178
Table 3. Comparison of exterior orientation parameters.
(Coordinates in feet.)
Parameter Monocomparator Auto Recognition
Result Result
Photo 73
Photo 74
Photo 73
Photo
74
Omega
-0 °14'48"
-0 °19'32"
-0 °13'12"
-0°20 '
43'
Phi
-0 °18'58"
-0 °12'00"
-0°17 , 49"
-0°13 '
27'
Kappa
1 ° 01'2 8 "
1°20'04"
1 ° 01'2 7 "
1°19 '
53'
X
55205.4
57011.7
55206.9
57010
.9
Y
26009.3
26102.5
26008.8
26103
.8
Z
3865.1
3843.1
3865.5
3843
.9
CONCLUSIONS
Coordinates of points on digital images can indeed be re
fined to significantly less than a whole pixel. This allows
scanning at larger pixel sizes while retaining desired
accuracy. The massive quantities of digital data in the
photography can thus be reduced, resulting in a cost savings
for data storage and computation.
Scanner distortion is still a definite problem which cannot
be neglected. Use of a reseau camera or a more stable
scanner should alleviate this problem.
Automatically generated DTMs are feasible and will likely
be used in the future to reduce cost and increase speed of
map compilation. The research described is just a small
step toward developing an automated mapping system. Further
research into automated mapping should be undertaken to
improve accuracies and reduce costs. The results achieved
in this investigation are encouraging.
REFERENCES
Keating, T.J., P.R. Wolf, and F.L. Scarpace, "An Improved
Method of Digital Image Correlation from Scanned Densito-
metric Data," Photogrammetric Engineering and Remote Sensing,
v. 41, n. 8, August, 1975.
Keating, T.J., Analytical Photogrammetry from Digitized
Image Densities'^ Ph.D. Thesis , University of Wisconsin, L975.
Masry, S.E., "Digital Correlation Principles," Photogram
metric Engineering, v 40, n 3, March, 1974.
Moik, J.G., Digital Processing of Remotely Sensed Images,
NASA Scientific and Technical Branch, 1980.
Wolf, P.R., and T.J. Keating, "Aerotriangulation Utilizing
Digital Correlation of Image Densities," Presented Paper at
the Aerial Triangulation Symposium, Department of Surveying,
University of Queensland, Australia, October, 1979.
Wolf, P.R., and J.C. Storey, "Automatic DTM Generation from
Digitized Image Densities," Presented Paper, ACSM-ASP
Spring Convention, Denver, Colorado, March, 1982.