XIII, Congress of the International Society for Photogrammetry 
Helsinki 1976 
Invited Paper of Commission 111 
SELF CALIBRATING BLOCK ADJUSTMENT 
H, Fbner, Stuttgart 
1. INTRODUCTION 
Detection and elimination of the systematic errors of photo- 
grammetric image or model coordinates is one of the main ob- 
jectives of recent research in aerial triangulation, This is 
understandable and consistent because not compensated syste- 
matic errors change the image or model accuracy to the worse 
and can propagate very unfavourably during block adjustment 
(see |1|). A striking disagreement between empirically obtained 
accuracy figures and the corresponding theoretical expectations 
can be the consequence (see |2| and |3|). 
The most direct way to reach the goal consists in the immediate 
determination of the systematic deformations by comprehensive 
system calibrations and the subsequent correction of the image 
or model coordinates. An alternative, but more indirect concept 
replaces the determination and elimination of the systematic 
errors by a compensation of their effects, This can be attained 
by proper flight dispositions in combination with more fold 
photo coverage or, in a more economic way, by appropriate post 
treatment of the adjusted block coordinates. A general inter- 
polation method, used for this purpose is linear least squares 
interpolation (see |4|), This method is very efficient in case 
of rather dense control. With a smaller number of control points 
however, the more general methods of system calibration yield 
significantly better results. In modern aerial triangulation 
therefore, priority is given to these methods. 
A real calibration of the photogrammetric system can be gained 
by test field calibration or by self calibrating block adjust- 
ment. Test field calibration allows for a detailed and accurate 
determination of the systematic deformations of the photogramme- 
tric data (see |5]). However, additional flight and measuring 
effort is required and the pre condition exists, that the cali- 
brating data are representative for the practical project, 
actually treated. In contrast to that, self calibrating block 
adjustment only uses the project data themselves. Here, the 
actual photogrammetric system is calibrated with regard to the 
actual terrestrial one, Consequently, only those systematic 
errors can be compensated, which show up on the basis of the 
available tie points and control points. 
The following representation of self calibrating block adjust- 
ment is restricted to the simultaneous method, where the syste- 
matic errors of image or model coordinates are compensated by 
additional parameters of the adjustment. An alternative solution, 
suggested by Masson d'Autume and picked up by Schilcher, shall 
only be mentioned here. This method determines and eliminates 
the systematic deformations iteratively, by repeated analyses of 
the residuals of the block adjustment (see |6| and |7]).