Aerotriangulation Data Reduction using AeroSys-AT

1
Aerotriangulation Data Reduction using
AeroSys-AT

• Collect AT Info
• Make a New AeroSys Project
• Translate Photocoordinate data
• Pre-processing
• Bundle Adjustment

2
Collect AT Info

• Gather Ground Control Point file
• Convert to AeroSys CTL format
• How good is your control?
• Get gcp sigma's!, Time
• Plot out in scatter chart PtID,X,Y
• Measure AT Data
• Softcopy or Analytical Plotter
• Export to desired format (ptb, etc.)
• Refined vs. Raw
• Collect Camera Calibration Info
• Focal Length, Xo, Yo, K0, K1, K2, K3, P1, P2, P3

3
Make New AeroSys Project

• Put data files into designated directory
• Measured photocoordinates (.ptb, etc)
• Ground Control (.ctl)
• Project (File) Basename CTL file
• Photocoordinate Format Type
• Block Configuration
• Camera Information

4
Translate Photocoordinate Data into AeroSys
(.REF) Format

• Verify input format type
• Refined vs. Raw
• Refined No Fiducials or Interior Points
• Raw How many fiducials 4 or 8
• Units millimeter or microns
• Did translation parse OK?

5
Data Pre-processing

• Prepro
• Photocoordinate Refinement (REFINE)
• Relative Orientation (RELORN)
• Strip Formation (STRIPFORM)
• Block Formation (BLOCKFORM)
• Model Coords to Ground (ESTIMATE)
• Photo Resection (RESECT)
• Point Intersection (INTERSECT)
• Merge data files (MERGE)
• Pre-Bundle Data Check (IMAGE RAYS)

6
Photocoordinate Refinement (REFINE)(raw
photocoordinates only)

• 2D-Affine transformation from plate coordinates
  to camera system
• Option to remove radial lens distortion
• Input .PHC, .CAL
• Output .REF

7
Relative Orientation (RELORN)

• Makes independent models from adjacent
  over-lapping photos in each strip
• Is direction of flight correct?
• Input .REF, .CAL, .CTL
• Output .REL

8
Strip Formation (STRIPFORM)

• Connects adjacent independent models together in
  a strip in model space coords
• Minimum 3 common points photo center
• Input .REL
• Output .STP

9
Block Formation (BLOCKFORM)

• Similar to STRIPFORM, but makes a single block of
  coordinates from adjacent strips in model space
• Checks that strips are tied together
• Ideal for AB-GPS application with few gcps
• Input .STP
• Output .BLK

10
Model Coordinates to Ground (ESTIMATE)

• Transforms model space coordinate to object space
  (ground) coordinates
• 2 Options
• Strip Polynomial Adjustment Input .STP, .CTL
• 2D/3D Hybrid transformation Input .BLK, .CTL
• Tie point analysis in log file
• Output .EST

11
Photo Resection (RESECT)

• Computes the Exterior Orientations of each photo
  in each strip
• Omega, Phi, Kappa, XL, YL, ZL
• Input .CAL, .REF, .EST
• Output .CAM, .RST

12
Point Intersection (INTERSECT)

• Computes object space (ground) coordinates for
  points missed-out during model and strip
  formation
• Input .REF, .EST, .RST
• Output updated .EST

13
Merge data files (MERGE)

• Merges data files from previous PREPRO step into
  a first approximation data file for the Aero
  bundle adjustment
• Inputs .CAL, .CAM, .EST, .REF
• Output .AER

14
Pre-Bundle Data Check (IMAGE RAYS)

• Performs space (point) intersections on all
  object (ground) points from initial
  approximations
• Warning Tool for gross blunders
• Input .AER
• Output GUI

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PREPRO Statistics

• .LOG text files for each step
• REFINE
• RELORN
• STRIPFORM
• BLOCKFORM
• ESTIMATE
• RESECT
• INTERSECT
• IMAGERAYS
• Full Statistics, observations and residuals

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Special PREPRO Features

• RELORN
• Auto eliminate gross misfits
• Explicitly remove observation with FLAG 0
• BLOCKFORM
• Reports used and un-used control points
• ESTIMATE
• Auto eliminate gross misfits
• Re-designates bad ground control into check
  points
• Tie-point reporting Threshold Limits on deltas
• RESECT
• Auto eliminate gross misfits

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Bundle Adjustment

• Aero.exe
• Input
• Prepro Approximations (.AER)
• Cycle
• Run
• Analyze Statistics
• Quick Summary
• Model Check
• Edit
• Output
• Adjusted Ground Coordinate (.XYZ)
• Adjusted Orientations (.ORN)
• Other formats (ORI, Itera, Dapor, Z/I, VirtuoZo,
  etc)

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Before we get started

• AeroSys main menu gui
• Title bar
• Data directory
• Project base name
• Menu Bar
• Button (Icon) Bar

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Main Menu Title Bar

• Data Directory
• G\AeroTriangulation\Projects\CityofSaintPaul\
• Project Basename
• TwinCities
• AeroSys file extensions ( )

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Main Menu Bar

• Pull-down Menus
• File
• Preferences
• Translate
• Aerial
• Bundle
• Utils
• Help

21
Main Menu Button Bar

• Project GUI
• Auto-Prepro
• Convert / Translate
• Prepro
• Aero Bundle

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Prepro Functions

• Refine
• RelOrn
• StripForm
• BlockForm
• Estimate
• Resect
• Intersect
• Merge
• Image Rays

• Flip-Flop
• Add GPS
• Legacy Functions
• Split
• Build
• Combine

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Prepro GUI
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Prepro GUI

• Status Info
• Options Group Box
• Quick Summary
• Messages
• Operation Buttons
• Function Tabs

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Prepro GUI

• Status Info
• Current Status
• Which Prepro step
• Progress Bar

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Prepro GUI

• Options Group Box
• Different for each step

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Prepro GUI

• Quick Summary
• Lists RMSE residuals

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Prepro GUI

• Messages
• Internal Processing

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Prepro GUI

• Operation Buttons
• GO start processing step
• NEXT advance to next step
• SKIP skip over processing step
• BACK back-up to previous step

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Prepro GUI

• Function Tabs
• Not Enabled, Visual Feedback Only
• Use operation buttons to navigate

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Set Operating Preferences

• File Preferences Aerial Auto-Sequence
• Run Sequence
• Options
• Passpoint Prefix
• Lens Distortion
• Estimate
• Check Image Rays

32
Program Run Sequence

• Check Box to enable step
• Usually start with RelOrn
• End with Aero Bundle

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Prepro Options

• Delete Passpoint Prefix
• Legacy option from JFKs historical RABATS/BRATS
• Required 99 to prefix passpoints
• Afterwards stripped-off prefix from the point ID

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Prepro Options

• Remove Lens Distortion
• For RAW photocoords only

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Prepro Options

• ESTIMATE step

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Prepro Options

• Pre-Bundle Adjustment Error Checking step

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Other Preferences

• Default Standard Deviations

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Other Preferences

• Max
• residual limits

39
Other Preferences

• Passpoint ID

Needed for RelOrn Poly Strip Adjustment
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Other Preferences

• Tie point thresholds

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Other Preferences

• Plug-in to your favorite text Editor

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Getting Started step 1

• Organize your data
• Project directory?
• Project basename?
• Ground control data
• sigma's?
• Camera calibration on-hand?
• Photocoordinate measurements
• Exported format

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Getting Started step 2

• Make AeroSys Project
• Launch Project GUI

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Getting Started step 2

• Need Info in for these categories

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Getting Started step 2(a.1)

• Select File New menu item
• from Project Info gui

Select Data Directory Enter Project Base Name
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Getting Started step 2(a.1)

• Data directory Project basename are extracted
  from file chooser

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Getting Started step 2(a.2)

• Select Ground Control (.CTL) file
• Click on 2 to get file chooser dialog

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Getting Started step 2(b)

• Select Photocoordinate Type
• Example PAT-B format, Refined, Unpaired

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Getting Started step 2(b)

• Special Settings for ABC32 and ALBANY
• Converts Strip Photo (position) Number into a
  unique Photo ID

Example Strip no.3, Photo no.11 Photo ID no. ?
? 311
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Getting Started step 2(c)

• Enter Block Configuration Info

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Getting Started step 2(c)

• First, set total number of flight strips

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Getting Started step 2(c)

• Next, assign data file to strip number
• Select Strip No. using spin buttons
• Click Green Plus to assign data file
• File parser will determine first, last
• and total photos in strip

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Getting Started step 2(c)

• Use
• Green plus sign to assign data file with chooser
• White text icon to view data file
• Red minus sign to remove assignment

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Getting Started step 2(c)

• Use
• Blue-green icon to swap first last photo Ids
• Direction of actual flight must be the same as
  the ordered IDs
• Hand enter photo IDs if data file contains all
  strips-in-1 file
• Photo Ids can be incremented by 2 in special
  overlap cases

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Getting Started step 2(c)

• Are all flight strips in 1 data file?
• Enter first last photo Ids by hand
• Click on, strips All-in-1 file
• Click on, Green Plus sign to get file chooser

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Getting Started step 2(d)

• Assign camera to project from data base

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Getting Started step 2(d)

• To add camera to data base
• Click on the blue arrow icon in URH corner

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Getting Started step 2(d)

• Click on
• Edit to modify an existing camera
• New to add a new camera
• Delete to remove a camera
• Done to finish input of data
• Select_OK to save camera entry
• Cancel to return without saving

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Getting Started step 2(d)

• Enter camera calibration data into gui, or
• Click the yellow file open icon to select a
  pre-existing
• AeroSys .CAL data file to import

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Getting Started step 2(d)

• Click on Save to write the new project file
• Click on OK to save and exit gui
• Click on Cancel to exit gui without saving

You are done setting up a project !
61
Getting Started after step 2

• Take a quick look at your project data directory
• Photocoordinate files .PTB
• Ground Control file .CTL
• Camera Info file .CAL
• Project file .PRJ
  (legacy .idx)

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Getting Started step 3

• Translate the photo coordinates to native AeroSys
  .REF refined format

Click here to translate
Settings are saved for next time you translate
63
Getting Started step 3

• Translation Options
• Supported Photocoordinate Formats

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Getting Started step 3

• Translation Options
• Coordinate Type
• Number of Fids
• Units

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Getting Started step 3

• Translation Feedback
• Parsing Error?

66
Getting Started step 3 ½

• Start Pre-processing . with REFINE
• Done only with RAW photocoordinate type such as
  ABC32 .TRI files
• If photocoords are refined, skip this step and go
  on to step 4
• Converts .PHC to .REF

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Getting Started step 4

• Start Pre-processing . with RELORN
• Relative Orientation of independent models

Click on GO
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Getting Started step 4

• If photo IDs are listed in reverse order (i.e.,
  opposite the direction of flight), go back to
  project setup, edit (i.e., swap), save and then
  re-translate photo coordinates

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Getting Started step 4

• Check Quick Summary window
• want ROs to be squeaky clean !!
• RMS_Vy lt 3.0 microns

• Click the NEXT button to proceed

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Getting Started step 5

• Next after RELORN is STRIPFORM
• Click on GO
• Just want models to reasonably connect together,
  dont sweat the residuals unless they are very
  large (order of magnitude in 100s of microns)

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Getting Started step 6

• Next after STRIPFORM is BLOCKFORM
• Click on GO
• Just want Strips to reasonably connect together,
  dont sweat the residuals unless they are very
  large (order of magnitude in 100s of microns)

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Getting Started step 7

• Next after BLOCKFORM is ESTIMATE
• Strip Polynomial or 2D-3D Hybrid transformation ?
• Prefer strip polynomial
• Does every strip have enough GCPs ?
• Otherwise, use Hybrid method
• Tie point analysis see log file

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Getting Started step 7

• Check Quick Summary
• Are residuals reasonable?

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Getting Started step 8

• Next after ESTIMATE is RESECT
• Check Quick Summary
• Do all Photo EOs solve?
• Dont sweat the residuals, just need to solve!

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Getting Started step 9

• Next after RESECT is INTERSECT
• Finds missed-out points in data

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Getting Started step 10

• Next after INTERSECT is MERGE
• Creates initial approximation (.AER) input file
  for the Aero.exe least-square bundle adjustment
  from previous PREPRO steps
• .CAL (camera info)
• .CAM (orientations)
• .EST (ground coords)
• .REF (photo coords)

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Getting Started step 11

• Next after MERGE is IMAGE RAYS
• Data checking for mis-IDed points

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Getting Started after step 11

• You are now ready to run the Aero bundle
  adjustment!!
• Things to keep in mind?
• Blunders still may exist in data
• Turn override option OFF until no blunders
• When only random error, turn override ON

79
Getting Started step 12

• Run the AERO.exe bundle adjustment
• Check operating parameters
• Override option
• Self-Cal
• AB-GPS
• Earth Curvature

80
Getting Started step 12

• AERO gui
• Click stop light icon to run

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Getting Started step 12-run

• Aero run-time GUI

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Getting Started step 12

• Aero Quick Summary gui

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Analysis Details

• Image space stats
• Final Sxy
• RMSE Vx Vy (mm)
• Standardized Residuals Wx Wy (unit-less)

84
Analysis Details

• Top Ten Largest Residuals
• Units mm

85
Analysis Details

• Root Mean Square Photocoordinate Residuals
• Units micrometers
• Vx Vy

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Analysis Details

• Final Weights assigned to photocoordinate
  observations
• Static Override Option OFF
• So Override ON

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Analysis Details

• What is Override Option?
• Feature that automatically balances the weights
  assigned to the photocoordinate observations with
  the other observational types in the block
  adjustment
• Want final So (S-naught) to equal 1.0
• Ensure optimal solution and needed by Data
  Snooping mathematics

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Analysis Details

• Standardized Photocoordinate Residuals
• Wx, Wy
• Unit-less statistic
• Outliers
• Greater than /- 3.29

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Analysis Details

• Possible Blunders?
• Click button to view list of suspected points
• Only the largest is the likely candidate !

90
Analysis Details

• Ground (object) Space Residuals
• RMSE for control
• Check Points List
• Wx, Wy, Wz
• Blunders List

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Analysis Details

• Post-Adjustment Predicted Coordinate Mean
  Accuracies
• Units ground control

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Analysis Details

• Want So to be 1.0
• Chi-square interval Lo ... 1.0 Hi
• Based on DOFs
• Why ?
• Balanced Weights
• Optimal Solution
• Data Snooping Theory

93
Analysis Details

• Evaluation Criterion
• RED critical fail
• YELLOW warning
• GREEN passed
• Use as guide, not gospel

94
Analysis Details

• Criterion Components
• Photocoords
• 1 - 4
• Ground Coords
• 5 - 7
• Error Budget
• 8 - 9

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Analysis Details
96
Analysis Details
97
Analysis Details
98
Analysis Details

• Mean predicted accuracies of aero-triangulated
  points in X, Y Z
• Represents 1 sigma

99
Analysis Details

• Want 90 confidence that error component of AT-ed
  points are no greater than one-sixth of contour
  interval
• One-sixth rule-of-thumb, not gospel

100
Analysis Details

• Want 90 confidence that error component of AT-ed
  points are no greater than one-sixth of delta
  map scale values

101
Analysis Details

• Quick access to Model Check Tool
• Tool to evaluate how well model AOs are expected
  to setup
• Check for bad models
• Check for bad points
• Check for duplicate points

102
Model Check Gui
103
Point Check Output

• 3103 2431584.352 1867925.503
  647.214 PP4
• 3 7 311_310 0.155 0.113
  0.133 . . .
• 3 8 310_309 0.665 -1.153
  -1.410 4.4 6.2 5.1
• 4 9 409_410 0.344 0.335
  -0.369 . . .
• 4 10 410_411 -0.237 0.330
  -0.415 . . .
• -9
  
• A dot . signifies that the residual is less
  than 3xs the mean RMSE, otherwise print how many
  times greater than the overall mean

104
AeroSys Output Files
Adjusted Orientations

• .ORN (AeroSys)
• .ASO (Z/I)
• .OPK (ER Mapper)
• .ORI (PAT-B)
• .Triang (Softplotter)

• Dapor.dat (BLUH)
• ITERA.dat (BINGO)
• .PXYZOPK ( ??? )
• .VZ.aop (VirtuoZo)

105
AeroSys Output Files
Adjusted Object (Ground) Space Coordinates

• .ADJ (AeroSys)
• .XYZ (AeroSys)
• .CON (ABC)
• .PXYZ (VirtuoZo)
• .GCP (R-Wel)

• .GPE (CalTran)
• .GPA ( ??? )
• .PBM (BC-Gov)
• .DATA
• .DATM

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AeroSys Output Files
Miscellaneous Files

• .AER (bundle input)
• .AQS (aero quick summary)
• .CQS (control quick summary)
• .PQS (pcoords quick summary)
• .CKP (check points)
• .ICA (image coords adjusted)
• .ELLIPSE (error ellipses)
• .RES (pcoords residuals)
• .PRJ (project file)

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Prepro Data Files

• .BLK (model coords as 1 block)
• .CAL (cam calibration)
• .CAM (camera orientations)
• .CTL (ground control)
• .EST (ground coordinates)
• .REF (refined photocoords)
• .PHC (raw photocoords)
• .REL (model coords)
• .RST (resection)
• .STP (model coords as per strip)