Improvements of Ortho-contour Photography
31
have treated these beams as to obey the optical law of paraxial ray. Some in
consistencies are naturally expected. The conjugate relation of F and S might
not be held concerning the lenses Li and L 2 , and if the quality of the two lenses
is not very good, the illuminating beams might come out of planes. In order to
avoid the latter defect we are intending to adopt cylindrical lenses for Li and L 2
in the next attempt. The second installation we have actually constructed is
shown in Photo. 1. As it is a test construction, it can not be said to be smart,
Photo 1.
being superfluous in some parts and insufficient in others. Ortho-contour photo
graphs taken with this equipment is shown in Photo. 2. The contours are far
clearer compared with those shown in the previous report. However, we have
not yet checked the accuracy of them. It seems that some testing are needed by
comparing the contours with those derived through the ordinary photogrammetry
or by checking contours of simple shaped objects by calculation.
Further attempt considerable
We have an intention of making the method applicable to all non-topographic
objects, at least, as large as a building, in future. In the present attempt we
fixed the slits S 0 , Si, and S 2 on a rigid plate S, but there is no need of doing so,
we can arrange, instead, the three groups Si-Li, S 0 ~L 0 , and S 2 -L 2 separately in
proper positions and directions, and give Si, S 0 , and S 2 parallel shifts of the same
speed by synchronous motors. The connection among the groups can be made
only by lead wire, and this means that there are no great difficulties for us in
taking a large triangle AS1LS2 when we work on a large object. In the present
experiment, however, in order to catch the consecutive contours it is necessary to
give shifts to the object or to the whole installation so as the optical depth of the