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		Ho-Youl, JUNG Ph. D, Associate Professor n Address: School of E.E.C.S., Yeungnam Univ., Dae-dong, Kyungsan-City, Kyungpook, Rep. of Korea n Tel: (Office) +82. 53. 810. 3545 n Fax: (Office) +82. 53. 810.4742 n E-mail: hoyoul@yu.ac.kr n Homepage: (Laboratory) http://image.yu.ac.kr
Main Page	Lecture Board (Administrator Only)			CV
Publications International Journals
1. Park H.J. and JUNG H.Y., “JPEG-2000 Compressed Image Retrieval Using Partial Entropy Decoding,” International Workshop on Multimedia Content Representation, Classification and Security (LNCS), 2006 (Submitted).
			Abstract. In this paper, we propose an efficient image retrieval method that extracts features through partial entropy decoding from JPEG-2000 compressed images. Main idea of the proposed method is to exploit the context information that is generated during context-based arithmetic encoding/decoding with three bit-plane coding passes. In the framework of JPEG-2000, the context of current coefficient is determined depending on pattern of the significance and/or sign of its neighbors to improve the efficiency of the MQ-coder probability estimation. One of nineteen contexts is at least assigned to each bit of wavelet coefficients starting from MSB (most significant bit) to LSB (least significant bit). As the context contains the directional variation of the corresponding coefficient’s neighbors, it represents the local property of image. In the proposed method, the similarity of given two images is measured by the difference between their context histograms in bit-planes. Through simulations, we demonstrate that our method achieves good performance in terms of the retrieval accuracy as well as computational complexity.
2. CHO J.W., R. Prost, CHUNG H.Y., and JUNG H.Y., “A Robust Blind Audio Watermarking Using Distribution of Sub-band Signals,” International Workshop on Multimedia Content Representation, Classification and Security (LNCS), 2006 (Submitted).
			Abstract. In this paper, we propose a statistical audio watermarking scheme based on DWT (Discrete Wavelet Transform). Our method modifies the variance of middle or high frequency band signals, referring to the lowest frequency band signals. It allows us to embed more robust and inaudible watermark. Simulation results show that the proposed method has a good performance in terms of robustness and inaudibility. Besides, our watermark extraction process is not only quite simple but also blind method.
3. KIM M.S., R. Prost, CHUNG H.Y., and JUNG H.Y., “A Blind Watermarking for 3-D Dynamic Mesh Model Using Distribution of Temporal Wavelet Coefficients,” International Workshop on Multimedia Content Representation, Classification and Security (LNCS), 2006 (Submitted).
			Abstract. In this paper, we present a watermarking method for 3-D mesh sequences with a fixed connectivity. The main idea is to transform each coordinate of vertex with the identical connectivity index along temporal axis using wavelet transform and modify the distribution of wavelet coefficients in temporally high (or middle)-frequency frames according to watermark bit to be embedded. Due to the use of the distribution, our method can retrieve the hidden watermark without any information about original mesh sequences in the process of watermark detection. To increase the watermark capacity, all verti-ces are divided into groups, namely bins, using the distribution of scaling co-efficients in low-frequency frames. As the vertices with the identical connec-tivity index over whole frames belong to one bin, their wavelet coefficients are also assigned into the same bin. Then, the watermark is embedded into each axis of the wavelet coefficients. Through simulations we show that the pro-posed is fairly robust against various attacks that are probably concerned in copyright protection of 3-D mesh sequences.
4. KIM M.S., CHO J.W., R. Prost, and JUNG H.Y., “Wavelet Analysis based Blind Watermarking for 3-D Surface Meshes,” 9^th Information Security Conference (LNCS), 2006 (Submitted).
			Abstract. As most previous wavelet analysis based 3-D mesh watermarking methods embed the watermark information into wavelet coefficients arranged in a certain order, they have not been used as blind schemes since the connectivity information must be exactly known in the watermark extraction process. In this paper, we propose blind watermarking methods based on wavelet analysis for 3-D mesh model. Two new techniques are introduced. One is to exploit the statistical features of scale coefficients on an approximation (low resolution) level for watermark embedding. Another is to extract the hidden watermark, not from the same resolution level as used in embedding process, but directly from the spatial domain. Wavelet analysis is not required in the watermark detection process, and then any pre-processing such as registration and re-sampling, is not needed. These techniques allow our methods to detect the watermark without referring to the original meshes and to be fairly robust against various attacks including topological ones. In addition, the proposed are applicable directly to irregular meshes by using irregular wavelet analysis.
5. CHO J.W., R. PROST, and JUNG H.Y., “An Oblivious Watermarking for 3-D Polygonal Meshes Using Distribution of Vertex Norms”, IEEE Transaction on Signal Processing (To be appeared).
			Abstract. Most conventional watermarking techniques of 3-D polygonal mesh models have been developed to be robust, mainly against distortion attacks that could cause visual deformation of the stego mesh model. Examples of distortion attacks include adding noise, smoothing, simplification, re-meshing, clipping and so on. Clearly, distortion-less attacks such as similarity transforms and vertex re-ordering should be carefully considered, since they could fatally destroy the hidden watermark without any perceptual change of the stego meshes. In this paper, we propose two oblivious watermarking methods for 3-D polygonal mesh models, which modify the distribution of vertex norms according to the watermark bit to be embedded. One method is to shift the mean value of the distribution and another is to change its variance. Histogram mapping functions are introduced to modify the distribution. These mapping functions are devised to reduce the visibility of watermark as much as possible. Since the statistical features of vertex norms are invariant to the distortion-less attacks, the proposed methods are robust against such attacks. In addition, our methods employ a blind watermark detection scheme, which can extract the watermark without referring to the cover mesh model. Through simulations we demonstrate that the proposed approaches are remarkably robust against distortion-less attacks. Besides, they are also fairly robust against various distortion attacks. PDF File Download (Preprint) Zip File Download (Execution files)
6. KIM M.S., S. VALETTE, JUNG H.Y., and R. PROST. “Watermarking of 3D Irregular Meshes based on Wavelet Multiresolution Analysis”, Digital Watermarking, Lecture Note in Computer Science (LNCS), Springer, Vol. 3710, pp. 313-324, Sep. 2005.
			Abstract. In this paper, we propose a robust watermarking method for 3-D triangle surface meshes. Most previous methods based on the wavelet analysis can process only semi-regular meshes. Our proposal can be applied to irregular as well as regular meshes by using recently introduced irregular wavelet analysis scheme. L2-Norm of the wavelet coefficients is modified in various multi-resolution levels to embed the watermark. We also introduced a vertex and face re-ordering process as pre-processing in both watermark embedding and extraction for the robustness against connectivity reordering attacks. In addition, our proposal employs blind watermark detection scheme, which can extract the watermark without reference of cover mesh model. Through the simulations, we prove that our approach is robust against connectivity reordering as well as various kinds of geometrical attacks such as lossy compression and affine transform. PDF File Download
7. CHO J.W., KIM M.S., R. PROST, CHUNG H.Y., and JUNG H.Y., “Robust Watermarking on Polygonal Meshes Using Distribution of Vertex Norms”, Digital Watermarking, Lecture Note in Computer Science (LNCS), Springer, Vol. 3304, pp. 317-327, Mar. 2005.
			Abstract. Most watermarking techniques for 3-D mesh models have mainly focused on robustness against various attacks, such as adding noise, smoothing, simplification, re-meshing, clipping, and so on. These attacks perceptually damage the stego model itself. Unlike watermarking of other multimedia data, serious attacks for 3-D meshes includes similarity transform and vertex re-ordering. They can fatally destroy the watermark without any perceptual degradation of the stego model. In this paper, we propose a new watermarking technique for 3-D polygonal mesh model, which modifies the distribution of vertex norms according to watermark bit to be embedded. In particular, the proposed employs blind watermark detection technique, which extracts the watermark without referring to cover meshes. The simulation results show that the pro-posed is remarkably robust against similarity transform and vertex re-ordering. PDF File Download
8. Cho J.W., PARK H.J., HUH Y., CHUNG H.Y., Jung H.Y., “Echo Watermarking in Sub-band Domain”, Digital Watermarking, Lecture Note in Computer Science (LNCS), Springer, Vol. 2939, pp. 447-455, Mar.
			Abstract. Echo hiding is a method for embedding information, called watermark, into an audio signal. In general, echo hiding is processed in the time domain by convolving audio signal with echo kernel, without any consideration of the frequency characteristics. In this paper, we propose an echo hiding technique, which inserts echo into sub-band signal so as to take account into the frequency characteristics. The proposed echo hiding enables to embed high-energy echo, while minimizing the host audio quality distortion. In addition, the proposed allows increasing watermark capacity, since it is possible to embed simultaneously some watermark bits into different sub-band signals. The simulation results show that the proposed is more effective than the conventional echo hiding, in terms of watermark capacity and robustness against various attacks. PDF File Download
9. Park J., JUNG H.Y., “On the Design of Nonfragile Guaranteed Cost Controller for a Class of Certain Dynamic Systems with State Delays,” Applied Mathematics and Computation, Vol. 150, No. 1, Feb. 2004, pp. 245~257.
10. Park J., JUNG H.Y., "On Exponential Stability of a Class of Nonlinear Systems including Delayed Perturbations,” Journal of Computational and Applied Mathematics, Oct. 2003, Vol. 159, pp. 467~471.
11. SEO Y.S., JOO S.H., JUNG H.Y., "An Efficient Quantization Watermarking on the Lowest Wavelet Subband," IEICE Transactions on Fundamentals, Aug. 2003, Vol. E86-A, No.8, pp.2053-2055.
12. Jung H. Y., Prost R., "Multi-channel Overlapping Rounding Transform for HINT and Subband Lossless Image Compression,” Signal Processing, Elsevier, Vol. 80, No. 12, Dec. 2000, pp.2609~2615.
13. Jung H. Y., Prost R., "Lossless Subband Coding System Based on Rounding Transform," IEEE Trans. on Signal Processing. Vol. 46, No. 6, Sep. 1998, pp.2535~2540.
14. Jung H. Y., Choi T. Y., Prost R., "Rounding Transform and Its Application For Pyramid Structured Coding," IEEE Trans. on Image Processing, Feb. 1998, Vol. 7, No. 2, pp. 234-237.
15. Jung H. Y., Prost R., Choi T. Y., "A Unified Mathematical Form of Walsh-Hadamard Transform For Lossless Image Data Compression," Signal Processing, Elsevier, 1997, Vol. 63, No.1, pp.35-43.
International Conferences
16. CHO J.W., KIM M.S., S. VALETTE, JUNG H.Y., R. PROST, “3-D Dynamic Mesh Compression Using Wavelet-Based Multiresolution Analysis”, ICIP 2006 (Submitted).
			Abstract. In this paper, we present a wavelet-based progressive compression method for 3-D dynamic meshes. Our method exploits the spatial and temporal redundancy. We encode the geometry of base mesh, the wavelet coefficients and the connectivity of each resolution level in order to reduce the spatial redundancy of intra meshes. For inter mesh coding, we encode the differences of geometry of base meshes and of their wavelet coefficients between adjacent frames to reduce the temporal redundancy. Our proposal is based on the wavelet-based multiresolution analysis which uses a perfect reconstruction filter bank and therefore it enables not only progressive representation but also lossless compression. The simulation results demonstrate that the proposed is applicable to lossy and lossless compression of 3-D dynamic meshes.
17. KIM M.S., CHO J.W., R. PROST, and H.Y. JUNG, “A robust blind watermarking for 3d meshes using distribution of scale coefficients based on irregular wavelet analysis”, ICASSP 2006 (Accepted).
			Abstract. We propose a new method for watermarking of 3D surface mesh. After irregular wavelet analysis, the watermark is embedded in the scale coefficients. We modify the mean of the distribution of the vertex norm of the approximation mesh in order to obtain blind scheme which does not require the original mesh for detection. Experimental results show the effectiveness of the proposed algorithm both in terms of invisibility and robustness against simplification and progressive lossy compression.
18. Seo Y. S., KIM M. S., PARK H. J., JUNG H. Y., CHUNG H. Y., HUH Y., LEE J. D., “A Secure Watermarking for JPEG-2000,” 2001 IEEE International Conference on Image Processing, ICIP-2001, Greece, pp. 530-533.
19. KIM Y. S., Valette S., JUNG H. Y., PROST R., “Local Wavelets Decomposition for 3-D Surfaces,” 1999 IEEE International Conference on Image Processing, ICIP-99, Kobe, Japan, October, 1999, pp. 357~360.
20. VALETTE S., KIM Y. S., JUNG H. Y., ISABELLE M.PROST R., “A Multiresolution Wavelet Scheme for Irregular Subdivided 3D Triangular Mesh,” 1999 IEEE International Conference on Image Processing, ICIP-99, Kobe, Japan, October, 1999, pp. 171-174.
21. Jung H. Y., Prost R., "Multi-port Filtering System for Lossless Image Compression," 1998 IEEE International Conference on Image Processing, ICIP-98, Chicago Illinois, USA., October, 1998. pp. 861-865
22. Jung H. Y., Prost R., "Décomposition sous bandes pour la compression d'images sans perte par extension de la Transformation par Arrondi (RT)," Seizieme Colloque Gretsi-1997, Grenoble France, Septembre, 1997, Vol. 1, pp. 207-210.
23. Jung H. Y., Prost R., "Rounding Transform Based Approach for Lossless Subband Coding," IEEE International Conference on Image Processing, ICIP-97, Santa Barbara California, USA., October, 1997, Vol. 2, pp. 274-278.
24. Jung H. Y., Choi T. Y., Prost R., "Rounding Transform for Lossless Image Coding," IEEE International Conference on Image Processing, ICIP-96, Lausanne Switzerand, September 1996, Vol. 1, pp. 65-68.
Last update have been done on May. 1, 2006