• The KIPS Transactions:PartB
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• v.19B no.1
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• pp.1-8
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• 2012

Mosaic is to make a big image by gathering lots of small materials having various colors. With advance of digital imaging techniques, photomosaic techniques using photos are widely used. In this paper, we presents an automatic photomosaic algorithm based on adaptive tiling and block matching. The proposed algorithm is composed of two processes: photo database generation and photomosaic generation. Photo database is a set of photos (or tiles) used for mosaic, where a tile is divided into $4{\times}4$ regions and the average RGB value of each region is the feature of the tile. Photomosaic generation is composed of 4 steps: feature extraction, adaptive tiling, block matching, and intensity adjustment. In feature extraction, the feature of each block is calculated after the image is splitted into the preset size of blocks. In adaptive tiling, the blocks having similar similarities are merged. Then, the blocks are compared with tiles in photo database by comparing euclidean distance as a similarity measure in block matching. Finally, in intensity adjustment, the intensity of the matched tile is replaced as that of the block to increase the similarity between the tile and the block. Also, a tile redundancy minimization scheme of adjacent blocks is applied to enhance the quality of mosaic photos. In comparison with Andrea mosaic software, the proposed algorithm outperforms in quantitative and qualitative analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.61-67
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• 2016

With the current high distribution rate of smart devices and the recent development of computing technology, user interest in multimedia, such as photos, videos, and so on, has rapidly increased, which is a departure from the simple pattern of information retrieval. Because of these increasing interests, image processing techniques, which generate and process images for diverse applications, are being developed. In entertainment recently, there are some techniques that present a celebrity's image as a mosaic comprising many small images. In addition, studies into the mosaic technique are actively conducted. However, conventional mosaic techniques result in a long processing time as the number of database images increases, because they compare the images in the databases sequentially. Therefore, to increase search efficiency, this paper proposes an algorithm to generate a mosaic image using a discrete cosine transform (DCT) hash. The proposed photo mosaic-generation algorithm is composed of database creation and mosaic image generation. In database creation, it first segments images into blocks with a predefined size. And then, it computes and stores a DCT hash set for each segmented block. In mosaic generation, it efficiently searches for the most similar blocks in the database via DCT hash for every block of the input image, and then it generates the final mosaic. With diverse experimental results, the proposed photo mosaic-creation algorithm can effectively generate a mosaic, regardless of the various types of images and sizes.

• Journal of the Korea Computer Graphics Society
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• v.11 no.3
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• pp.28-33
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• 2005

본 논문은 색종이 리스트를 미리 생성하여 필요할 때마다 불러들여 찢어 붙이는 방법의 색종이 모자이크 렌더링 기법을 소개한다. 색종이 리스트는 색종이 이외에도 잡지와 같은 다양한 종이들을 미리 생성하여 사용할 수 있기 때문에 여러 가지 형태의 모자이크를 표현 할 수 있다는 장점을 가진다. 색종이 모자이크를 생성하기 위해서는 색종이 타일의 선택, 모양 결정, 그리고 배치의 3가지 과정을 거쳐야 한다. 먼저 색종이 타일을 붙일 위치에서 가장 알맞은 타일을 리스트로부터 선택하고, 적절한 모양으로 찢는다. 마지막으로 입력 영상의 특징(경계선 등)이 유지될 수 있도록 타일을 배치하여 최종 결과 영상을 생성한다.

• Journal of the Korea Computer Graphics Society
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• v.6 no.3
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• pp.17-23
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• 2000

Recently, as it is growing concern about Non-Photo-Realistic Rendering, several researchers are studying to simulate conventional artistic expressions such as pen-and-ink, watercolor and impressionism techniques. In this paper, we describe a mosaic technique using color paper tore by hands. We will also try to represent real paper by using random midpoint displacement method (RMD) to express a shape of paper tore by hands without using cutters or scissors. The Perlin's noise function is used to express texture of paper.

• Journal of Korea Game Society
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• v.11 no.1
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• pp.139-146
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• 2011

We propose a photomosaic method using PCA(Principal Component Analysis), which uses PCA results to find the most similar candidate fast and correctly. When two images are projected onto a certain principal component, if their coefficients are similar, they are also likely to be similar. Thus our photomosaic method using PCA can take care of both colors and shapes of images. Our method using coefficient comparison is faster than the one using all color comparison and more correct than the one using average comparison. Our hardware accelerated photomosaic algorithm can handle video images in real-time.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.13-22
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• 2009

In this paper, we propose the 3D shape reconstruction method that combine the mosaic method and the active stereo matching using the laser beam. The active stereo matching method detects the position information of the irradiated laser beam on object by analyzing the color and brightness variation of left and right image, and acquires the depth information in epipolar line. The mosaic method extracts feature point of image by using harris comer detection and matches the same keypoint between the sequence of images using the keypoint descriptor index method and infers correlation between the sequence of images. The depth information of the sequence image was calculated by the active stereo matching and the mosaic method. The merged depth information was reconstructed to the 3D shape information by wrapping and blending with image color and texture. The proposed reconstruction method could acquire strong the 3D distance information, and overcome constraint of place and distance etc, by using laser slit beam and stereo camera.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.149-151
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• 2011

동적 모자이크 영상 생성을 위해서는 카메라의 움직임을 계산한 후에 객체의 움직임을 인지해야 한다. 본 논문에서는 어파인 파라미터로 카메라의 움직임을 추출 하였고 지역적 탐색으로 객체의 움직임을 탐지한다. 동적 객체가 존재하는 경우엔 동적 객체 판별을 위하여 영역 분할 방법을 통하여 계산한다. 그리고 동적 객체의 궤도를 표현하기 위하여 우선적으로 동적 객체를 추출하는데 추출 방법은 4분할 탐색 기법을 이용하여 추출하게 된다. 마지막으로 구축되어진 배경 모자이크 영상위에 동적 객체의 궤도르 표현한다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.167-171
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• 2007

본 논문에서는 타일의 크기를 적응적으로 결정하는 모자이크 방법을 제안한다. 우리는 이미지에서 에지(Edge)를 추출한 뒤, 결과 영상이 이 에지 정보를 보존하고, 각 타일들이 이 에지를 따르도록 한다. 에지 정보를 보존 하기 위하여 무게중심 보로노이 다이어그램(CVD: Centroidal Voronoi Diagram)을 계산할때 에지 회피기법을 적용하며, 에지를 따르는 타일을 생성하기 위하여 에지를 따르는 방향과 맨해튼 거리(manhattan distance)가 적용된 무게중심 보로노이 다이어그램을 사용한다. 이때, 우리는 그래픽 처리 장치(GPU: Graphics Processing Unit)를 이용하여 방향맵이나 보로노이 다이어그램을 더욱 빠르게 구할 수 있다. 우리는 타일의 크기를 각 보로노이 영역의 넓이에 비례하게 정함으로써, 기존의 모자이크 방법들이 해결하고자 했던 타일의 겹침 문제와 타일간의 빈 공간 문제를 개선하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.1
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• pp.1-9
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• 2002

Recently as it is growing concern about NPR(Non-Photorealistic Rendering), Several computer graphics researchers are studying to simulate conventional artistic expressions such as pen-and-ink illustrations, watercolor and impressionism technique. In the NPR it is important thing that someone can produce a representation looked like work drawn or manipulated people directly. In this paper we propose that the technique could make the mosaic work automatically, tore and tagged a paper by hands used to educational and artistical representation, we suggest various methods to express a shape and texture of paper tore by hands without using cutters or scissors.

• Journal of Digital Contents Society
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• v.18 no.7
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• pp.1367-1375
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• 2017

Recently, the use of land cover maps has been continuously increasing to analyze spatial patterns such as spatial compositions, functions and changes of landscape mosaics. In this paper, we propose a landscape analysis system that extracts patches, which is an element of landscape mosaics, in the land cover map using region-based image processing technique, and computes patch-based measures at patch level and class level. Also we propose a patch-based spatial pattern that can represent spatial relations using the computed measures. To validate the proposed system's effectiveness, we apply to Gwangju metropolitan city and analyze Gwangju's land use and spatial patterns.