• Journal of Broadcast Engineering
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• v.7 no.1
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• pp.45-54
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• 2002

This paper proposes a video compression algorithm using characteristics of wavelet coefficients. The proposed algorithm can provide lowed bit rate and faster running time while guaranteeing the reconstructed image qualify by the human virtual system. In this approach, each video sequence is decomposed into a pyramid structure of subimages with various resolution to use multiresolution capability of discrete wavelet transform. Then similarities between two neighboring frames are obtained from a low-frequency subband which Includes an important information of an image and motion informations are extracted from the similarity criteria. Four legion selection filters are designed according to the similarity criteria and compression processes are carried out by encoding the coefficients In preservation legions and replacement regions of high-frequency subbands. Region selection filters classify the high-frequency subbands Into preservation regions and replacement regions based on the similarity criteria and the coefficients In replacement regions are replaced by that of a reference frame or reduced to zero according to block-based similarities between a reference frame and successive frames. Encoding is carried out by quantizing and arithmetic encoding the wavelet coefficients in preservation regions and replacement regions separately. A reference frame is updated at the bottom point If the curve of similarity rates looks like concave pattern. Simulation results show that the proposed algorithm provides high compression ratio with proper Image quality. It also outperforms the previous Milton's algorithm in an Image quality, compression ratio and running time, leading to compression ratio less than 0.2bpp. PSNR of 32 dB and running tome of 10ms for a standard video image of size 352${\times}$240 pixels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.505-516
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• 2000

Cellular Neural Networks(CNN) is a nonlinear information-processing system that has a locally connected characteristic and is widely used in the real-time high speed image processing. In this paper, a practical system approach of time-multiplexing CNN implementations suitable for processing large and complex images using small CNN arrays is presented and $6\times6$ CNN hardware is designed for the processing of a large image. While previous implementations are mostly suitable for black and white applications because of the thresholded outputs, our approach is especially suitable for applications in gray image processing due to the analog nature of the state node. CNN chip is designed using a 0.65${\mu}{\textrm}{m}$ 2P2M(double poly, double metal) N-Well CMOS process technology. It contains about 15,400 devices on an area of about $1.85\times1.75$ md. The designed $6\times6$ CNN is tested for the edge detection of a large image input and it's performance is verified.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.29-40
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• 2002

In photogrammetry, the accuracy is analyzed by using the coordinate of the targeted position determined by the geometric principle, thus, the reliability depends on the accuracy of the coordinate of the targeted position. Thereby, geographic surveying is essential to perform such tasks, and it requires approximately $30{\sim}50%$ of total cost and times to produce a finalized map. The main purpose of this study is to determine the configuration of the disposition of minimum datum points and their configuration, which were determined by surveying values available through using the structure of block model based on the aerotriangulation. ortho projection image was produce and digital topographic map was achieved by the optima model(CASE7). We also performed comparative analysis about the result of local datum point and the accuracy of overlapping based on the surveying results. Consequently, it is possible to analyze the unknown position accurately with the optimal model., CASE 7, which is the minimum datum points configuration required to block adjustment. Furthermore, this optimal model, which provides the minimum datum points, results costs and time saving effects compared to the previous methodology.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1445-1454
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• 2006

To compress a specific part of an image with high quality or to transfer it, JPEG2000 standard offers an ROI(Region-of-Interest) image coding method. What is important in ROI coding is to process relative importance between ROI and background and to process ROI mask. We propose an adaptive ROI coding method supplemented the existing Implicit ROI coding and Modified implicit ROI coding to improve image quality and reduce ROI mask information. The proposed method is an EBCOT-based ROI coding that extracts ROI from the compressed bitstream, and gets the ROI mask information by classifying the codeblocks into 6 patterns. The information includes the pattern type(3bit) and the width(5bit) expressing the boundary between two regions for each codeblock. As a result, the method shows an excellent compression performance in ROI region as well as in the whole region of an image.

• The Transactions of the Korea Information Processing Society
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• v.5 no.12
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• pp.3185-3193
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• 1998

ATM망은 망 내부의 큐잉 랜덤 지연에 의한 CDV의 발생으로 클럭복원의 문제를 안고 있다. 큐잉에 의한 지연은 여러 가지 파라메터에 의해 좌우되며 특히 망의 부하와 트래픽이 전송되는 교환기의 수에 의해 크게 좌우된다. CBR 트래픽의 경우 이를 해결하기 위해 SAR 헤더에 송신부의 클럭 정보를 담아 보내고 수신부에서는 이 정보를 바탕으로 송신부의 클럭을 복원하는 SRTS 기법을 사용하고 있다. 그러나 실시간성을 요하는 VBR 트래픽은 CBR과는 달리 대역폭의 가변적인 성질을 가지고 있으며 그 변화가 다양하여 SRTS 기법을 그대로 적용하기 곤란하다. VBR의 경우에 CBR 전송을 위한 SRTS 기법을 그대로 적용하면 주파수의 가변성으로 인해 망 클럭 주파수에 비해 매우 낮은 주파수의 경우에는 사이클이 상대적으로 많아 정보의 정확성이 떨어지게 된다. 이를 방지하기 위해 서비스 클럭의 주파수가 낮은 경우에는 망 기준 주파수를 낮게 하므로써 정확성을 증가시킬 수 있다. 또한, VBR 트래픽의 경우 AAL1에서는 SRTS의 필요성이 강조되지 않으나 단지 CDV를 제거할 방법이 요구되어진다. 따라서 AAL1의 SRTS를 CDV의 측정을 위한 메카니즘으로 바꾸는 것이 필요하며, 각 기반으로하여 Wavelet 변환을 이용한 VBR 트래픽의 클럭 복원방식을 제안한다. 제안된 알고리즘은 ATM망에서 VBR 영상 서비스를 위한 AAL 계층에 이용이 가능하다. 시뮬레이션 결과는 wavelet 변환 블록에서 출력되는 계수 값을 선택하여 전송함으로써 VBR 트래픽의 보다 다양한 QoS를 만족시킬 수 있음을 보인다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.113-121
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• 2012

In this paper, we proposed fast and efficient algorithm for detecting near-duplication based on content based retrieval in large scale video database. For handling large amounts of video easily, we split the video into small segment using scene change detection. In case of video services and copyright related business models, it is need to technology that detect near-duplicates, that longer matched video than to search video containing short part or a frame of original. To detect near-duplicate video, we proposed motion distribution and frame descriptor in a video segment. The motion distribution descriptor is constructed by obtaining motion vector from macro blocks during the video decoding process. When matching between descriptors, we use the motion distribution descriptor as filtering to improving matching speed. However, motion distribution has low discriminability. To improve discrimination, we decide to identification using frame descriptor extracted from selected representative frames within a scene segmentation. The proposed algorithm shows high success rate and low false alarm rate. In addition, the matching speed of this descriptor is very fast, we confirm this algorithm can be useful to practical application.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.91-98
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• 2005

In this paper, we propose a temporal error concealment method based on the edge adaptive masking. In the method, four regions around the corrupted block - top, bottom, left, and right - are defined and the edge features of the regions are extracted by applying an edge operator for each direction. The size of a mask for the boundary matching is determined by the edge information, which can be considered as a criterion to measure the activity of the boundary region. In other words, it is determined such that the size of the mask is proportional to the amount of edge-component extracted from each region in order to yield the higher reliability on boundary matching. This process is equivalent to applying weights depending on the edge features, which leads the improved motion vector. In experiments, it is verified that the proposed method outperforms the conventional methods in terms of image quality, and then its merits and demerits are discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.45-48
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• 2019

Detection of crosswalk is an important issue for the blind to walk without the help of others. There is a braille block on the sidewalk, which helps the blind to walk. On the other hand, crosswalk is more dangerous due to the moving vehicles. However, there is no appropriate means to induce the blind. In this paper, we propose a method to detect crosswalk in front of a blind and estimate its direction using an image sensor. We adopt multi-ROIs and make their binary versions. In order to determine whether it is a crosswalk, two features are extracted; one is the number of crossing in the binary image and the other is the ratio of white area. We can also estimate the direction of the crosswalk through the slope of the projection data. We evaluated the performance using experimental dataset and the proposed algorithm showed 80% accuracy of detection.

• Journal of The Korean Association of Information Education
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• v.22 no.6
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• pp.613-628
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• 2018

The purpose of this study is to analyze the teaching and learning process of physical computing using coding block for elementary gifted students in science. In order to obtain implications for teaching physical computing, we set the learning objectives from the Computer and Information Literacy Evaluation Standards developed by the International Association for the Evaluation of Educational Achievement(IEA) and developed a teaching and learning program for physical computing through collaboration between science education and computer education experts according to learning objectives. The developed program was related to the use of the coding block MODI(TM) and 32 classes of physical computing instruction were conducted for 15 students of the 4th to 6th grade who belong to an education institute for the gifted in science affiliated to the University. In the physical computing class, the teaching and learning process was analyzed by collecting data such as classroom videos, class observation logs, teacher and student questionnaires, and interviews. Based on the results of the study, the implications of the teaching and learning process of physical computing using the coded blocks in the school education field were suggested. And we also explored the strategy of expanding the computational thinking through the activities of coding instruction to realize creative ideas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.78-83
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• 2014

This paper suggest an effective idea to implement an low area multi-mode one dimension transform block of HEVC(High Efficiency Video Coding). The time consuming multiplier path is designed to operate on low frequency. Normal multipliers dealing with variable operands are replaced with smaller constant multipliers which do the product with constant coefficient and variable only using shifters and adders. This scheme increases total multiplier counts but entire areas are reduced owing to smaller area of constant multiplier. Idle cycles caused by doubled multipliers enable to use multi-cycle paths on the cycle eating multiplier data path. Operating frequency is lowered by multi-cycle path but total throughput is maintained. This structure is implemented with TSMC 0.18 CMOS process library, and operated on 186MHz frequency to process a 4k($3840{\times}2160$) image. Max operating frequency is 300MHz.