Optimum software architecture for an analytical photogrammertric workstation and its integration into a spatial information environment
Abstract
This study has carried out a thorough investigation into the optimum software configuration for an analytical photogrammetric workstation. the options available for performing basic station's tasks such as mensuration, triangulation, stereomodel definition, stereomodel restoration and digitizing are explored. Using the R-space and the C-space concepts, a new methodology called the ARDOVS relations of vector spaces is developed. This enables the derivation of simplified vector-oriented algorithms fro implementing the software tools for the workstation. Eight software designs are implemented on the DSR-11 through the integration of the basic processes into different operational systems. An empirical cost function and a set of constraint functions in terms of automation content, speed of operation, production cost and achievable accuracy if the derived vector data are developed for a mathematical optimization scheme designed to select the optimum workstation design.
The investigation showed that there are difference in the performance of the software design possibilities for a photogrammetric workstation depending on the requirements for project time(speed of operation), operator involvement, and accuracy of the derived spatial information. However, the optimum software architecture for a workstation, in which minimum project time, minimum operator participation , and high spatial fidelity of the vector data are jointly critical is the BT_570 architecture, a comparator-based design which includes a bundle of triangulation, supplying the object space control points (including minor control points) to a stereomodel definition unit which employs the automated relative and absolute orientation computations to recover the model restoration data. Nevertheless, when the accuracy requirement may be somewhat relaxed, then the software design (BT_000) which employs bundle triangulation supplying only the exterior orientation parameters of the camera (image space) to a definition unit which recovers the model restoration data from these parameters will be most economical.
Furthermore, the necessity to minimize data acquisition cost by eliminating expensive intermediate data transfer which often requires data conversion from one format to another, a common feature of most of the CAD/DBMS systems currently in use, requires a direct integration of the photogrammetric workstation to a GIS. IN thsi work, the integration of the workstation to the CARIS GIS real time operational communication is achieved through the CARIS server interface and the Mailbox technology in the VAX VMS operating environment which allows many programs to operate in parallel and to share data synchronously.