• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.2
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• pp.335-345
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• 2021

The purpose of this study was to examine the effect of fabric movement on wrinkle recovery in a clothing care system and to propose an algorithm to improve wrinkle removal performance by adjusting fabric movements. With an increase in the reciprocating speed of the movement system, the number and amplitude of curves on the fabric also increased. This allowed the fabric to be applied to a larger tension, resulting in better wrinkle removal performance at higher speeds. However, even at high reciprocating speeds, wrinkles could not be removed effectively because of nodes at a few specific locations. Based on the results of fabric movement and wrinkle recovery, a complex movement algorithm was proposed with a mixture of various reciprocation speeds. It showed a 41%p (24%→65%) improvement of wrinkle recovery when compared with the conventional algorithm that showed simple fabric movement at 180 rpm. This was because the positions of nodes and antinodes changed continuously and the force by the reciprocating motion could be applied evenly to the fabric.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.195-203
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• 2015

In this paper, the dynamic behavior of wrinkled triangular solar sail was studied by finite element analysis. The analysis was proceeded first by performing static wrinkle analysis under tensile corner load on sail membrane, and then performing modal analysis. The membrane element method with wrinkle algorithm and the shell element post-buckling analysis method were used to account for the wrinkle deformation and the results were compared for analysis methods throughly. The comparison was also made to that without wrinkle consideration to investigate the effect of wrinkle deformation on the results. Cases with various loading cable angles were analyzed and the results were systematically examined.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.865-873
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• 2013

In this paper, numerical methods for wrinkle prediction of thin membrane were studied by finite element analysis. Techniques using membrane and shell elements were applied for triangular membrane. In case of membrane element method, the wrinkling was accounted for by the wrinkle algorithm of property modification, which was implemented to ABAQUS as a user subroutine. In case of shell method, geometrically nonlinear post-buckling analysis was performed to obtain the wrinkle deformation explicitly. The wrinkling deformation was induced by seeding the mesh with a random geometric imperfection. The results were investigated focusing on the mesh convergence and the solution accuracy.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.239-245
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• 2014

In this paper, a weighted value wrinkle detection method is suggested based on the analysis on the entire facial features such as face contour, face size, eyes and ears. Firstly, the main facial elements are detected with AAM method entirely from the input screen images. Such elements are mainly composed of shape-based and appearance methods. These are used for learning the facial model and for matching the face from new screen images based on the learned models. Secondly, the face and background are separated in the screen image. Four points with the biggest possibilities for wrinkling are selected from the face and high wrinkle weighted values are assigned to them. Finally, the wrinkles are detected by applying Canny edge algorithm for the interested points of weighted value. The suggested algorithm adopts various screen images for experiment. The experiments display the excellent results of face and wrinkle detection in the most of the screen images.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.25-33
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• 2009

In the paper, we proposed a new system to retrieve 3D wrinkle data based on stereo images. Usually, 3D reconstruction based on stereo images or video is very popular and it is the research focus, which has been applied for culture heritage, building and other scene. The target is object measurement, the scene depth calculation and 3D data obtained. There are several challenges in our research. First, it is hard to take the full information wrinkle images by cameras because of light influence, skin with non-rigid object and camera performance. We design a particular computer vision system to take winkle images with a long length camera lens. Second, it is difficult to get the dense stereo data because of the hard skin texture image segmentation and corner detection. We focus on semi-dense stereo matching algorithm for the wrinkle depth. Compared with the 3D scanner, our system is much cheaper and compared with the physical modeling based method, our system is more flexible with high performance.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3165-3177
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• 1999

With the recent outstanding advance in computer software and hardware, a number of researches to enhance the manufacturing speed and the process accuracy has been undertaken in many fields of textile industry. Frequently issued problems of automatic recognition of textile wrinkles in a grey scale image are as follows. First, changes in grey level intensity of wrinkles are so minute. Second, as both colors and patterns in a grey scale image appear in grey level intensity, it is difficult to sort out the wrinkle information only. Third, it is also difficult to distinguish grey level intensity changed by wrinkles from those by uneven illumination. This paper suggests a method of automatic recognition of textile wrinkles that can solve above problems concerned with wrinkles, which can be raised in a manufacturing process as one of errors. In this paper, we first make the outline of wrinkles distinctly, apply the block matching algorithm used in motion estimation, and then estimate block locations of target images corresponding to blocks of standard images with the assumption that wrinkles are kind of textile distortions caused by directional forces. We plot a "wrinkle map" considering distances between wrinkles as depths of wrinkles. But because mismatch can occur by different illumination intensity and changes in tensions and directions of the force, there are also undesirable patterns in the map. Post processing is needed to filter them out and get wrinkles information only. We use average grey level intensity of wrinkle map to recognize wrinkles. When it comes to textile with colors and patterns, previous researches on wrinkles in grey scale image hasn't been successful. But we make it possible by considering wrinkles as distortion.istortion.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.15-23
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• 2005

In this paper, the static and dynamic behavior of partly wrinkled membrane was studied. Membrane finite elements were used in the analysis and the wrinkling in the element was accounted for by a penalty-parameter material modeling which was implemented as a user subroutine to ABAQUS. The wrinkle algorithm was applied to a corner-loaded square membrane to investigate the effect of wrinkling on the static and dynamic behavior.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.406-414
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• 1997

A real-time inspection system is developed using line scan cameras. Several improved algorithms are proposed for real-time detection of defects in this automated inspection system. The major improved algorithms include the preprocessing, the threshold decision, and the clustering algorithms. The preprocessing algorithms are for exact binarization and the threshold decision algorithm is for fast detection of defects in 1-D binary images. The clustering algorithm is also developed for fast classifying of the defects. The system is applied to PCBs(Printed Circuit Boards) inspection. The typical defects in PCBs are pits, dent, wrinkle, scratch, and black spots. The results show that most defects are detected and classified successfully.

• Journal of KIISE:Software and Applications
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• v.32 no.3
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• pp.181-191
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• 2005

This article describes a simplified mathematical model and the relevant numerical algorithm to simulate the draped cloth on virtual human body. The proposed algorithm incorporates an elliptical, or non-consecutive, method to simulate the cloth wrinkles on moving bodies without resorting to the result of the past time-steps of drape simulation. A global-local analysis technique was employed to decompose the drape of cloths into the global deformation and the local wrinkles that will be superposed linearly The global deformation is determined directly by the rotation and the translation of body parts to generate a wrinkle-free yet globally deformed shape of cloth. The local wrinkles are calculated by solving simple elliptical equations based on the orthogonality between conjugate harmonic functions representing the wrinkle amplitude and the direction of wrinkles. The proposed method requires no interpolative time frames even for discontinuous body postures. Standing away from the incremental approach of time integration in conventional methods, the proposed method yields a remarkable reduction of CPU time and an enhanced stability. Also, the transient motion of cloth could be achieved by interpolating between the deformations corresponding to each static posture.

• Transactions of Materials Processing
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• v.32 no.5
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• pp.276-286
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• 2023

The field of sheet metal forming using press technology has become essential in modern mass production systems. Draw bead is often used to enhance formability. However, optimal draw bead design often requires excessive time and cost due to iterative experimentation and sometimes results in some defects. Given these challenges, there is a need to enhance formability by introducing segmented blank holders without draw beads. In this paper, the feasibility of a localized holding strategy using segmented blank holders is evaluated without the use of draw beads. The possibility for improving the formability was evaluated by utilizing a combination of the forming limit diagram and the wrinkle pattern-based defect indicators. Artificial neural networks were used for predicting defect indicators corresponding to arbitrary input holding forces and the NSGA-II optimization algorithm is used to find optimum blank holder forces yielding better defect indicators than the original process with drawbeads. Using optimum holding forces obtained from the proposed procedure, the stamping process with the segmented blank holders can yield better formability than the conventional process with drawbeads.