• Title/Summary/Keyword: visual distortion

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MPEG-7 Visual Identifier

  • Oh, Weon-Geun
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.41-44
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    • 2008
  • Digital visual information(image and video) plays an important role in our society, and everyday, more and more visual information is available from many sources around the world. And there is an increasing number of cases where the these visual informations are created, stored, retrieved, and re-used by computational systems. But information modification, distortion and compilation occurred through trans-coding or legal/illegal information processing often make these operations difficult. Subordinately, advanced technology or commercialized software for retrieving and identifying the desired information among these massive and diverse ones is strongly required. In the paper, some recent activities and technical content of MPEG-7 Visual Group are described, especially with regarding to Visual Identifier.

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An Objective Quality Assessment Based on Gabor Wavelet (Gabor 웨이블릿 기반 객관적 화질 평가)

  • 엄민영;최윤식;장석각;조봉관
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.6
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    • pp.81-88
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    • 2004
  • In this paper, we propose a new objective quality assessment method considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

A Study on Visual Humor Expression in Fake Technique Fashion

  • Kim, Jinyoung;Kan, Hosup
    • Journal of Fashion Business
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    • v.21 no.3
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    • pp.43-57
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    • 2017
  • This study concerns visual humor in fake technique fashion. While previous studies focused mainly on expression techniques of fake technique fashion, this study analyzed visual humor in fake technique fashion based on classification criteria of visual humor expression techniques, differenting this study from other studies. The purpose of this study was to derive visual humor in fake technique fashion by classifying cases of fake technique fashion, and re-classifying outcomes of primary classification based on criteria of visual humor expression techniques. As for methods, this theoretical study was conducted on humor, expression techniques of visual humor, fake fashion and fake expression techniques through literature review. Subsequently, 485 fake technique fashion images obtained from research were classified by expression techniques, and cases of fake technique fashion were analyzed. In addition, by combining this theoretical study with case studies, fake technique fashion was re-classified according to criteria of visual humor expression techniques to derive the characteristics of visual humor in fake technique fashion. Based on visual humor expression techniques, visual humor in fake technique fashion was created by distortion and transformation that made the fake look real by distorting or transforming the fake, enlargement and reduction that created new forms by altering familiar forms, and typeplay that added fun by changing familiar luxury logos into various forms.

The Compression of Normal Vectors to Prevent Visulal Distortion in Shading 3D Mesh Models (3D 메쉬 모델의 쉐이딩 시 시각적 왜곡을 방지하는 법선 벡터 압축에 관한 연구)

  • Mun, Hyun-Sik;Jeong, Chae-Bong;Kim, Jay-Jung
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.1
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    • pp.1-7
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    • 2008
  • Data compression becomes increasingly an important issue for reducing data storage spaces as well as transmis-sion time in network environments. In 3D geometric models, the normal vectors of faces or meshes take a major portion of the data so that the compression of the vectors, which involves the trade off between the distortion of the images and compression ratios, plays a key role in reducing the size of the models. So, raising the compression ratio when the normal vector is compressed and minimizing the visual distortion of shape model's shading after compression are important. According to the recent papers, normal vector compression is useful to heighten com-pression ratio and to improve memory efficiency. But, the study about distortion of shading when the normal vector is compressed is rare relatively. In this paper, new normal vector compression method which is clustering normal vectors and assigning Representative Normal Vector (RNV) to each cluster and using the angular deviation from actual normal vector is proposed. And, using this new method, Visually Undistinguishable Lossy Compression (VULC) algorithm which distortion of shape model's shading by angular deviation of normal vector cannot be identified visually has been developed. And, being applied to the complicated shape models, this algorithm gave a good effectiveness.

Color Image Quantization and Dithering Method based on HVS Characteristics

  • Ha, Yeong-Ho
    • Proceedings of the IEEK Conference
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    • 1999.06a
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    • pp.569-574
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    • 1999
  • New methods for both color palette design and dithering based on human visual system (HVS) characteristics are proposed. Color quantization for palette design uses the relative visual sensitivity and spatial masking effect of HVS. The dithering operation for printing uses nonlinear quantization, which considers the overlapping phenomena among neighbor printing dots, and then a modified dot-diffusion algorithm is followed to compensate the degradation produced in the quantization process. The proposed techniques can produce high quality image in the low-bit color devices.

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Advanced Real-Time Rate Control for Low Bit Rate Video Communication

  • Kim, Yoon
    • Journal of the Korea Computer Industry Society
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    • v.7 no.5
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    • pp.513-520
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    • 2006
  • In this paper, we propose a novel real-time frame-layer rate control algorithm using sliding window method for low bit rate video coding. The proposed rate control method performs bit allocation at the frame level to minimize the average distortion over an entire sequence as well as variations in distortion between frames. A new frame-layer rate-distortion model is derived, and a non-iterative optimization method is used for low computational complexity. In order to reduce the quality fluctuation, we use a sliding window scheme which does not require the pre-analysis process. Therefore, the proposed algorithm does not produce time delay from encoding, and is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better visual and PSNR performance than the existing TMN8 rate control method.

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Distribution of Target Bits based on Size, Motion and Distortion (크기, 움직임 및 왜곡 정보에 의한 목표비트 분배)

  • 지석상;황재정;이문호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.5
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    • pp.1085-1093
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    • 2000
  • An efficient bit rate distribution technique that distributes available bits for multiple objects based on motion vector magnitude, size of object shape, and coding distortion is presented. This coding concept using the three parameters was exploited in MPEG-4 multiple object coding. But the scheme is likely to produce poor results such as allocating more bits to less important objects and degrading picture quality, due to the lack of analysis and research in view of human visual aspect. In this paper importance of each object is represented by the three parameters and visually analyzed. Target bits are distributed according to coding distortion using the pre-assigned shape and motion information.

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The Design of Wide Angle Mobile Camera Corrected Optical Distortion for Peripheral Area (주변부 상의 왜곡을 보정한 모바일 광각 카메라의 광학적 설계)

  • Kim, Se-Jin;Jeong, Hye-Jung;Lim, Hyeon-Seon
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.4
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    • pp.503-507
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    • 2013
  • Purpose: This study was to design wide angle mobile camera corrected optical distortion for peripheral area, which were reduced optical distortion and TV distortion by using 4 aspherical lenses. Methods: The optical design was satisfied with ${\pm}1%$ optical distortion in viewing angle of $95^{\circ}$ and total length of optical system was less than 4.5 mm which was considering a thickness of mobile camera. 1/3.2 inch (5M) CCD sensor was used in the optical system and set design condition to satisfy MTF which was over than 20% in 140 lp/mm. Results: Optimized wide angle mobile camera showed ${\pm}1%$ optical distortion in full field of $95^{\circ}$ viewing angle and TV distortion was 0.46% so that distortion of peripheral area was reduce. MTF showed over than 20% in every field. Ray aberration and astigmatism were small amount so that it showed stable performance. Conclusions: Obtain wider and clearer view which is reduced image distortion of surrounding area via optical method in wide angle mobile camera which has wider view angle than current mobile camera. And it was able to fix a demerit when it occurred via software correction. It is able to apply to study of camera which is related to spectacles.

Estimation of Visual Evoked Potentials Using Time-Frequency Analysis (시-주파수 분석법을 이용한 시각자극 유발전위에 관한 연구)

  • 홍석균;성홍모;윤영로;윤형로
    • Journal of Biomedical Engineering Research
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    • v.22 no.3
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    • pp.259-267
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    • 2001
  • The visual evoked potentials(VEPs) is used to assist in the diagnosis of specific disorders associated with involvement of the sensory visual pathways. The P100 latency is an important parameter which is diagnosis of optic nerve disorders. There are characteristics of latency delay, wave distortion, amplitude deduction in abnormal subjects. It is difficult to diagnose in the case of producing peak at the P100 latency. In this paper, difference of pattern between normal VEPs and abnormal VEPs using the Choi-Williams distribution method is studied. We observed the relationship about time and spectrum. The result shown that normal VEPs had maximum spectral value at 20Hz~26.7Hz and abnormal VEPs had maximum spectral value at 16.7Hz~20Hz. Also normal VEPs spectrum is higher than abnormal VEPs spectrum.

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A Study on the Quantitative Analysis of View by the Projection Method in the Residential Buildings (주거용 건물에서의 투영법에 의한 조망의 정량적 분석에 관한 연구)

  • 김용이;김광우
    • Journal of the Korean housing association
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    • v.14 no.5
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    • pp.37-46
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    • 2003
  • The quantitative analysis of view tells how surroundings and sky are showed, and requires understanding of visual perception and three dimensional information of buildings. The visual perception and the existing projection methods for view analysis are examined. The results of this study are as follows: The visual perception on the size is determined by the visual angle, which can be described as a solid angle. The analysis of view by planar projection can be narrow-sighted according to the size of the window and the location of the viewpoint, which will cause the obstacles in the normal direction of the window interfere the view. For the analysis of view by fisheye projection, the area around the focus point is calculated wider than other areas, and so the view ratio depends on the position of the focus point. When analyzing sky view by dividing the sky vault into the differential area, the distortion by projection can be minimized.