1.5 A Synchronous Distributed Graphics Laboratory

The objective of this thesis is to implement a prototype of a virtual graphics laboratory for remote teaching. This laboratory should provide a synchronous communication platform, mainly intended to share images among participants. Its purpose should however go beyond the simple distribution of images. An environment should be created, which allows the teachers and students to work with the images.

In addition, it should be noted that the system should not be restricted to remote teaching purposes only. It should be possible to use the laboratory anywhere in the field of synchronous CSCW (see section 1.2). The laboratory would be applicable in same-place as well as different-place situations, given that specialists want to discuss image-related material.

Example:
It is often important in medicine to analyze image-related information. This could be x-ray images, retina scans, mammographies or similar images of interest. In most cases, medical advice of a specialist is needed who has a special knowledge and experience in that particular field. The graphics laboratory could be very useful in this case. A physician can log into the laboratory and load an image. This image is now also visible to other physicians and experts that are logged into the laboratory. It is not important if those users reside in the same hospital connected over a local network, or if they are located in different countries connected over the Internet. A user can ask and answer questions via the group chat facility. The set of image processing functions can be used to enhance the image or to emphasize important information within the image. Annotations and sketches can be made on the image with the help of the drawing aids, which should simplify the discussion concerning the image.

The laboratory should provide a shared space that fulfills the following requirements:

• Every session must be able to hold a significant number of shared images. The laboratory should support the most common types of image file formats. The possibility to retrieve images directly from the WWW would also be desirable.

• The laboratory should provide a rich set of image processing functions. Users may use those functions to process and enhance images or to emphasize certain information hidden in an image.

• It must be possible to set annotations within the image.

• The discussion about image material should be supported by drawing aids, with which participants could mark and emphasize features of the image. The drawings aids should be extensive enough to allow users to draw simple sketches and drafts. Those drawings should be removable and storable also.

• At least a text based group discussion facility should be implemented in order to allow synchronous group discussion.

The laboratory should of course also follow the requirements as explained in section 1.4.2:

• Platform independence
• Archival of objects
• Identifiable users
• User rights
• Simultaneous sessions

Guided by the given requirements, the implementation of the distributed graphics laboratory took place in two steps:

First, decisions had been made about the internal architecture of the laboratory. In addition, it was necessary to find an appropriate environment under which the software could be developed, i.e. which programming language should be used. This task is further described in chapter 3.

The second phase was the actual implementation of the software. For example, object models have been created and image processing algorithms had to be found and implemented. A detailed description of the inner structure of the laboratory will be given in chapter 4.