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GV-100 PHOTOGRAMMETRIC ENGINEERING 
IE 3 b2 
Fic. 3. Point designation for Stereo-Pair No. 2. FIG. 4. Point designation for Stereo-Pair No. 3. 
4) The photo base is 
ARD-—5i L60038.4-— 600 |. — 
= = — — — — — = 35.3 millimeters. 
h 6.00 
MEASURING THE OBJECT 
An aluminum test object is turned on a lathe and is measured by means of 
a micrometer. The dimensions are annotated in Figure 6. 
The purpose of this phase of the investigation is to determine how closely 
the same micrometer dimensions can be measured photographically with pre- 
viously determined calibration data of (1) the focal length (91.1 millimeters) 
and (2) the photo base (35.3 millimeters). kr *- 
The procedure is as follows: 
1) The measured. distance between points a and b (Figure 4) on the right € » 
negative of stereo-pair No. 3 is 19.35 millimeters. 
2) The measured distance between corresponding points A and B on the grid . 
in object space is 10.00 millimeters. 
3) The scale of the negative is 
ab 19.35 x 
= — = — = 1.935. 
AB 10.00 
4) The object distance (D) for stereo-pair No. 3 is 
; 1 1 u 
D=jfl1-1+—}=91.1(1-+4 ———] = 138.2 millimeters. 
S 1.935 
a 
Fıc. 5. Stereo-Pair No. 3. (Enlarged 2X for publication.) , 
-