• 대한의용생체공학회:의공학회지
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• 제15권1호
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• pp.57-62
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• 1994

The demand of image compression is increasing now for the integration of medical images into the hospital information system. Even though the quantitative distortion can be measured from the difference between original and reconstructed images, it doesn't include the nonlinear characteristics of human visual system. In this study, we have evaluated the nonlinear characteristics of human visual system and applied them to the compression of medical images. The distortion measures which reflect the characteristics of human visual system has been considered. This image compression procedure consists of coding scheme using JND (Just Noticeable Difference) curve, polynomial approximation and BTC (Block Truncation Coding). Results show that this method can be applied to CT images, scanned film images and other kinds of medical images with the compression ratio of 5-10:1 without any noticeable distortion.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.122-130
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• 2010

This paper presents an active ranging system based on laser structured-light image. The structured-light image processing is computationally efficient in comparison with the conventional stereo image processing, since the burdensome correspondence problem is avoidable. In order to achieve robustness against environmental illumination noise, an efficient image processing algorithm, i.e., integration of difference images with structured-light modulation is proposed. Distance equation from the measured structured light pixel distance and system parameter calibration are addressed in this paper. Experiments and analysis are carried out to verify performance of the proposed ranging system.

• 한국정밀공학회지
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• 제14권12호
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• pp.17-23
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• 1997

A 3-D vision system is developed to evaluate blanks' line up and monitor gap and thickness difference between blanks in tailored blank welding system. A structured lighting method is used for 3-D vision recognition. Images of sheared portion in blanks are irregular according to roughness of blank surface, shape of sheared geometry and blurring. It is difficult to get accurate and reliable informations in the case of using binary image processing or contour detection techniques in real time for such images. We propoe a new energy integration method robust to blurring and changes of illumination. The method is computationally simple, and uses feature restoration concept, different to another digital image restoration methods which aim image itself restoration and may be used in conventional applications using structured line lighting technique. Experimental results show this system measuring repeatability is .+-. pixel for gap and thickness difference in static and dynamic tests. The data are expected to be useful for preview gap control.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.396-399
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• 2009

In this paper, we present a method to define a color similarity between color images using Octree-based quantization and similar color integration. The proposed method defines major colors from each image using Octree-based quantization. Two color palettes to consist of major colors are compared based on Euclidean distance and similar color bins between palettes are matched. Multiple matched color bins are integrated and major colors are adjusted. Color histogram based on the color palette is constructed for each image and the difference between two histograms is computed by the weighted Euclidean distance between the matched color bins in consideration of the frequency of each bin. As an experiment to validate the usefulness, we discriminated the same clothing from CCD camera images based on the proposed color similarity analysis. We retrieved the same clothing images with the success rate of 88 % using only color analysis without texture analysis.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권2호
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• pp.173-181
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• 2004

본 논문에서는 움직이는 카메라로부터 획득한 연속영상에서 이동물체를 자동으로 검출하고 추적하는 시스템을 제안한다. 제안된 방법은 크게 이동물체 검출과 추적과정으로 나뉘어진다. 이동물체는 BBME(block-based motion estimation)와 DD(double difference)를 통합한 방법을 이용하여 검출된다. 검출된 이동물체는 히스토그램 백 프로젝션을 통하여 분할되며, 히스토그램 인터섹션과 XY-프로젝션을 사용하여 대상물체를 정합하고 추적된다. 본 논문에서는 컴퓨터 모의실험을 통하여 제안된 방법이 움직이는 카메라로부터 획득된 영상에서 이동물체를 검출하고 큰 오차 없이 추적함을 보였다.

• 비파괴검사학회지
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• 제32권3호
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• pp.276-283
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• 2012

In this study, it was studies the utilization of LIT(lock-in infrared thermography) which can detect defects in welded parts of ship and offshore structures. Quantitative analysis was used through methods of filtering and texture measurement of image processing techniques to find the optimized experimental condition. We verified reliability in our methods by applying image processing techniques in order to normalize evaluations of comparative images that show phase difference. In addition, low to mid exposure showed good results whereas high exposure did not provide significant results in regards to intensity of light exposure on surface. Lock-in frequency was satisfactory around 0.1 Hz regardless of intensity of light source we had. In addition, having the integration time of thermography camera inversely proportional to intensity of exposed light source during the experiment allowed good outcome of results.

• IEIE Transactions on Smart Processing and Computing
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• 제3권1호
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• pp.10-18
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• 2014

From the perspective of reducing the sampling cost of color images at high resolution, block-based compressive sensing (CS) has attracted considerable attention as a promising alternative to conventional Nyquist/Shannon sampling. On the other hand, for storing/transmitting applications, CS requires a very efficient way of representing the measurement data in terms of data volume. This paper addresses this problem by developing a measurement-coding method with the proposed customized Huffman coding. In addition, by noting the difference in visual importance between the luma and chroma channels, this paper proposes measurement coding in YCbCr space rather than in conventional RGB color space for better rate allocation. Furthermore, as the proper use of the image property in pursuing smoothness improves the CS recovery, this paper proposes the integration of a low pass filter to the CS recovery of color images, which is the block-based ${\ell}_{20}$-norm minimization. The proposed coding scheme shows considerable gain compared to conventional measurement coding.

• 대한공간정보학회지
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• 제23권1호
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• pp.81-88
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• 2015

위성센서 기술이 발전함에 따라서 가시광선, 적외선, 열적외선 영역 등의 파장대를 탐지하는 다양한 센서들이 발사되고 있다. 이에 따라, 다중센서 영상의 융합 및 통합에 대한 연구들이 진행되고 있으며, 이를 위해서는 다중센서의 정합이 필수적이다. 위성영상의 정합 및 자동기하보정을 위하여 SIFT, SURF와 같은 알고리즘이 제안되었다. 그러나, 광학영상과 열적외선 상의 경우 다른 분광특성을 가지고 있기 때문에, 기존의 영상정합기법을 적용할 경우에는 높은 정확도를 확보하기 어려운 문제를 지닌다. 본 연구에서는 SURF를 이용하여 참조영상의 특징점을 추출하였으며, 추출된 특징점의 위치를 기반으로 지역적 상관도를 추정하여 정합쌍을 추출하고자 하였다. 지역적 상관도의 경우에는 퓨리에 변환을 기반으로 하는 위상 상관도 기법을 적용하였다. 가상의 고해상도 다중센서 영상과 Landsat-8, ASTER 영상을 이용한 실험결과, 기존의 SURF를 활용한 정합기법과 비교하여 본 연구에서 제안한 방법이 두 영상 간 정합쌍을 더욱 효과적으로 추출할 수 있음을 확인하였다.

• 한국해양공학회지
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• 제26권5호
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• pp.25-30
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• 2012

This study examined the use of LIT (lock-in infrared thermography) to detect defects in the welded parts of ships and offshore structures. A quantitative analysis was used with the filtering and texture measurement of image processing techniques to find the optimized experimental condition. We verified the reliability of our methods by applying image processing techniques in order to normalize the evaluations of comparative images that showed a phase difference. In addition, it was found that a low to mid-range intensity of light exposure on the surface showed good results, whereas high exposure did not provide significant results. A lock-in frequency of around 0.1 Hz was satisfactory regardless of the intensity of the light source. In addition, making the integration time of the thermography camera inversely proportional to the intensity of the exposed light source during the experiment provided good results.

• 한국실내디자인학회논문집
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• 제23권6호
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• pp.22-32
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• 2014

Development of digital technology, which is individualizing and differentiating the world, makes time and space facilitate multi-layering in the contemporary society. It gives a large influence on the contemporary architecture that inducing the visual and spatial experience. Also, It generates new images through the skin of architecture, which implies the contingent and fluid characteristics. These phenomenon show that various parameters are working on the architectural skin simultaneously. Such complexity make the structure of open space and diversity that are homogenized and synchronized. Like this, the architectural skin implies 'multiplicity': qualitative difference which is enable to change and create new images. This characteristic generates instant images changing variously and semantics constantly by the function of skin as a filter. Also, the architectural skin integrates or relocates of relationships between the various information and elements appearing in contemporary society in order to escape the customary relationship between internal and external. Furthermore, the inside and outside of the mixture as a collection of sense has been recognized as one image. This image of mixture consists of one unified continuous integration and extend the meaning of a fluid interface not just surface of the building. The skin of the contemporary architecture is very technical, so its meaning and role is expanded as a complex that exchange interaction. This means that the skin itself has functional elements of the integrated multiple skin to assist. Also it can form a multi-layered relationship and act as a wide range of interfaces depending on the perception of the observer. Therefore the multiplicity of the architectural skin indicates the importance as a boundary that generate images of new life through the sensory perception and implicit force. And it shows potential as the intermediary to try to communicate.