Virtual Vellum
An e-Science demonstrator for the Arts and Humanities sponsored by
- Engineering and Physical Sciences Research Council
- UK e-Science
- Arts and Humanities e-Science Support Centre
Virtual Vellum is an EPSRC-funded e-science demonstrator project running from July-December 2006. The prime objective is to produce a versatile image viewing tool designed to appeal to Arts and Humanities researchers working with digitised images of various kinds (manuscripts included!). A stand-alone version is planned, for personal research, presentations or conference use, plus a tool for use on large datasets - accessed via Data and/or Access Grid. See also: http://www.shef.ac.uk/hri/projects/projectpages/virtualvellum.html
People
PI: Peter Ainsworth (French and HRI);
Technician Associate: Michael Meredith
JPEG
JPEG image compression is currently the predominant technique used for viewing high-resolution images in real-time (> 8k x 6k pixels). This is partly due to its affording a noticeably smaller file size as compared to the raw image, for example: a 144MB raw TIFF image can be compressed down to a 10MB JPEG file without too much noticeable degradation in quality. However, a 10MB file can still take a considerable time to download over the internet, and will in addition require a large amount of processing to convert it into a state such that it can be displayed to best advantage. This is why image-viewing tools currently available resort to ‘smashing up' the complete image into smaller fragments (a process known as ‘tiling'). This produces smaller JPEG file sizes but at the cost of requiring many JPEG files for each single, high-resolution TIFF image. When a user views an image, the software retrieves only the relevant JPEG sub-images for the portion of the main image that is being displayed.
JPEG 2000
The technique of fragmenting a single image into multiple JPEG images is, however, redundant with respect to pre-processing and storing the data. JPEG 2000 presents an attractive alternative, since it achieves the segmentation using a single file without redundancy. Furthermore, at similar compression ratios the JPEG 2000 compression technique achieves better visual results than its JPEG counterpart. Thus, compared to the original compression quality and ratios, we can either have smaller file sizes or high-quality encodings. An other useful property is that JPEG and JPEG 2000 files can be used together and are fully compatible with each other. So we can imagine, for example, using conveniently low-volume JPEG thumbnails as part of an overall JPEG 2000 environment.
JPEG 2000 AND JAVA
From a pilot prototype developed in Flash by Scriptura's Colin Dunn, we propose to develop an image viewer called "Virtual Vellum". It makes use of JPEG 2000 and Java to encode large collections of high-resolution images that can be viewed and manipulated in real-time. The image datasets will be accessed from either/both a local drive and a remote location over the internet. The Froissart Project provides the initial set of images, consisting of four complete digital manuscript surrogates.
VIRTUAL VELLUM
"Virtual Vellum" is written entirely in Java version 1.2. This makes it completely platform- independent. It can therefore run within a web page without the need for extra plug-in downloads, or as a stand-alone application, e.g. as a more user-friendly replacement for conventional viewers. The combined features of "Virtual Vellum" make it a very versatile image-viewing tool. We envisage it being used for online study and research, but also (for example) during live seminars, conference papers, public lectures or demonstrations. It will prove especially versatile when two or more images need to be called up rapidly by a lecturer or demonstrator, for side-by-side comparison.