Calculation of target masking effects for air to surface ordnance delivery

92 Pages·3.9 MB·en_US

by  Darlak, Joseph R.

NAVAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
CALCULATION OF TARGET MASKING
EFFECTS FOR AIR TO SURFACE
ORDNANCE DELIVERY
by
Joseph R. Darlak
December, 1996
Thesis Advisor: Morris Driels
Thesis
Approved for public release; distribution is unlimited.
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December 1996 Master's Thesis
TITLEAND SUBTITLECALCULATION OF TARGET MASKING FUNDING NUMBERS
EFFECTS FOR AIR TO SURFACE ORDNANCE DELIVERY
6. AUTHOR(S) Joseph R, Darlak
PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) PERFORMING
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Naval Postgraduate School ORGANIZATION
Monterey CA 93943-5000 REPORTNUMBER
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13. ABSTRACT(maximum 200words)
The Perspective View Generator (PVG) is a database driven simulation that displays a three-dimensional
synthetic environment from terrain information stored in a two-dimensional array. Each terrain element
is identified by coordinates which index the array. Each array value contains 32 bits of information
arranged to specify the greyshade, elevation and other features of the terrain at that position. Currently
there are few areas ofthe world digitally mapped in the data format accepted by the PVG.
The objective of this thesis is to enable the automatic generation of a database for use with the PVG
from information available from various sources. The project involves writing computer algorithms to
synthesize data from different sources and making modifications to the PVG functions. The source of
terrain information is aerial imagery and elevation information which is not resolved fine enough to
distinguish tree and building heights. The ability to modify the data base to include object heights allows
the PVG to show the target masking effects these objects have in a given region. The resulting synthetic
environment can be used for strike planning and as a mission tailored training tool.
14. SUBJECTTERMS Synthetic environments, terrain, visualization, target 15. NUMBER OF
PAGES89
masking
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Approved for public release; distribution is unlimited.
CALCULATION OF TARGET MASKING
EFFECTS FOR AIR TO SURFACE
ORDNANCE DELIVERY
Joseph R. Parlak
Lieutenant, United States Navy
B.S.M.E., United States Naval Academy, 1990
Submitted in partial fulfillment
of the requirements for the degree of
MASTER OF SCIENCE IN MECHANICAL ENGINEERING
from the
NAVAL£QSTGRADUATE SCHOOL
December 1996
(
C-Z.
DUDLEYKNOX
LIBRARY
ABSTRACT ™unjEREY CA
93943-5101
The Perspective View Generator (PVG) is a database driven simulation that
displays a three-dimensional synthetic environment from terrain information stored
in a two-dimensional array. Each terrain element is identified by coordinates which
index the array. Each array value contains 32 bits ofinformation arranged to specify
the greyshade, elevation and other features of the terrain at that position. Currently
there are few areas of the world digitally mapped in the data format accepted by the
PVG.
The objective ofthis thesis is to enable the automatic generation of a database
for use with the PVG from information available from various sources. The project
involves writing computer algorithms to synthesize data from different sources and
making modifications to the PVG functions. The source of terrain information is
aerial imagery and elevation information which is not resolved fine enough to
distinguish tree and building heights. The ability to modify the data base to include
object heights allows the PVG to show the target masking effects these objects have
in a given region. The resulting synthetic environment can be used for strike planning
and as a mission tailored training tool.
VI
....
TABLE OF CONTENTS
INTRODUCTION
I. 1
OVERVIEW OF SYNTHETIC ENVIRONMENTS
A. 2
B. THE PERSPECTIVE VIEW GENERATOR (PVG) 3
1 Mechanics of Ray Tracing 3
2. Organization of Information in the Data Array 5
3. Information Retrieval 7
4. Image Rendering 13
OBJECTIVE
H. 17
EXPERIMENTS
JJI. 19
A. INDIVIDUAL TREES 19
B. INDIVIDUAL BUILDINGS 22
C. MODIFICATIONS TO THE PVG 22
Ray Trace Algorithm 23
1
a. Adjusting Ray Trace Back-Step 24
b. Retaining Previous Height 24
c. Boundary Check 25
2. Data Interpretation Algorithm 28
a. Distinguishing Between Natural and Man-Made Objects
28
b. Use ofPrevious Height to Distinguish Rooffrom Walls
29
c. Use of Surface Normal to Distinguish Walls 30
D. TERRAIN INFORMATION CONVERSION 30
USER INTERFACE
E. 31
Real Time Editing 35
1
2. Making Database Changes 35
a. Marking a Search Area 37
b. Searching for Similar Adjacent Pixels 38
3. Generation ofTree Stands 38
4. Generation ofBuildings 39
IV. DISCUSSION 43
A. SUGGESTED FOLLOW-ON RESEARCH 43
1 Transition from Edit to Full-Speed Mode 43
2. Refine Edit Process 44
a. Marking Edit Areas 44
b. Undo/Redo 45
c. Improved Tree Distributions 45
vn
d. Refined Surface Normal Assignment and Interpretation
46
TARGET MOTION
B. 46
CONCLUSION
V. 47
APPENDIX A. ZIGZAG.C 49
APPENDIX HITGRND.C
B. 53
APPENDIX DATAGEN.C
C. 57
APPENDIX D. EDIT.C 59
APPENDIX E. TREES.C 71
LIST OF REFERENCES 73
BIBLIOGRAPHY
75
INITIAL DISTRIBUTION LIST 77
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