Project Jigsaw:


SUMMARY: The project uses a high-speed, large-memory computer, together with plenty of storage, for the manipulation of large composited images (up to about A3 size, or 1.6 million pixels) and their serving across the World Wide Web in response to requests from an existing server ( The project, focussed on the great Buddhist stupa monument of Borobudur - and called Jigsaw because it deals with image segments just like a jigsaw - will for the first time offer a seamless transition between 3D vector graphics (in the first case a model of Borobudur) and the bit-mapped graphics of the 3000+ images of the monument. Other spaces to be mapped will be the ANU campus, and specific houses at Pompeii, in the form of virtual tours.

BACKGROUND TO THE PROJECT: Digital images are increasingly important in Web work because of faster networks, and better and faster digitizing and storage technologies. In Art History teaching and research, for example, they are often searched via databases, and displayed in browsers. The higher the resolution of the image, the better quality it is, and the more information it contains. It is a common argument that digitising should, wherever possible, be done only once, and at the highest (feasible) resolution. Images can then be archived full-size, and cut down to lower resolutions for current use. The resolution of digital images depends on the characteristics of the capturing device, and very high quality is now possible, for use in specialised viewing tasks (restoration, analysis, transcription of documents), and for printing to achieve near-photographic quality (e.g. for books or posters). The best digital cameras now offer six megapixels (i.e. up to poster-size), which is now within sight of the resolution of traditional film.

Web browsers are dependent, however, upon the characteristics not only of the machines on which they reside, but also on the vagaries of networks, with the result that images are either of low quality or impossibly lengthy to load. How might Web technologies, which are so dependent upon the speed of networks, conveniently be used to examine, retrieve and manipulate large images? Project Jigsaw aims to provide an innovative answer.

JIGSAW: In a jigsaw the image, which started as a complete picture, has been cut up into discrete sections, and is put together by the user. This project aims to do the same with digital images, in two ways: composition makes a completely new composite image of discrete individual files (such as sections of slides, digitised as individual images); conversely, decomposition takes whole, large images, and break them down into sections for manipulation and storage. cf. Figure 2 (attached). Such flexibility should allow work both with video cameras and with high-resolution scanners. Thus the Sony DXP950 (1.6 megapixels: purchased with funds provided by a 1994 Large Equipment bid) can focus close enough to do "air-reconnaissance" overlay images of a 35mm or 6x6 slide or negative, whilst a scanner would produce one large image. For high-resolution shots "in the field", the Hasselblad/Kodak digital camera setup offers 2036x3060 images written to a PCMCIA flash card: these images can then be "decomposed" for storage and manipulation, whilst film negatives or transparencies taken with the same camera but without the digital back are treated to the "air reconnaissance" method described above.

The procedures for images produced with DXP950 and scanner, or with the Hasselblad/Kodak combination, are symmetrical: the former need composition, the latter decomposition. Similar software routines should be applicable therefore for both.

MODELLING THE WORLD IN THREE DIMENSIONS: The equipment is used to model the world from "photographic" images, hung on a computer-modelled armature. The development of the necessary techniques will focus on the Buddhist stupa at Borobudur, because this is the most difficult and intricate exercise; and houses at Pompeii (British School at Rome), Permanent Sample Sites (Forestry) and other virtual spaces will then be built.

Jigsaw will use a "mixed" system, where a 3D model is the armature on which to position low-resolution versions of the high-quality images of the reliefs and other features of the monument. Such modelling will be helped by the regular layout and pyramidal shape of the stupa. Each polygom forming the 3D model will be mapped directly to http URLs of the artwork images, so that clicking on a specific area of the model will bring up the relief or statue which is located there. Hence what the user sees (through the "window" in the Web browser - essentially the viewport on the images) is photographic (i.e. in the form of bitmaps, not vectors), because the armature will be hidden by the representations of photographs which clothe it.

This means that, whereas the model of the stupa really is three-dimensional, it is still only the "map-reference" for viewing the actual artworks. In effect, then, Jigsaw consists of a series of two-dimensional objects in front of which the viewer can manoeuvre in three-dimensional space.

To prepare images for the project, we can proceed in either of two directions, namely by composition or by decomposition (cf. attached diagram):

ADVANTAGES OF JIGSAW: The ability to view large images (up to 6 megapixels, or about poster size) across the Web has not yet been attempted, let alone the notion of "linked" images. The techniques we are developing will be applicable in many disciplines, because all the technologies used are generalised; examples include:

  1. ecology / land management: (including satellite data): external environments (Dept of Forestry);
  2. walk-throughs of complex buildings, such as museums and galleries: Joye Volker (ITA); the Drill Hall gallery is an obvious target;
  3. simulated cityscapes;
  4. landscapes: landscape art on the Web (Photomedia Workshop, ITA);
  5. architectural structures: Borobudur (Dept of Art History);
  6. archaeological sites: especially those where items (statues, wall paintings, furniture - cf. Pompeii) have been moved elsewhere; this will be demonstrated with work on The Pompeii Project, on which we are collaborating with The British School at Rome, and with Italian archaeologists by offering digitizing and display facilities;
  7. battlefields: where clickable maps can relate the landscape today both to that of the battle, and to data in other formats;
  8. teaching (1): Web images for Science Communication (Scientific Communication Centre);
  9. teaching (2):Use in the proposed Master's by Coursework, Graduate Diploma, and Graduate Certificate programs in Digital Media & the Web;
  10. teaching (3): Use in the Forestry & Art History units currently being considered by Open Learning Australia for offering as Web-based distance learning units (the first from ANU);
  11. teaching (4): Use of the Web by the Photomedia Workshop (ITA) as a "virtual studio";
  12. publicity: the proposed virtual tour of the ANU campus, or of a campus college;

MANIPULATING PHOTOGRAPHIC DATA WITH ZOOM: The photographic data should be viewable from a distance, and from close up; and, just as the human eye can wander left, right, up and down, so the "window" in the Web browser should allow the user to do likewise. The initial transition from clickable polygon on the 3D model, to bitmapped image of a relief, has already been explained. But how does one then manipulate such large bitmapped images over the Web? There are certainly difficulties. Theuser with a Web browser could be at the other side of the world, and suffering from a slow network, or a modem. To view images of thumbnail size is easy, because these have been standardised on at about 12Kb, so load quickly. Similarly, video-resolution images generated with standard video technology (i.e. about 760 by 625 pixels in PAL) load relatively quickly.

Zoom, a demo version of which is available at, is a program allowing the user to view in a Web browser a small version of a large image. A detail can be selected by clicking on a notional rectangle first top-left, and the bottom-right, whereupon the software fetches and displays the selected detail at something approaching the detail's full size (depending, of course, on the dimensions of the detail selected). The user may then download the selected detail, or order the whole image to be converted to one of a variety of formats, and sent by email or stored on the server's anonymous ftp site for collection within 24 hours. This setup works well with images of any resolution although, with larger images, further steps are required to produce smooth transitions which buffer what the viewer sees in the Web browser from the potentially very large image files on disk.

This is where Jigsaw comes in: the beauty of the project is the ability to move seamlessly from the manipulable model (vectors) via examination of thumbnail-size images of reliefs, to close examination of high-quality photographic (bitmap) images. cf Figure 3 (attached).

TECHNICAL DESCRIPTION: SOFTWARE & MANAGEMENT: Programs will be needed to chop up and stitch together the images (written in-house), to translate between formats (public domain: netpbm tools), and to provide facilities for manipulation, viewing and retrieval over the Web; this module, called zoom, is in progress (see above).

The "visible" side of the project begins with a 3D representation of the Borobudur stupa (or a Pompeian house, or a Permanent Sample site, or other "spaces"), clothed in texture-mapped polygons. Each of these polygons is a "marker" for an individual relief, held on disk at high resolution, and mapped onto each polygon. The quality of the product will depend upon the ability of the user manipulating the Web browser to view the Borobudur reliefs at any distance and angle, and for the images to be dynamically resized whilst maintaining image quality.

Manipulating the large images involved requires plenty of processing power. The smallest images dealt with would be those taken with the Sony DXP950 Video Camera which, using a half-pixel shift to its three CCDs, writes data to its custom frame buffer which, after vertical interpolation, are converted from ppm into JPEGs of about 500Kb each. We already have over 4,000 of these. Much higher quality "in-the-field" images are possible with the Hasselblad/Kodak combination, offering over four times the resolution of the Sony-produced images. Again, as with 35mm slides, any 6x6 negatives or slides photographed with the Hasselblad would therefore be photographed in each of its four quadrants, giving approximately 1.6 megapixels for each quadrant - hence about 6 megapixels. These are the images ready for composition when needed, as described above.


  1. Part of the mission of the Faculty of Arts at the Australian National University is develop ways of using the latest technology as an aid in teaching and learning ... range of methods for interactive learning (Strategic Plan II, 125-7). The same document notes the same requirement for the ANU as a whole (ibid., 273), and emphasizes (274) the role of electronic publishing. Again, The ArtServe W3 server has won international acclaim for making thousands of images available across the Internet and for pioneering the delivery of visual learning material to students (ibid., 122). In addition, we aim to produce a virtual tour of the ANU campus to aid ANU's current Web publicity drive, in order to attract new students.

  2. This direction is confirmed by the ANU's Strategic Plan 1998-2004, underlined by the Information Technology section of this Plan, and elaborated upon in the Strategic Issues Discussion Paper of 12 June 1998 where, under IT, we read that The ANU has been a leader in utilising and adapting IT to enhance its research, teaching and administrative functions. The University was an early adopter of the WWW as an electronic publishing platform and a number of groups within the University have achieved an international reputation based on the quality of their web publishing. The ANU will enhance its national role by building on its achievements as an essential node in this new academic network.

  3. In learning specifically, this will include targettiong learning: Among the highest priority academic objectives for information technology developments is to create on-campus student learning environments as part of the foundations for future flexible delivery of courses. Such environments will facilitate students' access to course materials and the international information sources to further extend their intellectual horizons.
  4. Project Jigsaw, with its inventive explorations of high-quality web-based VRML modelling in disciplines from Botany and Forestry to Art History, should make a significant contribution to the ANU's strategy.