Young-Nam Oh

Digital Watermarking For Copyright Protection Of Mpeg2 Compressed Video

Digital watermarking is the technique which embeds an invisible signal including owner identification and copy control information into multimedia data such as audio, video, images, for copyright protection. This paper proposes a new watermarking technique which is appropriate for the MPEG-2 video coding system by extending the direct sequence spread spectrum. The proposed watermarking scheme in this paper minimizes the perceptual degradation of video quality, caused by the embedded watermark through controlling the strength and area of embedding with respect to the global and local characteristics of the video sequences. And this technique can also directly extract the embedded watermark from the watermarked MPEG-2 compressed video stream without using original video sequences. Simulation results show that the proposed scheme is robust to various attacks to remove the embedded watermark and is feasible for real time system implementation.

Device for reproducing multi-channel audio by using two speakers and method therefor

A device and a method for reproducing a multi-channel audio signal with only two speakers preserving the sound field of multi-channel audio reproduction, thereby providing vivid realism to a user (listener). The device for reproducing multi-channel audio to thereby provide vivid realism to a user by using two speakers includes a data restorer to decode a received multi-channel audio signal and to restore the multi-channel audio data of a frequency domain; a directivity preserving processor which has a center channel direction function and a stereo surround channel direction function based on a head related transfer function indicative of the characteristic of the frequency variation due to the head of the user for audio signals of center and stereo surround directions, to mix the center channel audio data and the stereo surround channel audio data multiplied by the direction function with left and right main channel audio data, and to output directivity-preserved left and right main channel audio data to two main channels; and a process domain converter to convert the directivity-preserved left and right main channel audio data into audio data of a time domain.

Quantization control for improvement of image quality compatible with MPEG2

A new quantization control method for a moving picture coding system, based on MPEG 2 video syntax, is discussed. The quantization control method consists of MB (macro block) activity calculation and rate control. In considering of human visual characteristics and coding efficiency, the quantization control method performs a high quality compression of the digital video signal. >