Abstract
In this paper, A Digital Photogrammetric Workstation (DPW) on Windows NT which can be used in city planning is brought forward Much new technologies such as image auto-match, computer vision, graphics and image processing are adopted. This system can be applied in large scale digital mapping black and white/color Ortho-image making, city 3D model rebuilding and data of 3D city GIS acquiring / update. It is very effective tool for processing city spatial data.

A Digital Photogrammetric Workstation comprises the computer system stereoscopic display device, 3D measurement device, I/O device and correspond software (Shown in Figure 1 and Figure 2). In the following we’’ll explain the make –up and design of this system through hardware system and software system in detail.

1. The make-up and design of hardware systems
Hardware system consists of the computer system high refresh rate and large screen monitor (dual monitor) Stereoscopic display device, 3D measurement device, I/O device. Their installations are as follows:

(1)The installations of computer system are as follows:

Pentium II CPU 300Hz

128MB RAM, 8GMB HD

17” High refresh rate monitor (dual monitor)

(2)Stereoscopic display device

LCD glasses

Control emitter

(3)3D measurement device

Hand-wheel Foot-wheel

Encode

Control switch

3D mouse

Date interface card

(4)I/O device

High solution scanner

Tape recorder

High resolution plotter

All of the devices and apparatus above are of standard making with the exception of 3D measurement devices and control emitter which are produced by our own research institute.


Figure1 : DPW photo


Figure 2 DPW Logical Frame

2.Make-up and design of software system in the Digital Photogrammetric WorkStation
The whole system consists of nine model. There are original information control, digital image orientation, DEM extraction, object collection, graphic edit, topographic import, digital aerial triangulation, ortho-image making and 3D model rebuild. The whole system is developed by VC++5.0 in Windows NT 4.0 environment. The make-up of the software system is shown in Figure 3.

The function of original information control is to input and manage original information which include aerial photography information, survey area information and survey topographic information.

The function of digital image orientation : There are two kinds of system orientations. One is carried on directly by the pixel measurement value of digital aerial triangulation input. The other is carried on by the system itself dependently, which include inter-orientation relative-orientation and absolute-orientation. The above orientation is done by automatic and semi-automatic image match.


Figure 3 DPW Software Model

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