Setting the threshold values for the math model (bundle adjustment)

If you are having difficulty with your math model, such as a root mean square (RMS) error, you can modify the thresholds to adjust the acceptable deviation of the x, y, and z coordinates or the omega, phi, and kappa angles.

OrthoEngine recalculates the math model several times to find the best possible solution. The best possible solution is determined when the residual errors of the ground control points (GCP) and tie points (TP) occur within the limit set in the thresholds of the x, y, and z coordinates, the angle threshold, or until the limit in the number of iterations is reached. By adjusting the thresholds, you control the precision of the math model.

Note: The available options vary according to the type of math model; that is, not all options described herein may appear.

To set the threshold values for the math model

In the Bundle Adjustment Settings window, in the Triangulation mode list, click the mode you want to use:
- Traditional block bundle
- Enforced fitting
- Relative-absolute orientation
  When you select this option, select a value in the Absolute orientation options list.
- Relative orientation
- Absolute orientation
  When you select this option, select a value in the Absolute orientation options list.
- Free network adjustment
For information about each mode, see About the bundle-adjustment settings
In the Number of iterations box, type the maximum number of times for OrthoEngine to attempt to calculate the math model.
In the XYZ threshold box, type the acceptable tolerance, in meters, for the exterior-orientation (EO) x, y, and z coordinates.
In the Angle threshold box, type the acceptable deviation, in degrees, for the the omega, phi, and kappa angles.
To compute the math model as you make changes, select the Continuously compute model check box.