| Abstract | At the Canada Centre for Remote Sensing (CCRS) we have recently developed a new image analysis system (CIAS). This system is used both by CCRS scientists and outside investigators to analyze remotely
sensed imagery from aircraft and satellite platforms. This paper describes the hardware and software architecture of CIAS, some algorithms for image correction, enhancement, and classification, and provides examples of output products from the
system.
The CIAS is composed of two sub-systems, the CIAS-70 sub-system configured around a modified General Electric IMAGE 100 system6 and the CIAS-40 sub-system centred around a PDS colour microdensitometer. In addition to major modifications
to the IMAGE 100 hardware, we, in association with Computing Devices company and DIPIX, have also designed and implemented an array processor optimized for classification. This image analysis processor enables one to classify, for example, a full
LANDSAT frame (7 x 1000000 pixels; four bands) into 93 classes with maximum likelihood discrimination in less than 14 minutes. Three separate data paths permit parallel image processing activity to occur. One of the large disk drives is dual-ported
and interfaced to both the CIAS-70 sub-system's PDP-11/70 minicomputer and to the PDP-11/40 minicomputer of the CIAS-40 sub-system. The three-colour flatbed read/write microdensitometer can be used, for example, to quickly scan an aerial photograph
for analysis on the CIAS-70 sub-system. A high speed interprocessor communication link ensures that tasks on both systems which require shared resources are correctly sequenced.
Image input media are computer compatible tapes in CCRS-JSC format9,
EROS Data Centre formats, or photographs. A graphics tablet is used for limited digitization of map information, selection of map information, selection of training and test sites, and for map overlay. Output products are single-class plots scaled
to approximately match map scales from 1:50,000 to 1:1,000,000, colour photographs produced on the PDS microdensitometer, the CCRS colour strip film recorder, or listings of statistical results, such as class acreages. Examples of some of these
products are shown together with procedures for outside investigators to obtain access to this equipment for remote sensing image analysis. |