THE DSR11 IMAGE CORRELATOR 
James Bethel 
Kern Instruments, Inc. 
Geneva Road 
Brewster, NY 10509 
presented at ISPRS Commission II, May 1986 
ABSTRACT 
The DSR11 image correlation system, ACOR, is described and some current 
development efforts are outlined. Some data samples are analyzed in which 
problems in correlation have occurred, and some strategies for solving 
these problems are presented. Avenues for future enhancement of the system 
are discussed. 
INTRODUCTION 
The automation of height determination in stereo-photogrammetry is a 
process which has been under development for a number of years. The 
process has been in limited production, in an on-line mode, on some very 
sophisticated systems, and on some lower precision systems for orthophoto 
production. Likewise there exist off-line, batch oriented systems working 
directly with digital images. The intent with the Autamated Correlation 
System, ACOR, is to provide a system which can be supplied with, or 
retrofitted to a standard analytical restitution instrument, the Kern 
DSR11, and which can provide significant assistance to the operator in the 
task of collecting large numbers of elevation points in an automated/in- 
teractive mode. 
THE SYSTEM 
The hardware components, the mathematical algorithms, and the associated 
software have been described in several earlier papers, (Cogan, 1984 and 
Bethel, 1986). Briefly the system consists of solid state video cameras 
for the two stages, a frame grabber, and height determination software 
based on the VLL or vertical line locus method. The mode of data 
collection is strictly at regular grid points defined by the ground 
coordinate system. The system has been shown to perform best with small to 
medium scale photography in general. The time taken per point is 1 to 2 
seconds for points with good image structure, and an overall rate of 
approximately 5 seconds per point considering the time for resampling at 
problem points and for manual intervention. 
566