (SMDs). Experimentation revealed that the proposed automatic inspection method could successfully detect defects with up to 95% accuracy for both types (Types 1 and 2) of SMD LEDs. The online inspecting speed was on average under 0.3 s per image.
Automatic Surface Inspection for Directional Textures Using Discrete Cosine Transform
(2009)
Chen, Ssu-Han
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Perng, Der-Baau
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工業工程與管理學系
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Department of Industrial Engineering and Management
A new global image restoration scheme using discrete cosine transform (DCT) is proposed in this paper. This DCT-based image restoration scheme can be used for inspecting the defects in directional texture surfaces automatically. The input spatial domain image is first transformed into DCT domain. The dominating directions of the textures in the input image will be compacted to orthogonal straight lines, respectively, throughout the direct current (DC) component in the spectrum. The linear primitives associated with high-energy frequency components in the DCT domain are eliminated by reducing them to zero and then transformed back to the spatial domain. This procedure will have all directional textures be blurred and will preserve only local defects if they are initially embedded in the input image. Experiments on a variety of product surfaces with directional texture such as straight, slant, orthogonal, and slant orthogonal linear primitives are given to demonstrate the effectiveness and robustness of the proposed method.
Automatic surface inspection for directional textures using nonnegative matrix factorization
(2010-05-01)
Perng, Der-Baau
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Chen, Ssu-Han
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工業工程與管理學系
;
Department of Industrial Engineering and Management
A global image restoration scheme using nonnegative matrix factorization (NMF) is proposed in this paper. This NMF-based image restoration scheme can be used for inspecting the defects in directional texture surfaces automatically. Decomposing the gray level of image pixels into an ensemble of row vectors, we first reduce the data set from original data space into a lower-dimensional NMF space. The repetitive and periodical primitives are well reconstructed by two lower-dimensional basis and weight matrices with nonnegative elements, named nonnegative matrix approximation (NMA). Then the local defects will be revealed by applying image subtraction between the original image and the NMA. As a consequence, the directional textures are eliminated, and only local defects are preserved if they initially are embedded in the surface. A supervised heuristic, elbow of residual curve rule, is devised which helps users to determine a proper basis space size of a specific image. Experiments on a variety of directional texture surfaces are given to demonstrate the effectiveness and robustness of the proposed method.
Design and development of a new machine vision wire bonding inspection system
(2007-09-01)
Perng, Der-Baau
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Chou, Cheng-Chuan
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Lee, Shu-Ming
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工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, we developed a fast and robust machine vision system for wire bonding inspection. The defects caused by a bonding wire being broken, lost, shifted, shorted, or sagged in an integrated circuit (IC) chip can be inspected automatically. A new lighting environment was devised which will highlight the slope of the bonding wire and suppress the background from being extracted. First, a set of machine vision algorithms were designed to filter out the defects of broken wire, lost wire, shifted wire, and shorted-out wire. Second, the 3-D type defect of sagged wire can be detected by inspecting the change of the bonding wire slope, derived from a single 2-D image. Some illustrations are given to show the efficiency and effectiveness of the proposed novel wire bonding vision inspection system.
Directional textures auto-inspection using discrete cosine transform
(2011)
Perng, Der-Baau
;
Chen, Ssu-Han
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
This paper describes a global image restoration scheme using a discrete cosine transform (DCT) that can be used to detect defects in directional textured surfaces automatically. The input spatial domain image is first transformed into the DCT domain so that the dominant directions of the texture in the input image will be compacted into the orthogonal straight lines or impulses through the direct current (DC) component of the spectrum. The linear primitives associated with the high-energies in the DCT domain are eliminated by reducing them to zero before transforming back to the spatial domain. Finally, the defects, if any, are extracted by the thresholding method. Experiments on a variety of product surfaces with directional textures such as straight, slanted, orthogonal, slanted orthogonal, and oblique linear primitives were conducted in this paper. The proposed scheme would blur directional textures and preserved only local defects if they were initially embedded in the image. Furthermore, some preliminary experiments were also conducted to demonstrate the proposed scheme was insensitive to horizontal and vertical shifting, changes in illumination, and image rotation.
Directional textures auto-inspection using principal component analysis
(2011-08-01)
Chen, Ssu-Han
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Perng, Der-Baau
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工業工程與管理學系
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Department of Industrial Engineering and Management
This paper describes a global image restoration scheme using a principal component analysis that can be used to inspect defects in directional textured surfaces automatically. Decomposing the gray level of image pixels into an ensemble of row vectors, the input spatial domain image is transformed into principal component space so that the directional textures are well approximated by first k major components and their corresponding weight vectors, named truncated component solution (TCS). Then the local defects will be revealed by applying image subtraction between the original image and the TCS. This procedure blurs all directional textures and preserves only the local defects that were initially embedded in the input image. These defects, if any, are finally extracted by thresholding. Experiments on a variety of product surfaces with directional textures such as straight, slanted, orthogonal, slanted orthogonal, and oblique linear primitives were conducted to demonstrate the effectiveness and robustness of the proposed method. Furthermore, some preliminary experiments were also conducted to demonstrate the proposed scheme was insensitive to horizontal and vertical shifting, changes in illumination, and image rotation.
Illumination system for wire bonding inspection
(2007-02-20)
Perng, Der-Baau
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Chou, Cheng-Chuan
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Lee, Shu-Ming
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工業工程與管理學系
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Department of Industrial Engineering and Management
A novel lighting system was devised for 3D defect inspection in the wire bonding process. Gold wires of 20 mu m in diameter were bonded to connect the integrated circuit (IC) chip with the substrate. Bonding wire defects can be classified as 2D type and 3D type. The 2D-type defects include missed, shifted, or shorted wires. These defects can be inspected from a 2D top-view image of the wire. The 3D-type bonding wire defects are sagging wires, and are difficult to inspect from a 2D top-view image. A structured lighting system was designed and developed to facilitate all 2D-type and 3D-type defect inspection. The devised lighting system can be programmed to turn the structured LEDs on or off independently. Experiments show that the devised illumination system is effective for wire bonding inspection and will be valuable for further applications.
Special Issue: Challenges for Advanced Technology Foreword
(2009-09-01)
Wen, Ue-Pyng
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Sheu, D. Daniel
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Hwang, Sheue-Ling
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Perng, Der-Baau
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工業工程與管理學系