The Extract Image Processing System

The Extract image processing system was developed in 1992 by Mark Dobie as a test bed for methods for feature extraction from remotely sensed images. As such, it allows an image to be manipulated in many different ways. These may produce new images which are displayed in a new window, allowing further manipulation, or they may produce vector data which can be overlaid on the image display.

Each window allows the full range of algorithms to be applied and the can select areas or points of interest to guide the algorithms. Extract maintains a history of the operations that result in the image in each window. This figure shows a typical extract digitising session.

Here are some features of extract...

Contrast stretching, thresholding, lookup table operations.
Edge detection, interest operators, histogram equalisation.
Plane combination, isolated point removal, line point detectors.
Morphology operations
D'esopo vector digitising.
Minimum spanning tree network digitising.

The image processing core of extract is provided by the imagelib library of image processing routines. From this point of view, extract can be seen as a graphical user interface to the routines in imagelib. Extract provides an Open Look user interface, although it is currently being enhanced to give a Motif interface and there is some support for a Microsoft Windows interface.

Extract is currently being used and extended by a number of projects so that new areas such as interactive segmentation and texture analysis can be explored. Extract is also being converted into an advanced viewer for the Microcosm distributed multimedia information system.

Text and images by Mark Dobie, back to Mark's home page