STATE-OF-THE-ART OF CLOSE-RANGE PHOTOGRAMMETRY 
NON-CONVENTIONAL IMAGES 
By non-conventional images is meant im- 
aging systems that do not use a lens and an 
image plane and thus are not frame photo- 
graphs based on the central projection of the 
object onto an image plane. To this group 
belong x-rays, scanning electron microscopes 
(SEM), TV-systems, different types of scan- 
ning images, digital images, and even pan- 
oramic and continuous strip photography, as 
well as holographic and Moire techniques. 
Most of the measurements made on these 
types of images are made by those other than 
photogrammetrists, such as physists, 
mechanical engineers, physicians, geolo- 
gists, forresters, and so on. Except for the 
measurement of x-ray images, photogram- 
metric activities in the area of non- 
conventional images have been rather li- 
mited. 
X-ray is from a geometric point of view very 
similar to conventional photogrammetry, be- 
cause the imaging system very well realizes 
central projection, sometimes even better 
than lens-camera photography. The photo- 
grammetric calibration of x-ray systems is 
performed by using the same methods as for 
non-metric cameras, the only difference 
being that the object test points are made ofa 
material of different radiotransparency?. 
Complete, partial, and “on-the-job” calibra- 
tion approaches are applied. There are, on 
the market, x-ray systems with double tubes 
and rapid cassette exchange mechanisms, 
which provide an excellent means for taking 
nearly simultaneous stereo photographs. 
However, the stereo photographs are usually 
taken with ordinary equipment and with a 
few seconds’ time interval, moving either the 
tube or the object between exposures. 
Calibration of scanning electron micros- 
copes (SEM) using the self-calibration 
method has proved to be very efficient. 
Parameters for radial, tangential, and spiral 
distortions are introduced into the adjust- 
ment together with the scale factors, object 
orientation parameters and co-ordinates of 
points on the test object. The introduction of 
the distortion parameters has increased the 
accuracy of the mathematical model very 
much, which is of great importance for the 
three-dimensional technique with SEM 824 
The present definition of the activities of 
Commission V includes space photogram- 
metry, which encompasses images from re- 
mote sensing systems. Many other commis- 
sions have dealt with this subject and the 
working group on “Geometrical Aspects of 
Remote Sensing” was formed under Com- 
75 
mission III. The reader is referred to the re- 
ports from this group.!? 
The Moiré technique has been developed 
in Japan and a direct method immediately 
gives contours on the object itself. This can 
then be photographed using single or stereo 
cameras. Deformations can also be recog- 
nized very conveniently. Theory, instrumen- 
tation, and applications in medicine and in- 
dustry are described by Takasaki.?9 
Holography and its potential for making 
measurements has been treated by many. 
(See Mikhail?5) The interested reader is re- 
ferred to the rich literature on coherent optics 
for a further study of this broad and expand- 
ing part of physics. 
MEASURING INSTRUMENTS 
Analogue instruments used in close-range 
photogrammetry can be divided into three 
groups: 
1. Normal case plotters. They are often a 
part of a close-range photogrammetric 
system. 
2. Universal first order plotters. These 
have fairly large ranges for w, à, «, Z, c, 
and B, and are used for both aerial and 
terrestrial photographs. 
3. Mapping plotters. These are designed 
for aerial mapping and accept vertical or 
nearly vertical photographs, and can 
sometimes be used for close-range 
photogrammetry. 
Technical details for the first and second 
types are given and discussed in the litera- 
ture.23.14 
The metric and stereometric cameras from 
several manufacturers have adapters for tilt- 
ing the cameras to predetermined angles. As 
a result some of the manufacturers also have 
developed a tilt correction device to be in- 
serted between the plotter (stereo model) and 
the drafting table, so as to have the projection 
planes vertical or horizontal even for tilted 
photography, without the use of large w-tilts 
in the plotter. This means that a universal 
plotter is no longer necessary for the evalua- 
tion of tilted models. This must be regarded 
as a great advantage for many architectural 
and civil engineering applications, where a 
graphical output is used for the presentation 
of the results. 
The analytical instruments are widely used 
for non-topographical photogrammetry be- 
cause of the use of non-metric cameras, and 
also because of the necessity for further 
treatment, in computers, of the primary 
photogrammetric results (object co- 
ordinates). This is, of course, due to the rich