• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.281-284
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• 2007

A realization for image distortion correction processing system with DSP processor is presented in this paper. The image distortion correcting algorithm is realized by DSP processor for focusing on more real time processing than image quality. The lens and camera distortion coefficients are processed by YCbCr Lookup Tables and the correcting algorithm is applied to reverse mapping method for geometrical transform. The system experimentation results in the processing time about 34.6 msec on $720{\times}480$ curved image at 150 degree visual range.

• Structural Engineering and Mechanics
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• v.10 no.2
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• pp.93-110
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• 2000

An alternative interpretation of the completeness requirements for the higher order elements is presented. Apart from the familiar condition, $\sum_iN_i=1$, some additional conditions to be satisfied by the shape functions of higher order elements are identified. Elements with their geometry in the natural form, i.e., without any geometrical distortion, satisfy most of these additional conditions inherently. However, the geometrically distorted elements satisfy only fewer conditions. The practical implications of the satisfaction or non-satisfaction of these additional conditions are investigated with respect to a 3-node bar element, and 8- and 9-node quadrilateral elements. The results suggest that non-satisfaction of these additional conditions results in poorer performance of the element when the element is geometrically distorted. Based on the new interpretation of completeness requirements, a 3-node element and an 8-node rectangular element that are insensitive to mid-node distortion under a quadratic displacement field have been developed.

• Progress in Medical Physics
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• v.7 no.1
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• pp.3-7
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• 1996

The accuracy in target localization of CT, MR, and digital angiography were investigated for stereotactic radiosurgery. The images using CT and MR were obtained out of geometrical phantom which was designed to produce exact coordinates of several points within a 0.lmm error range. The slice interval was 3mm and FOV was 35cm for CT and 28cm for MR. These images were transferred to treatment planning computer using TCP/IP in forms of GE format. Measured 3-D coordinates of these images from planning computer were compared to known values by geometrical phantom. Anterior-posterior and lateral films were taken by digital angiography for measurement of spatial accuracy. Target localization errors were 1.2${\pm}$0.5mm with CT images, 1.7${\pm}$0.4mm with MR-coronal images, and 2.1${\pm}$0.7mm with MR-sagittal images. But, in case of MR-axial images, the target localization error was 4.7${\pm}$0.9mm. Finally, the target localization error of digital angiography was 0.9${\pm}$0.4mm. The accuracy of diagnostic machines such as CT, MR, and angiography depended on their resolutions and distortions. The target localization error mainly depended on the resolution due to slice interval with CT and the image distortion as well as the resolution with MR However, in case of digital angiography, the target localization error was closely related to the distortion of fiducial markers. The results of our study should be considered when PTV (Planning Target Volume) was determined.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.601-605
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• 2009

Due to the fact that fish-eye lens can provide super wide angles with the minimum number of cameras, field-of-view over 180 degrees, many vehicles are attempting to mount the camera system. Camera calibration should be preceded, and geometrical correction on the radial distortion is needed to provide the images for the driver's assistance. However, vehicle fish-eye cameras have diagonal output images rather than circular images and have asymmetric distortion beyond the horizontal angle. In this paper, we introduce a camera model and metric calibration method for vehicle cameras which uses feature points of the image. And undistort the input image through a perspective projection, where straight lines should appear straight. The method fitted vehicle fish-eye lens with different field of views.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.18-24
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• 2004

SPECT technology is used for the reconstructed image in the field of industry noncontact measurement system. One of the distortion problems in reconstructed image quality is a collimator characterictic. The image distortion is caused by a geometrical structure of the collimator. This paper indicated a correction method to remove the image distortion by the structure of the collimator, and compared with the existing correction method. The correction. method removed the image distortion to use deconvolution of projection data with the shift-variant blurring function in the frequency domain. In this pater, I simulated with the collimator angle and distance between the detector and the center of object. and verified with expeimental data. The validity and limitation of correction method is studied for actual industrial applications.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.10
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• pp.1021-1028
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• 2009

In this paper, a location identification for a cleaning robot using a camera shooting forward a room ceiling which kas three point landmarks is introduced. These three points are made from a laser source which is placed on an auto charger. A fisheye lens covering almost 150 degrees is utilized and the image is transformed to a camera image grabber. The widly shot image has an inevitable distortion even if wide range is coverd. This distortion is flatten using an image warping scheme. Several vision processing techniques such as an intersection extraction erosion, and curve fitting are employed. Next, three point marks are identified and their correspondence is investigated. Through this image processing and image distortion adjustment, a robot location in a wide geometrical coverage is identified.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.52.2-53
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• 2017

We develop a methodology to use the redshift dependence of the galaxy 2-point correlation function (2pCF) as a probe of cosmological parameters. The positions of galaxies in comoving Cartesian space varies under different cosmological parameter choices, inducing a redshift-dependent scaling in the galaxy distribution. This geometrical distortion can be observed as a redshift-dependent rescaling in the measured 2pCF. The shape of the 2pCF exhibits a significant redshift evolution when the galaxy sample is analyzed under a cosmology differing from the true, simulated one. Other contributions, including the gravitational growth of structure, galaxy bias, and the redshift space distortions, do not produce large redshift evolution in the shape. We show that one can make use of this geometrical distortion to constrain the values of cosmological parameters governing the expansion history of the universe. This method could be applicable to future large scale structure surveys, especially photometric surveys such as DES, LSST, to derive tight cosmological constraints. This work is a continuation of our previous works as a strategy to constrain cosmological parameters using redshift-invariant physical quantities.

• Fashion & Textile Research Journal
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• v.15 no.3
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• pp.325-335
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• 2013

This work develops a motif design integrated with geometrical patterns in traditional ddeoksal and that can be applied to a scarf design so that traditional elements unique to Korean culture can be developed further for a modern application to various design fields. For the research method, literature reviews on op art and traditional ddeoksal were conducted with Adobe Illustrator CS3 and Adobe Photoshop CS3. As for the motif combination, such applications were taken as five pieces from the works of Victor Vasarely and some traditional ddeoksal shapes such as oblique line pattern, taegeuk pattern, and geometrical pattern. Abstract and geometrical images were borrowed from op art and ddeoksal for image expression. The total number of works selected was eleven. To realize the applied scarf design, a motif layout was performed with the scarf center or rim highlighted so that each design feature could be remarkable based on the motif combination. With the function of scaling, rotation, opacity control, filtering effect, the changed images were shown through motif distortion. In addition, this work applies a single combined motif to products for a possible transformation into handkerchiefs and boutique scarfs in the case of smaller sized scarfs.

• Journal of Fashion Business
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• v.18 no.2
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• pp.14-28
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• 2014

This study analyzed the group of experts who were related to cubism, selected among the works of 2010~2013 Paris Collection based on F.G.R.(Focus Group Research). According to the results of this study, there were appeared first, 'a one-piece dress' second, 'H silhouette' third, 'cotton', in case of item distribution and frequency. The analysis was done by using the manner of expression, cubical expression, exaggeration, distortion, dismantlement, geometrical division of face, mix-match look, wraparound repetition, asymmetric structure, etc. Based on the outcomes of the analysis on figurative design elements, this study adjusted three manners appearing on cubism fashion style. First, it was 'avant garde manner' of constitution or 'dismantlement' which was compiled into multi-view representations of overlaps and viewpoints by repetitive use of color tone trimming detail. Second, it was 'geomagnetic block placement' which expresses cubism with geometric partitioning of surface and separation of panel by cutting disintegration. Finally, it was 'distortion and simplification of silhouette' which is a distortion created by constitution-line pressed thin with silhouette. It maximizes the beauty of human body outline, which was distorted by three-dimensional-manipulation, and simplified by ellipsis for another shape for the extension or expansion of detail trimming.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2116-2120
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• 2007

A realization for image distortion correction processing system with DSP processor is presented in this paper. The image distortion correcting algorithm is realized by DSP processor for focusing on more real time processing than image quality. The lens and camera distortion coefficients are processed by the Lookup Tables and the correcting algorithm is applied to reverse mapping method for geometrical transform. The system experimentation results in the processing time about 31.3 msec $720{\times}480$ wide range image, and the image is stable and spontaneous to be about 8.3% average PSNR variation with changing a wide angle.