Research Document Imaging Storage System

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Storage System for Document Imaging
also known as EDM Storage System

Dr. Eugene Ageenko

Storage System Requirements

1. Small storage space
2. Lossless reconstruction
3. Fast decompression
4. Quick preview
5. Spatial access to the image (direct access to the image fragments in compressed file)

Storage System Description

The decompression of the entire image can be a major source of inefficiency. High-speed channels are not always available and the transmission of the entire document (even compressed) to client side might cause inconvenient delays so that the system loses its interactivity. In some applications (GIS) decompressed file size can also exceed the available memory resources.

At the same time, only a small part of the image is often needed, or the image is processed and/or viewed fragment by fragment. Typical viewing devices have a smaller resolution than the original raster image and thus, only a small fragment of the entire image may be viewed at a time.

Proposed EDM Storage System (based on JBIG) meets all above requirements. Images can be efficiently browsed using their thumbnails. Spatial access together with a fast "on-the-fly" decompression (2.5 times faster than JBIG) allows the user to operate directly on the compressed data without retrieving the entire image. Thus, when image is scrolled, new portion of the data is retrieved, decompressed and depicted.

Spatial access is sufficiently supported by clustering the image into fixed size blocks. Pointers (indices) to the clusters are stored at the beginning of the image file to allow direct access to them. The clusters are separately compressed using a semi-adaptive context modeling and two-stage coding process. The two stages include block level codes forming thumbnail image and supporting quick preview property, and pixel-level codes for exact reconstruction of the clusters.

Storage System Architecture

Continue to EDM Storage System Architecture and Features page

Further reading

The requirements and the system are described in details in the following article:

Enhanced JBIG-based Compression Method for Satisfying Objectives of Engineering Document Management System (article in PDF)

Other articles on the topic can be found in Publications section.

Demonstration

Continue to EDM Storage System Demonstration page