• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.5 s.311
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• pp.48-56
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• 2006

In this paper, we proposed the high quality audio watermarking algorithm using MDCT/IMDCT (Modified DCT/Inverse Modified DCT) with psychoacoustic model. Generally, a digital audio watermark is embedding the frequency domain after frequency transform of the digital audio data but the digital audio quality is affected by watermarking. In our scheme, the digital audio data is spread with PN((Pseudo Noise) code and then audio watermark is embedded in MDCT processing that refers psychoacoustic model. In MDCT processing, according to the shape of filter bank output, the block switching selects a window sequence that has 256, 1,024 or 2,048 points interval for high quality audio. The author confirm that when watermark weight ${\alpha}$ is 2.5 below, the detection ratio of watermark is a satisfied to SDMI's(Secure Digital Music Initiative) recommendation 50% above and SM is $50{\sim}68dB$ range with mainly 4 kind of attacks(Compression, Cropping, FFT and Echo).

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.17-23
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• 2003

In this Paper. we Propose a digital watermarking scheme for digital images based on a perceptual model, the frequency masking, texture making, and luminance masking Properties of the human visual system(HVS), which have been developed in the context of image compression. We embed two types of watermark, one is pseudo random(PN) sequences, the other is a logo image. To embed the watermarks, original images are decomposed into $8\times8$ blocks, and the discrete cosine transform(DCT) is carried out for each block. Watermarks are casted in the low frequency components of DCT coefficients. The perceptual model adjusts adaptively scaling factors embedding watermarks according to the local image properties. Experimental results show that the proposed scheme presents better results than that of non-perceptual watermarking methods for image qualify without loss of robustness.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.274-292
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• 2011

This paper proposes an efficient coding method of the depth-map which is different from the natural images. The depth-map are so smooth in both inner parts of the objects and background, but it has sharp edges on the object-boundaries like a cliff. In addition, when a depth-map block is decomposed into bit planes, the characteristic of perfect matching or inverted matching between bit planes often occurs on the object-boundaries. Therefore, the proposed depth-map coding scheme is designed to have the bit-plane unit coding method using the adaptive XOR method for efficiently coding the depth-map images on the object-boundary areas, as well as the conventional DCT-based coding scheme (for example, H.264/AVC) for efficiently coding the inside area images of the objects or the background depth-map images. The experimental results show that the proposed algorithm improves the average bit-rate savings as 11.8 % ~ 20.8% and the average PSNR (Peak Signal-to-Noise Ratio) gains as 0.9 dB ~ 1.5 dB in comparison with the H.264/AVC coding scheme. And the proposed algorithm improves the average bit-rate savings as 7.7 % ~ 12.2 % and the average PSNR gains as 0.5 dB ~ 0.8 dB in comparison with the adaptive block-based depth-map coding scheme. It can be confirmed that the proposed method improves the subjective quality of synthesized image using the decoded depth-map in comparison with the H.264/AVC coding scheme. And the subjective quality of the proposed method was similar to the subjective quality of the adaptive block-based depth-map coding scheme.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.7
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• pp.9-15
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• 1994

This paper proposes a image compression algorithm which stores and transmites image data efficiently. The proposed compression algorithm modify enhances compression rate by modified ZIG-ZAG Scanning in JPEG standard algorithm which is based on 2D-DCT. And the up-compatible method of proposed algorithm can solve compatible problem with JPEG that is cased by modified ZIG-ZAG Scanning. And this paper presentes a block diagram of hardware for real-time processing.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.233-236
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• 1996

A new method of blocking effects reduction is proposed in this paper for use in low bitrate image coding. We use 28 DCT kernel functions of which boundary values are linearly independent, and Gram-Schmidt process is applied to the boundary values in order to obtain 28 boundary-orthonormal basis images. Then we use these basis images to obtain the correction terms for blocking artifacts reduction. A threshold of block discontinuity is introduced for improvement of visual quality by reducing image blurring. We also investigate the number of basis images needed for efficient blocking artifacts reduction when the compression ratio changes.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.131.1-131
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• 2001

At the present time, multimedia chip, internet application, and network equipment is designed by using ARM core. Because it has a good debugging, software compiler and needed low power. We must process a data coding to send a multimedia data by real time. So need to connect software and hardware algorithm. In this research, We design interface for ARM9/AMBA based board using VHDL for these function implementation. The board is used the ARM company´s ARM940T for software function implementation and Xilinx company´s Virtex E2000 for hardware function algorithm. The various hardware algorithm (ME,ME,DCT) block for performance can be implemented on this system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1028-1040
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• 2000

Since image data has large data amount, proper image compression is necessary to transmit and store the data efficiently. Image compression brings about bit rate reduction but results in some artifacts. This artifacts are blocking artifacts, mosquito noise, which are observed in DCT based compression image, and ringing artifacts, which is perceived around the edges in wavelet based compression image. In this paper, we propose directional postprocessing technique which improved the decoded image quality using the fact that human vision is sensible to ringing artifacts around the edges of image. First we detect the edge direction in each block. Next we perform directional postprocessing according to detected edge direction. Proposed method is that the edge direction is block. Next performed directional postprocessing according to detected edge direction. If the correlation coefficients are equivalent to each directions, postprocessing is not performed. So, time of the postproces ing brings about shorten.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1117-1120
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• 1999

The main purpose of padding methods is to extend the boundary segments of arbitrarily shaped objects to a regular grid so that the common block based coding technique, such as 8${\times}$8 DCT, can be applied. In the conventional padding methods used in MPEG-4: LPE and zero padding, the main process is based on 8${\times}$8 blocks. On the contrary, we propose a new padding method based on pixel-by-pixel. The proposed method puts pixels into a multi-busier using the typical value of each boundary blocks and reproduces new boundary blocks. Simulation results show that the proposed method reduces the conventional padding method and improves the coding efficiency of the conventional padding method.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.2
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• pp.46-52
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• 2011

This paper presents adaptive spread-spectrum watermarking scheme on the H.264/AVC video. The H.264/AVC has become popular video coding since it's compression performance has been improved greatly. That is why there is not enough space for embedding watermark using the spread-spectrum method. To overcome this problem, we propose selective block embedding scheme. The blocks which don't contain non-zero DCT (Discrete Cosine Transform) coefficients are selected by value. So we have enough space to embed watermarks. Experimental result shows that proposed scheme improves recovery rates of watermark about 12% and reduces distortion of watermarked video.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2001.05a
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• pp.318-324
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• 2001

In this paper we propose the adaptive scheme to place more search points as long as the operation tapability of the motion estimator in the video codec permits. And the proposed algorithm takes advantage of the intuitive fact that the quality of the decoded video is more degraded as the spatial frequency of the corresponding block is increased due to the augmentation of local minima per unit area. Thererore, we propose the scheme to enhance the quality by locating relatively more search points in the block with high frequency components by analyzing the spatial frequencies of the video sequence. As a result, the proposed scheme can adaptively place more search points possibly permitted by the motion estimator and guarantees better quality compared to the TSS and FS.