This document discusses the history and fundamentals of digital photogrammetry. It describes the evolution from analog to digital photogrammetry and how computer hardware and software have advanced the discipline. The key aspects covered include digital image characteristics like resolution, sampling and quantization. It also outlines common image processing operations, hardware requirements, and software functions needed for digital photogrammetry like image matching, rectification and visualization.

1. DigitalDigital PhotogrammetryPhotogrammetry
Presented by:Presented by:
Dr.Dr. HamidHamid EbadiEbadi

2. BackgroundBackground
First GenerationFirst Generation
AnalogAnalog PhotogrammetryPhotogrammetry
AnalyticalAnalytical PhotogrammetryPhotogrammetry
DigitalDigital PhotogrammetryPhotogrammetry

3. PhotogrammetricPhotogrammetric GenerationsGenerations
1850
1900
1950
2000
first generation
analog photogrammetry
analytical photogrammetry
digital photogrammetry

4. Computer Generations andComputer Generations and
PhotogrammetricPhotogrammetric DisciplineDiscipline
--digitaldigital photogrammetryphotogrammetry
--realreal--timetime photogrammetryphotogrammetry
--knowledge based SWknowledge based SW
--expert systemsexpert systems
-- natural languagenatural language
processingprocessing
--parallel processingparallel processing
--RISC architectureRISC architecture
--VHSICVHSIC
--optical disk storageoptical disk storage
55
ComputerComputer--assistedassisted
photogrammetryphotogrammetry
--new languagesnew languages
--(PASCAL(PASCAL--MODULA)MODULA)
--IGS, DBMSIGS, DBMS
--Microprocessors, PCMicroprocessors, PC
--VLSIVLSI
--networkingnetworking
44
--time sharingtime sharing
--operating systemsoperating systems
--Virtual memoryVirtual memory
--IC memoryIC memory
--minicomputersminicomputers
--mag.diskmag.disk storagestorage
33
--higher level languageshigher level languages
(FORTRAN(FORTRAN--COBOL)COBOL)
--transistorstransistors
--magnetic core memorymagnetic core memory
22
--machine codemachine code--Vacuum tubesVacuum tubes11
PhotogrammetricPhotogrammetric
DisciplineDiscipline
SoftwareSoftwareHardwareHardwareGenerationGeneration
- analytical photogrammetry
-aerial triangulation
-correlation
-analytical plotter

5. TerminologyTerminology--Or the Lack ThereofOr the Lack Thereof

6. Generic DigitalGeneric Digital PhotogrammetryPhotogrammetry EnvironmentEnvironment
Scanner Digital Camera
Digital Image
Display Computer Storage
User Interface
Film Recorder Plotter
orthophoto map
Photograph

7. Properties of Digital ImageryProperties of Digital Imagery
Definition of Digital ImageDefinition of Digital Image
Spatial Resolution and Geometric AccuracySpatial Resolution and Geometric Accuracy
Radiometric ResolutionRadiometric Resolution

8. Definition of Digital ImageDefinition of Digital Image
xx
PixelPixelyy
1 20
0
1
2
∆y
∆x
photograph
Columns
Rows
N-1
M-1

9. Spatial Resolution and GeometricSpatial Resolution and Geometric
AccuracyAccuracy
943.721943.72130720 *30720 * 30720307207.57.5
235.931235.93115360 *15360 * 15360153601515
58.98258.9827680 *7680 * 768076803030
14.74614.7463840 *3840 * 384038406060
0.6860.6861920 *1920 * 19201920120120
0.9220.922960 *960 * 960960240240
0.2300.230480 *480 * 480480480480
0.0580.058240 *240 * 240240960960
Storage RequirementStorage Requirement
(MB)(MB)
Number of PixelsNumber of PixelsPixelPixel Size(micronSize(micron))

10. Classification of Processes and Tasks inClassification of Processes and Tasks in
DigitalDigital PhotogrammetryPhotogrammetry
System Level TasksSystem Level Tasks
Low Level TasksLow Level Tasks
Middle Level TasksMiddle Level Tasks
High Level TasksHigh Level Tasks

11. Classification of Processes and Tasks inClassification of Processes and Tasks in
DigitalDigital PhotogrammetryPhotogrammetry
Object recognitionObject recognition
Image interpretationImage interpretation
Understand imagesUnderstand imagesHigh levelHigh level
Surface reconstructionSurface reconstruction
Feature reconstructionFeature reconstruction
Group, segment imagesGroup, segment imagesMiddle levelMiddle level
Image processing:Image processing:
orientations, digitalorientations, digital
orthophotoorthophoto, DEM, AT, DEM, AT
Process, match images,Process, match images,
extract featuresextract features
Low levelLow level
Manipulate digitalManipulate digital
imageryimagery
Store, access, display,Store, access, display,
imagesimages
System levelSystem level
TasksTasksProcesses, AlgorithmsProcesses, AlgorithmsCategoryCategory

12. Relationship of DigitalRelationship of Digital PhotogrammetryPhotogrammetry toto
Other DisciplineOther Discipline
Scene Description
Digital Image
Computer Graphics
Computer Vision
Digital image
Processing

13. Fundamentals of DigitalFundamentals of Digital
PhotogrammetryPhotogrammetry
Why use Digital Images?Why use Digital Images?
Advantages of using Digital Images:Advantages of using Digital Images:
–– Appropriate way for displaying and MeasurementAppropriate way for displaying and Measurement
–– StabilityStability
–– Applying image Enhancement is possibleApplying image Enhancement is possible
–– Automation can be appliedAutomation can be applied
–– Real timeReal time phptogrammetryphptogrammetry is not out of accessis not out of access

14. Characteristics of Digital DataCharacteristics of Digital Data
DigitizationDigitization
–– IntensityIntensity
–– Gray ValueGray Value
–– DensityDensity
SamplingSampling
Quantization of gray levelsQuantization of gray levels
NoiseNoise

15. Concept of SamplingConcept of Sampling

16. Theory of SamplingTheory of Sampling

17. Concept of QuantizationConcept of Quantization

18. Signal versus NoiseSignal versus Noise

19. Charge Coupled Devices (Charge Coupled Devices (CCDsCCDs))
CharacteristicsCharacteristics
–– Size of the arraySize of the array
–– Pixel sizePixel size
–– Dynamic rangeDynamic range
–– Geometric aspect (Lens Distortions)Geometric aspect (Lens Distortions)
–– Transfer of Data from sensor to storageTransfer of Data from sensor to storage
–– Time taken to record an imageTime taken to record an image
Pixel size and ResolutionPixel size and Resolution
–– SpatialSpatial
–– RadoimetricRadoimetric
–– SpectralSpectral

20. Image ProcessingImage Processing
OperationsOperations
–– EnhancementEnhancement
–– RestorationRestoration
–– CompressionCompression
–– ClassificationClassification
EnhancementEnhancement
–– Contrast StretchingContrast Stretching
–– FilteringFiltering
ResamplingResampling

21. Contrast StretchingContrast Stretching

22. Contrast StretchingContrast Stretching

23. ResamplingResampling of Digital Imagesof Digital Images

24. Data AcquisitionData Acquisition
CCD CamerasCCD Cameras
ScannersScanners
–– Drum ScannersDrum Scanners
–– Linear ArraysLinear Arrays
–– CCD ArraysCCD Arrays
Data CompressionData Compression
–– JPEGJPEG

25. Hardware for DigitalHardware for Digital
PhotogrammetryPhotogrammetry
Basic Hardware RequirementsBasic Hardware Requirements
–– High Resolution DisplayHigh Resolution Display
–– Flexible image memory with fast access for real timeFlexible image memory with fast access for real time
roamingroaming
–– Interface capability for scanners and camerasInterface capability for scanners and cameras
–– Interface with output devicesInterface with output devices
–– Image enhancement processorImage enhancement processor
–– 3D measurement with special control devices3D measurement with special control devices
–– SubpixelSubpixel accuracyaccuracy
–– Data capture in a GIS or CADData capture in a GIS or CAD
Stereoscopic ViewingStereoscopic Viewing
Special Hardware requirementsSpecial Hardware requirements

26. Software Requirements for DPSoftware Requirements for DP
Standard Requirements:Standard Requirements:
–– Handling Image DisplayHandling Image Display
–– MeasurementMeasurement
Recording Pixel CoordinatesRecording Pixel Coordinates
–– Determination of OrientationsDetermination of Orientations
Inner Orientation including Calibration parametersInner Orientation including Calibration parameters
Relative and absolute orientations,Relative and absolute orientations, BBundle Adjustmentundle Adjustment
–– TransformationsTransformations
–– Image Processing FunctionsImage Processing Functions
Image MatchingImage Matching
Edge DetectionEdge Detection
–– Digital RectificationDigital Rectification
–– VisualizationVisualization
AutomationAutomation

27. ReferencesReferences
T. Schenk,T. Schenk, ““ DigitalDigital PhotogrammetryPhotogrammetry””, Terra, Terra
Science, 1999Science, 1999
M.M. KasserKasser and W.and W. EgelsEgels,, ““ DigitalDigital
PhotogrammetryPhotogrammetry””, Taylor and Francis, 2002, Taylor and Francis, 2002
H.H. EbadiEbadi,, ““ Advanced Analytical AerialAdvanced Analytical Aerial
TriangulationTriangulation””, Lecture Note,, Lecture Note, K.N.ToosiK.N.Toosi
University of Technology, 1999University of Technology, 1999
T.C.TangT.C.Tang,, ““Digital Image CorrelationDigital Image Correlation””,, UCSEmUCSEm
Report, 1988Report, 1988