• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.302-308
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• 2010

In MRI, the Ferromagnetic artifact is generated by the metalization within in which the before inspection removal is impossible and the distortion of an image is brought. The distortion measure according to the steel for each sequence of T1 image and magnetic field intensity are analyzed and minimized method is looked into. We used SIEMENS 1.5T and 3.0T MRI for experiment equipment. First, it places within the Phantom making a metalization(Ti+Al, Stainless, Nitinol) on 1.5T, 3.0T MRI and the T1 weighted image for each Sequence is acquired. The distortion of an image and about adjacent portion change of the metal material were compared through the obtained image, we analyzed. In all metalizations, a distortion was generated and a distortion was few in particularly, and Titanium-Aluminium alloy. And the extent of a distortion was worse image in the Turbo spin Echo. The use of the Titanium-Aluminium alloy the inserted in an internal material of the metalization is recommend. and, equipment of 1.5T the patient inserting a metal in an internal is used in an inspection than equipment of 3.0T. Also, the sequence is suitable when it obtains the optimum T1 weighted image of an impersonate to use the Turbo spin Echo.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.1-12
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• 2008

This paper presents automatic moving object detection method using the rotating camera covering larger area with a single camera. The proposed method is based on the edge segment matching which robust to the dynamic environment with illumination change and background movement. The proposed algorithm presents an edge segment based background panorama image generation method minimizing the distortion due to image stitching, the background image generation method using Generalized Hough Transformation which can reliably register the current image to the panorama image overcoming the stitching distortions, the moving edge segment extraction method that overcome viewpoint difference and distortion. The experimental results show that the proposed method can detect correctly moving object under illumination change and camera vibration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.408-414
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• 2010

When we are collecting traffic information on CCTV images, we have to install the detect zone in the image area during pan-tilt system is on duty. An automation of detect zone with pan-tilt system is not easy because of machine error. So the fisheye lens attached camera or convex mirror camera is needed for getting wide area images. In this situation some troubles are happened, that is a decreased system speed or image distortion. This distortion is caused by occlusion of angled ray as like trembled snapshot in digital camera. In this paper, we propose two methods of de-blurring to overcome distortion, the one is image segmentation by nonlinear diffusion equation and the other is deformation for some segmented area. As the results of doing de-blurring methods, the de-blurring image has 15 decibel increased PSNR and the detection rate of collecting traffic information is more than 5% increasing than in distorted images.

• 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.

• Nutrition Research and Practice
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• v.6 no.2
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• pp.175-181
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• 2012

The widespread pursuit of a thin physique may have a detrimental impact on the wellbeing of preadolescents. The influence of body image distortions on the lifestyles, dieting behaviors, and psychological factors was investigated in 631 fifth and sixth grade children in Kyeonggi-do, Korea. Children were classified into three weight groups (underweight, normal, and overweight) and three perception groups (underestimation, normal, and overestimation). Necessary information was obtained by questionnaire, and each subject's weight status was determined by the Rohrer index calculated from the annual measurement records, which were obtained from the school. According to their current weights, 57.4% of children were normal and 32.2% were overweight or obese, 16.6% of the children overestimated their body weight, and 55.2% had an undistorted body image. Overweight children had desirable lifestyles and dietary habits and presented reasonable weight control behaviors. Compared to those without distortion, the overestimated group had greater interest in weight control ($P$ = 0.003) and dissatisfaction with their body weights ($P$ = 0.011), presented unhealthy reasons to lose weight ($P$ = 0.026), and had higher scores for "feeling sad when comparing own body with others" ($P$ = 0.000) and for "easily getting annoyed and tired" ($P$ = 0.037), even though they had similar obesity indices. More subjects from the overestimation group ($P$ = 0.006) chose drama/movies as their favorite TV programs, suggesting a possible role for the media in body image distortion. These findings suggest that body image distortion can lead preadolescents to develop stress about obesity and unhealthy dieting practices, despite similar obesity indices to those without distorted body images. These results emphasize the importance of having an undistorted body image.

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.255-259
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• 2018

Purpose: This study proposes a new ball-type phantom for evaluation of the image layer of panoramic radiography. Materials and Methods: The arch shape of an acrylic resin phantom was derived from average data on the lower dental arch in Korean adult males. Metal balls with a 2-mm diameter were placed along the center line of the phantom at a 4-mm mesiodistal interval. Additional metal balls were placed along the 22 arch-shaped lines that ran parallel to the center line at 2-mm buccolingual intervals. The height of each ball in the horizontal plane was spaced by 2.5 mm, and consequently, the balls appeared oblique when viewed from the side. The resulting phantom was named the Panorama phantom. The distortion rate of the balls in the acquired image was measured by automatically calculating the difference between the vertical and horizontal length using $MATLAB^{(R)}$. Image layer boundaries were obtained by applying various distortion rate thresholds. Results: Most areas containing metal balls (91.5%) were included in the image layer with a 50% distortion rate threshold. When a 5% distortion rate threshold was applied, the image layer was formed with a small buccolingual width along the arch-shaped center line. However, it was medially located in the temporomandibular joint region. Conclusion: The Panorama phantom could be used to evaluate the image layer of panoramic radiography, including all mesiodistal areas with large buccolingual width.

• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.448-457
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• 2004

As computer Programs for cephalometric analysis were developed in diagnosis & treatment planning, digital imaging of film-based cephalograms came to be needed. When a digital camera is used, a problem encountered the image distortion produced according to the focal length, which causes errors in indentifying landmarks. In addition, changes in the image size and compression ratio will inevitably produce a low quality image, causing errors in identifying landmarks. Hence. we have found the focal length producing the least image distortion when digital imaging the film-based cephalograms and the minimal digital camera setting which helps to identify the correct landmarks using the COOLPIX4500 digital camera (Nikon, Japan). The results were as follows The image distortion was minimized at a focal length of 16.4mm (79.4mm when converted into a 35mm film camera) when digital imaging the film-based cephalograms. When wide imaging, with a focal length of under IS.4mm, barrel distortion was found and when tole imaging. with a focal length of over 15.4mm pincushion distortion was found. The minimal digital camera setting was $2272{\times}1704$ pixel at normal (1/8) compression from which we can identify the correct landmarks at the same level as tracing the film-based cephalograms manually. As a result. when digital imaging the film-based cephalograms, using a COOLPIX4500 digital camera (Nikon, Japan), the focal length should be 16.4mm the pixel image size over $2272{\times}1704$, and the compression ratio over normal (1/8).

• Journal of Power System Engineering
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• v.15 no.4
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• pp.25-30
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• 2011

This study is made to provide with a method for correcting the geometric distortion of the digital radiography image by analytical approach based upon the inverse square law and Beer's law. This study is aimed to find out and improve a mathematic model of nonlinear type. Variations in the alignment of the X-ray source, the object, and imaging plate affect digital radiography images. A model which is expressed in parameter values; e.g, angle, position, absorption coefficient, length, width and pixel account of radiography source, is developed so as to match the sample image. For the best correction of the digital image that is the most similar to the model image, a correction technique based upon tangent is developed; then applied to the digital radiography images of steel tubes. As a result, the image correction is confirmed to be made successfully.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.471-478
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• 2011

High resolution Pan-sharpening technique is becoming increasingly important in the field of remote sensing image analysis as an essential image processing to improve the spatial resolution of original multispectral image. The general scheme of pan-sharpening technique consists of upsampling process of multispectral image and high-pass detail injection process using the panchromatic image. The upsampling process, however, brings about image blurring, and this lead to spectral distortion in the pan-sharpening process. In order to solve this problem, this paper presents a new method that adopts image restoration techniques based on optimization theory in the pan-sharpening process, and evaluates its efficiency and application possibility. In order to evaluate the effect of image restoration techniques on the pansharpening process, the result obtained using the existing method that used bicubic interpolation were compared visually and quantitatively with the results obtained using image restoration techniques. The quantitative comparison was done using some spectral distortion measures for use to evaluate the quality of pan-sharpened image.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.2
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• pp.185-190
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• 2013

The previous steganographic methods by using the interpolation were difficult to estimate the distortion because the size of cover image is extended by interpolation algorithms. In this paper, to solve the problems of previous methods proposed the improved steganographic method based on the pixel replacement algorithms. In our method, we cannot extend a cover image, but also can estimate exactly the distortion of the stego-images. In the experimental results, the estimated distortion and embedding capacity of stego-image are shown on three pixel replacement methods.