This paper deals with the problem of reconstructing the locations of n
points in space from m different images without camera calibration. I
t shows how these problems can be put into a similar theoretical frame
work. A new concept, the reduced fundamental matrix, is introduced. It
contains just 4 parameters and can be used to predict locations of po
ints in the images and to make reconstruction. We also introduce the c
oncept of reduced fundamental tensor, which describes the relations be
tween points in 3 images. It has 15 components and depends on 9 parame
ters. Necessary and sufficient conditions for a tensor to be a reduced
fundamental tensor are derived. This framework can be generalised to
a sequence of images. The dependencies between the different represent
ations are investigated. Furthermore a canonical form of the camera ma
trices in a sequence are presented.