• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.469-472
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• 2005

In this paper, we propose a new deinterlacing algorithm based on motion estimation and compensation with variable block size. Motion compensated methods using a fixed block size tend to produce undesirable artifacts when there exist complicated motion and high frequency components. In the proposed algorithm, the initial block size of motion estimation is determined based on the existence of global motion. Then, the block is divided depending on block characteristics. Since motion compensated deinterlacing may not always provide satisfactory results, the proposed method also use an intrafield spatial deinterlacing. Experimental results show that the proposed method provides noticeable improvements compared to motion compensated deinterlacing with a fixed block size.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.7
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• pp.62-69
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• 1992

The conventional BMA is performed with the fixed block size. For better performance at low bitrate, the block size is required to be large in relatively stationary area, while small in moving area. Thus, in this paper, a video coding technique using variable block size model is proposed. It decides the block size based on the degree of local motion defined by the local mean and variance of blocks. Computer simulation shows that the proposed method gives comparable performance to the conventional one with less bits required for motion vector coding.

• Journal of IKEEE
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• v.6 no.2 s.11
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• pp.111-118
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• 2002

In this paper, we present a variable block method to reduce additive computational requirements in determining step-size of variable step-size LMS (VS-LMS) algorithms. The block length is inversely proportional to the changing of step-size in VS-LMS algorithm. The technique reduces computational requirements of the conventional VS-LMS algorithms without a degradation of performance in convergence rate and steady state error. And a method for deriving initial step-size, when the input is zero mean, white Gaussian sequence, is proposed. For demonstrating the good performances of the proposed method, simulation results are compared with the conventional variable step-size algorithms in convergence speed and computational requirements.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.20-23
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• 1996

The block matching algorithm for the motion estimation is relatively simple to implement, and thus widely applied in image sequence coding such as H.261, MPEG- I and MPEG-2. Most techniques of the block matching method use fixed-size blocks for the motion estimation. And their success relies on the assumption that the motion within each block is uniform. But if the block size is increased to reduce the number of motion vectors for high data compression, the estimated image brings about many errors. In this paper, the variable-sized blocks are used to solve this problem. And the top down method is used to select the block size.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.423-429
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• 2001

In this paper, we propose the improved method for retrieving images with DC element of DCT that is used in image compression such as JPEG/MPEG. The existing method retrieves images with DC of fixed block size DCT. In this method, the increase in the block size results in faster retrieving speed, but it lessens the accuracy. The decrease in the block size improves the accuracy, however, it degrades the retrieving speed. In order to solve this problem, the proposed method utilizes the variable block size DCT. This method first determines the existence of object regions within each block, and then creates an image region table. Based on this table, it determines the size of each block, following a simple rule; decrease the block size in the object regions, and increase the block size in the background regions. The proposed method using variable block size DCT improves about 15% in terms of the accuracy. Additionally, when there rarely exist images of same pattern, it is able to retrieve faster only by comparing the image region patterns.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.5
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• pp.1089-1095
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• 1996

We propowe a variable block-size transform coding. The size of transform block is adapted by the activity of the block, If the activity is lower than the given threshold, then the block-size is enlarged. In this paper, we use the energy of the transformed cofficients with high frrequency instead of the block variance as the block activity. The computer simulation results show that the reconstruction image by the proposed activeity measure gives superior picture quality to that by the block variance and the mean absolute difference.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.1
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• pp.72-80
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• 1994

In this paper, a new variable block-size transform coding algorithm using information of segmentation is proposed. In general variable block-size transform coding algorithms, the information which is used to form variable blocks is thrown away, but in the proposed algorithm, the information of segmentation which is composed of texture and contour information is maintained for efficient coding. That is, the number of blocks can be reduced by contour information, a DC component of block can be predicted by texture information, and the region compensation, which reduces mean difference between regions, using texture and contour information can diminish the magnitude of AC components. The result is that the proposed algorithm has improved highly the coding efficiency of DC and AC components.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.39-47
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• 2017

The Depth Picture can be Encoded by the Plane Coding Mode that is the Method for Coding Mode by Considering a Part of the Picture as the Plane. In this Paper, we Propose the Method of Determining the Variable-sized Block for Variable Block Coding in the Plane Coding Mode for the Depth Picture. The Depth Picture Can be Encoded in the Plane Coding Through Estimating the Plane Which is Close to Pixels in the Block Using Depth Information. The Variable-sized Block Coding in the Plane Coding can be Applied as Follows. It Calculates the Prediction Error between Predicted Depths by the Plane Estimation and the Measured Depths. If Prediction Error is Below the Threshold, the Block is Encoded by Current Size. Otherwise, it Divides the Block and Repeats Above. If the Block is Divided Below the Minimum Size, the Block is not Encoded by the Plane Coding Mode. The Result of the Simulation of the Proposed Method Shows that the Number of Encoded Block is Reduced to 19% as Compared with the Method Using the Fixed-sized Block in the Depth Picture Composed of one Plane.

• Journal of Biomedical Engineering Research
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• v.10 no.2
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• pp.173-178
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• 1989

A vector quantization technique using a variable block size was applied to image compression of digitized X -ray films. Whether the size of VQ block should be subdivided or not is determined experimentally by the threshold value. The simulation result shows that the performance of the proposed vector quantizer is suitable for the medical image coding, which is applicable to PACS( Picture Archiving and Communication System).

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.381-384
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• 2009

In the Wyner-Ziv coding, compression performance highly depends on the quality of the side information since better quality of side information brings less channel noise and less parity bit. However, as decoder generates side information without any knowledge of the current Wyner-Ziv frame, it doesn't have optimal criterion to decide which block is more advantageous to generate better side information. Hence, in general, fixed block size motion estimation (ME) is performed in generating side information. By the fixed block size ME, the best coding performance cannot be attained since some blocks are better to be motion estimated in different block sizes. Therefore if there is a way to find appropriate ME block of each block, the quality of the side information might be improved. In this paper, we investigate the effects of variable block sizes of ME in generating side information.