The on-line data obtained during an experimental run can be recorded on 9-track tape for 
further analysis. To facilitate the implementation of this part of the methodology, the data can be 
transferred to the Programmable Remote Job Entry System (PRJES). Here the data can either be 
output on the high speed line printer or sent, by means of the interfaced line, to the NRCC computer 
center for further analysis. 
Given this description of the experimental-measurement system, the development of the real- 
time video photogrammetry system will now be described. 
DEVELOPMENT OF THE REAL-TIME VIDEO PHOTOGRAMMETRY SYSTEM — The real-time video photo- 
grammetry system has been developed in accordance with the functional description of the video 
sampling processor and the analytical basis for the single camera solution. This system, comprising 
measurements with analysis, is naturally composed of two sequential processes: 
1) the measurement process with the video camera and the computer controlled sampling 
processor by means of which, on-line with the scan, the area and moments (Ai, M,;, M,;) 
are derived for the level disciminated signal within multiple window apertures i and are 
transferred to the computer, as shown in Figure 7. { 
2) the analysis process with its calculating and logical procedures by means of which, given 
the measure data (A;, M,i» M,;) the desired information is derived. In the case of the 
single camera solution, with four targets, the centroids are derived from the Ai, Mjj; M,j 
data, the photo co-ordinates are calculated and then, by means of the computing procedures 
for the solution equations (viz. Kratky(7)), the relative position and orientation of the 
targetted object are calculated. This analysis process may be continued by other com- 
puting procedures to filter the data and calculate velocities for use in machine control 
tasks (such as the Shuttle-RMS). 
The Measurement Process — Although the target luminance, background luminance, the optical quality 
of the lens, and other factors affect the capability and quality of the measurements, the actual pro- 
cess of making the measurements is afforded by the scan of the video camera and, in this case, on-line 
with the scan, the video sampling processor. Although it might appear from the formulation of the 
design and Equations (11) and (12) that this video sampling processor is simply a means of sampling 
the video signal to derive the centroids of the targets as the photo co-ordinates for the single camera 
solution, it is in fact more broadly based on set theory and sampling theory. As such, the design of 
this video sampling processor has a well defined analytical basis for extended applications. Before 
proceeding from the functional block diagram for the process as shown in Figure 7 to the control 
signal distribution diagram of Figure 15 for its on-line real-time implementation, the basic elements 
of the general process shall be briefly stated. 0 
1) By means of the video raster scan and the horizontal oscillator the continuum of points 
in the image plane of the camera is discretized into the discrete set of points Xr, yr. 
2) By means of the window position/size discrimination logic, the set of points of Xr, Yr 6 
within the window aperture are discriminated out as the set of points x;, y;. 
3) By means of the level discrimination logic, the set of all voltages Vs (X;, y;) are discrimi- 
nated into two sets; R;(x;, ÿ;) = 1 and R,(x;, yı)=0. 
4) The distribution of R4 (x;, y;) in xj, y; can then be described by its moments, where for 
the kt" order moment, using the same notation as Equation (12), 
24 
| with p + 
respectiv 
second n 
window. 
signals x 
two func 
(9 1) 
2) 
derived. 
to the y- 
on-line v 
design) I 
disorimi 
(s. Mo) 
is used f 
9 
the winc 
in the vi 
are also 
origin is 
prototy] 
one can,