M.O. Bici

Multiple Description Scalar Quantization Based 3D Mesh Coding

In this paper, we address the problem of 3D model transmission over error-prone channels using multiple description coding (MDC). The objective of MDC is to encode a source into multiple bitstreams, called descriptions, supporting multiple quality levels of decoding. Compared to layered coding techniques, each description can be decoded independently to approximate the model. In the proposed approach, the mesh geometry is compressed using multiresolution geometry compression. Then multiple descriptions are obtained by applying multiple description scalar quantization (MDSQ) to the obtained wavelet coefficients. Experimental results show that, the proposed approach achieves competitive compression performance compared with existing multiple description methods.

Packet Loss Resilient Transmission of 3D Models

This paper presents an efficient joint source-channel coding scheme based on forward error correction (FEC) for three dimensional (3D) models. The system employs a wavelet based zero-tree 3D mesh coder based on progressive geometry compression (PGC). Reed-Solomon (RS) codes are applied to the embedded output bitstream to add resiliency to packet losses. Two-state Markovian channel model is employed to model packet losses. The proposed method applies approximately optimal and unequal FEC across packets. Therefore the scheme is scalable to varying network bandwidth and packet loss rates (PLR). In addition, distortion-rate (D-R) curve is modeled to decrease the computational complexity. Experimental results show that the proposed method achieves considerably better expected quality compared to previous packet-loss resilient schemes.

Evaluation of disparity map characteristics for stereo image coding

In order to compress stereo image pairs effectively, disparity compensation is the most widely used method. In this paper we examined the effects of using different disparity maps and their properties in an embedded JPEG2000 based disparity compensated stereo image coder. These properties include the block size, estimation method and the resulting entropy of the disparity map. Experimental results show that basic block matching gives better results than ground truth, especially on occluded regions and boundaries.

Distributed 3D dynamic mesh coding

In this paper, we propose a distributed 3D dynamic mesh coding system. The system is based on Slepian and Wolfs and Wyner and Zivs information-theoretic results. Our system extends the ideas in distributed video coding to 3D dynamic meshes with constant connectivity. The connectivity of the sequence and key frames are encoded and decoded by a conventional static mesh coder. The Wyner-Ziv frames are encoded independent of key frames but decoded jointly with decoded key frames. The joint decoding is performed by the low density parity check codes and the side information generated by linear interpolation of decoded key frames. Experimental results show that better rate-distortion performance is obtained compared to encoding each frame by a static mesh coder.

3D Mesh Coding Using Multiple Description Scalar Quantizers

In this paper, we address the problem of 3D model transmission over error-prone channels using multiple description coding (MDC). The objective of MDC is to encode a source into multiple bitstreams, called descriptions, supporting multiple quality levels of decoding. Compared to layered coding techniques, each description can be decoded independently to approximate the model. In the proposed approach, the mesh geometry is compressed using multiresolution geometry compression. Then multiple descriptions are obtained by applying multiple description scalar quantization (MDSQ) to the obtained wavelet coefficients. Experimental results show that, the proposed approach achieves competitive compression performance compared with existing single and multiple description methods

Importance of side information generation for distributed video coding

Distributed Video Coding (DVC) is a new coding paradigm, based on two information-theoretic results, which allows exploiting source statistics at the decoder only. This architecture, therefore, enables very simple encoders to be used in video coding. Wyner-Ziv video coding is a particular case of DVC which deals with lossy source coding where side information is available at the decoder only. In this paper, the performance improvement of Wyner-Ziv coding by using better side information generated by motion compensated frame interpolation algorithms proposed in literature is examined.

Using disparity map compensation for stereo image coding

In order to compress stereo image pairs effectively, disparity compensation is most widely used. In this paper we examined the performances of using different disparity maps and their properties. These properties include the block size, estimation method and the resulting entropy of the disparity map. Experimental results show that basic block matching gives better results than ground truth, especially on occluded regions and boundaries.