• Title/Summary/Keyword: Image Distortion

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Image Distortion Correction Processing System Realization for Fisheye Lens Camera (어안렌스 카메라의 영상왜곡보정처리 시스템 구현)

  • Ryu, Kwang-Ryol;Kim, Ja-Hwan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.11
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    • pp.2116-2120
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    • 2007
  • A realization for image distortion correction processing system with DSP processor is presented in this paper. The image distortion correcting algorithm is realized by DSP processor for focusing on more real time processing than image quality. The lens and camera distortion coefficients are processed by the Lookup Tables and the correcting algorithm is applied to reverse mapping method for geometrical transform. The system experimentation results in the processing time about 31.3 msec $720{\times}480$ wide range image, and the image is stable and spontaneous to be about 8.3% average PSNR variation with changing a wide angle.

Body Image Distortion and Related Factors among Female Adolescents in Korea - Based on the 14th Korean Youth Health Behavior Survey - (한국 청소년 여학생의 신체이미지 왜곡 실태와 영향요인 - 제14차 청소년건강행태조사 이용 -)

  • Chung, Nak-Young;Kye, Senghee
    • Journal of the Korean Society of Food Culture
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    • v.37 no.3
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    • pp.256-264
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    • 2022
  • This study was undertaken to examine body image distortion among female adolescents and identify related factors. Raw data from the 14th Korean Youth Health Behavior Survey were used. The proportion of participants exhibiting body image distortion was 39.5%, with the ratio being higher among female students of normal weight as compared to underweight female students. Logistic regression revealed that the risk of having a distorted body image was higher among high school females than in middle school females having lower subjective academic performance and household economic status. In addition, the risk of having a distorted body image was higher for students who drank alcohol when compared to students who did not drink, for the group engaging vigorously in physical activity (exercise) more than three times per week as opposed to the group exercising less than three times per week, and for the group consuming less than one serving of fruit per day as compared to the group consuming more than one serving of fruit per day. Taken together, the results of this study indicate that continuous nutrition education needs to be provided so that adolescents can correctly perceive their body images and form desirable eating habits.

A Compensation for Distortion of Stereo-scopic Camera Image Using Neuro-Fuzzy Inference System (뉴로-퍼지 추론시스템을 이용한 입체 영상 카메라의 왜곡 영상 보정)

  • Seo, Han-Seog;Yim, Wha-Young
    • The Journal of the Korea institute of electronic communication sciences
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    • v.5 no.3
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    • pp.262-268
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    • 2010
  • In this paper, this study restores the distorted image to its original image by compensating for the distortion of image from a fixed-focus camera lens. The various developments and applications of the imaging devices and the image sensors used in a wide range of industries and expanded use, but due to the needs of the small size and light weight of the camera, the distortion from acquiring images of the distorted curvature of the lens tends to affect many. In particular, the three-dimensional imaging camera, each different distortion of left and right lens cause the degradation of three-dimensional sensitivity and left-right image distortion ratio. we approached the way of generalizing the approximate equations to restore each part of left-right camera images to the coordinators of the original images. The adaptive Neuro-Fuzzy Inference System is configured for it. This system is divided from each membership function and is inferred by 1st order Sugeno Fuzzy model. The result is that the compensated images close to the left, right original images. Using low-cost and compact imaging lens by which also determine the exact three-dimensional image-sensing capabilities and will be able to expect from this study.

Calibration of Fisheye Lens Images Using a Spiral Pattern and Compensation for Geometric Distortion (나선형 패턴을 사용한 어안렌즈 영상 교정 및 기하학적 왜곡 보정)

  • Kim, Seon-Yung;Yoon, In-Hye;Kim, Dong-Gyun;Paik, Joon-Ki
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.4
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    • pp.16-22
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    • 2012
  • In this paper, we present spiral pattern which suits for optical simulator to calibrate fisheye lens and compensate geometric distortion. Using spiral pattern, we present calibration without mathematical modeling in advance. Proposed spiral pattern used to input image of optical simulator. Using fisheye lens image, we calibrate a fisheye lens by matching geometrically moved dots to corresponding original dots which leads not to need mathematical modeling. Proposed algorithm calibrates using dot matching which matches spiral pattern image dot to distorted image dot. And this algorithm does not need modeling in advance so it is effective. Proposed algorithm is enabled at processing of pattern recognition which has to get the exact information using fisheye lens for digital zooming. And this makes possible at compensation of geometric distortion and calibration of fisheye lens image applying in various image processing.

A New Mobile Watermarking Scheme Based on Display-capture

  • Bae, Jong-Wook;Jung, Sung-Hwan
    • 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.

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Analysis of Image Distortion on Magnetic Resonance Diffusion Weighted Imaging

  • Cho, Ah Rang;Lee, Hae Kag;Yoo, Heung Joon;Park, Cheol-Soo
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.381-386
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    • 2015
  • The purpose of this study is to improve diagnostic efficiency of clinical study by setting up guidelines for more precise examination with a comparative analysis of signal intensity and image distortion depending on the location of X axial of object when performing magnetic resonance diffusion weighted imaging (MR DWI) examination. We arranged the self-produced phantom with a 45 mm of interval from the core of 44 regent bottles that have a 16 mm of external diameter and 55 mm of height, and were placed in 4 rows and 11 columns in an acrylic box. We also filled up water and margarine to portrait the fat. We used 3T Skyra and 18 Channel Body array coil. We also obtained the coronal image with the direction of RL (right to left) by using scan slice thinkness 3 mm, slice gap: 0mm, field of view (FOV): $450{\times}450mm^2$, repetition time (TR): 5000 ms, echo time (TE): 73/118 ms, Matrix: $126{\times}126$, slice number: 15, scan time: 9 min 45sec, number of excitations (NEX): 3, phase encoding as a diffusion-weighted imaging parameter. In order to scan, we set b-value to $0s/mm^2$, $400s/mm^2$, and $1,400s/mm^2$, and obtained T2 fat saturation image. Then we did a comparative analysis on the differences between image distortion and signal intensity depending on the location of X axial based on iso-center of patient's table. We used "Image J" as a comparative analysis programme, and used SPSS v18.0 as a statistic programme. There was not much difference between image distortion and signal intensity on fat and water from T2 fat saturation image. But, the average value depends on the location of X axial was statistically significant (p < 0.05). From DWI image, when b-value was 0 and 400, there was no significant difference up to $2^{nd}$ columns right to left from the core of patient's table, however, there was a decline in signal intensity and image distortion from the $3^{rd}$ columns and they started to decrease rapidly at the $4^{th}$ columns. When b-value was 1,400, there was not much difference between the $1^{st}$ row right to left from the core of patient's table, however, image distortion started to appear from the $2^{nd}$ columns with no change in signal intensity, the signal was getting decreased from the $3^{rd}$ columns, and both signal intensity and image distortion started to get decreased rapidly. At this moment, the reagent bottles from outside out of 11 reagent bottles were not verified from the image, and only 9 reagent bottles were verified. However, it was not possible to verify anything from the $5^{th}$ columns. But, the average value depends on the location of X axial was statistically significant. On T2 FS image, there was a significant decline in image distortion and signal intensity over 180mm from the core of patient's table. On diffusion-weighted image, there was a significant decline in image distortion and signal intensity over 90 mm, and they became unverifiable over 180 mm. Therefore, we should make an image that has a diagnostic value from examinations that are hard to locate patient's position.

Reversible Secret Image Sharing Scheme Using Histogram Shifting and Difference Expansion (히스토그램 이동과 차분을 이용한 가역 비밀 이미지 공유 기법)

  • Jeon, B.H.;Lee, G.J.;Jung, K.H.;Yoo, Kee Young
    • Journal of Korea Multimedia Society
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    • v.17 no.7
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    • pp.849-857
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    • 2014
  • In this paper, we propose a (2,2)-reversible secret image sharing scheme using histogram shifting and difference expansion. Two techniques are widely used in information hiding. Advantages of them are the low distortion between cover and stego images, and high embedding capacity. In secret image sharing procedure, unlike Shamir's secret sharing, a histogram generate that the difference value between the original image and copy image is computed by difference expansion. And then, the secret image is embedded into original and copy images by using histogram shifting. Lastly, two generated shadow images are distributed to each participant by the dealer. In the experimental results, we measure a capacity of a secret image and a distortion ratio between original image and shadow image. The results show that the embedding capacity and image distortion ratio of the proposed scheme are superior to the previous schemes.

Fitting to Panchromatic Image for Pansharpening Combining Point-Jacobian MAP Estimation

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.24 no.5
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    • pp.525-533
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    • 2008
  • This study presents a pansharpening method, so called FitPAN, to synthesize multispectral images at a higher resolution by exploiting a high-resolution image acquired in panchromatic modality. FitPAN is a modified version of the quadratic programming approach proposed in (Lee, 2008), which is designed to generate synthesized multispectral images similar to the multispectral images that would have been observed by the corresponding sensor at the same high resolution. The proposed scheme aims at reconstructing the multispectral images at the higher resolution with as less spectral distortion as possible. This study also proposes a sharpening process to eliminate some distortions appeared in the fused image of the higher resolution. It employs the Point-Jacobian MAP iteration utilizing the contextual information of the original panchromatic image. In this study, the new method was applied to the IKONOS 1m panchromatic and 4m multispectral data, and the results were compared with them of several current approaches. Experimental results demonstrate that the proposed scheme can achieve significant improvement in both spectral and block distortion.

Smart Rectification on Satellite images

  • Seo, Ji-Hun;Jeong, Soo;Kim, Kyoung-Ok
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.75-80
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    • 2002
  • The mainly used technique to rectify satellite images with distortion is to develop a mathematical relationship between the pixel coordinates on the image and the corresponding points on the ground. By defining the relationship between two coordinate systems, a polynomial model is designed and various linear transformations are used. These GCP based geometric correction has performed overall plane to plane mapping. In the overall plane mapping, overall structure of a scene is considered, but local variation is discarded. The highly variant height of region is resampled with distortion in the rectified image. To solve this problem this paper proposed the TIN-based rectification on a satellite image. The TIN based rectification is good to correct local distortion, but insufficient to reflect overall structure of one scene. So, this paper shows the experimental result and the analysis of each rectification model. It also describes the relationship GCP distribution and rectification model. We can choose a geometric correction model as the structural characteristic of a satellite image and the acquired GCP distribution.

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Conversion of Fisheye Image to Perspective Image Using Nonlinear Scaling Function (비선형 스케일링 함수를 이용한 어안 영상의 원근 변환)

  • Kim, Tae-Woo;Cho, Tae-Kyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.1
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    • pp.117-121
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    • 2009
  • The fisheye image acquired with a fisheye camera has wider field of view than a general use camera. But large distortion of the object in the image requires conversion of the fisheye image to the perspective image because of user's difficult perception. The existing Ishii's method[1] has the problem that the object can has sire and geometrical distortion in the transformed image because it uses equidistance projection. This paper presented a conversion technique of the fisheye image to the perspective image using sealing function. In the experiments, it was shown that our method reduced size and geometrical distortion by applying the scaling function.