• Journal of KIISE:Software and Applications
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• v.31 no.7
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• pp.901-910
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• 2004

In this paper, we propose a content-based MPEG transcoding method using a discontinuity feature in the Discrete Cosine Transform (DCT) domain. A DCT block is transcoded differently depending on the height of dominant discontinuity within a block. In the experiment, we show the result that the video quality of content-based transcoding is better than that of a constant cut-off method and the processing time of the adaptive method is much faster compared with the pixel domain methods in the same bandwidth.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1141-1151
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• 1997

In this paper the Maximum Block Method is suggested for the Feature Extraction of stokes of off-line Chinese characters.The Maximum Block Method is a technique which enlarges the block from the first found pixel that wxtracts the skeleton and features of the input characters.The maximum Block mthod is an adequate technique for the correct extraction of the features since the exsting thining methods have shortcomings of making the feature extraction difficult from the distoritions generated from the effiects of the parial noises,inflection points and blemishes. The printed outputs and chinese books of the middle and high school students,and other materials are used for the test.It was found that the Maxthod is also an effective technique for the extraction of skeleton line and features,which is the preoprocessing of the pattern recognition,for the Korean chracters and English as well as chinese chracters.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.966-974
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• 1999

완전 탐색 블록 정합 알고리즘(FBMA)은 다양한 움직임 추정 알고리즘 중 최상의 움직임 추정을 할 수 있으나, 방대한 계산량이 실시간 처리의 적용에 장애 요소이다. 본 논문에서는 완전 탐색 블록 정합 알고리즘에 비해 더 낮은 계산량과 유사한 화질을 가지는 새로운 고속 움직임 추정 알고리즘을 제안한다. 제안한 방법에서는 공간적인 상관성을 이용함으로써 적절한 탐색 영역의 크기를 예측할 수 있다. 현재 블록의 움직임 추정을 위하여 이웃 블록이 가지고 있는 움직임과 탐색 영역의 크기를 이용하여 현재 블록의 탐색 영역을 적응적으로 변화시키는 방법이다. 이 예측값으로 현재 블록의 탐색 영역 크기를 결정한 후, FBMA와 같이 이 영역 안의 모든 화소점들에 대하여 현재 블록을 정합하여 움직임 벡터를 추정한다. 컴퓨터 모의 실험 결과 계산량 측면에서 제안 방법이 완전 탐색 블록 정합 알고리즘보다 50%정도 감소하였으며, PSNR 측면에서는 0.08dB에서 1.29dB 정도 감소하는 좋은 결과를 얻었다.Abstract Full search block-matching algorithm (FBMA) was shown to be able to produce the best motion compensated images among various motion estimation algorithms. However, huge computational load inhibits its applicability in real applications. A new motion estimation algorithm with lower computational complexity and good image quality when compared to the FBMA will be presented in this paper. In the proposed method, The appropriate search area can be predicted by using the temporal correlation between neighbouring blocks. For motion estimation of the current block, it is the method changing adjustably search area of current block by using motion and search area size of the neighbouring block. After deciding search area size of the current block with this predicted value, we estimate motion vector that matching current block like the FBMA for every pixel in this area. By the computer simulation the computation amount of the proposed method can be greatly decreased about 50% than that of the FBMA and the good result of the PSNR can be attained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1506-1517
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• 1999

In this paper, we propose two fast block matching algorithm using the distribution of mean absolute difference (MAD) at the search region overlapped with neighbor blocks and pixel subsapmling. The proposed methods use the lower and upper bound of MAD at the overlapped search region which is calculated from the MAD of neighbor block at that search position and MAD between the current block and neighbor block. In the first algorithm, we can reduce the computational complexity by executing the block matching operation at the only necessary search points. That points are selected using the lower bound of MAD. In the second algorithm, we use the statictical distribution of actual MAD which exists between the lower bound and upper bound of MAD. By using the statistical distribution of actual MAD, we can significantly reduce the computational complexity for motion estimation. after striking space key 2 times.

• Journal of Intelligence and Information Systems
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• v.12 no.1
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• pp.33-41
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• 2006

This paper presents a method that automatically recognizes products into model type, which it flows with the conveyor belt. The specific interlaced image are occurred by moving image when we use the NTSC based camera. It is impossible to process interlaced images, so a suitable post-processing is required. For the purpose of this processing, after it remove interlaced images using de-interlacing method, it leads rectangle region of object by thresholding. And then, after rectangle region is separated into several blocks through edge detection, we calculate pixel numbers per each block, re-classify using its average, and classify products into model type. Through experiments, we know that the proposed method represent high classification ratio.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.107-110
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• 2018

Image compression is the application of Data compression on digital images. The (DCT) discrete cosine transform is a technique for converting a time domain to a frequency domain. It is widely used in image compression. First, the image is divided into 8x8 pixel blocks. Apply the DCT to each block while processing from top to bottom from left to right. Each block is compressed through quantization. The space of the compressed block array constituting the image is greatly reduced. Reconstruct the image through the IDCT. The purpose of this research is to understand compression/decompression of images using the DCT method.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.6
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• pp.91-99
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• 2004

This paper proposed two transcodiing methods, which maintain the same spatio-temporal resolution and reduce a spatial resolution, to convert a H.264 video bitstream into an MPEG-4 video bitstream. When the H.264 video bitstream is transformed into the MPEG-4 video bitstream, the conversions between H.264 block types and MPEG-4 block types are performed by minimizing distortion and the ${\times}4$ block-based motion vector mapping is performed. The proposed two transcoding methods run 4.14～5.1 times as fast as the cascaded transcoding methods in MPEG-4 encoder side, while the PSNR (peak-signal-to ratio) is slightly degrade with maximum 0.3dB.

• The Journal of Natural Sciences
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• v.7
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• pp.67-73
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• 1995

In this paper, a new texture segmentation-based image coding technique which performs segmentation based on properties of the human visual system (HVS) is presented. This method solves the problems of a segmentation-based image coding technique with constant segments by proposing a methodology for segmenting an image into texturally homogeneous regions with respect to the degree of roughness as perceived by the HVS. The segmentation is accomplished by thresholding the fractal dimension so that textural regions are classified into three texture classes; perceived constant intensity, smooth texture, and rough texture. It is very important to determine the proper block size for estimating the fractal dimension. Good quality reconstructed images are obtained with about 0.1 to 0.25 bit per pixel (bpp) for many different types of imagery.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.7
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• pp.116-123
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• 1999

of a block if the method uses the quantization parameter depending on the bitrate control, and consequently it influence the image quality of video. In this paper, we propose a new method using the following three steps : calculating an averaging (Average of Sum, AS) value in each pixel's block of images, earning an average value of differences between each pixels and As (Differential Averaging Block Pixels, DABP), and finally achieving an improved coefficient values by the DABP and DCT coefficients. Simulation results show that the quality of moving picture could be improved by the proposed method.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.57-67
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• 2008

In this paper, we present an adaptive block matching motion estimation using optical flow. In the proposed algorithm, we calculate the temporal and spatial gradient value for each pixel value from tile differential filter, and estimate the optical flow which is used to decide the location and the size of the search region from the gradient values by least square optical flow algorithm. In particular, the proposed algorithm showed a excellent performance with fast and complex motion sequences. From the computer simulation for various motion characteristic sequences. The proposed algorithm shows a significant enhancement of PSNR over previous blocking matching algorithms.