• Journal of Information Processing Systems
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• v.13 no.3
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• pp.599-617
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• 2017

Due to the rapid growth and expansion of the Internet, the digital multimedia such as image, audio and video are available for everyone. Anyone can make unauthorized copying for any digital product. Accordingly, the owner of these products cannot protect his ownership. Unfortunately, this situation will restrict any improvement which can be done on the digital media production in the future. Some procedures have been proposed to protect these products such as cryptography and watermarking techniques. Watermarking means embedding a message such as text, the image is called watermark, yet, in a host such as a text, an image, an audio, or a video, it is called a cover. Watermarking can provide and ensure security, data authentication and copyright protection for the digital media. In this paper, a new watermarking method of still image is proposed for the purpose of copyright protection. The procedure of embedding watermark is done in a transform domain. The discrete cosine transform (DCT) is exploited in the proposed method, where the watermark is embedded in the selected coefficients according to several criteria. With this procedure, the deterioration on the image is minimized to achieve high invisibility. Unlike the traditional techniques, in this paper, a new method is suggested for selecting the best blocks of DCT coefficients. After selecting the best DCT coefficients blocks, the best coefficients in the selected blocks are selected as a host in which the watermark bit is embedded. The coefficients selection is done depending on a weighting function method, where this function exploits the values and locations of the selected coefficients for choosing them. The experimental results proved that the proposed method has produced good imperceptibility and robustness for different types of attacks.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.75-82
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• 2009

The comparison of images uses PSNR generally. In the case that PSNR value is above 35, it is hard to distinguish the quality of images. In 2006 Lee has proposed the protocol to be able to prove ownership of image using publishing MSB bit strings of original image instead of original images and used the new function to measure correlation of MSB bit strings of two images. In the view of measuring the quality of images, correlation is a bit different from PSNR. That is, if an object image to gene ate from an original image has lower quality, PSNR has very low value, but though the quality is bad, correlation of the images is very high in the view of similarity. In this paper, we modify MSB comparison function that LEE suggested and propose the ICOR function, then analyze the possibility to decide correlation of two images.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.1
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• pp.9-17
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• 2007

In this study, Digital Elevation Models (DEMs) were constructed from color images, grayscale images and each bands (Red, Green, Blue) of color image, and the accuracies of each DEMs were evaluated, And then, correlation coefficients between left and right images of each stereopairs were analyzed. The DEM can be constructed conventionally from the digital map and stereopair images using image matching. The image matching requires stereo satellite images or aerial photographs. In case of rotor aerial photographs, these are to be scanned in 3 bands (Red, Green, Blue). For this study, 5 types of images were acquired; color, grayscale, RED band, GREEN band, and BLUE band image. DEMs were constructed from 5 types of stereopair images and evaluated using elevation points of digital maps. In order to analyze the cause of various accuracies of each DEMs, the similarity between left and right images of each stereopairs were analyzed. Consequently, the accuracy of the DEM constructed from RED band images of color aerial photograph were proved best.

• The KIPS Transactions:PartB
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• v.10B no.4
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• pp.367-372
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• 2003

The existing watermarking techniques for copyright protection of a digital image are fragile in geometric distortion and it is hard to detect whether it was manipulated artificially. In this paper, we proposed the new copyright protection system that can authorize a digital mage and :an embed or extract a robust watermark in a artificial manipulation in order to solve these problems. In a watermarking part, the proposed a watermarking technique embeds a watermark in a phase component after a Complex Wavelet Transform (CWT) with an original image, and a watermark is extracted from an watermarked image by stages. A copyright about an image can be insisted on than a threshold after comparing a correlation of an original watermark with an extracted watermark if large. In an authentication part of a digital image, EZW (Embedded Zerotree Wavelet) is used, and an authentication cord of an watermarked image is generated. An authentication code of an image to have been distribute to is compared with a generated authentication cord, and artificial operation isn´t than a threshold if large. The proposed copyright protection system through performance evaluation display that it was robust in geometric distortion and a artificial operation was able to be detected.

• Journal of Digital Convergence
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• v.15 no.1
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• pp.311-320
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• 2017

The purpose of this study investigates the relationships between nurses' image, professional self-concept and nursing professionalism in nursing students, and explore the plan of nursing education for the establishment of exemplary nursing professionalism in nursing students. A convenience sample of 292 subjects were recruited from one university in G city. And data were collected from November 11 to November 15, 2015. Data were analyzed using t-test, ANOVA, Pearson's Correlation, Stepwise Multiple linear regression analyses with SPSS 21.0 Program. The nursing professionalism of nursing students showed a significantly positive correlation of nurses' image(r=.821, p<.001) professional self-concept(r=.701, p<.001). Fifty-seven percentage of the variance was explained by nurses' image, professional self-concept and grade. Therefore, on the basis of this study's result, when nursing educational programs are developed to make positive professionalism, these factors need to be consider.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.153-160
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• 2009

In relation to digital elevation model(DEM) production using high resolution satellite imagery, existing studies present that DEM accuracy differently show according to land cover property. This study therefore proposes auto-selection method of window size for correlation matching according to land cover property of IKONOS Geo-level stereo image. For this, land cover classified image is obtained by IKONOS color image with four bands. In addition, correlation-coefficients are computed at regular intervals in pixels of the window-search area to shorten of matching time. As the results, DEM by the proposed method showed more accurate than DEM using the fixed window-size matching. We estimate that accuracy of the proposed DEM improved more than DEM by digital map and ERDAS in agricultural land.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.933-941
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• 2006

In this paper, we proposed an efficient coding method for digital hologram (fringe pattern) acquired by a CCD camera or by computer generation using multi-view prediction technique and MPEG video compression standard technique. It proceeds each R, G, or B color component separately. The basic processing unit is a partial image segmented into the size of $N{\times}N$. Each partial image retains the information of the whole object. This method generates an assembled image for a row of the segmented and frequency-transformed partial images, which is the basis of the coding process. That is, a motion estimation and compensation technique of MPEG is applif:d to the reconstructed images from the assembled images with the disparities found during generation of assembled image and the original partial images. Therefore the compressed results are the disparity of eachpartial image to form the assembled image for the corresponding row, assembled image, and the motion vectors and the compensated image for each partial image. The experimental results with the implemented algorithm showed that the proposed method has NC (Normal Correlation) values about 4% higher than the previous method, by which ours has better compression efficiency. Consequently, the Proposed method is expected to be used effectively in the application areas to transmit the digital hologram data. can be identified in comparison with the previous researches and commercial IPs.

• Journal of Digital Contents Society
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• v.6 no.2
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• pp.113-118
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• 2005

In this paper, the reconstruction scheme of lost block in the transmission of block coded image is proposed. Due to differential coding of dc coefficient in JPEG images when JPEG image are transmitted over wireless communications, the effect of errors can destroy entire blocks of the image. Therefore, we aim to reconstruct the lost information using correlation between the lost block and its neighbor blocks. In order to evaluate the performance of this scheme, we inserted some intentional block error into the test images. And we obtained good results objectively and subjectively by experiments.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.372-374
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• 2003

The optical flow theory can be utilized for automatically tracking and positioning homologous points in digital video (DV) image sequences. In this paper, the Lucas-Kanade optical flow estimation (LKOFE) method and the normalized cross-correlation (NCC) method are compared and analyzed using the DV image sequences acquired by our SONY DCRPC115 DV camera. Thus, an improved optical flow estimation procedure, called 'Iterated Optical Flow Estimation (IOFE)', is presented. Our test results show that the trackable range of 3${\sim}$4 pixels in the LKOFE procedure can be apparently enlarged to 30 pixels in the IOFE.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.6
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• pp.26-32
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• 2015

In this study, it is evaluated for fracture toughness to analyze crack resistance properties of particulate reinforced composite propellant. Fracture toughness test using WST specimen is conducted by temperature conditions from $50^{\circ}C$ to $-60^{\circ}C$. Evaluation method for fracture toughness calculated using an equation suggested by ASTM E399 with linear elastic fracture mechanics. From these result, splitting loads and stress intensity factors of propellant increase according to decrease of test temperature. Also, the strain fields of specimen surface using digital image correlation increase as temperature decreased from $50^{\circ}C$ to $-40^{\circ}C$, but it sharply decreases at $-60^{\circ}C$ because of brittle behavior.