Embedded Morphological Dilation Coding for 2D and 3D Images

Current wavelet-based image coders obtain high performance thanks to the identification and the exploitation of the statistical properties of natural images in the transformed domain. Zerotree-based algorithms, as Embedded Zerotree Wavelets (EZW) and Set Partitioning In Hierarchical Trees (SPIHT), offer high Rate-Distortion (RD) coding performance and low computational complexity by exploiting statistical dependencies among insignificant coefficients on hierarchical subband structures. Another possible approach tries to predict the clusters of significant coefficients by means of some form of morphological dilation. An example of a morphology-based coder is the Significance-Linked Connected Component Analysis (SLCCA) that has shown performance which are comparable to the zerotree-based coders but is not embedded. A new embedded bit-plane coder is proposed here based on morphological dilation of significant coefficients and context based arithmetic coding. The algorithm is able to exploit both intra-band and inter-band statistical dependencies among wavelet significant coefficients. Moreover, the same approach is used both for two and three-dimensional wavelet-based image compression. Finally we the algorithms are tested on some 2D images and on a medical volume, by comparing the RD results to those obtained with the state-of-the-art wavelet-based coders

SVC CE1: STool - a native spatially scalable approach to SVC

4noThis documents describes the UNIBS-SCL proposal in response to the MPEG21 SVC CE1 [1]. Our scalable video coding scheme, called STool, is based on a 2D+t+2D structure and is implemented using a modified version of the Microsoft Research Asia (MSRA) reference software [2] plus some modifications and tools which has been used in substitution. The STool architecture has been implemented in two different systems. In System-1 the modules provided in the MSRA software have been used to build the new STool architecture. In System-2 we test a new entropy coder, called GOF-EMDC, which is an extended version of the EMDC coder [3]. At the time GOF-EMDC codec and other parts of System-2 have not been optimized in many aspects, therefore we can expect better performance from our system in the next future. Despite this fact System-2 provides similar coding performances when compared to System-1. In addition, System-2 is much more flexible in many aspects, it guarantees a major number of functionalities and better fulfill the requirements list. Therefore with System-1 we intend to demonstrate the characteristics of the STool architecture, especially with respect to the reference software used, while with System-2 we customize and add functionalities to Stool. We submitted extraction and decoding software for both Systems-1 and System-2, System-1 coded sequences for both scenarios 1 and 2 and System-2 coded sequences for scenario 2 only. For System-2 scenario 1 we only had deadline problems. No technical problems actually exist to produce such sequences.ISO/IEC JTC1/SC29/WG11 MPEG2004/M11368 70th meeting, Oct. 2004, Palma de Mallorca, ESopenopenADAMI N.; BRESCIANINI M.; LEONARDI R; SIGNORONI A.Adami, Nicola; Brescianini, Michele; Leonardi, Riccardo; Signoroni, Albert

Cyclostationary error analysis and filter properties in a 3D wavelet coding framework

The reconstruction error due to quantization of wavelet subbands can be modeled as a cyclostationary process because of the linear periodically shift variant property of the inverse wavelet transform. For N-dimensional data, N-dimensional reconstruction error power cyclostationary patterns replicate on the data sample lattice. For audio and image coding applications this fact is of little practical interest since the decoded data is perceived in its wholeness, the error power oscillations on single data elements cannot be seen or heard and a global PSNR error measure is often used to represent the reconstruction quality. A different situation is the one of 3D data (static volumes or video sequences) coding, where decoded data are usually visualized by plane sections and the reconstruction error power is commonly measured by a PSNR[n] sequence, with n representing either a spatial slicing plane (for volumetric data) or the temporal reference frame (for video). In this case, the cyclostationary oscillations on single data elements lead to a global PSNR[n] oscillation and this effect may become a relevant concern. In this paper we study and describe the above phenomena and evaluate their relevance in concrete coding applications. Our analysis is entirely carried out in the original signal domain and can easily be extended to more than three dimensions. We associate the oscillation pattern with the wavelet filter properties in a polyphase framework and we show that a substantial reduction of the oscillation amplitudes can be achieved under a proper selection of the basis functions. Our quantitative model is initially made under high-resolution conditions and then qualitatively extended to all coding rates for the wide family of bit-plane quantization-based coding techniques. Finally, we experimentally validate the proposed models and we perform a subjective evaluation of the visual relevance of the PSNR[n] fluctuations in the cases of medical volumes and video coding

State-of-the-Art and Trends in Scalable Video Compression with Wavelet Based Approaches

3noScalable Video Coding (SVC) differs form traditional single point approaches mainly because it allows to encode in a unique bit stream several working points corresponding to different quality, picture size and frame rate. This work describes the current state-of-the-art in SVC, focusing on wavelet based motion-compensated approaches (WSVC). It reviews individual components that have been designed to address the problem over the years and how such components are typically combined to achieve meaningful WSVC architectures. Coding schemes which mainly differ from the space-time order in which the wavelet transforms operate are here compared, discussing strengths and weaknesses of the resulting implementations. An evaluation of the achievable coding performances is provided considering the reference architectures studied and developed by ISO/MPEG in its exploration on WSVC. The paper also attempts to draw a list of major differences between wavelet based solutions and the SVC standard jointly targeted by ITU and ISO/MPEG. A major emphasis is devoted to a promising WSVC solution, named STP-tool, which presents architectural similarities with respect to the SVC standard. The paper ends drawing some evolution trends for WSVC systems and giving insights on video coding applications which could benefit by a wavelet based approach.partially_openpartially_openADAMI N; SIGNORONI. A; R. LEONARDIAdami, Nicola; Signoroni, Alberto; Leonardi, Riccard