Accuracy Assessment of Analytical Orientation Process in Close range Photogrammetry

Abstract

This paper studies data manipulation using analytical relative orientation process to determine the exterior orientation parameters. This process can be accomplished by two scenarios; the first one is implemented using collinearity condition while the second one is implemented using coplanarity condition. The final results of both scenarios will be a three dimensional (3D) model and in order to specify the more precise scenario in reconstruction of (3D) models Root Mean Square Error (RMSE) for each scenario was computed. Absolute orientation process was used to transform coordinates of the model system into coordinates of the ground system then (RMSE) for each was computed. The difficulty of obtaining Ground Control Points (GCPs) that covers the photogrammetric project had been overcome by establishing a Portable Control System (PCS) .This (PCS) is a block made of an Aluminum alloy that had been shaped by a (TNC) milling machine to produce plane surfaces on it. The points of intersection of the produced surfaces on the block was labeled or coded and the distances between these points were measured manually by the digital vernier caliper 150mm and micrometer. These points represented control points in the captured images also a specific point within the block was chosen to be the center of this control system and all the remaining points was calculated with reference to it. The calculated (RMSE) for collinearity condition was 1.0212 mm. while for coplanarity condition was 1.0230 mm. So the precision of both models is nearly identical moreover coplanarity condition was more feasible for the requirements of close range photogrammetry.

Keywords

• close range photogrammetry
• collinearity condition
• coplanarity condition
• exterior orientation parameters
• and initial values relative orientation