A "standard" image capture, storage and retrieval system

Palynology and many other biological and geological disciplines depend on photographic documentation of the objects observed. We built the system described below using "standard" computer and video hardware and software components, which are cheap, easily installed and friendly in use. We prefer this solution to custom designed products, which often are difficult to use and expensive to update in the modern day fast developing computer world.

I (Niels) asked one of my colleagues (HC), who is one of the GEUS computer experts, to help me selecting a video camera, a picture grabbing system and an image catalogue for my PC to replace the classical camera and film technique. In addition the annoying tendency of old prints and film to fade and become mouldy has been solved by storing images on CD-ROM from which they may be recovered on any PC, MAC or UNIX computer system.

The system we created is not unique, and parts of it may be omitted or replaced by other products. We present this experience in the hope that it may help other colleagues to acquire some useful and cheap equipment.

The image path from the microscope to the CD-ROM starts with a standard surveillance video camera (price a few hundred US dollars) with a resolution of 460 TV lines in colour. All settings on the video camera are used in "auto" mode. The video camera comes with a C/CS mount. It is installed on the microscope on a video camera tube.The additional lenses usually required for a photo camera are not needed. Even the "family video camera" may be used, if it has a removable lens.

The output of the video camera should match the input on the video grabber card and may be composite or Y/C. A Y/C (super-video) output is to be preferred, as this gives a slightly better quality than composite video. Composite video signals can easily be converted to super-video and vice versa. This, however, requires a converter, which is an additional cost.

The video signal is transferred to the computer by a MRT Video Port Pro video grabber card. This card is a "credit card" size card (PCMCIA) which we use both on a laptop computer directly and on the stationary PC by an adapter socket.

In the computer, there are several software possibilities for capturing the images (single video frames). There is an "invisible" program (TWAIN) that allows all TWAIN-aware programs to capture images directly. Programs from Microsoft, Adobe and Corel and our image database program, MiniCat by Prostar are among the TWAIN-aware. Secondly we have a dedicated image capture and processing programme that comes with the card, MRT Image Wizard (Version 3.2). We have tested this programme. It consists of two separate screen-capture programmes: a very simple "MRT Image Office" and a more advanced program "Image Wizard". The latter allows not only pre- and post image capture image processing, adjustment of colour, contrast, light etc., but also many advanced processing functions, for example, image sharpening, softening, rotation, negative-to-positive conversion, sculpturing and edge thinning and thickening. A "stacking" feature allows the digitisation and addition of multiple images to suppress noise and enhance light recovery from the microscope if required.

After processing images are stored in the MiniCat Catalogue Builder programme that allows the addition of text to the images. Images may be displayed as "thumbnail images" for easy comparison of multiple images or as slide shows to display more detail. A text search system is built in. Images stored in this database are compressed automatically. The program necessary to view the database is built into the resulting file and may be distributed freely along with the database on a floppy or CD-ROM. The processed images are also stored on CD-ROM outside the database to ensure that they may be retrieved by any computer that supports this standard, including DOS or Windows based PC's, MAC's or any UNIX box.

To prepare plates for publication programmes as Fractal Imager and Corel Photopaint have been chosen. Text processing programmes like Word for Windows also have facilities for the inclusion of images.

To store images on CD-ROM a Hewlett Packard CD burner was acquired. It comes complete with SCSI adapter card and two sets of software, the simplest possible by HP and an advanced version, Eazy CD Pro by Adaptec.

The CD burner solves the problem of storing images for 20 years without any degradation in quality on a medium that will not be too exotic by then because of the wide distribution of the CD medium. The recording surface of a CD-ROM is vulnerable to scratches though and should be handled carefully. It is possible to have the surface lacquered to protect it.

The system is functioning very well, and we will of course help with additional comments and addresses, if others should be interested in using a similar video system set up.

The MiniCat programmes from Prostar Interactive Media can be found at http://www.minicat.com. Other relevant web addresses are: Fractal Imager by Iterated Systems (http://www.iterated.com/); Hewlett Packard CD-burner 4020 (http://www.hp.com/); MRT Video Port Professional (http://www.mrtmicro.com/); Syquest EZ135 removable hard disk (http://www. syquest.com/).

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  This article first appeared in CAP Newsletter 20(1):16-17, 1997.