21. Hofmann, O. 
Germany (F.R.G.) 
SATELLITE TELEVISION SYSTEM 
The operation principle of a satellite television recording system, without moving mechanical parts will be 
explained. The television recording is done by continuous line scanning with constantly open aperture. The 
scanning line is divided by several mirror-strips and led to vidicons. 
By insertion of prisms, line sections can be dispersed spectrally, so that multispectral records are possible 
without additional camera tubes. 
The essential characteristics of the system, among others the ability of stereoscopic recording, are discussed. 
22. Hopkins, R.E. 
Dutton, D. 
United States 
STANDARDIZATION OF THE OPTICAL TRANSFER FUNCTION 
The mathematical concept of an Optical Transfer Function in optical system evaluation is now widely 
understood and is being used extensively in specifying and analyzing lenses. Most optical designers are now 
able to calculate the OTF of their designs. Several instruments which measure the OTF are commercially 
available. 
It would be appropriate to standardize on several of the definitions in this field and record in one document 
the acceptable procedures for measuring OTF. The British Standards Institution has prepared a draft of a 
British Standard, which is a major step towards meeting the need. It is perhaps written too much around one 
particular method for measuring OTF. It should be possible to write the standard to encompass the basic 
principles and allow a wide variety of methods. 
There is need, however, for further development in the use of OTF measurements. The present OTF test 
equipment supplies the user with a larger number of OTF curves for several focus and field positions. In order 
to decide if a lens is acceptable, it is necessary to reduce all the data to a single ‘figure of merit' for the optical 
system. Acceptable merit functions for a lens are needed far more than new variations on how to measure 
OTF. 
23... Kraft, C.L. 
United States 
ACHROMATIC AND CHROMATIC 
STEREOSCOPIC PERFORMANCE 
The photogrammetrist who is skilled in perceiving depth in achromatic stereoscopic imagery may not have a 
similar skill with chromatic imagery. Roch (1954) demonstrated the appearance of different planes as a 
function of color (hue) on well printed maps and for binocular microscope examinations of old-time color 
films. Einthoven (1885) had offered a theoretical explanation, and Luckiesh (1918) effectively measured 
‘retiring’ and *advancing' colors. Which colors advance or recede for any individual may be a product of what 
combination of eye angles and eye axes he personally possesses. 
A black and white stereo test was developed and named the Critical Limen Stereo Test. The prototype consists 
of six pairs of stereoscopic transparencies depicting a matrix of discs that are varied in size, brightness and 
height displacement. This test was designed to, and does, measure the performance of people with exceptional 
stereoscopic skill.