• Science of Emotion and Sensibility
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• v.24 no.2
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• pp.57-64
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• 2021

It has long been speculated that the visual system should use a coding strategy that takes advantage of statistical redundancies in images. But how such a coding strategy should manifest in neural responses has been less clear. Low-level image structure related to the power spectrum of natural images appears to be captured by a hard-wired efficient code in the retina of the fly and precortical structures like the LGN of cats that maximizes information content through the limited capacity channel of the optic nerve. But visual images are typically filled with higher-order structure beyond that captured by the power spectrum and visual cortex is not constrained by the same capacity limits as the optic nerve. Whether and how visual cortex can flexibly code for higher order redundancies is unknown. Here we show using psychophysical techniques that the neural response in early human visual cortex may be modulated by orientation redundancies in images such that a visual feature that is contained within a predictive pattern results in slower reaction times than a feature that deviates from a pattern, suggesting lower neural responses to predictable stimuli in the visual cortex. Our results point to a neural response in early visual cortex that is sensitive to global patterns and redundancies in visual images and is in marked contrast to standard models of cortical visual processing.

• Journal of KIISE
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• v.41 no.11
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• pp.900-910
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• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of multi view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, improved prediction structure and motion estimation method is proposed in this paper. The proposed prediction structure exploits an average distance between the current picture and its reference pictures. The proposed prediction structure divides every GOP into several groups to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. And the proposed motion estimation method uses a hierarchical search strategy. This strategy method consists of modified diamond search pattern, progressive diamond search pattern and modified raster search pattern. Experiment results show that the complexity reduction of the proposed prediction structure and motion estimation method over JMVC (Joint Multiview Video Coding) reference model using hierarchical B pictures of Fraunhofer-HHI and TZ search method can be up to 40~70% while maintaining similar video quality and bit rates.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.329-336
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• 2017

In video compression, Motion Estimation(ME) limits the performance of image quality and generated bit rates. However, it requires much complexity in the encoder part. Multi-view video uses many cameras at different positions. Multi-view video coding needs huge computational complexity in proportion to the number of the cameras. To reduce computational complexity and maintain the image quality, an effective motion estimation method is proposed in this paper. The proposed method exploiting the characteristics of motion vector distribution and the motion of video. The proposed is a kind of a hierarchical search strategy. This strategy consists of multi-grid rhombus pattern, diagonal pattern, rectangle pattern, and refinement pattern. Experiment results show that the complexity reduction of the proposed method over TZ search method and PBS (Pel Block Search) on JMVC (Joint Multiview Video Coding) can be up to 40~75% and 98% respectively while maintaining similar video image quality and generated bit rates.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.333-341
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• 2014

Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. Multi-view video coding requires high computational complexity. To reduce computational complexity and maintain the image quality, an effective early termination motion estimation method is proposed in this paper. The proposed method exploiting the characteristic of motion vector distribution uses a hierarchical search strategy. This strategy method consists of multi-grid square search pattern, modified diamond search pattern, small diamond search pattern and raster search pattern. Experiment results show that the speedup improvement of the proposed method over TZ search method and FS(Full Search) method JMVC (Joint Multiview Video Coding) can be up to 1.7~4.5 times and 90 times faster respectively while maintaining similar video quality and bit rates.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2C
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• pp.132-140
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• 2007

In this paper, we proposed a new technique to encode and decode the digital hologram. Since the digital hologram (or fringe pattern) is generated by interference of light, it has much different property from natural 2D (2 dimensional) images. First, we acquisite optical-sensed or computer-generated hologram by digital type, and then extract a chrominance component. The extracted digital hologram for coding is separated into segments to use multi-view properties. The segmented hologram shows the similar characteristics with picturing an object with 2D cameras in various point of view. Since fringe pattern is visually observed like as noise, we expect that the fringe pattern has poor coding efficiency. To obtain high efficiency, the segment is transformed with DCT (Discrete Cosine Transform) which resembles hologram generation process with high performance. Each transformed segment passes the 3D scanning process according to time and spatial correlation, and is organized into a video stream. Since the segment which correspond to frame of a video stream consists of the transformed coefficients with wide range of value, it is classified and re-normalized. Finally it is compressed with coding tools. The proposed algorithm illustrated that it has better properties for reconstruction of 16 times higher compression rate than the previous researches.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.415-416
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• 2006

In this paper, we proposed a new coding technique of digital hologram video using 3D scanning method and video compression technique. The proposed coding consists of capturing a digital hologram to separate into RGB color space components, localization by segmenting the fringe pattern, frequency transform using $M{\tiems}N$ (segment size) 2D DCT (2 Dimensional Discrete Cosine Transform) for extracting redundancy, 3D scan of segment to form a video sequence, motion compensated temporal filtering (MCTF) and modified video coding which uses H.264/AVC.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.39-45
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• 2010

Most traffic in the real internet is TCP traffic. Therefore newly proposed network coding schemes must consider their effects on TCP performance. However, in most studies on network coding, performance evaluation has been conducted using other types of traffic than TCP traffic because network coding has effects on the pattern of packet transmission, which again can impact TCP performance. In most packet transmission schemes based on network coding for wireless mesh networks, it is determined which node, among the ones that received a broadcasted packet, should encode and forward it. In this paper, we examine how the forwarder nodes impact TCP performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1500-1506
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• 2015

In this paper, en efficient broadcast scheme with acknowledged mode is proposed. Specifically, based on stochastic pattern of ACK/NACK across all users and index coding, adaptive coding scheme with XOR operation is used at the transmitter. At each receiver, packets are decoded using layered decoding method with already successfully decoded packets. From numerical results, proposed index coded broadcast scheme is shown to be more efficient than naive broadcast scheme in the sense of average total number of transmitted packets.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.278-283
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• 1998

The interval approach to the linguistic expression coding nears us to the human idea. Thus, what seems "weak" for a person can appear very weak for another person or for the same person in others circumstances. However, the utilization of intervals is not restrained to the cases of linguistic expression coding. Indeed, the interval can facilitate the solution of several problems.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1867-1871
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• 1989

One of the most common problems in pattern recognition and image processing is filling the interior of a region when its contour is given. The existing algorithms of the filling are parity check technique, seeding technique, and technique based on chain coding the boundaries. In this paper, a very simple but effective technique for filling the interior of bounded region is proposed. This algorithm is based on the information of binary-coded boundary direction and covers some of the drawbacks reported in the earlier relevant works.