Skip to main content
Table of Contents

Orientation data coordinate system conventions

The exterior orientation conventions of images that are supported as input to Reality Studio, the supported orientation of the image coordinate system with respect to its exterior orientation, and an overview of the compatibility of data generated from common postprocessing software are described below.

Camera position coordinates (x,y,z)

Camera position coordinates define the position of the camera center at the instance an image is captured. Camera position coordinates can be imported from a text navigation file containing GNSS\INS data, Inpho project file (.prj), HxMap orientation files (.gori), or SURE orientation files (.ori). The units of the camera positions are defined by the coordinate system specified at the time of import.

Camera rotation angles (omega, phi, kappa)

Camera rotation angles define the orientation of the camera at the instance an image is captured. The rotation can be imported from a text navigation file containing GNSS\INS data or from a well-known orientation file format. When orientation data is imported using a text file, the supported rotation convention is as follows:

  • Omega, phi, and kappa are counter-clockwise (mathematically positive) rotation angles in the specified angular unit used to transform a point from the camera coordinate system to a world coordinate system (cam-to-world).

  • The rotation transformation matrix can follow either the x,y,z sequence (0) or the y,x,z sequence (1), which are defined as follows:

    • 
Rcam_2_world = Rx(omega)*Ry(phi)*Rz(kappa)    (0)

    • 
Rcam_2_world = Ry(phi)*Rx(omega)*Rz(kappa)    (1)

  • The rotations are applied on the rotated axes.

Image coordinate system and exterior orientation

The image coordinate system of each view must coincide with its exterior orientation. The default convention of most postprocessing software defines the x-axis of exterior orientations in flight direction. If the x-axis of the camera is not aligned with the flight direction, you need to specify the necessary rotation of the image coordinate system so that it meets the correct input convention. To do this, modify the axis orientation value in the Image Coordinate System section of the Capture Session pane.

Compatibility with postprocessing software

When exporting navigation data from postprocessing software, consider the following:

  • The direction of the transformation (world-to-cam or cam-to-world)

  • The order of rotations applied (x,y,z; y,x,z; z,y,x; and so on)

Reality Studio supports a cam-to-world transformation and the x,y,z rotation sequence. If you have existing data with different conventions, it may be possible to import it with minor modifications. For example, if the transformation direction is world-to-cam and the order of rotation is z,y,x, negating the sign of all angles (multiplying each angle by –1) allows you to load the data into Reality Studio.

The subsections below describe findings and recommendations based on initial testing to help you use navigation data from some postprocessing software.

AEROoffice (IGI)

Exterior orientation that is exported using the MATCH-AT-AWE format type is supported by Reality Studio.

POSPac (Trimble Applanix)

You can export this data using the following conventions:

  • Transformation—Cam-to-world

  • Rotation order—x,y,z

HxMap (Hexagon)

The exterior orientation exported from HxMap is supported by Reality Studio.

Note:

Export data from multicamera systems as .csv files only. HxMap orientation files (.gori) for multicamera systems are not supported.

When using .gori files, the principal point offset must be zero.

Ultramap (Vexcel)

The rotation order of the exterior orientation exported from Ultramap is supported by Reality Studio. Select the Phi-Omega-Kappa sequence from the supported Rotation Definition options.

Back to top