Chris W. Honsinger

Digital Heritage: Applying Digital Imaging to Cultural Heritage

This PDF file contains the editorial “Digital Heritage: Applying Digital Imaging to Cultural Heritage” for JEI Vol. 16 Issue 01

Book Rvw, Compressed Image File Formats: JPEG, PNG, GIF, XBM, BMP, 1/e, by John Miamo

Programmers involved in the electronic imaging industry are often confronted with developing image file format libraries. While in many cases simply purchasing a third party library is the most efficient way to do this, there are many new applications requiring code written from scratch. Embedded operating systems in digital cameras, printers, and scanners are examples of applications where the support of third party vendors is lacking.

Improved compression technique for multipass color printers

A multipass color printer prints a color image by printing one color place at a time in a prescribed order, e.g., in a four-color systems, the cyan plane may be printed first, the magenta next, and so on. It is desirable to discard the data related to each color plane once it has been printed, so that data from the next print may be downloaded. In this paper, we present a compression scheme that allows the release of a color plane memory, but still takes advantage of the correlation between the color planes. The compression scheme is based on a block adaptive technique for decorrelating the color planes followed by a spatial lossy compression of the decorrelated data. A preferred method of lossy compression is the DCT-based JPEG compression standard, as it is shown that the block adaptive decorrelation operations can be efficiently performed in the DCT domain. The result of the compression technique are compared to that of using JPEG on RGB data without any decorrelating transform. In general, the technique is shown to improve the compression performance over a practical range of compression ratios by at least 30 percent in all images, and up to 45 percent in some images.