Massimo Ravasi

A scalable and programmable architecture for 2-D DWT decoding

The compression of still images by means of the discrete wavelet transform (DWT), adopted in the JPEG-2000 and MPEG-4 standards, is becoming more and more widespread because it yields better performance than other compression methods, such as discrete cosine transform. The demand of efficient architectures for 2-D DWT coding and decoding for a variety of different applications and embedded systems is rapidly increasing. This paper presents the implementation of a 2-D DWT decoder for Mallat-tree decomposition, suitable for low power applications, such as portable devices. The decoder design has been synthesized and validated in 0.35-/spl mu/m CMOS technology. The architecture is scalable according to the desired maximum image size, the maximum DWT kernel length, and arithmetic accuracy, and it is programmable at run-time to process different image sizes and use different DWT kernels.

High-Level Algorithmic Complexity Analysis for the Implementation of a Motion-JPEG2000 Encoder

The increasing complexity of processing algorithms has lead to the need of more and more intensive specification and validation by means of soft- ware implementations. As the complexity grows, the intuitive understanding of the specific processing needs becomes harder. Hence, the architectural imple- mentation choices or the choices between different possible software/hardware partitioning become extremely difficult tasks. Automatic tools for complexity analysis at high abstraction level are nowadays a fundamental need. This paper describes a new automatic tool for high-level algorithmic complexity analysis, the Software Instrumentation Tool (SIT), and presents the results concerning the complexity analysis and design space exploration for the implementation of a JPEG2000 encoder using a hardware/software co-design methodology on a Xilinx Virtex-II™ platform FPGA. The analysis and design process for the im- plementation of a video surveillance application example is described.

Wavelet image compression for mobile/portable applications

Wavelet image compression offers several advantages over existing methods such as the DCT adopted in the JPEG standard, and has now been adopted by MPEG-4. This paper presents some wavelet codec implementation architectures obtained by a joint optimization of both the algorithmic and architectural features, according to system hardware and software strategy. Results are presented which allow optimization of system performance either for dedicated ASIC design or for embedded software implementation based on available execution speed and cache memory performance.

An introduction to MPEG-G, the new ISO standard for genomic information representation

The MPEG-G standardization initiative is a coordinated international effort to specify a compressed data format that enables large scale genomic data to be processed, transported and shared. The standard consists of a set of specifications (i.e., a book) describing: i) a nor-mative format syntax, and ii) a normative decoding process to retrieve the information coded in a compliant file or bitstream. Such decoding process enables the use of leading-edge com-pression technologies that have exhibited significant compression gains over currently used formats for storage of unaligned and aligned sequencing reads. Additionally, the standard provides a wealth of much needed functionality, such as selective access, data aggregation, ap-plication programming interfaces to the compressed data, standard interfaces to support data protection mechanisms, support for streaming and a procedure to assess the conformance of implementations. ISO/IEC is engaged in supporting the maintenance and availability of the standard specification, which guarantees the perenniality of applications using MPEG-G. Fi-nally, the standard ensures interoperability and integration with existing genomic information processing pipelines by providing support for conversion from the FASTQ/SAM/BAM file formats. In this paper we provide an overview of the MPEG-G specification, with particular focus on the main advantages and novel functionality it offers. As the standard only specifies the decoding process, encoding performance, both in terms of speed and compression ratio, can vary depending on specific encoder implementations, and will likely improve during the lifetime of MPEG-G. Hence, the performance statistics provided here are only indicative baseline examples of the technologies included in the standard.