Imec News

Archive 2002

IMEC introduces an innovative wavelet transform IP block for high-end image compression


The local wavelet transform block enables high-speed, high-end image compression at reduced memory cost

Leuven, Belgium, October 8, 2002 --- IMEC, Europe’s leading independent microelectronics R&D center, has developed a local wavelet transform (LWT) IP block to reduce the memory requirements in wavelet-based image compression. The LWT, based on block-based wavelet techniques, reduces the memory access cost by roughly a factor 3 while producing results equal to those of non block-based wavelet techniques.

Wavelets are increasingly used in image compression schemes because of their intrinsic scalability features, which enable new functionalities such as, progressive transmission, automatic adaptation to network and terminal resources, etc. The LWT additionally supports features like region-of-interest coding in an efficient way. Wavelets are the technology underlying recent compression standards including JPEG2000 and MPEG-4 Visual Texture Coding. Currently, they are also being considered for scalable video coding for future versions of MPEG-4 and for space-based compression in the context of the CCSDS (Consultative Committee for Space Data Systems) standardization.

Mainly due to memory cost, (especially for large image sizes), wavelets typically come with a higher implementation cost than traditional block-based techniques such as the widely used JPEG. IMEC’s LWT block computes the wavelet transform on a block basis, resulting in a reduction of the memory access cost by roughly a factor 3, while producing results equal to non block-based wavelet techniques.

IMEC’s LWT functionality has been designed in an instruction-based custom processor with a dedicated instruction set for maximum flexibility of image size, wavelet filter type, block size, etc. The LWT processor requires on average only 3 to 4 cycles per pixel, versus 6 for state-of-the-art (non LWT) optimized implementation approaches.

To demonstrate its features, IMEC has integrated its LWT processor into a high-speed wavelet-based encoder for large high-quality images (e.g. remote sensing). The FPGA (field programmable gate array) realization of the LWT allows processing of more than 10 Msamples/s at a clock frequency of 40 MHz.

The LWT processor is generically applicable. All wavelet-based image compression schemes where high-speed and/or memory cost is an issue, can benefit from applying IMEC’s LWT. For example, by using the LWT block together with a JPEG2000 compression stage, the tiling approach that introduces artifacts in the resulting image is avoided and the data-transfer and storage cost is kept under control.

IMEC’s patented solutions for implementing the LWT functionality in any multimedia application are available for licensing. Target companies are IDMs (integrated device manufacturers) or fabless companies that are looking for next-generation multimedia appliances or chip sets to facilitate these appliances.


Notes to editors

About IMEC

IMEC was founded in 1984 and today is Europe’s largest independent research center in the field of microelectronics, nanotechnology, enabling design methods and technologies for ICT systems. IMEC's activities concentrate on the design technology for integrated information and communication systems; silicon process technology; silicon technology and device integration; nanotechnology, microsystems, components and packaging; solar cells; and advanced training in microelectronics. IMEC is headquartered in Leuven, Belgium, and has a staff of more than 1200 people including over 350 industrial residents and guest researchers. IMEC has a 0.13µm 200mm pilot line and is ISO9001 certified. Its revenue of more than 120Meuro is derived from agreements and contracts with the Flemish government and companies, the EC, MEDEA+, the European Space Agency, equipment and material suppliers, and semiconductor and system-oriented companies worldwide. News from IMEC is located at

For more information:

Katrien Marent

Corporate Communication Manager

IMEC, Kapeldreef 75

B- 3001 Leuven, Belgium

Tel +32 16 28 18 80       Fax +32 16 28 16 37


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