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A MICROPROCESSOR-CONTRO LLED 
ORTHOPHOTOPROJECTOR SYSTEM 
MADE IN CHINA 
Senior Engneer Liu Xian Ling 
The Research Institute of Surveying & Mapping 
Beijing, China 
Commission II 
ABSTRACT 
The first orthophotoprojector designed by China has been success- 
fully turned out recently. The paper describes in the first place 
its principle, construction, error analysis, computer control, ope- 
rational experience and test results, and in the second place a 
simple analytical plotter called "DEM Producer", which has been de- 
signed by combining Intel 8086 single board computer with stereo- 
comparator to provide, mainly, DEM data for the projector. 
1 ORTHOPHOTOPROJ ECTOR 
In order to satisfy the needs of the people for orthophoto maps an 
orthophotoprojector has been developed. This projector is based on 
the differential rectification through optical slit projection and 
is controlled by a 16-bit single board processor. The principle of 
the optic-mechanical instrument is shown in Figure 1. 
The movement range of the image carriers240mm both in x and y. 
The magnification m changable within Tet 
The image rotation do 3609, 
The movement of the drum in object space 700mm by 700mm both in x 
and y. 
The most delicate part of optics is the ZOOM system, and the rota- 
tion of the drum is very important for the mechanism. The imporvant 
task the optics does is to assume a high resolution, because the 
resolution can not be controlled by a programmer.