• 한국인쇄학회지
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• 제15권1호
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• pp.85-96
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• 1997

The color difference between original and printed copy is affected mainly by ink trapping and optical properties of overprinted ink layer. Since the general expression itself about ink trapping is affected also by the optical properties, the analysis of color difference using the ink trapping only cannot be certain. This study will show a new approaching method for optical analysis of spectral reflectance and the effect of printing sequence on color difference in multi-color overprints under the condition of excluding completely the ink trapping problems by means of using transparent film as a substrate.

• 한국인쇄학회지
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• 제16권1호
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• pp.13-24
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• 1998

The color difference caused by the overprinting sequence of ink in multicolor printing is due to both trapping and optical properties of ink layers. Hence the effect of optical properties only cannot be analyzed without removing the effect of ink trapping This study was carrier out for the purpose of analyzing optically the color difference caused by only the optical properties of ink under the various printing sequence. The present optical analysis for overprints showed a good agreement with the experimental result. It is expected that this study may contribute to decreasing the color difference between the original and the printed reproduction in multi-color printing.

• 한국인쇄학회지
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• 제14권2호
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• pp.65-80
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• 1996

Ink trap is one of the important factors to determine the color in multi-color overprints. This study was carried out for the purpose for analyzing the relationships between ink traps and color differences in two-color solid overprints. The specimens were printed under four different conditions that the overprinting ink sequence of M(Magenta) or C(Cyan) and the overprinting method of W(Wet-on-Wet) or D(Wet-on-Dry) were changed altermately, that is M+C-W or C+M-W and M+C-D or C+M-D.

• 조명전기설비학회논문지
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• 제28권3호
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• pp.14-17
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• 2014

We studied visual clarity according to the difference of color temperature by using black and white printed paper and four sheets of colored paper under LEDs. We tested students in their twenties, under 3,000, 4,000, 5,700 and 6,500K LEDs (Ra=80). The results show visual clarity is proportioned to color temperature.

• 전자공학회논문지B
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• 제29B권3호
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• pp.47-54
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• 1992

This paper presents an image processing method which emphasizes a certain perception feeling on a color image. A series of fuzzy image processing schemes are proposed, which transform an color image represented in the LCH coordinate system to the image with a certain perception feeling based on the rules and fuzzy inference. To obtain the rules, results of the sensory perception tests are applied to the quantification theory. The proposed schemes can be effectively utilized in the color copy system, since printed outputs possibly look better than originals.

• 한국정보처리학회논문지
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• 제4권1호
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• pp.270-279
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• 1997

지도 영상에 포함된 문자들을 효율적으로 인식하기 위해서는, 문자 영역만을 추 출하여 독립된 계층으로 만드는 전처리 단계가 선행되어야 한다. 본 논문에서는 칼라 지도 영상의 색 정보를 대화식 클러스터링 기법에 의해 색 별로 분리하고, 문자 영역 을 추출하는 알고리즘을 제안하였다. 제안된 대화식 클러스터링 기법은 칼라 영상 중 에서 사용자가 분리하기 원하는 색을 대화식으로 선택하여 각각의 선택된 색을 중심 으로 클러스터를 형성하고 분리한다. 문자를 추출하는 알고리즘은 문자를 표현하는 색만을 추출한 이전 영상을 벡터 데이터화 한 후 각 원시 요소들의 상호 관계를 고려 하여 직선, 원, 문자의 세 계층으로 분류하는 것으로서, 문자와 직선이 중첩되어, 하 나의 연결 요소를 이루고 있을 때에도 효과적으로 문자를 분리할 수 있다. 알고리즘 의 평가를 위해 1:3,000의 지번약도에 대한 실험을 수행하였으며, 선분과 문자가 중 첩되어 있는 경우에도 각각 분리할 수 있음을 확인하였다.

• The Journal of Advanced Prosthodontics
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• 제15권3호
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• pp.145-154
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• 2023

PURPOSE. The objective of this study was to investigate how internal structures influence the overall and marginal accuracy of full arch preparations fabricated through additive manufacturing in different printing systems. MATERIALS AND METHODS. A full-arch preparation digital model was set up with three internal designs, including solid, hollow, and grid. These were printed using three different resin printers with nine models in each group. After scanning, each data was imported into the 3D data processing software together with the master cast, aligned and trimmed, and then put into the 3D data analysis software again to compare the overall and marginal deviation whose results are expressed using root mean square values and color maps. To evaluate the trueness of the resin model, the test data and reference data were compared, and the precision was evaluated by comparing the test data sets. Color maps were observed for qualitative analysis. Data were statistically analyzed by one-way analysis of variance and Bonferroni method was used for post hoc comparison (α = .05). RESULTS. The influence of different internal structures on the accuracy of 3D printed resin models varied significantly (P < .05). Solid and grid models showed better accuracy, while the hollow model exhibited poor accuracy. The color maps show that the resin models have a tendency to shrink inwards. CONCLUSION. The internal structure design influences the accuracy of the 3D printing model, and the effect varies in different printing systems. Irrespective of the kind of printing system, the printing accuracy of hollow model was observed to be worse than those of solid and grid models.

• 한국인쇄학회지
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• 제18권2호
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• pp.29-40
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• 2000

Recently. color proofing in printing industry grow rapidly. If an order decide color from known color information in the case of color reproduction, we can reduce expenses and time. In color proofing the best important point must be closed proofed color to primary color and secondary color. Model-based approaches have the advantages of faster recharacterization and the opportunity of simulating product enhancements such as changes in ink properties and halftoning. In this paper, we transformed the dot area of CMYK to CIELAB color space using color reproduction models. Firstly, we measured spectral reflectance of primary color printed by Matchprint II and the data was used to find tone reproduction curve using regression equation, and than we applied at primary color model, such as Murray-Davies, Yule-Nilsen, and mixed color model, such as Kubelka-Munk, relaxed version of spectral Neugebauer. In such results, the Kubelka-Munk model resulted in the best spectral reconstruction accuracy followed by relaxed version of spectral Neugebauer model, color difference is 2.8401.

• 한국인쇄학회:학술대회논문집
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• 한국인쇄학회 2000년도 춘계 학술발표회 논문집
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• pp.25-34
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• 2000

Recently, color proofing in printing industry grow rapidly. If an order decide color from known color information in the case of color reproduction, we can reduce expenses and time. In color proofing the best important point must be closed proofed color to primary color and secondary color. Model-based approaches have the advantages of faster recharacterization and the opportunity of simulating product enhancements such as changes in ink properties and halftoning. In this paper, we transformed the dot area of CMYK to CIELAB color space using color reprodution models. Firstly, we measured spectral reflectance of primary color printed by Matchprint II and the data was used to find tone reproduction curve using regression equation, and than we applied at primary color model, such as Murray-Davies, Yule-Nilsen, and mixed color model, such as Kubelka--Munk, relaxed version of spectral Neugebauser. In such results, the Kubleka-Munk model resulted in the best spectral reconstruction accuracy followed by relaxed version of spectral Neugebauer model, color difference is 2.8401.

• 한국포장학회지
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• 제27권3호
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• pp.203-210
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• 2021

With the development of package printing technology, the package has expanded from the basic function of protecting products to the marketing function through package design. Color, the visual element that composes the package design, is delivered to the consumer most quickly and effectively. As color marketing of these package designs expands, accurate color reproduction that the product wants to express is becoming more important. The color of an object is transmitted by absorption and scattering of light. Spectral reflectance refers to the intensity of light reflected by an object at different wavelengths by the spectral effect. As a result, the color of the object is expressed in various colors. Packaged printing inks have their own absorption and scattering coefficients, and the Kubelka-Munk model for color reproduction and prediction defines the relationship between these correlation coefficients through reflectance. In the Kubelka-Munk model for color reproduction and prediction, the relationship between the absorption and scattering coefficients (K/S) of printed material is predicted as the sum of the K/S values according to the mixing ratio of all color ink used. In this study, the reflectance of the measured print is reversely calculated at the mixing ratio of print ink using the Kubelka-Munk model. Through this, the relationship value of the ink-specific absorption/scattering coefficient constituting the final printed material is predicted. Delta E is derived through the predicted reflectance, and the similarity between the measured value and the predicted value is confirmed.