Vr Mapping
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VrTwo Orientation (vr2ori.exe)
Photogrammetric stereo model orientation program
Interior Orientations
Batch (IntBat)
Exterior Orientation
Single (ImpExt)
Measurement
Orientation Single
Exterior Orientations
Batch (ExtBat)
Measurement
Orientations Batch (MeaBat)
Create Epipolar Images
Batch (CreEpi)
Left Interior Orientation
(LefInt)
Right Interior Orientation
(RigInt)
Corner Interior
Orientations (CorInt)
View Relative
Orientation 3D (VieRel)
Vr Mapping Coordinate File
Format
VrTwo Orientation is used to create stereo image pairs (or models) for viewing in the VrTwo and VrLite mapping software. Stereo models may be generated manually or by importing the results from various aerial triangulation programs. Orientations may be performed on a single model or multiple models may be oriented in a batch mode. The importing of models from aerial triangulation may be performed from the exterior orientations or from the measurements used to tie images and strips together.
VrTwo Orientation will start by opening the Main Window.

Pulling down a menu and selecting an item may start commands. Commands may also be started from a key-in using the command name. Each command name is the first three letters of the first two words on the pull down. For example: The command name for Open Project is OpePro. If this rule is not followed the key-in is listed after the command in parenthesis.
The Main Window in Image Utility contains the command pull
down menus, a key-in area, two information areas, a progress bar and the
coordinate display. Commands names may be
typed into the key-in area at almost any time.
On the border of the Main Window is shown the active project name.
VrTwo Orientations main purpose is to create stereo models containing left and right image pairs that can be used by VrTwo. These models consist of left and right epipolar images and an orientation parameter file. The parameter file has the extension of .orp, and contains the orientation parameters required for VrTwo to work with stereo images. VrTwo Orientation is project based, and requires a project to be created before any processing can be done. A project in VrTwo Orientation contains a list of images, camera files, and model definitions. Each project in VrTwo Orientation is divided into models. Each model contains one left image and one right image, resulting in a stereo image pair.
The following files are needed to set a stereo model.
Following is a typical workflow for VrTwo orientations.
1. Create the camera calibration (.cam) file
2. Create the VrTwo orientation project
3. Create or import interior orientations
4. Perform relative and absolute orientations manually, or import them from aerial triangulation exterior orientations or image measurements.
The Vr Image Utility program may be used to prepare the images for the project by attaching the strip location, image pixel size and camera to each image. It can also be used to perform automatic interior orientations. The VrTwo orientation program can also be used to set up the images for the project. If several programs such as VrTwo Orientation, Vr Orthophoto or Vr Aerial Triangulation will use the same images then Vr Image Utility should be used to set up the images so the other programs may import the project file.
FilePreferences are used to set operating parameters for the VrTwo Orientation Program.

Use default directory? Defines the usage of the default directory. The default directory is used as the start directory for items such as dialog boxes in which files may be selected. This value may be set to Yes or No.
Default directory Defines the default directory which will be used if Use default directory is set to Yes.
Zoom scale factor (buttons 3,4) Several of the orientations such as Relative Orientation allow zooming in and out on the images. This parameter is the scale factor that will be used when zooming in with button #4 (Mouse center button) and zooming out with button #4.
Image parameter file (.vim) location Each image used in the VrTwo orientation program has an associated parameter (.vim) file. This file contains the interior orientation values and other image parameters. The image parameter file has the same name as the image but with a .vim file extension. These parameter files may be stored in the same directory (folder) as the images or they may be stored in the project folder. The two options for this value are Image Folder and Project Folder.
Show point labels in Relative and Absolute? When making observations in relative and absolute orientations point labels that show the point sequence number follow the measuring mark. These labels may be turned off if needed. Some graphics cards a slow when updating these labels and turning off the labels is necessary.
Use stereo in View Relative Orientation 3D When using the view relative orientation 3D function from the Orientation pull-down it is possible to view the model configuration in true 3D. This is possible if the computer has the necessary 3D hardware.
Offset Increment in View Relative Orientation 3D The view relative orientation 3D function allows the interactive placement of the model view point offsets. This parameter is used as the increment when adjusting the offsets.
Scale Increment in View Relative Orientation 3D The view relative orientation 3D function allows the interactive modification of the image size scale factors. This parameter is used as the increment when adjusting these scale factors.
Exits VrTwo Orientation.
CameraThe camera menu is used to
create, edit and import camera calibration parameters.
The New Camera allows the user to create and edit a new
camera calibration file. The user will
be prompted for the file name for the new camera. Camera files in Vr Mapping have the .cam file
name extension. See Edit Camera below
for information on editing a camera file.
Edit Camera allows the user to edit an existing camera
calibration file. The camera edited does
not need to be one of the current cameras and any existing camera file may be
edited. When edit camera is started the
user will be prompted for a camera file name and when exiting the user will
have the opportunity to save the modified camera calibration parameters.

Description A
text entry that describes the camera for user reference may be entered in this
field. This description is for user
reference only and is not used in model orientation.
Fiducial
units The units of the coordinate positions may be one of
several different units which include millimeters, inches or pixels. Many of the programs that are used to
calibrate handheld cameras output the focal length of the camera in
pixels. The coordinates entered in to
represent the fiducial positions must be the same units specified here.
Focal
length The distance from the camera focal point to the center of
the lens is the focal length of the lens.
This value is provided by the camera
calibration report and is entered as the same units as the Fiducial units.

Photo
size X Y The size dimensions of the images are specified with
these two parameter values. The size
entered must be in the same units as the Fiducial units.
Calib
principal point X Y The calibrated principal point (also
known as the point of best symmetry) is the point whose position is determined
as a result of the camera calibration and is available from the camera calibration
report. This coordinate position must be
entered as the same units as the Fiducial units.
Fiducial
X Y The coordinate positions for up to eight fiducials may be
entered and must be in the same units as the Fiducial units. Most aerial cameras have eight fiducials and
it is strongly recommended that all eight be entered and used when computing
interior orientation. When using only
four fiducials errors may occur and not shown in the residuals if the wrong
camera calibration is selected.

Lens distortion causes imaged
positions to be displaced from the ideal or true locations. In aerial cameras these distortions are
normally minimal but can still have an effect on accuracy. Some of the digital cameras have large lens
distortions and radial distortions must be entered for accurate mapping
results.
Adjustment
mode There are two methods of
representing radial distortions which are by distance or with polynomial
values. Most camera calibration programs
output radial distortions values as polynomial parameters. Note that Angular parameters are listed as an
option as one of the adjustment modes but this method is currently unsupported.
Distance
Parameters Radial distortions that are
represented as concentric rings about the camera lens calibrated principal
point may be entered as distance parameters.
The radial distortions shown below are from a small format camera and
show high radial distortion values.

Radial
distance increment This value represents the
distance between the concentric rings that make up the distance
parameters. This value is entered in as
the same units as the Fiducial units.
Distortion
value n The distortion values for each
distance are entered in these parameter values.
There may be up to 15 values and they are entered as the same units as
the Fiducial units.
Angular
Parameters The computation of radial
distortions by angular parameters is currently unsupported. Please use distance or polynomial parameters

Polynomial
Parameters The polynomial values and
principal point or autocollimination are provided by the camera calibration
report. The mathematical model used is
based on the Simultaneous Multi-camera Analytical Calibration (SMAC) method. Care should be taken when entering these
parameters as entry errors will cause model orientation errors and distortions
and will affect model accuracy.
Entry of Exponential Notation
The k0-k4 values and the p1-p4
values are entered into the Polynomial Parameters dialog box in exponential
notation. The values entered from the USGS camera calibration report may have
the decimal place moved one position to the left depending on the number
entered. For example:
USGS value: 0.1403x10-3
Value typed: .1403e-3
Shown value: 1.403000e-004

K0-K4 Up to five K coefficient values may be
entered. These are coefficients of
symmetric radial lens distortion from the camera calibration report. These values are entered in exponent
form.
P1-P4 Up to four P coefficient values may be
entered. These are the coefficients of
decentering distortion fro the camera calibration report. These values are entered in exponent form.
PPA X Y The principal point of autocollimation is
provided from the camera calibration report.
ISAT (CamIsa) Imports camera calibrations from an ISAT
file. The ISAT file can contain several
camera definitions.

ISAT
camera file The ISAT camera file is defined in this field and this
file name is normally camera.
CoordinatesThe Coordinates menu provides functions to create and edit coordinate files. Please refer to Vr Mapping Coordinate File Format for information on the format and layout of the coordinate files used in VrTwo Orientation.
A new coordinate file may be created with this command. The Format, State Plane Zone, Datum, UTM Zone and Units in the Edit Header dialog box are for user reference and are currently unused by the software. The user is prompted for a coordinate file name and then can enter the coordinate file parameters as follows:

Layout The layout specifies the fields to place in the coordinate file and their order. Options are:
Name X Y Z Cx Cy, Cz
Name Y X Z
Cy Cx, Cz
X Y Z Name
Cx Cy, Cz
Y X Z Name
Cy Cx, Cz
Name X Y Z
Name Y X Z
X Y Z Name
Y X Z Name
X Y Name
Y X Name
Where:
Name Point name
X Y Z Coordinates
Cx Cy Cz X Y Z point
weights
Format Coodrinate formats include state plane, UTM
(Universal Transverse Mercator) and Geographic.
State Plane Zone Each state plane zone has a code and this code may
be entered in this field.
Datum Coordinate datum which includes two NAD (North American Datum) zones
which are NAD 1927 or NAD 1983. The U.S.
State Plane Zones (NAD 1983) represents the State Plane Coordinate System
(SPCS) Zones for the 1983 North American Datum within
UTM Zone If the format is set to UTM the UTM (Universal
Transverse Mercator) zone code may be entered in this field. There are 60 longitudinal projection
zones that cover the earths surface numbered 1 to 60 starting at 180°W. Each
of these zones is 6 degrees wide, apart from a few exceptions around
Units Units specify the coordinate units that make up xyz coordinates in the file. The possible coordinate units are; US Foot, International Foot, Meters, Inches or Pixels.
Coordinates in an existing coordinate file may be edited using this command. The editing options include Add, Change and Delete. When this command is started the user can open any coordinate (.cor) file and the edited file may be saved when exiting the command.

Sort Sorts the coordinate file based on the point name.
Search Searches for a coordinate point by name. If the point name being searched for is found it will become the current point.
Edit Header Allows the editing of the coordinate file header. (See the Edit Header in New Coordinate File).
Name The point name may be alpha numeric and may be up to 32 characters in length.
X Y Z The coordinate values for the point.
CX CY CZ Point weights. These may be used in the coordinate file depending on the File Layout (see New Coordinate File). Normally point weights are expressed in ground units.
Add The current point will be added to the coordinate file
Change The current point will be updated with the current Name, X, Y, Z, CX, CY and CZ values.
Delete The current point will be deleted.
When defining coordinates it is possible to have points in which all three axis are not defined. In the case of a vertical only point the x and y values are not used and in the case of a horizontal only point the z is not used. The Null Axis Value defines the value that will indicate that an axis does not have a coordinate value. This value is typically zero but in cases where zero is a valid coordinate value in the map data a value such as -999 should be used.

ProjectThe Project menu is used to manage VrTwo Orientation projects and has the ability to create, open, save, edit and delete projects. Change Drive allows projects to be moved between different drives and folders. The Vr Two Orientation project file name has a .vpr file name extension.
Creates a new project and allows starts Edit Project.
Opens an existing project. It is not necessary to close the current project before opening another. All current project parameters will be saved automatically before another is opened.
Saves the current project with a different file name
Allows editing of the current project.

Project name This field displays the current project file. This file was created when the project was created in Project -> New Project. The field is for display only and cannot be modified.
Coordinates The project ground coordinate file may be set in this field by pressing the [ ] button at the end of the field. When importing orientations from aerial triangulation this file should contain the coordinates for the pass, tie and ground control points. A coordinate file of this type is always produced from an aerial triangulation adjustment.
Photo overlap This field defines the approximate photo forward overlap and is expressed as a percentage. Typical aerial mapping jobs use 60% photo overlap.
Model directory The model orientation process produces parameter and image files needed for the display of stereo. The Model Directory field defines the target directory (folder) in which these files will be placed. The files placed in the directory are the epipolar images, the orientation parameter (.orp) files and the model definition (.vmo) files. Leaving this field blank will place these files in the project directory.
Images The Images area of the dialog box contains a display list of the images that are currently in the project, the Define Images and Import Image Util buttons.
Define Images Pressing this button will start the Define Images dialog (see below).
Import Image Util If images have been previously defined in the Vr Image Utility program these parameters may be transferred to this program by pressing this button. This will avoid re-entering these parameters. The Vr Image Utility project file has a file name extension of .iup.
Models The Models area of the dialog box contains a display of the currently defined models with the model parameters and the Add Model, Remove Model, Report and Add Models buttons. The active models name is highlighted in the list of models and any model may become active by clicking its model name.
Left image The left image name for the current model is displayed in this field and by be changed by clicking on the field and selecting a new image from the list.
Right image The right image name for the current model is displayed in this field and by be changed by clicking on the field and selecting a new image from the list.
Resample mode There are three modes available when re-sampling images to create epipolar images which include Nearest Neighbor, Bilinear and Bicubic. These re-sampling modes affect the quality of the output image and the time it takes to create the epipolar images as follows:
· Nearest Neighbor - Fastest re-sampling time, lower quality. High contrast edges will appear more jagged using this mode
· Bilinear Medium re-sampling time, medium image quality. The image quality is softer than nearest neighbor and is normally acceptable for stereo viewing.
· Bicubic Highest re-sampling time, highest image quality. The image quality is the softest of the three methods. Bicubic re-sampling is commonly used when creating orthophotos.
Image resolution This field specifies the resolution of the epipolar images and is expressed in millimeters. For example; 12 microns would be entered as 0.012 millimeters. The resolution of the epipolar images do not need to be the same as the original image although using the same resolution is recommended. In cases when the debugging of a stereo model orientation and re-sampling is done multiple times while testing orientation parameters, it is useful to re-sample at a higher resolution such as 30 microns (0.030 millimeters) to obtain a stereo model quickly. Over sampling is a process to using a higher image resolution for the epipolar images. This results in a softer image but does not increase the models accuracy and increases the size of the epipolar images.
Offset X, Offset Y The offset values move the viewing center for the stereo model. These are needed in close range photogrammetry when there are high camera angles to the object being photographed. For aerial photogrammetry these values are normally set to zero. See View Relative Orientation 3D under the Orientation pull-down for a 3D graphical display of the image geometry.
Image size scale factor X, Image size scale factor Y These scale factors are used to adjust the size of the area covered by the epipolar images. The area re-sampled is based on the Photo Overlap setting but enlarging the size is needed in some cases. These values are normally set to 1.0 which is no scale factor. See View Relative Orientation 3D under the Orientation pull-down for a 3D graphical display of the image geometry.
Add Model Pressing this button allows a single model to be added to the list of models. After the model is added the left and right images must be selected and the epipolar re-sampling image parameters must be set. To check the orientation of the left and right images it is possible to go to Orientation -> Relative Orientation to view the left and right images.

Delete Model Deletes the current model from the model list after verification.
Report Pressing this button produces a report in a text window about the current file which includes the project name, image names and parameters. The contents of this window may be cut and pasted into another document.
Add Models Forms and adds models in a batch mode based on the images defined in Define Images. The format of the model names is defined in the Model Name Format dialog box. Options include the ability to include the strip number, left and right numbers and separator characters in the model name. The Update button shows the current format in the upper part of the dialog box based on a strip number of 1 and left and right photo numbers of 2 and 3.

Number of strip characters Defines the number of characters to use for the strip number at the beginning of the model name. Set to blank to disable the output of this field.
Separator character(s) Characters may be used to separate the strip number from the next field. Set to blank to disable the output of this field.
Number of left photo characters Defines the number of characters to use for the left photo number. Set to blank to disable the output of this field.
Separator character(s) - Characters may be used to separate fields. Set to blank to disable the output of this field.
Number of strip characters Defines the number of characters to use for the strip number. It is possible to include the strip number before the left and right photo numbers. Set to blank to disable the output of this field.
Separator character(s) - Characters may be used to separate fields. Set to blank to disable the output of this field.
Number of right photo characters Defines the number of characters to use for the right photo number. Set to blank to disable the output of this field.
Update - The Update button shows the current format in the upper part of the dialog box based on a strip number of 1 and left and right photo numbers of 2 and 3.

The Add Model Epipolar Resampling Parameters dialog box defines the parameters to use during the creation of epipolar images for stereo viewing.
Resample mode There are three modes available when re-sampling images to create epipolar images which include Nearest Neighbor, Bilinear and Bicubic. These re-sampling modes affect the quality of the output image and the time it takes to create the epipolar images as follows:
Image resolution This field specifies the resolution of the epipolar images and is expressed in millimeters. For example; 12 microns would be entered as 0.012 millimeters. The resolution of the epipolar images do not need to be the same as the original image although using the same resolution is recommended. In cases when the debugging of a stereo model orientation and re-sampling is done multiple times while testing orientation parameters, it is useful to re-sample at a higher resolution such as 30 microns (0.030 millimeters) to obtain a stereo model quickly. Over sampling is a process to using a higher image resolution for the epipolar images. This results in a softer image but does not increase the models accuracy and increases the size of the epipolar images.
Offset X, Offset Y The offset values move the viewing center for the stereo model. These are needed in close range photogrammetry when there are high camera angles to the object being photographed. For aerial photogrammetry these values are normally set to zero. See View Relative Orientation 3D under the Orientation pull-down for a 3D graphical display of the image geometry.
Image size scale factor X, Image size scale factor Y These scale factors are used to adjust the size of the area covered by the epipolar images. The area re-sampled is based on the Photo Overlap setting but enlarging the size is needed in some cases. These values are normally set to 1.0 which is no scale factor. See View Relative Orientation 3D under the Orientation pull-down for a 3D graphical display of the image geometry.
Delete current models? Setting this parameter to Yes will delete the current models. WARNING: The deletion of models will delete their model orientations.
The Define Images or Import ImageUtil options are used to identify the images in the project and to assign image parameters such as the photo name format, camera name, strip location and pixel size to each image. If you have already set up a project in Image Utility and performed interior orientations, then use the Import ImageUtil option. This will read the list of images from the Image Utility project, and will automatically recognize the image settings and interior orientation.
Selecting Define Image will display a new dialog box allowing you to add the images to the project. Each image has a camera file, strip location, and pixel size assigned to it. Use this dialog to assign the correct parameters to all images in the project. A camera file must be added to the project from this dialog before adding any photos to the dialog. It is important that the Strip and Photo Num display correctly beside each image. This is controlled by setting the proper Name Format for the images.
Images may be highlighted in the dialog box by placing the mouse pointer on an image and dragging. The shift key plus a mouse click may be used to highlight a range of images and the control (Ctrl) key plus a mouse click may be used to highlight additional images.

The first four rows of the dialog box contain the template to be applied to a group of highlighted images or may be applied to all images. These first four rows contain the project cameras, film strip location, photo pixel size and photo name format.
Project cameras Up to 10 project cameras can be defined.
Film strip location The film strip location is the location of the cameras data strip in reference to the rotation of the image. This parameter is not dependent on the direction of flight but the orientation of the image as the user is viewing it. Following is an example of strip locations
The following model consists of Image 1 on the left and Image 2 on the right to construct a model. The data strip is to the left.

The same model as above but the images have been rotated 180 degrees making Image 2 on the left and Image 1 on the right. Along with the image rotation, the strip location is also rotated.

Photo pixel size The photo pixel size is the actual size of each pixel based on the fiducial coordinate units. This is normally expressed in millimeters but may be in inches or pixels. If the fiducial coordinate units is pixel then the photo pixel size is always 1.
Strip-Photo separator character, Strip digits, Photo digits These three fields define the Photo Name Format and set the format for decoding the strip number and photo number from and image file name. Please see Photo Name Format for more information about these parameters.
It is possible to move a job to another directory (folder) and drive and re-define the location of the parameter files needed for orientation and the formation of stereo models. When this command is started the user will be prompted for an existing VrTwo Orientation parameter (.vpr) file. The new locations for the various model orientation parameter files may be defined in the dialog box shown below.

The current project may be deleted using this command. Before the project is deleted a warning dialog box is displayed and the user must confirm the delete.

ImportImport provides methods of orientating stereo models from the results generated by a variety of aerial triangulation programs. The importing of Interior Orientations in batch mode is available along with the ability to import exterior orientations or measurements in single model mode or batch.
There are two methods of performing relative and absolute orientations using Import.
Exterior Orientation Six independent parameters called the elements of exterior orientation express the spatial position and angular orientation of a tilted image. The process of aerial triangulation determines these six parameters for each photograph and the availability of these exterior orientations for two overlapping images allows a model setup. The values that make up an exterior orientation are Omega, Phi, Kappa, X, Y, Z. The Omega, Phi and Kappa are the rotations about the x, y and z axis of the image and the X, Y and Z is the nodal point of the camera lens which is where the light rays appear to cross in the camera lens.
Measurements In the process of aerial triangulation over lapping and side lapping images are joined together using pass points for over lapping images and tie points for side lapping images. Each of these points is placed at a common ground location on each photograph. In the process of importing measurements for model orientations these points are read for the left and the right images and relative and absolute orientations are performed. Common point names that have an entry in the coordinate file will be used during the absolute orientation computations.
Please see the document Importing Orientations for more information about these two methods and the various input formats.
Prerequisites:
The user is expected to know information and details of the format that is being imported. The Importing Orientations document should be read before attempting to import model orientations.
In the process of orientating models interior orientations must be preformed on all images before the stereo model can be set. There are several methods to accomplish interior orientations which include:

Import orientation file The ASCII file that contains the interior orientation measurements is defined in this field. The user must know the correct file for the import format. When importing Orima .iop files any .iop file may be selected and all .iop files must be in the same folder as the file selected.
Interior orientation file format The format of the input interior orientation file may be specified as:
Depending on the Interior orientation file format selected one of the following dialog boxes may appear to request more information about the input format:
ISAT

Strip number location - In the ISAT photo file there are two possible locations in which the strip number may be stored. These locations are:
· Embedded with the photo number The strip number is part of the photo name following the photo_parameters keyword. For example, the record:
begin photo_parameters 205 strip_id 2
would assume the strip number and photo number to be included in the 205 field and the 2 after the strip_id would be ignored. If the number of strip characters was 1 and the number of photo characters was 2 then strip 2, photo 5 would be decoded from the 205 field.
· After the strip_id keyword The strip number follows the strip_id keyword which is on the same record as the photo_parameters keyword. For example, the record
begin photo_parameters 101 strip_id 3
would assume the photo number as 101 and the strip number as 3.
Selecting Images to
Orient
The following dialog box is display before importing begins which allows the user to select the images to orient. By default all images are selected.

After completion of each interior the results of the import are placed into the information dialog box.

The single model exterior orientation input orients a pair of images into a single model by using the six exterior orientation parameters from the two images.

Exterior orientation file This field defines the file containing the exterior orientation parameters. This file will normally contain the parameters for multiple images which consist of an entire job or a single aerial triangulation bundle adjustment. Please refer to the document Importing Orientations for more information on the various formats.
Exterior orientation file format This field the format of the file selected in the Exterior orientation file field.
ISAT photo File
When importing exterior orientations from the ISAT photo file some additional information is required about the location of the strip number.

Strip number location - In the ISAT photo file there are two possible locations in which the strip number may be stored. These locations are:
· Embedded with the photo number The strip number is part of the photo name following the photo_parameters keyword. For example, the record:
begin photo_parameters 205 strip_id 2
would assume the strip number and photo number to be included in the 205 field and the 2 after the strip_id would be ignored. If the number of strip characters was 1 and the number of photo characters was 2 then strip 2, photo 5 would be decoded from the 205 field.
· After the strip_id keyword The strip number follows the strip_id keyword which is on the same record as the photo_parameters keyword. For example, the record
begin photo_parameters 101 strip_id 3
would assume the photo number as 101 and the strip number as 3.
Many of the orientation file formats require additional information about the strip and photo numbers

The Photo Name Format dialog box defines the format for decoding the strip number and photo number from and image file name. Please see Photo Name Format for more information about these parameters.

The two images to use for orientation are selected by choosing the Left photo and the Right photo. The exterior orientation file and number of images read is shown along with the current model at the top of the dialog box.
Mean model ground elevation - The mean ground elevation defines the average ground elevation of the model or job and may be approximate.
Delta Kappa rotation value Some situations require a rotation angle to be added to the Kappa (rotation about the Z axis) value in the exterior orientation file. This will be required if the images were rotated from their original positions. It is suggested that an angle of zero is first attempted and if the import does not produce a viewable stereo model then a rotation value of 180 should be entered. The possible rotation values are 0, 90, 180 and 270 degrees.

When the import of the model is complete a dialog box will display the model name and the relative and absolute residuals. If these residuals are high the user should try adding 90 degrees to the Delta Kappa rotation value and attempting the orientation again. Pressing the Yes button will start the process of generating epipolar images for stereo viewing. Pressing the No button will skip the generation of epipolar images.
When the import of a model using exterior orientation is complete the VrTwo Orientation program may be exited and VrTwo may be started to view the model. The viewing of the model in relative orientation in the VrTwo Orientation program is not available when this method is used.
The single model measurement orientation input orients a pair of images into a single model by using the common measured points from the two images. These points are typically measured in an aerial triangulation program and are available in a variety of formats.

Once a measurement input format is selected a dialog box is displayed prompting for additional file format parameters. These parameters typically include the photo measurement file name and the coordinate units. Following is the Import PATB Orientation dialog box.

Photo measurement file This field defines the measurement parameter file name. It is typical for the measurements for many images to be in a single input file.
Coordinate units The coordinates that represent the photo measurements in the input file may expressed in millimeters or microns. The user may need to view the input file in a text editor to determine the value for this parameter. Most photo coordinate systems are in millimeters so an x, y coordinate of -26.499567, 2.2979591 would indicate millimeters while an x, y coordinate of -26499567, 22979591 would indicate microns.
Some formats require more information about the input format such as the JFK format.

Photo measurement file This field defines the measurement parameter file name. It is typical for the measurements for many images to be in a single input file.
JFK fiducial read order When reading the interior orientations using the JFK aerial triangulation software the operator may read the fiducials in any order. The order used by the aerial triangulation operator must be know and entered in the field. If only four fiducials were observed (not recommended) the unused fiducials are entered with a value of zero. For example: 12340000.
The left and right image names are selected in the next step.

After the left and right images are selected the measurements are imported and the relative and absolute orientations are computed. The results are shown in the information dialog box.

When the model import is complete the results of the import may be viewed in Orientation -> Relative Orientation and Orientation -> Absolute Orientation.
It is possible to orientate many stereo models using exterior orientations with Exterior Orientations Batch. Before Exterior Orientations Batch can be run the project must be set, the models must be defined and interior orientations must be complete.

Exterior orientation file This field defines the file containing the exterior orientation parameters. This file will normally contain the parameters for multiple images which consist of an entire job or a single aerial triangulation bundle adjustment. Please refer to the document Importing Orientations for more information on the various formats.
Exterior orientation file format This field the format of the file selected in the Exterior orientation file field.
Mean model ground elevation - The mean ground elevation defines the average ground elevation of the model or job and may be approximate.
Delta Kappa rotation value Some situations require a rotation angle to be added to the Kappa (rotation about the Z axis) value in the exterior orientation file. This will be required if the images were rotated from their original positions. It is suggested that an angle of zero is first attempted and if the import does not produce a viewable stereo model then a rotation value of 180 should be entered. The possible rotation values are 0, 90, 180 and 270 degrees.
Create Epipolar images and pyramids? The importing of orientations will perform relative and absolute orientations and produce residuals to show the results of the orientations. Setting this parameter to No will allow the display of the results without generating epipolar images or image pyramids. It is suggested this parameter is first set to No to check the orientations before processing the images for stereo viewing.
ISAT photo File
When importing exterior orientations from the ISAT photo file some additional information is required about the location of the strip number.

Strip number location - In the ISAT photo file there are two possible locations in which the strip number may be stored. These locations are:
· Embedded with the photo number The strip number is part of the photo name following the photo_parameters keyword. For example, the record:
begin photo_parameters 205 strip_id 2
would assume the strip number and photo number to be included in the 205 field and the 2 after the strip_id would be ignored. If the number of strip characters was 1 and the number of photo characters was 2 then strip 2, photo 5 would be decoded from the 205 field.
· After the strip_id keyword The strip number follows the strip_id keyword which is on the same record as the photo_parameters keyword. For example, the record
begin photo_parameters 101 strip_id 3
would assume the photo number as 101 and the strip number as 3.
If the Strip Number Location for the ISAT photo file was specified as Embedded with the photo number then the following dialog box will be displayed.

The Photo Name Format dialog box defines the format for decoding the strip number and photo number from and image file name. Please see Photo Name Format for more information about these parameters.
The following dialog box is display before importing begins which allows the user to select the images to orient. By default all images are selected.

After completion of import the results of the import are placed into the information dialog box.

It is possible to orientate many stereo models using measurement orientations with Measurement Orientations Batch. Before Measurement Orientations Batch can be run the project must be set, the models must be defined and interior orientations must be complete.

Photo measurement file This field defines the measurement parameter file name. It is typical for the measurements for many images to be in a single input file.
Measurement orientation file format This field the format of the file selected in the Photo measurement file field.
Create Epipolar images and pyramids? The importing of orientations will perform relative and absolute orientations and produce residuals to show the results of the orientations. Setting this parameter to No will allow the display of the results without generating epipolar images or image pyramids. It is suggested this parameter is first set to No to check the orientations before processing the images for stereo viewing.
Depending on the orientation file format selected one of the following dialog boxes may appear to request more information about the input format:
ISAT

Strip number location - In the ISAT photo file there are two possible locations in which the strip number may be stored. These locations are:
· Embedded with the photo number The strip number is part of the photo name following the photo_parameters keyword. For example, the record:
begin photo_parameters 205 strip_id 2
would assume the strip number and photo number to be included in the 205 field and the 2 after the strip_id would be ignored. If the number of strip characters was 1 and the number of photo characters was 2 then strip 2, photo 5 would be decoded from the 205 field.
· After the strip_id keyword The strip number follows the strip_id keyword which is on the same record as the photo_parameters keyword. For example, the record
begin photo_parameters 101 strip_id 3
would assume the photo number as 101 and the strip number as 3.
ATLAS, ISSBA, ORIMA,
PATB, VRAT

The Photo Name Format dialog box defines the format for decoding the strip number and photo number from and image file name. Please see Photo Name Format for more information about these parameters.
PATB

Coordinate file units The coordinates that represent the photo measurements in the input file may expressed in millimeters or microns. The user may need to view the input file in a text editor to determine the value for this parameter. Most photo coordinate systems are in millimeters so an x, y coordinate of -26.499567, 2.2979591 would indicate millimeters while an x, y coordinate of -26499567, 22979591 would indicate microns.
After completion of import the results of the import are placed into the information dialog box.

When the model import is complete and epipolar images have been created the results of the import may be viewed in Orientation -> Relative Orientation and Orientation -> Absolute Orientation.
In many of the orientation methods the creation of epipolar images may be skipped. Create Epipolar Images creates these images in a batch mode.

Create epipolar images The parameter sets the creation mode for the epipolar images. Options are If they dont exist and Create all epipolar images.
OrientationThere are three methods of performing interior orientations in Vr Mapping. The auto correlated automatic interior orientation process is available in the Vr Image Utility (imageutill.exe) program, importing interior orientations or manually reading the fiducials. The Left / Right Interior Orientation is the manual method. A project must be set up and the camera calibration file must be defined before starting this command.

There are four windows or dialog boxes that make up the interior orientation application.
Residuals This is the dialog box in the upper left corner of the screen. The Residuals dialog box shows the current residuals of the adjustment. After the third fiducial is read the image pixel size is shown in the lower left corner of this dialog.

To drive to a fiducial point the point number may be selected with the mouse.
Overview The overview window is in the upper right corner of the screen and shows the entire image. If the cursor is moved into this window the shape of the cursor will change to a square and a press of the left mouse button will display that portion of the image in the measurement window below.

The fiducial numbers are displayed in the overview window.
Measurement This window displays an enlarged area of the image and allows the observations of fiducials. The controls for the measurement window are displayed in the Menu Keys dialog box to the left.

Fiducials are measured by pressing the left mouse button. See Menu Keys below for all the display controls.
Menu Keys The display and measurement controls for the measurement window are displayed in the Menu Keys dialog box. Several buttons on the menu keys are mapped onto the mouse and all buttons may be used by pressing the corresponding Fkeys on the system keyboard. For example; to zoom out the F3 key on the system keyboard may be pressed. Note that the buttons cannot be pressed with mouse clicks.

1 Measure (Left) Measurement button for fiducial observations. This is mapped to the left mouse button.
2 Center (Right ) Centers the screen at the current cursor location. This is mapped to the right mouse button.
3 Zoom out Zoom out using the zoom scale factor specified in Preferences.
4 Zoom in (Center) Zooms in using the zoom scale factor specified in Preferences. This is mapped to the center wheel button on the mouse.
5 Next fiducial Advances to the next fiducial.
6 Set fid size Sets the fiducial size by digitizing lower left and upper right points around the fiducial. The value is used to set the Fiducial size in the camera calibration which is used for Automatic Interior Orientations in the Vr Image Utility (imageutil.exe) program.
9 Tips Displays several helpful tips.
The relative orientation command performs manual relative orientations with one of three options when reading points.
· Mono-comparator mode A common point is read in the left image and the right image. This is useful when reading photo identifiable items such control point panels.
· Autocorrelation assist The cursor is positioned on one image and the common location is found on the other. The cursor may be positioned in the left or right image.
· Stereo The two images may be displayed in stereo and parallax may be cleared using a method similar to clearing parallax on analytical instruments.
After completion of relative orientation, epipolar images may be created which will produce a viewable stereo model.

There are six windows or dialog boxes that are displayed during relative orientation.
Residuals This is the dialog box in the upper left corner of the screen. The Residuals dialog box shows the current residuals of the adjustment.

Any point may be driven to by clicking on its sequence number. A least six points must be read before a solution will be computed. To add a measurement the Add Measurement button should be pressed first then the points should be located on the images.
Menu Keys The display and measurement controls for the measurement window are displayed in the Menu Keys dialog box. Several buttons on the menu keys are mapped onto the mouse and all buttons may be used by pressing the corresponding Fkeys on the system keyboard. For example; to zoom out the F3 key on the system keyboard may be pressed. Note that the buttons cannot be pressed with mouse clicks.

1 Measure (Left) Measurement button for fiducial observations. This is mapped to the left mouse button.
2 Center (Right ) Centers the screen at the current cursor location. This is mapped to the right mouse button.
3 Zoom out Zooms out using the zoom scale factor specified in Preferences.
4 Zoom in (Center) Zooms in using the zoom scale factor specified in Preferences. This is mapped to the center wheel button on the mouse.
5 Next fiducial Advances to the next fiducial.
6 Stereo Changes the measurement mode to stereo. See The Relative Orientation Stereo Window below.
7 Correlate The cursor may be positioned in either the left or right measurement window and F7 may be pressed to find the common point in the other image. The result of the correlation will be displayed in the Residual dialog box and in the Menu Keys dialog box. The user has an option to accept or reject the correlation result. The result of the correlation is a number from zero to one with one being perfect. Following are guidelines on the result from correlation:
Overview and Measurement Windows The four windows along the bottom of the screen are the overview and measurement windows. The two outer windows are the overview and the two inner windows are the measurement. If the cursor is moved into one of the overview windows the cursor will change into a square. Pressing the right mouse button while in one of the overview windows will copy an enlarged area of the image into the corresponding measurement window.

The Relative
Orientation Stereo Window

Pressing button #6 when in relative orientation switches the measurement mode to stereo and parallax at the point of interest may be cleared similar to the method used on analytical stereo plotters. The following controls are available when in stereo.

1 Measure Measures the point in stereo and records the position on both images.
2 Move One/Both Toggles the movement of the images from both moving to one moving. When the mode is set to one image moving then parallax can be cleared at that location.
3 Toggle Move Side Toggles the image side to move between left and right when clearing parallax.
4 Reset Rotation Resets the current image rotation. See Rotating One Image below.
5 Reset Scale Resets the current image scale to 1.0. See Scaling One Image below.
6 Next Point Advances to the next point in relative orientation
7 Correlate Correlates the two images to a common point in both images or puts the dot on the ground.
8 Parameters Allows the setting of stereo parameters.
9 Rotate 90 Rotates both images 90 degrees from their current rotations. This is useful when viewing stereo between strips because side by side overlap does not produce viewable stereo in this situation.
* Help Displays help on additional key sequences for viewing features. The * keys is F10 on the system keyboard.
# Abandon Quits stereo mode and returns to the previous relative orientation layout.
Additional Features
and Controls When in Stereo Mode
This command creates epipolar images of the current model. This step is normally included in the orientation process after relative orientation but may be used here if the step was skipped earlier.

Resample mode There are three modes available when re-sampling images to create epipolar images which include Nearest Neighbor, Bilinear and Bicubic. These re-sampling modes affect the quality of the output image and the time it takes to create the epipolar images as follows:
· Nearest Neighbor - Fastest re-sampling time, lower quality. High contrast edges will appear more jagged using this mode
· Bilinear Medium re-sampling time, medium image quality. The image quality is softer than nearest neighbor and is normally acceptable for stereo viewing.
· Bicubic Highest re-sampling time, highest image quality. The image quality is the softest of the three methods. Bicubic re-sampling is commonly used when creating orthophotos.
Image resolution This field specifies the resolution of the epipolar images and is expressed in millimeters. For example; 12 microns would be entered as 0.012 millimeters. The resolution of the epipolar images do not need to be the same as the original image although using the same resolution is recommended. In cases when the debugging of a stereo model orientation and re-sampling is done multiple times while testing orientation parameters, it is useful to re-sample at a higher resolution such as 30 microns (0.030 millimeters) to obtain a stereo model quickly. Over sampling is a process to using a higher image resolution for the epipolar images. This results in a softer image but does not increase the models accuracy and increases the size of the epipolar images.
Offset X, Offset Y The offset values move the viewing center for the stereo model. These are needed in close range photogrammetry when there are high camera angles to the object being photographed. For aerial photogrammetry these values are normally set to zero. See View Relative Orientation 3D under the Orientation pull-down for a 3D graphical display of the image geometry.
Image size scale factor X, Image size scale factor Y These scale factors are used to adjust the size of the area covered by the epipolar images. The area re-sampled is based on the Photo Overlap setting but enlarging the size is needed in some cases. These values are normally set to 1.0 which is no scale factor. See View Relative Orientation 3D under the Orientation pull-down for a 3D graphical display of the image geometry.
After the completion of interior and relative orientations and the generation of epipolar images a viewable stereo model is produced. The next step in orientation is to tie this model to a known ground control system. This is the absolute orientation step of model orientation. When performing manual absolute orientation at least three elevations and two horizontal positions must be known at photo identifiable positions in the model area.
NOTE: The absolute orientation stereo window is a static image window meaning the images are non-moving and the floating mark is moving. There may be situations in which the floating mark is well above or below the model surface making the viewing of stereo difficult.
The use of the Home key on the system keyboard is useful in this situation. Pressing this key places the floating mark at the same elevation as the window frame. While driving the floating mark to the ground surface, the Home key should be pressed periodically to make stereo viewing more comfortable. The Mean Z (button #6) will drive the elevation to the average model elevation based on the control points.
When driving the cursor to the ground surface using the wheel on the system mouse, the Shift key on the system keyboard may be held which allies a 4x multiplier to the Z movement scale for faster movement.

There are three windows or dialog boxes that are displayed during relative orientation.
Residuals This is the dialog box in the upper left corner of the screen. The Residuals dialog box shows the current residuals of the adjustment.

Any point may be driven to by clicking on its sequence number. An axis of any point in the adjustment may be floated or taken out of the absolute orientation solution by driving to the point then checking its Float axis.
Menu Keys The display and measurement controls for the measurement window are displayed in the Menu Keys dialog box. Several buttons on the menu keys are mapped onto the mouse and all buttons may be used by pressing the corresponding Fkeys on the system keyboard. For example; to zoom out the F3 key on the system keyboard may be pressed. Note that the buttons cannot be pressed with mouse clicks.

1 Measure (Left) Measurement button for absolute orientation observations. This is mapped to the left mouse button.
2 Center (Center ) Centers the screen at the current cursor location. This is mapped to the center wheel button on the mouse. The Home key on the system keyboard performs the same function.
3 Zoom out (Right) Zooms out using the zoom scale factor specified in Preferences. This is mapped to the right mouse button. The Page Up key on the system keyboard performs the same function but zooms out at 2x increments.
4 Zoom in Zooms in using the zoom scale factor specified in Preferences. The Page Down key on the system keyboard performs the same function but zooms in at 2x increments.
5 Next fiducial Advances to the next fiducial.
6 Mean Z Drives the elevation of the floating mark to the average elevation of the control points in the model. In cases when the floating mark is well above or below the model surface it may be difficult viewing stereo. Driving to the mean elevation of the model places the Z in a sane location.
Measurement Window -

This three-dimensional view window is used to measure control points.
The Corner Interior Orientations will compute the interior orientations of the current left and right model images using corners. When using images in which the camera has not been calibrated or when using images that do not have fiducials the Corner Interior Orientation to establish a generic interior orientation. When using this format the Import orientation file parameter above does not need to be defined.

Sides to compute This parameter defines the sides to compute which include Both, Left or Right.
It is possible to view the geometry of the stereo model and how it interacts with the two images, the focal lengths, the model areas and the image angles and projections. This tool is useful when viewing stereo geometry for close range applications. Information in the window shows the Omega, Phi and Kappa angles in degrees, the Bx, By and Bz shifts in Fiducial Units and the photo overlap. Refer to File -> Preferences for preference parameters for the Relative Orientation 3D window.

XOfs, YOfs These two controls graphically show the x and y offsets of the images to the stereo model plane. The stereo model plane is show as a white rectangle. The offset values move the viewing center for the stereo model. These are needed in close range photogrammetry when there are high camera angles to the object being photographed. For aerial photogrammetry these values are normally set to zero.
ScaleX, ScaleY These two controls graphically show the x and y scale factors of the images to the stereo model plane. These scale factors are used to adjust the size of the area covered by the epipolar images. The area re-sampled is based on the Photo Overlap setting but enlarging the size is needed in some cases. These values are normally set to 1.0 which is no scale factor.
The controls to rotate and manipulate the viewing of the 3D model are:
There are situations when the current model needs to be reset or cleared. Clear current model clears all or part of the steps used in model orientation for the current model.

Orientation to delete The orientation step or steps may be deleted which include All, Relative and Absolute or Absolute Only.
The bundle adjustments are currently under development. WARNING: Do not use any command in this menu.

AboutDisplays this VrTwo Orientation help document
Displays the current software version.

The Vr Mapping coordinate file (.cor) consists of a header and a list of point names, coordinates and optional weights. Fields may be arranged in several different orders. The file is an ASCII file and may be viewed with any text editor. Documentation about the file format is included in each file header. Following is a typical Vr Mapping coordinate file.
#
Coordinate File
#
Layout - Field Order Min number of fields
# 0
NAME X Y Z CX CY CZ
3
# 1
NAME Y X Z CY CX CZ
3
# 2
X Y Z NAME CX CY CZ
4
# 3
Y X Z NAME CY CX CZ
4
# 4
NAME X Y Z
3
# 5
NAME Y X Z
3
# 6
X Y Z NAME
4
# 7
Y X Z NAME 4
# 8
X Y NAME
3
# 9
Y X NAME
3
#
#
Format - Coordinate format
#
0 State plane
#
1 UTM
#
2 Geographic Decimal Degrees
#
#
SpZone - State plane zone
#
#
Datum - Datum
#
0 NAD1927
#
1 NAD1983
#
#
UtmZone - UTM Zone
#
1-60 UTM zone number
#
#
Units - Coordinate units
# 0
Us Foot
# 1
International Foot
# 2
Meters
# 3
Inches
# 4
Pixels
#
Layout 4
Format 0
SpZone 901
Datum 0
UtmZone
17
Units 0
#
201
837831.194130 951352.037020 303.8200
202
836399.079330 951266.642540 337.6800
203
837994.618340 950634.951710 299.6000
204
836711.670600 950565.198920 326.3200
205
836018.411470 950724.804370 309.2900
Any record starting with a # symbol is considered a comment. The Layout is the most important keyword in the file as it specifies the order of the fields.
Importing a file to
use as a Vr Mapping coordinate (.cor) file.
Any ASCII file that is in the following format may be read by Vr Mapping. The file must have a .cor file name extension and the fields must be separated by one or more blanks or tabs. Following is an example of an ASCII file that would be acceptable to reading by Vr Mapping. This file consists of a point name followed by X Y and Z.
35
1410993.867000
667652.883000 268.0300
36
1421351.907000
670064.772000 251.8240
37
1432756.960000
660002.435000 438.6740
38
1426080.595000
651648.623000 417.5070
39
1437426.118000
648649.673000 256.5350
99999
1440539.957000
647417.838000 241.1880
2727011
1410534.575000
658885.235000 294.5090
2727012
1412335.275000
659061.598000 280.9620
2727021
1410279.378000
661225.872000 260.6650
2727022
1412458.095000
661055.148000 284.6200
2727023
1413884.366000
661259.361000 425.0660
2727031
1410433.453000
663554.024000 267.3830
2727032
1412556.566000
663154.921000 244.1890
2727033
1414464.428000
663015.598000 460.9970
Various processes such as aerial triangulation and model orientation require use of an image strip and photo number. These numbers are typically encoded in the image file name and the Photo Name Format describes the method for extracting this information.

There are three parameters that make up the Photo Name Format which include a separator character, number of digits for the strip number and number of digits for the photo number. If the separator character is used to describe the format then the number of digits for the strip and photo numbers are not needed. If the file name does not have a separator character then the number of digits values must be used.
The photo separator character may be Underbar _, Dash -, or Tilde (~) and the number of digits may be from 1 to 9. If the photo separator character is set to None then the Number of digits fields will be used. Following are several examples of the Photo Name Format.
Photo
name: 23-56.tif
Photo
separator character: Dash
Number
of digits for strip number: any
Number
of digits for photo number: any
Strip
number: 23
Photo
number: 56
Photo
file name: 23056.tif
Photo
separator character: None
Number
of digits for strip number: 2
Number
of digits for photo number: 3
Strip
number: 23
Photo
number: 56
Photo
file name: 23056.tif
Photo
separator character: None
Number
of digits for strip number: 3
Number
of digits for photo number: 2
Strip
number: 230
Photo
number 56