The Advanced Semiconductor Research Center of the National Institute of Advanced Industrial Science and Technology (AIST), one of independent administrative institutions, has been dedicated to R&D works on the data compression for high quality graphic arts, based on the results of the "Real World Computing Project" and under the "R & D for International Standardization Project", entrusted by Ministry of Economy, Trade and Industry (METI). A proposal derived from the Project was presented at the ISO/IEC JTC1/SC29/WG1 Meeting held in July 2003 in France, and approved as an Amendment for the ISO/IEC 14492(JBIG2), an international standard for encoding bi-level image (high quality graphic arts image), owing to support from the Industrial Standards Section, Public Relations Department of the AIST and the collaboration with the Information Technology Standards Commission of Japan.

While the international standardization is dominated by European countries and it is rather difficult to put Japanese technologies into the standards, the AIST succeeded to be accepted its technology into the international standards.

The data compression ratio achieved by the AIST method is more than 20 % higher (or, in some cases, more than 30 % higher) than that of the current international standards, JBIG2, owing to optimizing the parameters of data compression program by the genetic algorithm. When using a color page of European newspaper of 1270 dpi quality as test data, the data size was reduced to less than 1/60, and in case of color book data of 2400 dpi, to less than 1/100.

The spread of the international standards accepted here will not only promote the cost reduction based on digital printing and publication (Fig. 1), but also substantially contribute to the development of digital printing machine industry (e.g. CTP and DI printer), to accelerate the expansion of markets for new generation publications, such as on demand and electronic publishing.

In the previous system, steps before RIP were processed digitally, and subsequently, analog media were used such as films and press plates, involving such problems as: (1) Hands of skilled workers are needed for avoiding degrading of image quality caused by repeated analog-to-analog conversions, and (2) Enormous costs were required for transport and storage of actual films and press plates. These problems can be fully solved by digitizing the entire work flow. However, enormous cost required for transfer and saving of large-sized graphic-arts image (high resolution digital image) provided an unavoidable barrier for the digitalization of the work flow. The AIST technology allows to solve the problems by compressing graphic-arts image data into a compact size.

NOTES: RIP = Raster Image Processor, hardware and software to convert text and graphic data generated by the application software into data format printable on a printer. CTP = Computer To Plate, prepress machine or prepress operation to prepare a press plate not by using films, but by directly imaging on aluminum plates under the control of computer. DI (= Direct Imaging) Printer, a printer incorporated with a CTP mechanism within it.

Fig. 1. Digitalization of printing work flow and the compression technology of AIST.