City Research Online

Abstract

In the measurement of structural deformation by analytical close-range photogrammetry, design is a necessity. The design of precision, reliability and sensitivity for photogrammetry alone and photogrammetry with measured distances is studied. The methods which have been developed for design based on the three criteria above mentioned can be used to meet the specifications in many deformation surveys.

The problem of optimal design can be classified in terms of four interconnected problems: zero-, first-, second-, and third order design. Zero-order design problems have been solved by adopting the free bundle adjustment method (inner constraints).

As a "one-number" indicator of the precision, for sake of comparative studies, the mean variance of the object point co-ordinates has been adopted. For reliability assessment, the redundancy number lying between 0 and 1 has been discussed and shown to be advantageous over other measures especially in pre-analysis studies.

Of primary concern in the design of a network is the sensitivity of that network for the detection of point movements at some given level of statistical significance.

A new method has been developed dealing with the sensitivity of a series of formulated deformation models and successfully applied to the different simulated networks.

The main conclusions are that (1) the more cameras used,the more precise the network becomes; (2) not only the number of cameras but also the configuration of the cameras affects reliability in a significant way; (3) the higher the number of cameras used,the less sensitive the network is to hypothesised deformation; and (4) the addition of distances, measured by the conventional methods, to a large degree, does not significantly improve the results of the precision, reliability and sensitivity.

This leads to the advocation of the argument that photogrammetry alone, in deformation measurement, can be used without any survey measurements.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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