• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2000년도 춘계 학술발표회 논문집
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• pp.17-24
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• 2000

The Joint Photographic Experts Group (JPEG) is a standara still-image compression technique, established by the International for Standardization (ISO) and International Telecommunication Standardization Sector (ITUT). The standard is intended to be utilized in the various kinds of color still imaging systems as a standard color image coding format. Because JPEG is a lossy compression, the decompressed image pixel values are nto the same as values before compression. Image of JPEG compression is often made to JPEG recompression at saving to apply JPEG compression of color image. In general, JPEG is a lossy compression and compression image is predicted to be varied image quality according to recompressed Q-factor. Various distortions of JPEG compression and JPEG recompression has been reported in previous paper. In this paper, we compress four difference color samples (photo image, gradient image, vector drawing image, text image) according to various Q-factor, and then compressed images are recompressed according to various Q-factor once again. As the results, we inspect variation of quality and file size of recompressed color image, and ensure the optimum recompression factor.

• 한국인쇄학회지
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• 제18권2호
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• pp.55-68
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• 2000

Joint photographic experts group (JPEG) is a standard still-image compression technique, established by the international organization for standardization (ISO) and international telecommunication standardization sector (ITUT). The standard is intended to be utilized in the various kinds of color still imaging systems as a standard color image coding format. Because JPEG is a lossy compression, the decompressed image pixel values are not the same as the value before compression. Various distortions of JPEG compression and JPEG recompression has been reported in various papers. The Image compressed by JPEG is often recompressed by same type compression method in JPEG. In general, JPEG is a lossy compression and the quality of compressed image is predicted that is varied in according to recompression Q-factor. In this paper, four difference color samples(photo image, gradient image, gradient image, vector drawing image, text image) were compressed in according to various Q-factor, and then the compressed images were recompressed according to various Q-factor once again. As the result, this paper evaluate the variation of image quality and file size in JPEG recompression and recommed the optimum recompression factor.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
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• pp.11-14
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• 2000

We present an image retrieval method that improves retrieval rate by using the fusion of histogram and wavelet moment features. The key idea is that images similar to a query image are selected in DB by using the wavelet moment features. Then the result images are retrieved from the selected images by using histogram method. In order to evaluate the performance of the proposed method, we use Brodatz texture database, MPEG-7 T1 database and Corel Draw photo. Experimental result shows that the proposed method is better than each of histogram method and wavelet moment method.

• 한국멀티미디어학회논문지
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• 제22권5호
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• pp.527-534
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• 2019

Recently, Photo editing softwares such as digital cameras, Paintshop Pro, and Photoshop digital can create counterfeit images easily. Various techniques for detection of tamper images or forgery images have been proposed in the literature. A form of digital forgery is copy-move image forgery. Copy-move is one of the forgeries and is used wherever you need to cover a part of the image to add or remove information. Copy-move image forgery refers to copying a specific area of an image itself and pasting it into another area of the same image. The purpose of copy-move image forgery detection is to detect the same or very similar region image within the original image. In this paper, we proposed fast detection of forgery image using four step search based on discrete cosine transform and a four step search algorithm using discrete cosine transform (FSSDCT). The computational complexity of our algorithm reduced 34.23 % than conventional DCT three step search algorithm (DCTTSS).

• 한국게임학회 논문지
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• 제6권2호
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• pp.45-50
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• 2006

실 세계 공간에 가상 물체를 사실적으로 합성하기 위해서는 공간 내에 존재하는 조명정보 등을 분석해야 한다. 본 논문에서는 카메라에 대한 사전 교정(calibration)없이 카메라 및 조명의 위치 등을 추정하는 새로운 조명공간 재구성 방법이 제안된다. 먼저, 어안렌즈(fisheye lens)로부터 얻어진 전방향(omni-directional) 다중 노출 영상을 이용해 HDR (High Dynamic Range) 래디언스 맵(radiance map)을 생성한다. 그리고 다수의 대응점으로부터 카메라의 위치를 추정한 다음, 방향벡터를 이용해 조명의 위치를 재구성한다. 또한 대상 공간 내 많은 영향을 미치는 전역 조명과 일부 지역에 국한되어 영향을 주는 방향성을 갖는 지역 조명으로 분류하여 조명 환경을 재구성한다. 재구성된 조명환경 내에서 분산광선추적(distributed ray tracing) 방법으로 렌더링한 결과로부터 사실적인 합성영상이 얻어짐을 확인하였다. 제안된 방법은 카메라의 사전 교정 등이 필요하지 않으며 조명공간을 자동으로 재구성할 수 있는 장점이 있다.

• 전자공학회논문지S
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• 제35S권3호
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• pp.93-101
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• 1998

In Integrated Tube Components(ITC) process in themanufacturing of color display tube, we describe the necessity of the convergence measurement method using photo sensors. Compared with methods using 1D or 2D cameras, its characteristics is to use of moving image patterns and fixed sensors. This measurement method is formulated as the measurement problem of the phase difference in phase changing periodic signals. The convergence measurement system using photo sensors, for the good performance, must have a small standard deviation for the repetitive measurement in the same condition and a fast measurement time for thecovergence change. By above two conditions, we proposed the real time measurement algorithm of the pahse difference using fundametal and harmonic in phase changing periodic signals. And, the proposed algorithm is applied to the convergence measurement system.

• 한국컴퓨터정보학회논문지
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• 제19권7호
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• pp.17-25
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• 2014

영상 기록을 남기는 장치들에서 신원을 파악할 수 있는 이미지를 확보할 때 입력 영상이 실물인지 사진인지를 구분하는 것은 중요한 문제이다. 단일 영상과 센서 등을 이용하여 단순하게 대상까지 거리만의 측정으로 구분하는 방법은 많은 약점을 가지고 있다. 따라서 본 논문은 스테레오 영상을 이용하여 관찰대상까지 거리뿐만 아니라, 얼굴영역의 깊이 지도를 만들어 입체감을 체크함으로써 단순 사진과 실물 얼굴을 구별하는 방법에 관한 것을 제안한다. 사진과 실물 얼굴을 촬영하고 여기에서 측정된 깊이지도 값을 이용하여 학습 알고리즘에 적용한다. 반복적인 학습을 통해 정확하게 실물과 사진을 구분하는 패턴을 찾았다. 제안한 알고리즘의 유용성은 실험으로 검증하였다.

• 한국인쇄학회지
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• 제21권1호
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• pp.35-44
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• 2003

Because of computer developing, the digital image making the use of many a field of application with - web-above, electronic publishing. printing, dynamic image management and photo CD production etc., however many problems of save and management. The management image use of compression moth which don't have a affect on image, reduce file size. A study used sequential DCT0based mode and progressive DCT-based mode of JPEG(Joing Photographic Experts Group) compression method and Wavelet compression method. Therefore, the analog image and digital image was changed and applied by several stages according to compression rate. It made inquiries of the optimum compression rate that be compared quality transformation between original image and compressed image. As compression image was printing simply, the quality was studied by subjective valuation method, that was studied propriety and usefulness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1449-1462
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• 2013

We present a novel approach to producing facial caricature with Simpson cartoon style based on Moving Least Squares (MLS). We take advantage of employing the caricature stylization rule of caricature artist, Justin. Our method allows Simpson-style cartoon character similar to user's features by using Justin's technique, which is a set of caricature stylization rules. Our method transforms input photo image into Simpson style caricature by using MLS approximation. The unique characteristics of user in the photo can be detected by comparing to the mean face feature and the input face feature extracted by AAM(Active Appearance Model). To exaggerate the detected unique characteristics, we set up the exaggeration rules using Justin's technique. In addition, during the cartooning process, user's hairs and accessories are used to the deformed image to make a close resemblance. Our method preserves the reliable and stylized caricature through the exaggeration rules of the actual caricature artist's techniques. From this study, we can easily create a Simpson-style cartoon caricature to resemble user's features by combining a caricature with existing cartoon researches.

• 한국멀티미디어학회논문지
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• 제12권11호
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• pp.1539-1546
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• 2009

사진이론에 따르면 선은 사진의 구도와 분위기를 결정하는 중요한 요소다. 본 논문에서는 사진의 기본 요소 중 하나인 직선 성분을 이용하여 두 사진의 구도 차이를 측정하는 방법을 제안하였다. 선의 어떤 패턴이 구도를 구분 짓는지 파악하기 위해 구도가 동일한 사진에서 나타나는 특징과 다른 구도에서 나타나는 특징을 분석하였다. 분석된 특징을 반영하여 구도차이 측정방법을 설계하였고 제안 방법의 성능평가를 위해 쿼리 사진과 구도가 유사한 사진을 검색하는 시스템을 구현하였다. 구현된 검색 시스템은 상위 10개 내의 결과에서 최고 85%정도의 정확도를 나타내었고 사진 내에 물체가 포함되어도 유사한 구도의 사진을 검색하는 성능을 유지하였다.