Yoshihiro Noguchi

A Method of Embedding Binary Data into JPEG Bitstreams

This paper considers irreversible coding by JPEG, and proposes a method of embedding binary data into the image. The proposed method embeds the information into the AC coefficients after quantization. The information is embedded in the AC coefficients of higher frequency, and by setting the quantization table corresponding to these AC coefficients to small values, visual image degradation is limited. In the proposed method, the embedded information is completely recovered in decoding, leaving little effect on the image after recovering the information. The coded sequence can be decoded using a conventional JPEG decoder, even in an environment where the information is not to be recovered or cannot be recovered. The method is designed so that image degradation is also limited in such a case.

A fast full search block matching algorithm for MPEG-4 video

In MPEG-4, motion vectors on both 16/spl times/16 macroblocks and 8/spl times/8 blocks could be used. We propose a block matching algorithm which can find both of them with small computational complexity. It is shown that the number of operations for motion estimation (ME) can be reduced by an expanded successive elimination algorithm (SEA) while maintaining the same accuracy of the full search ME algorithm. In the SEA, the efficiency of reducing the number of ME operations mostly depends upon the appropriate selection of an initial motion vector for searching. We first propose the method of the initial motion vector selection for SEA. We then expand the traditional SEA for the MPEG-1 or MPEG-2 for MPEG-4 in which both 16/spl times/16 macroblocks and 8/spl times/8 blocks are used. In consequence of our simulation, the significance of the proposed method is verified.

A method of extracting embedded binary data from JPEG bitstreams using standard JPEG decoder

We proposed a method for embedding binary data into JPEG bitstreams and extracting embedded data from JPEG bitstreams using the standard JPEG decoder. In the proposed method, we can decode the image from the embedded binary data JPEG bitstreams first using the traditional standard JPEG decoder, and then we can extract the embedded binary data perfectly by the post-processing from the decoded JPEG image. For the post-processing, we use only the decoded image data to extract the embedded binary data. Namely, we do not need any kind of particular parameters, which are used for JPEG decoding, such as quantization table value. Thus, we can use the traditional standard JPEG decoder for the pre-processing of extracting binary data. Furthermore, we address the effect of the calculation bit accuracy of the DCT and inverse discrete cosine transform (IDCT) for extracting embedded binary data perfectly as post-processing. Simulations using extracting embedded binary data as post-processing are presented to quantify some performance factors of concern. We confirmed that the proposed method could be of practical use.

A method of inserting binary data into MPEG bitstreams for video index labeling

We propose a method for inserting optional binary data into MPEG bitstreams. By inserting additional information like index label effectively into video database, we can deal the additional information with video data itself easily. The proposed method allows us to extract the inserted data perfectly though the MPEG video is a lossy algorithm, and the quality of the decoded images after extracting additional information is almost the same as that of the ordinary MPEG bitstreams. Moreover, the standard MPEG decoder can be used for decoding the bitstreams with inserted binary data. In that case, the additional binary data remains in bitstreams but can decode images without obvious image degradation. To verify the effectiveness of our method, we show simulation results for binary data insertion.