• Journal of Korea Multimedia Society
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• v.8 no.2
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• pp.201-210
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• 2005

This paper proposes a power efficient 2-dimensional DCT/IDCT architecture driven by input data to be processed. The architecture achieves low power by taking advantage of the typically large fraction of zero and small-valued input processing data in video and image data compression. In particular, it skips multiplication by zero and dynamically activates/deactivates required bit-slices of fine-grain bit partitioned adders within multipliers and accumulators using simple input ANDing and bit-slice MASKing. The processed results from 1-D DCT/IDCT do not have unnecessary sign extension bits (SEBs), which are used for further power reduction in matrix transposer. The results extracted by bit-level transition activity simulations indicate significant power reduction compared to conventional designs.

• Smart Media Journal
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• v.3 no.4
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• pp.16-21
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• 2014

HEVC is the latest joint video coding standard with ITU-T SG16 WP and ISO/IEC JTC1/SC29/WG11. Its coding efficiency is about two times compared to H.264 high profile. Intra prediction has 35 directional modes including dc and planer. However an accurate mode decision on lots of modes with SSE is too costly to implement it with hardware. The key idea of this paper is a DCT shared architecture to reduce the complexity of HEVC intra encoder. It is to use same DCT block to quantize as well as to calculate SSE in RDO. The proposed intra encoder uses two step mode decision to lighten complexity with simplified RDO blocks and shares the transform resources. Its BD-rate increase is negligible at 20% on hardware aspect and the operating clock frequency is 300MHz@60fps on FHD ($1920{\times}1080$) image.

• The Journal of the Acoustical Society of Korea
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• v.18 no.6
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• pp.77-83
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• 1999

H.263 is an international standard of ITU-T that can makes the service such as video phone, video conference in the transmission line less than 64Kbps. This recommendation draft has used motion estimation/compensation, transform coding and quantizing methods. TMN5 used for the performance estimation of H.263 has fundamentally used DCT in transform coding method and presented quantizer for quantizing the DCT transform coefficient. This paper is presenting adaptive quantizer effectively able to quantize DCT coefficient considering the human visual sensitivity while the structure of TMN5 is maintaining. As quantizer that proposed DCT-based H.263 could make transmit more frame than TMN5 in a same transfer speed, it could lower the frame drop effect. And the luminance signal appeared the difference of -0.3 ～ +0.7dB in the average PSNR for the estimation of objective image quality and the chrominance signal appeared the improvement in about 1.5dB in comparision with TMN5. As a result it can attain the better image quality compared to TMN5 in the estimation of subjective image quality.

• Journal of Broadcast Engineering
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• v.28 no.1
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• pp.100-108
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• 2023

In hybrid block-based video coding, transform coding converts spatial domain residual signals into frequency domain data and concentrates energy in a low frequency band to achieve a high compression efficiency in entropy coding. The state-of-the-art video coding standard, VVC(Versatile Video Coding), uses DCT-2(Discrete Cosine Transform type 2), DST-7(Discrete Sine Transform type 7), and DCT-8(Discrete Cosine Transform type 8) for primary transform. In this paper, considering that DCT-2, DST-7, and DCT-8 are all linear transformations, we propose an inverse transform that reduces the number of multiplications in the inverse transform by using the linearity of the linear transform. The proposed inverse transform method reduced encoding time and decoding time by an average 26%, 15% in AI and 4%, 10% in RA without the increase of bitrate compared to VTM-8.2.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1138-1142
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• 2002

Dansamchunghyul-tang(丹參淸血湯) is a new formula consist of Salviae Miltiorrhizae Radix and some oriental herbs to treatment of hyperlipidemia. In this study, we investigated the effects of the water extract of Dansamchunghyul-tang(DCT) on hyperlipidemia of the rat. We here studied the influence of DCT on hyperlipidemia in Sprague-Dawley rats. The hyperlipidemia was induced by Triton WR-1339 (tyloxapol) intravenous injection at 200mg/kg body weight. After 18 h, blood was collected for the determination of plasma total cholesterol, triglyceride, phospholipid, HDL-cholesterol, and LDL-cholesterol concentrations. In the model of hyperlipidemia induced by triton WR-1339 in rats, DCT showed decreasing effects on total cholesterol, triglyceride, phospholipid level significantly, in a dose-dependent fashion. DCT showed dose-dependent effects on HDL-cholesterol and LDL-cholesterol level insignificantly. In conclusion, DCT showed significant effects on hyperlipidemia, and the present findings indicate that DCT may prove potentially useful for treatment of hyperlipidemia.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.3
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• pp.135-138
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• 2014

This paper devices a facial expression recognition method robust to overfitting using 2D-DCT and EHMM algorithm. In particular, this paper achieves enhanced recognition performance by setting up a large window size for 2D-DCT feature extraction and extracting the observation vectors of EHMM. The experimental results on the CK facial expression database and the JAFFE facial expression database showed that the facial expression recognition accuracy was improved according as window size is large. Also, the proposed method revealed the recognition accuracy of 87.79% and showed enhanced recognition performance ranging from 46.01% to 50.05% in comparison to previous approaches based on histogram feature, when CK database is employed for training and JAFFE database is used to test the recognition accuracy.

• The KIPS Transactions:PartB
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• v.11B no.2
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• pp.125-132
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• 2004

In this paper, a watermark inserting method according to the sensitivity of human visual system and minimizing distortion of original DCT coefficients in DCT transform domain is proposed. The proposed method inserts a more robust watermark in the insensitive block of human vision by reordering the blocks according to the human visual system which is appropriate to the JPEG image compression. It also enhances the invisibility and robustness in high compression rate in terms of the watermark inserting method within the block which minimizes distortions of original DCT coefficients. The computer simulation results show that the proposed method maintains high image quality and good robustness in high compression rate compared with conventional watermarking method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.1000-1010
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• 2006

This paper proposes a new architecture for DCT-based motion estimation and compensation. Previous methods do riot take sufficient advantage of the sparseness of 2-D DCT coefficients to reduce execution time. We first derive a recursion equation to perform DCT domain motion estimation more efficiently; we then use it to develop a wavefront array processor (WAP) consisting of processing elements. In addition, we show that the recursion equation enables motion predicted images with different frequency bands, for example, from the images with low frequency components to the images with low and high frequency components. The wavefront way Processor can reconfigure to different motion estimation algorithms, such as logarithmic search and three step search, without architectural modifications. These properties can be effectively used to reduce the energy required for video encoding and decoding. The proposed WAP architecture achieves a significant reduction in computational complexity and processing time. It is also shown that the motion estimation algorithm in the transform domain using SAD (Sum of Absolute Differences) matching criterion maximizes PSNR and the compression ratio for the practical video coding applications when compared to tile motion estimation algorithm in the spatial domain using either SAD or SSD.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.3
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• pp.34-40
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• 2003

The paper presents a method to detect dissolve shots of video scene change detections in an MPEG compressed domain. The proposed algorithm uses color-R DCT coefficients of Ⅰ, P-frames for a fast operation and accurate detection and a minimum decoding process in MPEG sequences. The paper presents a method to detect dissolve shot for three-dimensional visualization and analysis of Image in order to recognize easily in computer as a human detects accurately shots of scene change. First, Color-R DCT coefficients for 8*8 units are obtained and the features are summed in a row. Second, Four-step analysis are Performed for differences of the sum in the frame sequences. The experimental results showed that the algorithm has better detection performance, such as precision and recall rate, than the existing method using an average for all DC image by performing four step analysis. The algorithm has the advantage of speed, simplicity and accuracy. In addition. it requires less amount of storage.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.11-17
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• 2023

This paper proposes a lightweight deep learning network for detecting an image splicing forgery. The research on image forgery detection using CNN, a deep learning network, and research on detecting and localizing forgery in pixel units are in progress. Among them, CAT-Net, which learns the discrete cosine transform coefficients of images together with images, was released in 2022. The DCT coefficients presented by CAT-Net are combined with the JPEG artifact learning module and the backbone model as pre-learning, and the weights are fixed. The dataset used for pre-training is not included in the public dataset, and the backbone model has a relatively large number of network parameters, which causes overfitting in a small dataset, hindering generalization performance. In this paper, this learning module is designed to learn the characterization depending on the DCT domain in real-time during network training without pre-training. The DCT RRU-Net proposed in this paper is a network that combines RRU-Net which detects forgery by learning only images and JPEG artifact learning module. It is confirmed that the network parameters are less than those of CAT-Net, the detection performance of forgery is better than that of RRU-Net, and the generalization performance for various datasets improves through the network architecture and training method of DCT RRU-Net.