• Journal of Korean Society for Quality Management
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• v.44 no.3
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• pp.527-540
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• 2016

Purpose: The purpose of this study was to propose contrast metric which is based on the human visual perception and thus it can be used to improve the quality of digital images in many applications. Methods: Previous literatures are surveyed, and then the proposed method is modeled based on Human Visual System(HVS) such as multiscale property of the contrast sensitivity function (CSF), contrast constancy property (suprathreshold), color channel property. Furthermore, experiments using digital images are shown to prove the effectiveness of the method. Results: The results of this study are as follows; regarding the proposed contrast measure of complex images, it was found by experiments that HVS follows relatively well compared to the previous contrast measurement. Conclusion: This study shows the effectiveness on how to measure the contrast of complex images which follows human perception better than other methods.

• Journal of the Institute of Convergence Signal Processing
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• v.15 no.2
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• pp.24-29
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• 2014

Digital mammography is the most common technique for the early detection of breast cancer. To diagnose the breast cancer in early stages and treat efficiently, many image enhancement methods have been developed. This paper presents a multi-scale contrast enhancement method in the Laplacian pyramid for the digital mammogram. The proposed method decomposes the image into the contrast measures by the Gaussian and Laplacian pyramid, and the pyramid coefficients of decomposed multi-resolution image are defined as the frequency limited local contrast measures by the ratio of high frequency components and low frequency components. The decomposed pyramid coefficients are modified by the contrast measure for enhancing the contrast, and the final enhanced image is obtained by the composition process of the pyramid using the modified coefficients. The proposed method is compared with other existing methods, and demonstrated to have quantitatively good performance in the contrast measure algorithm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.6
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• pp.659-664
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• 2004

It is important to measure precisely the size and velocity of micro-bubbles used in various field. The synchrotron X-ray micro-imaging technique was employed to measure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Phase contrast images were obtained at interfaces of micro-bubbles between water and air due to their different refractive indices. The X-ray micro-imaging technique was found to measure an optical fiber with an accuracy of 0.2%. Micro-bubbles of 20∼60$\mu\textrm{m}$ diameter moving upward in an opaque tube (${\Phi}$＝2.7mm) were tested to measure bubble size and up-rising velocity. For DI water, the measured velocity of micro-bubbles is nearly proportional to the square of bubble size, agreed well with the theoretical result. In addition, the synchrotron X-ray micro-imaging technique can measure accurately the size and velocity of several overlapped micro-bubbles.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1744-1748
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• 2004

It is important to measure precisely the size and velocity of micro-bubbles used in various field. The synchrotron X-ray micro-imaging technique was employed to measure the size and velocity of micro-bubbles moving in an opaque tube simultaneously. Phase contrast images were obtained at interfaces of micro-bubbles between water and air due to their different refractive indices. The X-ray micro-imaging technique was found to measure an optical fiber with an accuracy of 0.2%. Micro-bubbles of $10{\sim}60{\mu}m$ diameter moving upward in an opaque tube (${\phi}=2.7mm$) were tested to measure bubble size and up-rising velocity. For DI water, the measured velocity of micro-bubbles is nearly proportional to the square of bubble size, agreed well with the theoretical result. In addition, the synchrotron X-ray micro-imaging technique can measure accurately the size and velocity of several overlapped micro-bubbles.

• Journal of the Korea Fashion and Costume Design Association
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• v.11 no.2
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• pp.1-10
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• 2009

The purpose of this study is to investigate harmonious color schemes based on a length proportion of upper and lower parts of a body by; understanding of the harmonious length proportion of a square measure of a color in color coordination of fashion design, and presenting a mutual relation of the length proportion of a square measure of a color according to the various way of color schemes and proportions. For this study, monochromatic scheme, analogous scheme and complementary scheme were adapted as the color schemes, and each color scheme was coordinated by analogous tone and contrast tone. Also, 1:1 symmetry proportion, 1:2 harmonic proportion, 1:1.618 golden section, 1:3 and 1:5 contrast proportion were used as the square measure of a color. For the survey, 12 sets of color sample were organized. The survey was conducted 182 of university students majored in fashion design, and 143 responded samples were analyzed using SPSS 12. The result of the study is as follows: 1:5 contrast proportion is most inharmonious in general, and 1:1 symmetry proportion is followed. It is thought that too much or same length of the square measure of colors has less attractive effect of coloring. On the other hand, 1:1.618 golden section and 1:2 harmonic proportion are accepted to be harmonious in all color schemes. The length proportion of the square measure of a color had more influence on harmony of color coordination in fashion design rather than color schemes. Though, on the assumption that people have a similar perception about the color image of fashion design, it will play an important role in strengthening or diminution of color in cloth if the coloring effect of the length proportion of the square measure of a color is used in fashion design and wearing of clothes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2737-2753
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• 2013

In this study, we propose a novel salient object detection strategy based on regional contrast and relative spatial compactness. Our algorithm consists of four basic steps. First, we learn color names offline using the probabilistic latent semantic analysis (PLSA) model to find the mapping between basic color names and pixel values. The color names can be used for image segmentation and region description. Second, image pixels are assigned to special color names according to their values, forming different color clusters. The saliency measure for every cluster is evaluated by its spatial compactness relative to other clusters rather than by the intra variance of the cluster alone. Third, every cluster is divided into local regions that are described with color name descriptors. The regional contrast is evaluated by computing the color distance between different regions in the entire image. Last, the final saliency map is constructed by incorporating the color cluster's spatial compactness measure and the corresponding regional contrast. Experiments show that our algorithm outperforms several existing salient object detection methods with higher precision and better recall rates when evaluated using public datasets.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.4
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• pp.231-238
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• 2017

Detecting small infrared targets from the low-SCR images at a long distance is very hard. The previous Local Contrast Method (LCM) algorithm based on the human visual system shows a superior performance of detecting small targets by a background suppression technique through local contrast measure. However, its slow processing speed due to the heavy multi-scale processing overhead is not suitable to a variety of real-time applications. This paper presents a lightweight real-time small target detection algorithm, called by the Improved Selective Local Contrast Method (ISLCM), to reduce the scale-invariant computational overhead. The proposed ISLCM applies the improved local contrast measure to the predicted selective region so that it may have a comparable detection performance as the previous LCM while guaranteeing low scale-invariant computational load by exploiting both adaptive scale estimation and small target feature feasibility. Experimental results show that the proposed algorithm can reduce its computational overhead considerably while maintaining its detection performance compared with the previous LCM.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.2
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• pp.1-13
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• 2017

In This Paper, we find the Target Candidate Region and the Location of the Candidate Region by Performing the Morphological Difference Calculation and Pixel Labeling for Robust Small Target Detection in Infrared Image with low SNR. Conventional Target Detection Methods based on Morphology Algorithms are low in Detection Accuracy due to their Vulnerability to Clutter in Infrared Images. To Address the Problem, Target Signal Enhancement and Background Clutter Suppression are Achieved Simultaneously by Combining Moravec Algorithm and LCM (Local Contrast Measure) Algorithm to Classify the Target and Noise in the Candidate Region. In Addition, the Proposed Algorithm can Efficiently Detect Multiple Targets by Solving the Problem of Limited Detection of a Single Target in the Target Detection method using the Morphology Operation and the Gaussian Distance Function Which were Developed for Real time Target Detection.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.33-40
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• 2009

This paper proposes the assessment method for objective quality-evaluation-index of mosaic images. Quality assessment was evaluated using seam-line method and similarity and contrast of adjacent images. The evaluation measure was calculated based on selected evaluation criteria and compared with human visual inspection. It was found that quantitative quality evaluation measure showed that the evaluation results were similar to human visual check. Conclusively experimental results proved that proposed evaluation measure could be used for quantitative and objective quality assessment of mosaic images.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.141-147
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• 2015

The contrast of a display is generally evaluated by using the ratio of the minimum luminance to the maximum luminance of the display. However, this contrast ratio is not matched with perceived contrast because it uses only physical characteristic of display without considering human perceptual characteristics. In this paper, the proposed contrast measure that considers perceptually discriminable brightness within the range of display brightness is suggested. First, the range between the minimum and maximum brightness of display in CIECAM02 color space is calculated to measure the length of perceived brightness for the display. Next, brightness ranges which are perceptually same at each brightness level are determined by applying Weber-Fechner ratio and then, the number of brightness values within each brightness range is counted. Finally, perceptually discriminable brightness is defined as the sum of ratio between the number of brightness values in each brightness range and the perceptual contrast length of the display. In the experiments, preference test using various displays with random brightness patches is performed to evaluate perceived contrast. As a result, the proposed measure is more consistent with human perception than the previous contrast measures.