• Journal of the Korea Computer Graphics Society
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• v.12 no.1
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• pp.9-15
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• 2006

본 논문에서는 점묘화를 생성하기 위한 회화적 렌더링 기법을 제안한다. 신인상파(Neo-Impressionist) 화가 쇠라는 캔버스위의 독립 색채들은 망막위에서 재조직된다는 이론을 바탕으로 점묘화를 제안한다. 이는 색의 병치혼합과 보색대비를 이용해 빛의 가산혼합이 회화작품에 적용될 수 있도록 하기위해 브러시 스트로크로 작은 점을 이용한다. 이러한 점묘화를 표현하기위해서 쇠라의 작품과 동시대의 색이론 분석을 통해 색의 분할과 병치혼합의 이론적 배경을 알아보고 이를 통해 점묘 스트로크의 색상, 모양, 방향등을 결정할 수 있는 알고리즘을 소개한다. 먼저 신인상파의 팔레트 분석을 통해 칼라모델을 설계한다. 그리고 입력영상을 영상분할 기법을 이용해 공간적 구도를 잡고 각 분할 영역의 관계를 고려해 색상을 할당한다. 각 할당된 색은 보색과 함께 정의된다. 각 분할영역은 해당영역에서 표현될 수 있는 색상의 작은 점묘 브러시 스트로크로 렌더링이 된다. 이때 입력영상의 밝기정보를 유지할 수 있도록 점묘 스트로크는 색상이 결정된다. 점묘 스트로크의 방향은 입력영상의 에지방향을 따르도록 보간법을 이용해 계산한다.

• Journal of KIISE:Software and Applications
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• v.27 no.1
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• pp.62-73
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• 2000

In this paper, we propose a criteria which can be applied to classify conventional color feature based Content Based Image Retrieval (CBIR) methods with its application areas, and a new image retrieval method which can represent sufficient spatial information in the image and is powerful in invariant searching to translation, rotation and enlargement transform. As the conventional color feature based CBIR methods can not sufficiently include the spatial information in the image, in general, they have drawbacks, which are weak to the translation or rotation, enlargement transform. To solve it, they have represented the spatial information by partitioning the image. Retrieval efficiency, however, is decreased rapidly as increasing the number of the feature vectors. We classify conventional methods to ones using 1st order relations and ones using 2nd order relations as their color object relation, and propose a new method using 3rd order relation of color objects which is good for the translation, rotation and enlargement transform. It makes quantized 24 buckets and selects 3 high scored histogram buckets and calculates 3 mean positions of pixels in 3 buckets and 3 angles. Then, it uses them as feature vectors of a given image. Experiments show that the proposed method is especially good at enlarged images and effective for its small calculation.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.1
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• pp.49-55
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• 2008

The face extraction is very important to provide the images of the roads and road sides without the problem of privacy. For face extraction form roadside images, we detected the skin color area by using HSI and YCrCb color models. Efficient skin color detection was achieved by using these two models. We used a connectivity and intensity difference for grouping, skin color regions further we applied shape conditions (rate, area, number and oval condition) and determined face candidate regions. We applied thresholds to region, and determined the region as the face if black part was over 5% of the whole regions. As the result of the experiment 28 faces has been extracted among 38 faces had problem of privacy. The reasons which the face was not extracted were the effect of shadow of the face, and the background objects. Also objects with the color similar to the face were falsely extracted. For improvement, we need to adjust the threshold.

• Journal of Korea Multimedia Society
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• v.5 no.4
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• pp.415-425
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• 2002

In this paper, we present a content-based image retrieval method which is based on the feature extraction in the wavelet transform domain. In order to overcome the drawbacks of the feature vector making up methods which use the global wavelet coefficients in subbands, we utilize the energy value of wavelet coefficients, and the shape-based retrieval of objects is processed by moment which is invariant in translation, scaling, rotation of the objects The proposed methods reduce feature vector size, and make progress performance of classification retrieval which provides fast retrievals times. To offer the abilities of region-based image retrieval, we discussed the image segmentation method which can reduce the effect of an irregular light sources. The image segmentation method uses a region-merging, and candidate regions which are merged were selected by the energy values of high frequency bands in discrete wavelet transform. The region-based image retrieval is executed by using the segmented region information, and the images are retrieved by a color, texture, shape feature vector.

• Journal of Korea Multimedia Society
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• v.16 no.6
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• pp.700-707
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• 2013

In this paper, we propose a non-rigid registration method of lung parenchyma in temporal chest CT scans using region binarization modeling and locally deformable model. To cope with intensity differences between CT scans, we segment the lung vessel and parenchyma in each scan and perform binarization modeling. Then, we match them without referring any intensity information. We globally align two lung surfaces. Then, locally deformable transformation model is developed for the subsequent non-rigid registration. Subtracted quantification results after non-rigid registration are visualized by pre-defined color map. Experimental results showed that proposed registration method correctly aligned lung parenchyma in the full inspiration and expiration CT images for ten patients. Our non-rigid lung registration method may be useful for the assessment of various lung diseases by providing intuitive color-coded information of quantification results about lung parenchyma.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.567-570
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• 2003

본 논문에서는 연속영상 속에 있는 얼굴영역을 칼만 필터를 이용하여 추적하는 방법을 제안한다. 제안된 방법은 영역-기반접근(region-based approach)방법인 워터쉐드 알고리즘을 이용하여 초기 영역 분할 작업을 한 후 얼굴칼라 모델과의 매칭작업을 통해서 얼굴영역을 찾아내는 얼굴검출 단계와 추출된 얼굴영역의 칼라정보를 칼만 필터의 입력으로 하여 얼굴을 추적하는 단계로 구성되어 있다. 실험결과를 통하여 제안된 방법이 배경이 복잡한 영상에 대해서도 효율적으로 얼굴을 추적할 수 있음을 보인다.

• Journal of the Korea Computer Graphics Society
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• v.9 no.1
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• pp.11-18
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• 2003

본 논문에서는 회화적 렌더링에서 칼라변환을 이용한 브러쉬 스트로크의 생성에 관한 새로운 알고리즘을 제안한다. 본 논문의 브러쉬 스트로크 생성을 위한 전체적인 구성은 다음과 같다. 첫째, 두 장의 사진(한 장의 소스 이미지와 한 장의 참조 이미지)을 입력으로 하여 칼라 변환 이론을 적용하여 색상 테이블이 바뀐 새로운 이미지를 생성한다. 이 방법은 소스 이미지의 칼라 분포 형태를 창조 이미지의 칼라 분포 형태로 변환하기 위해, 선형 히스토그램 매칭이라 불리는, 간단한 통계학적 방법을 이용한다. 둘째, 가우시안 블러링과 소벨 필터를 이용하여 에지를 검출한다. 검출된 에지는 브러쉬 스트로크 렌더링 시 에지 부분에서 스트로크를 클리핑 함으로써 이미지의 윤곽선 보존을 위해 사용된다. 셋째, 브러쉬 스트로크의 방향을 결정하기 위한 방향맵을 생성한다. 방향맵은 입력 영상에 대한 영역 분할 및 병합을 토대로 만들어진다. 영역별 각 픽셀들에 대해 이미지 그래디언트에 기초한 일정한 방향을 부여함으로써 방향맵을 구성한다. 넷째, 구성된 방향맵을 참조하여 브러쉬 스트로크 생성의 기초가 되는 베지어 곡선(Bezier Curve)의 제어점(Control point)을 설정한다. 실제 회화작품에서 사용되는 브러쉬 스트로크는 일반적으로 곡선의 형태를 이루므로 곡선 표현이 가능한 베지어 곡선을 이용하여 브러쉬 스트로크를 표현하였다. 마지막으로, 생성된 브러쉬 스트로크를 에지부문에서 클리핑하고 배경색을 참조하여 블렌딩하거나 퐁 조명 모델을 이용하여 이미지에 적용하게 된다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.153-156
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• 2000

Recently, there has been studied on feature extraction method for efficient content-based image retrieval. Especially, Many researchers have been studying on extracting feature from color Information, because of its advantages. This paper proposes a feature and its extraction method based on color correlogram that is extracted from color information in an image. the proposed method is computed from the image segmented into two parts; the complex part and the plain part. Our experiments show that the performance of the proposed method is better as compared with that of the original color correlogram method.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.602-606
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• 2008

LCD is supplied light by BLU(Back Light Unit) and the light represents color by each color filter. Also LCD adjusts the amount of light by controlling liquid crystal between the glass of upper plate and one of lower. However, it is impossible to completely exclude light due to the structural and physical characteristic of liquid crystal. Therefore, on transfering light through optical sheet and liquid crystal, many problems are generated. They are related with energy efficiency and get effective for the contrast of LCD to have lower contrast ratio than other display devices. To solve the problems, many techniques have been studied and developed but don't exist keys to solution for them. Among methods, local dimming is one example to be applied to LCD. In this paper we propose image processing algorithm for local dimming of BLU of LED used as light source. The proposed algorithm extracts maximum luminance signal and lights using each extracted signal on segmented region of BLU. Also the proposed algorithm generates image signal in corresponding to luminance of the segmented region and supplies them with LCD panel to represent image with improving luminance ratio.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.429-435
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• 2003

In this paper, we propose improved binary tree vector quantization with consideration of spatial sensitivity which is one of the human visual properties. We combine weights in consideration with the responsibility of human visual system according to changes of three primary color in blocks of images with the process of splitting nodes using eigenvector in binary tree vector quantization. Also we propose the novel quality measure of the quantization images that applies MTF(modulation transfer function) to luminance value of quantization error of color image. The test results show that the proposed method generates the quantized images with fine color and performs better than the conventional method in terms of clustering the similar regions. Also the proposed method can get less quantized level images and can reduce the resource occupied by the quantized image.