Photogrammetric Block Research Articles

The Use of Auxiliary Airborne Sensor Data in SPACE-M Photogrammetric Block Adjustments

The mathematical formulation used in the photogrammetric block adjustment program SPACE-M has recently been extended to accommodate auxiliary airborne sensor data corresponding to the position and/or attitude of the aerial camera at the time of film exposure. Examples of such systems are statoscopes, laser profilometers, Inertial Navigation Systems (INS) and the Global Positioning System (GPS). The description of the use of these auxiliary data in SPACE-M is outlined and references are given to other related formulations. Test results with simulated and limited real data are presented with some analysis of the implications for topographical mapping and other applications.

On precision requirements for integrated survey control densification by photogrammetric block adjustment

The paper derives a method to establish the precision to be met by a net of coordinated points determined by photogrammetric block adjustment, when the precision specifications for relocation of property boundaries from this net of points are given. The method discussed is of importance to both the problems of planning and of evaluation. Practical examples are used to illustrate these points.

Results from a Precise Photogrammetric Densification of Urban Control Network

Adjustment of a photogrammetric block located in the city of Sudbury, Ontario, demonstrates that an accuracy of 2 cm in planimetric coordinates can be achieved using a minimum number of control points if additional constraints in the form of observed spatial distances are combined with the photogrammetric mathematical model to reduce the control point requirement. This accuracy has been estimated by error ellipsoids of the adjusted ground coordinates, and by independent field checking. The data have also been used to compare different mathematical functions for the compensation of systematic errors in the method of bundle adjustment with self-calibration.

Photogrammetric Block Adjustment

Photogrammetric Block Adjustment

Co-ordination of survey marks by photogrammetry

Reports on the effectiveness of combining South Australian field survey and photogrammetric block adjustment procedures to derive the coordinates of survey marks. Preliminary analysis was made of factors contributing towards accidental and systematic errors. The conclusion is that a gain in economy and efficiency can be achieved.

Block-adjustment by independent rays, using a relaxation method

A simple method for computing the adjustment of a photogrammetric block, using a geometrically-defined relaxation method, is described. Angles measured between the individual rays in the perspective bundles, rather than the more usual bundle or model transformations, are relaxed. The method is suitable for use on small to medium size computers.

Mathematical-Statistical Methods for the Analysis of Aerial Triangulation Adjustment Errors Using a Computer Program

In practice, photogrammetrists use a single statistic reliability interval criterion, based on the mean square errors, to judge the accuracy of adjustment of photogrammetric blocks. Even in some cases, if the practical and theoretical distributions of frequency interval agree, such a test does not make it possible to establish the closeness of their convergence nor the degree of their difference. In other words, to get a complete picture of the character of the distribution of errors in the adjusted photogrammetric blocks, it is insufficient to investigate any single statistic. In the Research and Development Section of the Topographical Survey Directorate, a computer program (SABA) has been designed to analyze the errors of photogrammetric block adjustments, compute various statistical parameters and check the sample distribution using Kolmogorov criterion. Based on the decision taken, the correspondence between the empirical and theoretical distribution series are checked using the criterion χ2. The program divides the adjusted block to make a comparative evaluation of accuracies in the different sub-blocks. In this case, in addition to Kolmogorov and χ2 tests, the program checks the reliability intervals of the means and mean square errors of the samples and uses Fisher criterion ‘F’ to check the hypothesis of the equality of dispersion. SABA is coded in Fortran IV and Compass for the CDC CYBER 74 and requires a central memory of 28K decimal works. SABA is the acronym for Statistical Analysis of Block Adjustment.

On the random error propagation in relatively large networks

A relatively large network is one which covers a large area whereas each observation only involves points within a small local area. For such networks an efficient method is described to establish the lower bounds for the spectral norm of the covariance matrix of the rigorously adjusted co-ordinates. The method utilizes a classification of observations and networks which is thought to be interesting in itself. The weakness of pure angular networks is revealed to stem from the fact that such networks offer little resistance to conformal distortions of the network. A numerical example is given. Asymptotic results for block-type networks are obtained which apply among others to photogrammetric bundle block networks.

Some remarks on the principle and practice in the adjustment of photogrammetric blocks in connection with further automation of plotting!

Some remarks on the principle and practice in the adjustment of photogrammetric blocks in connection with further automation of plotting!

Some remarks on the principle and practice in the adjustment of photogrammetric blocks in connection with further automation of plotting!

Some remarks on the principle and practice in the adjustment of photogrammetric blocks in connection with further automation of plotting!