• 한국인쇄학회지
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• 제19권2호
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• pp.58-67
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• 2001

Gamut mapping is a technique that acts on cross-media color reproduction to transform a color between devices for the purpose of enhancing the appearance or preserving the appearance of an image. Gamut mapping essentially produces color conversion error which depends the gamut mapping method, source and destination devices, and sample points for gamut modeling. For color space conversion between monitor colors and printer colors, empirical representation using sample measurements is currently widely utilized. Color samples are uniformly selected in the device space such as CMY or RGB, represented as color patches, and then measured. However, in the case of printer, these color samples are not evenly distributed inside the printer gamut and the color conversion error is increased. Accordingly, this paper introduces a equally distributed color sampling method in CIELAB space, a device- independent color space, to reduce color conversion error, and the performance is analyzed via color space conversion experiments using tetrahedral interpolation.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2000년도 추계학술발표회 논문집
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• pp.0.3-0
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• 2000

Gamut mapping is a technique that acts on cross-media reproduction to transform a color between devices for the purpose of enhancing the appearance or preserving the appearance of an image. Gamut mapping essentially produces color conversion error which depends the gamut mapping method, source and destination devices, and sample points for gamut modeling. For color space conversion between monitor colors and printer colors, empirical representation using sample measurements is currently widely utilized. Color samples are uniformly selected in the device space such as CMY or RGB, represented as color patches, and then measured. However, in the case of printer, these color samples are not evenly distributed inside the printer gamut and the color conversion error is increased. Accordingly, this paper introduces a equally distributed color sampling method in CIELAB space, a device-independent color space, to reduce color conversion error, and the performance is analyzed via color space conversion experiments using tetrahedral interpolation.

• ETRI Journal
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• 제25권3호
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• pp.156-170
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• 2003

Gamut compression algorithms have traditionally been defined functionally and then tested with deductive methods, e.g., psychophysical experiments. Our study offers an alternative, an inductive method, in which observers judge image colors to represent the original images more accurately. We developed a computer-controlled interactive tool that modifies the color appearance of pictorial images displayed on a monitor. In experiments, observers used the tool to alter color pixels according to the region of color space to which they belonged. We created three different gamut compression algorithms based on the observer experimental data. Observer groups evaluated the performance of the newly-developed algorithms, existing gamut compression algorithms, and an image based on the average observers' results from experiments in this study. The study of gamut extension is unlike the study of gamut compression in that it mainly deals with the degree of image pleasantness as judged by observers. The results of the gamut extension experiments in this study not only make available worthwhile data but also suggest a methodology for using the observer experimental tool for future gamut extension research.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.80-84
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• 2009

This paper investigates the relationship between the compression ratio and the gamut area for a reconstructed image when using JPEG and JPEG2000. Eighteen color samples from the Macbeth ColorChecker are initially used to analyze the relationship between the compression ratio and the color bleeding phenomenon, i.e. the hue and chroma shifts in the a*b* color plane. In addition, twelve natural color images, divided into two groups depending on four color attributes, are also used to investigate the relationship between the compression ratio and the variation in the gamut area. For each image group, the gamut area for the reconstructed image shows an overall tendency to increase when increasing the compression ratio, similar to the experimental results with the Macbeth ColorChecker samples. However, with a high compression ratio, the gamut area decreases due to the mixture of adjacent colors, resulting in more grey.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1232-1235
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• 2009

Image compression techniques such as JPEG and MPEG induce losses of image quality. These losses are usually investigated on the spatial distortions from reconstructed images. Representative specifications are blocking artifacts, color bleeding and smearing. However, the compression techniques also influence the color information. The distortion of color information means distortion of gamut characteristics such as gamut size and unique color from the CIELAB values for each pixel in the reconstructed images. Accordingly, this paper introduces the investigation of the relationship between image compression and the gamut characteristics for reconstructed images using MPEG compression. The results show the consist variation of gamut, hue, and chroma due to MPEG compression.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2002년도 춘계 학술발표회
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• pp.10-18
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• 2002

On the process of cross-media color reproduction, a key feature is the use of gamut mapping techniques to adjust the different color gamuts between displays and printers. Even though a number of GMAs have been published, but there are no method satisfactory enough for more exect color reproduction. In this paper, the gamut mapping methods of nearest point clipping(NPC), centroid clipping (SLIN), straight clipping and cusp clipping(CUSP) were tested and analyzed with color difference, and a new gamut mapping algorithm based on variable anchor point method was proposed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.1759-1762
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• 2003

This paper proposes the method that design CLUT(color look-up table) simultaneously processing gamut mapping and color space conversion using only LUT without complex computation. After we construct LUT composed of scanner gamut and printer gamut, we extend L$\^$*/a$\^$*/b$\^$*/ points based on input L$\^$*/a$\^$*/b$\^$*/ to include input scanner L$\^$*/a$\^$*/b$\^$*/ Input RGB image of scanner is converted into CIEL$\^$*/a$\^$*/b$\^$*/ using regression (unction. CIELAB values of scanner are convened into CMY values including gamut mapping processing without additional gamut mapping using the proposed CLUT. In the experiments, the proposed method resulted in the similar color difference, but reduced the complexity computation compared with processing gamut mapping and color space conversion respectively

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
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• pp.106-109
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• 2003

This paper presents a hue preserving gamut mapping algorithm for color monitor and printer. The gamuts of monitor and printer are set by the profile of color reproduction media, specified by ICC(International Color Consortium) and provided by vendors, then those gamuts are represented on the CIE xy color space. In case that the color of monitor are located on out-of-gamut of printer, these are clipped on the point of gamut boundary of printer towards a reference white point. On the other hand, colors are in-gamut of printer are unchanged. An image generated by the algorithm keeps a ratio of each pixel of original image. Advantages of the algorithm are easy to implement and fast processing time than other algorithms which involve hue preserving especially in CIELAB color space.

• 대한전자공학회논문지SP
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• 제41권2호
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• pp.1-10
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• 2004

본 논문에서는 복잡한 연산을 거치지 않고 칼라 참조표만으로 색역 사상과 색공간 변환을 동시에 처리하는 칼라 참조표를 설계하였다. 스캐너와 프린터의 색역을 구성하는 참조표를 만들고 스캐너에서 계산된 색역 데이터를 색역 확장하여 칼라 참조표의 입력 CIEL/sup */a/sup */b/sup */ 값으로 사용한다. 칼라 참조표 생성을 위한 입력 CIEL/sup */a/sup */b/sup */ 값들은 가변 다중 닻점 색역 사상 방법을 사용하여 색역 사상된 CMY 값으로 계산된다. 제안한 칼라 참조표는 칼라 운영 시스템에 적용하여 스캐너 RGB 입력영상을 다항 회귀 방정식을 이용하여 CIEL/sup */a/sup */b/sup */ 색공간으로 변환한 후에 제안한 칼라 참조표를 이용하여 색역 사상과 동시에 색공간 변환을 처리하게 된다. 실험에서는 제안한 방법이 직접 계산에 의한 색역 사상 방법에 비해서 색차는 유사하면서 연상의 복잡도는 줄이는 결과를 얻었다.

• 대한전자공학회논문지SP
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• 제42권2호
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• pp.69-80
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• 2005

최근 영상 및 광학 소자 산업의 발달과 디지털 방송으로 TV등의 디스플레이 장치들이 슬림화 및 대형화되는 추세에 따라 기존 CRT를 대신하고 있다. 특히 LED, Laser등을 이용한 광 색역 디스플레이 장치들은 CRT에서는 표현할 수 없는 고채도의 색을 표시한 수 있는데 기존의 TV신호를 그대로 적용할 경우 색상의 왜곡이 큰 부작용으로 작용한다. 따라서 본 논문에서는 이와 같은 광 색역 디스플레이 장치에서 색상의 왜곡을 없애고 기존 CRT에 비해 넓은 색역을 충분히 활용할 수 있는 색역 사상에 대하여 연구하였다. 색역 사상은 동일색상에서 채도를 향상 시키는 방법이 일반적으로 사용되나 채도의 과도 상승으로 인한 부작용이 나타난 수 있다. 따라서 본 논문에서는 이러한 부작용을 방지하기 위해 밝기와 채도를 같이 상승 시키는 벡터 사상을 제안 하고자 한다. 이 벡터 사상은 색도가 변하지 않아서 영상이 보다 자연스럽다는 장점이 있다. 또 입력과 출력 색역의 기하학적 특성에 따라서 발생할 수 있는 계조 뭉침이나 윤곽선 효과를 색역 맞춤을 통해 보상하였다. 이와 같은 색역 사상과 색역 맞춤을 이용하여 광색역 디스플레이에서 색상 왜곡을 방지하고 자연스러운 영상을 재현할 수 있다.