STEREO MATCHING FOR STEREO MODE CCD LINEAR SENSORS 
Ryosuke Shibasaki 
Public Works Research Institute 
Ministry of Construction 
Asahimachi,Toyosatomachi,Tukubagun,Ibaragi 
Shunji Murai 
Institute of Industrial Science 
University of Tokyo 
7-22, Roppongi, Minatoku, Tokyo, Japan 
ABSTRACT 
The biggest head ache of stereo matching based on image 
correlation is that it is impossible to verify whether the 
recognized conjugate point is true or false. The past experience 
showed that the point with maximum corelation coefficient is not 
always true point. 
In order to improve this weakpoint, the authors proposed 
double check system using three stereo rays, that is, triplet 
method. A simulated CCD stereo images with three sights, that 
is, fore, vertical and aft were generated for the test. Only if 
the conjugate point which was determined from a stereo image of 
fore and vertical coincides with the same point from a stereo 
image of vertical and aft, the point can be said to be very 
likely true. If not, these two points include some error. 
Although the triplet method requires the more computing 
time, increasing the reliability of stereo matching is more 
important. The test result showed that error detection was much 
improved. 
INTRODUCTION 
The authors have presented several papers on automated three 
dimensional measurement using stereo CCD linear sensors by 
simulation method. (1),(2) 
There is a trade off between base-height ratio (B/H) and 
height accuracy. That is, if B/H is high, theoretical height 
accuracy will be improved while the accuracy of stereo matching 
will be decreased. 
In order to improve the reliability of stereo matching, the 
authors propose in the paper to introduce triplet methods instead 
of the conventional two rays matching. 
Presented Paper to ISPRS Com. III Symposium held in 
Rovaniemi, Finland, August 18-22, 1986 
225