• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.1
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• pp.64-72
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• 1995

We propose a new image coding method which takes into account both statistical redundancy and perceptual irrelevancy of the DCT coefficients so as to provide a high quality of the reconstructed images with a reduced transmission bit rate First, a block of DCT coefficients are decomposed into 16 subvectors so as for a subvector to convey key information about one of the low-pass or the dirctional filtered images. Then, the most significant subvector is selected as the principal edge of the block and then vector quantized. After that, the residuals of the block are computed and then sequentially quantized through aforementioned procedure until the quantization distortion is smaller than the target distortion. The proposed scheme is good at encoding images with a variety of transmission bit rates, especially at very low bit rate coding. In addition, it is another benifit of the proposed scheme that an image can be quantized with a wide range of the transmission bit rates by simply adapting the stopping criterion of the sequential vector quantizer according to the target distortion of the reconstructed image.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.1
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• pp.13-23
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• 2015

Recently, a few image-processing based mobile urine testers have actively been studied since the urine-analysis result can be available to the user in real time immediately after the test is done. However, the accuracy of test result can be severely degraded due to variable illumination environments and a variety of manners to capture the image with a camera embedded in the smartphone according to different users. This paper proposes the Check4Urine system, a novel smartphone-based portable urine-analysis tester and provides three techniques to improve such a performance degradation problem robust to various test environments and disturbances, which are the compensation algorithm to correct the varying illumination effect, an urine strip detection algorithm robust to edge loss of the object image, and the color decision algorithm based on the pre-processed reference table. Experimental results show that the proposed Check4Urine system increases the accuracy of urine-analysis by 20-50% at various test conditions, compared with the existing image-processing based mobile urine tester.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.173-176
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• 2008

Lake studies play an important role in water management, ecology, and other environmental issues. Typically, monitoring lake levels is the first step on the lake studies. However, for the Prairie Pothole Region (PPR) of North America having millions of small lakes and potholes, on-site measurement for lake levels is almost impossible with the conventional gage stations. Therefore, we employed Geographic Information System (GIS) and remote sensing approach with the Shuttle Radar Topography Mission data to extract lake levels. Several image processing techniques were used to extract lake levels for January, 2000 as a one-time snapshot which will be useful in historic lake level reconstruction. This study is associated with other remote sensing datasets such as Landsat imagery and Digital Orthophoto Quadrangle (DOQ). In this research, firstly, image processing techniques like FFT filtering, Lee-sigma, masking with Canny Edge Detector, and contouring were tested for lake level estimation. The semi-automated contouring technique was developed to accomplish the bulk processing for large amount of lakes in this region. Also, effectiveness of each method for bulk processing was evaluated.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.431-438
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• 2016

In this paper, we present an upsampling technique for depth map image using color and depth weights. First, we construct a high-resolution image using the bilinear interpolation technique. Next, we detect a common edge region using RGB color space, HSV color space, and depth image. If an interpolated pixel belongs to the common edge region, we calculate weighting values of color and depth in $3{\times}3$ neighboring pixels and compute the cost value to determine the boundary pixel value. Finally, the pixel value having minimum cost is determined as the pixel value of the high-resolution depth image. Simulation results show that the proposed algorithm achieves good performance in terns of PSNR comparison and subjective visual quality.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.658-663
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• 2003

A process of 3-D stereo particle image velocimetry(PIV)was developed for the measurement of an illuminated sliced section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transformation of the oblique-angled image to the right-angled image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criteria, and finally 3-D display as the post processing. An experimental system was also used for the application of the proposed method. Two high speed digital CCD cameras and an Argon-Ion Laser for the illumination were adopted to clarify the time-dependent characteristics of the leading edge extension(LEX) in a highly swept shape applied to a delta wing found in modern air-fighters.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.407-415
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• 2016

In this paper, an aviation image fusion method is proposed for creating an informative fused image through gray scale images within noise. The proposed method is based on an adaptive guided filter which adjusts regulation parameter of the filter based on peak signal noise ratio (PSNR) in order to behave as an edge-preserving filtering property. Simulation results demonstrate that the proposed method preserves the edge information of the input image and reduces the noise effect while maintaining designed PSNR.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.164-167
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• 1997

The treatment setup of patients during irradiation is an important aspect in relation to the success of radiotherapy. Imaging with the treatment beam is a widely used method or verification of the radiation field position relative to the target area, prior to or during irradiation. In this paper, Real time digital radiography system was implemented or verification of local error between simulation plan and radiation therapy machine. Portal image can be acquired by CCD camera, image board and pentium PC after therapy Radiation was converted into light by a metal/fluorescent Screen. The resulting image quality is comparable to film, so the imaging system represents a promising alternative to film as a method of verifying patient positioning in radiotherapy. Edge detection and field size measurement were also implemented and detected automatically for verification of treatment position. Field edge was added to the original image or checking the anatomical treatment verification by therapy technicians. By means of therapy efficiency improvement and decrease of Radiation side effects with these techniques, Exact Radiation treatments are expected.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.841-849
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• 2001

The pixel information of the object was obtained sequentially and pixels were clustered to a label by the line labeling method. Feature points were determined by finding the slope for edge pixels after selecting the fixed number of edge pixels. The slope was estimated by the least square method to reduce the detection error. Once a matching point was determined by comparing the feature information of the object and the pattern, the parameters for translation, scaling and rotation were obtained by selecting the longer line of the two which passed through the matching point from left and right sides. Finally, modified Hausdorff Distance has been used to identify the similarity between the object and the given pattern. The multi-label method was developed for recognizing the patterns with more than one label, which performs the modified Hausdorff Distance twice. Experiments have been performed to verify the performance of the proposed algorithm and method for simple target image, complex target image, simple pattern, and complex pattern as well as the partially hidden object. It was proved via experiments that the proposed image matching algorithm for recognizing the object had a good performance of matching.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.60-69
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• 1999

Motion compensation by affine transform has been proposed as a solution to the artifact problems in very low bit rate video coding and a HMA(Hexagoanl Matching Algorithm) has been proposed for refine motions estimation. When dividing images with an affine transform, as image objects do not necessarily conform to triangle patterns. In this paper we propose a method that first divides an image into triangular patches according to its edge information and then further divides the image into more detailed triangular patches where more complicated edge information occurs. We image propose a PMA(Polygona Matching Algorithm) for refine motion estimation because of the different triangle pattern types of neighboring blocks and its performance is compared with H.263.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.1050-1056
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• 2000

In this paper, We Propose the automobile license plate extraction method using Discrete Cosin Transform and Correlation fem automobile image obtained through digital camera. The automobile license plate is consisted of the character and rectangle background of it. We extracted the automobile edge image by the DCT processing of automobile image and Obtained the automobile license plate from the automobile edge image by Correlation processing. We separated characters from automobile license plate using the projection histogram. Compare to the previous methods, we obtained the good result from extracting the automobile license plate at night, very strong light and bad weather.