• Journal of the Optical Society of Korea
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• v.18 no.1
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• pp.89-94
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• 2014

It is established that the perceived image contrast is affected by surround luminance. In order to get the same perceived image contrast, the optimum surround compensation ratios for those surround conditions is needed. Much research has been performed for dark, dim, and average surrounds. In this study, a wide range of surround luminance from dark up to $2087cd/m^2$ was considered. Using magnitude estimation method, the change in perceived brightness of six test stimuli was measured under seven surround conditions; dark, dim, 2 levels of average, bright, and 2 levels of over-bright surrounds. To drive the perceived image contrast from the perceived brightness, two different definitions of contrast were tested. Their calculated results were compared with the visual data of our previous work. And to conclude, the perceived contrast compensation ratios were 1:1.11:1.2 for average, dim and dark surrounds. These were close to CIECAM02 model (1:1.17:1.31). Besides, for average, bright, over-bright1 and over-bright2 surrounds the ratios 1:1.17:1.42:1.69 were determined. For intermediate or more extreme surround conditions, the compensation ratio was obtained from the linear interpolation or extrapolation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.5056-5078
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• 2018

In this work we propose a compression technique that makes use of linear and perceptually uniform CIE $La^*b^*$ color space in the JPEG image compression framework to improve its performance at lower bitrates. To generate quantization matrices suitable for the linear and perceptually uniform CIE $La^*b^*$ color space, a novel linear Contrast Sensitivity Function (CSF) is used. The compression performance in terms of Compression Ratio (CR) and Peak Signal to Noise Ratio (PSNR), is further improved by utilizing image dependent, variable and non-uniform image sub-blocks generated using a proposed histogram-based merging technique. Experimental results indicate that the proposed linear CSF based quantization technique yields, on an average, 8% increase in CR for the same reconstructed image quality in terms of PSNR as compared to the conventional YCbCr color space. The proposed scheme also outperforms JPEG in terms of CR by an average of 45.01% for the same reconstructed image quality.

• Journal of radiological science and technology
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• v.37 no.2
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• pp.101-107
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• 2014

The purpose of this study was investigated optimal exposure condition in digital magnification mammography to decrease radiation dose and increase image quality of the examinee. Auto mode, the average glandular dose is higher than the manual mode. Average glandular dose and image quality were many differences on between grid and air gap technique in auto mode. However, Average glandular dose and signal-to-noise ratio were not different on between grid and air gap technique in manual mode. The signal-to-noise ratio was increased when using the air-gap technique in both mode. According to result, air gap technique may reduce average glandular dose and increase signal-to-noise ratio in digital magnification mammography.

• Journal of Information Processing Systems
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• v.19 no.6
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• pp.858-869
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• 2023

As one of the pivotal techniques of image restoration, single-channel blind source separation (SCBSS) is capable of converting a visual-only image into multi-source images. However, image degradation often results from multiple mixing methods. Therefore, this paper introduces an innovative SCBSS algorithm to effectively separate source images from a composite image in various mixed modes. The cornerstone of this approach is a novel triple generative adversarial network (TriGAN), designed based on dual learning principles. The TriGAN redefines the discriminator's function to optimize the separation process. Extensive experiments have demonstrated the algorithm's capability to distinctly separate source images from a composite image in diverse mixed modes and to facilitate effective image restoration. The effectiveness of the proposed method is quantitatively supported by achieving an average peak signal-to-noise ratio exceeding 30 dB, and the average structural similarity index surpassing 0.95 across multiple datasets.

• Journal of Korea Multimedia Society
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• v.12 no.6
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• pp.815-823
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• 2009

Most of existing watermarking schemes insert and extract a watermark, focusing on the visual conservation of an original image. However, existing watermarking schemes could be difficult for a watermark detection in case of various distortion caused by display-capture devices. Therefore, we propose a new display-capture based mobile watermarking scheme. The proposed watermarking scheme is a new concept for embedding a watermark, which uses the generated image instead of a given original image. For effective watermark decoding, we also present a method for detecting the background image whose error bit can not be corrected because of various heavy distortion and for avoiding it from the decoding process. For this scheme, we adopt distortion coefficients of camera calibration when we separate a background image from a captured image. For finding available correction bits of ECC through the decoding process, we capture 30,000 images and then calculate the separation ratio of a background image and the average error bits per an image. As experimental result, the separation ratio of a background image is about 96.5% in 30,000 captured image. And the false alarm ratio shows about $5.18{\times}10^{-4}$ in the separated background image. And also we can confirm the availability of real-time processing because the mean execution time is about 82ms per an image for capturing and decoding.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1268-1271
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• 2002

The major threat of geometric manipulations is that they change the positions of watermarks, therefore the detection process fails to extract watermark properly. Since they cause the same effects on the host image as watermarks simultaneously, evaluating the distorted host image can be helpful to measure the nature of distortions. In this paper, we propose a geometrical distortion-resilient watermarking algorithm based on this property. Firstly we evaluate the orientation of a host image by filtering it with directional Gabor kernels, then we insert embedding pattern aligned to the estimated orientation. In its detection step, we evaluate the orientation again by Gabor filtering, then simply project and average the projected value to obtain a 1-D projection average pattern. Finally, auto-correlation function of the 1-D projection average pattern identifies periodic peaks. Analysed are experimental results against geometrical attacks including aspect ratio changes.

• Journal of Fashion Business
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• v.19 no.5
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• pp.34-47
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• 2015

Sexiness is the image of a person who attracts attention regardless of his/her age, and today's society has created a more positive impression by transforming the image into something others consider even more attractive. Consequently, we begin to take interest in makeup, - a means of portraying a good impression. Eyebrow makeup in particular, being at the center of the determining factor of a good facial image, can be thought of as the makeup that can most effectively transform one's image. The purpose of this study was to analyze the difference in perceived sexiness depending on the general perception of eyebrow makeup. This study produced an eyebrow stimulus that applied the average rate of change in an image transformation of different eyebrows in order to raise the objective credibility of the sensibility evaluation so it could determine the figure of influence that eyebrows had on facial impressions. The research results showed that the majority of female university students believed that eyebrows were an effective means of expression in changing facial images and attributed a higher mature and sexy image if the average ratio of change was higher. The study, could also identify that a sexy image was perceived when the average rate of change was between 0.39~0.44. In addition, when the gradient of the shape of the viewers' own eyebrows was low, it could be verified that they perceived an image to be sexy from seeing eyebrows with a relatively high gradient.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.120-127
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• 2016

In order to acquire digital x-ray images, developing radiography detectors have been recently conducted based on the DR (digital radiography) technology. The noise property of the radiography detector can be observed from measuring the NNPS (normalized noise power spectrum) using uniform exposure images. Here, the image difference of two images is used to remove the fixed pattern noise in measuring the detector NNPS. In this paper, two average images are first calculated using several images and then their difference is used to calculate an NNPS value. Here, the obtained NNPS value is usually lower than the true detector NNPS due to the average. Hence, a compensation constant, which is a function of the number of used images, is also proposed to compensate the NNPS value to obtain the true detector NNPS. Furthermore, another measurement method, in which the ratio of the average images is used, is proposed. Through NNPS measuring experiments using real x-ray images, it is observed that the proposed method can provide further accurate NNPS measurements.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.251-259
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• 2022

Purpose : This study was conducted to check the effect on nursing college students' major satisfaction, adjustment to college life and nurse's image nursing students before clinical practical education. Methods : The study surveyed 209 college students majoring in nursing science in the city of B for the period of April through May 2022. The collected data were analyzed using SPSS/WIN 22.0 to determine the frequency, percentage ratio, average, and standard deviation. Statistical analyses included the t-test, analysis of variance, pearson's correlation coefficients. Results : As a result of this study, the average degree of satisfaction with majors was 3.88±.50, the average of college life adaptation was 3.26±.47, and the average of the nurse image was 3.90±.51. The major satisfaction according to the general characteristics of the study subjects showed a statistically significant difference in the motive for choosing a department (F=3.70, p=.003) and the thought of a nursing job (F=2.95, p=.004). The adjustment to college life according to the general characteristics of the study subjects showed a statistically significant difference in grade (F=3.50, p=.001), department selection motivation (F=2.69, p=.022) showed a statistically significant difference. The nurse image showed a statistically significant difference in residence type (F=6.00, p=.001) and nursing job thinking (F=2.11, p=.036). The correlation between the variables of the study subjects showed that major satisfaction was found to have a positive correlation with adjustment college life (r=.51, p<.001) and nurse image (r=.54, p<.001). It was found that adjustment college life had a positive correlation with the nurse image (r=.32, p<.001). Conclusion : The higher the degree of satisfaction with the major of nursing students prior to clinical practice education, the higher the degree of adaptation to college life. It is need to intervention studies that can improve the image of positive nursing.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.139-148
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• 2020

The purpose of this study is to propose a method to optimize the performance of Digital Radiography (DR) by analyzing the effect of exposure time change on the stability of radiation output and image quality. The experimental method was used to change the exposure time to 50 msec, 100 msec, 200 msec, and 400 msec so that the Percentage Average Error (PAE), Time-to-Radiation Dose Curve, Signal to Noise Ratio (SNR), Contrast to Noise Ratio (CNR) and theses analysis were performed to evaluate the normal operation of parameters, radiation output and image quality. As a result, all the parameters used in the experiment showed the Percentage Average Error in the normal range, and the shorter the exposure time, the stability of radiation output and image quality decrease. In conclusion, it was found that the performance of Digital Radiography can be optimized when stable radiation output and image quality are applied by applying 100 msec ~ 200 msec exposure time.