Developments in analytical instrumentation

Abstract

The situation regarding photogrammetric instrumentation has changed quite dramatically over the last 2 or 3 years with the withdrawal of most analogue stereo-plotting machines from the market place and their replacement by analytically based instrumentation. While there have been few new developments in the field of comparators, there has been an explosive development in the area of small, relatively inexpensive analytical stereo-plotters based on the use of microcomputers. In particular, a number of new instruments have been introduced by manufacturers who mostly have not been associated previously with photogrammetry. Several innovative concepts have been introduced in these small but capable instruments, many of which are aimed at specialised applications, e.g. in close-range photogrammetry (using small-format cameras); for thematic mapping (by organisations engaged in environmental monitoring or resources exploitation); for map revision, etc. Another innovative and possibly significant development has been the production of conversion kits to convert suitable analogue stereo-plotting machines such as the Topocart, PG-2 and B-8 into fully fledged analytical plotters. The larger and more sophisticated analytical stereo-plotters are mostly being produced by the traditional mainstream photogrammetric systems suppliers with several new instruments and developments being introduced at the top end of the market. These include the use of enlarged photo stages to handle images up to 25 × 50 cm format; the complete integration of graphics workstations into the analytical plotter design; the introduction of graphics superimposition and stereo-superimposition; the addition of correlators for the automatic measurement of height, etc. The software associated with this new analytical instrumentation is now undergoing extensive re-development with the need to supply photogrammetric data as input to the more sophisticated G.I.S. systems now being installed by clients, instead of the data being used mostly in the digital mapping systems operated in-house by mapping organisations. These various new hardware and software developments are reported upon and analysed in this Invited Paper presented to ISPRS Commission II at the 1988 Kyoto Congress.