Assess an alignment result

Once the alignment processing is complete, you can assess the quality of the results using the Quality Assurance tool and the visualization options in the Display group on the Alignment tab.

Quality Assurance tool

You can perform quality assurance on the various aspects of the alignment using the Quality Assurance tool . The Quality Assurance view has the following tabs:

• Overview—Provides general information about the processed alignment and a statistical overview of various quality attributes. The quality attributes are organized into groups based on the type of statistic they represent. Each quality attribute has a histogram chart and a table that show the data distribution and statistical overview. The bins of the histograms are colored to indicate the quality of the attributes and symbolize the respective alignment element on the globe.
• Control Points—Provides detailed statistical information about the alignment results of the control points. Inspect the table to detect possible outliers and errors.
• Automatic Tie Points—Provides detailed statistical information about the alignment results of the automatic tie points. Inspect the table to detect possible outliers and errors.
• Manual Tie Points—Provides detailed statistical information about the alignment results of the manual tie points. Inspect the table to detect possible outliers and errors.
• Camera Poses—Provides detailed statistical information about the alignment results of the camera poses for each camera session. Inspect these tables to detect possible outliers and errors.
• Cameras—Provides detailed statistical information about the alignment results of the camera's internal parameters. Choose a camera from the drop-down menu and inspect this view to detect possible outliers and errors. The Camera Residual Plot view allows you to inspect reprojection errors and detect remaining systematic errors in the camera calibration such as uncompensated distortion. It also provides additional tools to customize the view. Choose the attribute you want to investigate from the Select Attribute drop-down list and provide a Bin Size value using the slider. Click a bin to open a pop-up with additional statistics.

Tip:

• To sort tables by attribute, double-click the corresponding column header.
• Selected elements on the tables appear as selected in the Globe view.
• To edit selected control points or manual tie point measurements, click Edit on the toolbars of the Control Points or Manual Tie Points tabs.

Visualization options

Once an alignment is processed, you can change the symbology of the alignment elements to represent their attributes. Assessing the quality of the alignment in a spatial context can help you detect problematic areas, and make informed decisions.

The visualization options are in the Display group on the Alignment tab.

Tip:

To turn the visibility of an alignment element on and off, click its respective button in the Display group (click the button, not the drop-down arrow). To change the symbology of alignment elements, click the respective drop-down arrow and click the attribute.

The visualization options for each alignment element are listed below.

• The following are the Camera Poses visualization options:
  • Default —The default visualization
  • Camera —The camera that corresponds to the camera pose
  • Automatic Tie Points per Image —The number of automatic tie points extracted from each image that is used in the alignment
  • Linked Cameras per Image —The number of cameras linked by having image measurements of the same automatic tie points
  • Position Residuals in X —The residual of the x-coordinate component for each camera pose in the alignment
  • Position Residuals in Y —The residual of the y-coordinate component for each camera pose in the alignment
  • Position Residuals in Z —The residual of the z-coordinate component for each camera pose in the alignment
  • Rotation Residuals in Omega —The residual of the omega angular component for each camera pose in the alignment
  • Position Residuals in Phi —The residual of the phi angular component for each camera pose in the alignment
  • Position Residuals in Kappa —The residual of the kappa angular component for each camera pose in the alignment
• The following are the Control Points visualization options:
  • Image Measurements —The number of image measurements for each control point in the alignment
  • Cameras —The number of unique cameras for each control point in the alignment
  • Maximum Reprojection Errors —The maximum value of all reprojection errors for each control point in the alignment
  • RMS of Reprojection Errors —The mean value of all reprojection errors for each control point in the alignment
  • Position Residuals in X —The residual of the x-coordinate component for each control point in the alignment
  • Position Residuals in Y —The residual of the y-coordinate component for each control point in the alignment
  • Position Residuals in Z —The residual of the z-coordinate component for each control point in the alignment
• The following are the Automatic Tie Points and Manual Tie Points visualization options:
  • Image Measurements or —The number of image measurements for each automatic or manual tie point in the alignment
  • Cameras or —The number of unique cameras for each automatic or manual tie point in the alignment
  • Maximum Reprojection Errors or —The maximum value of all reprojection errors for each automatic or manual tie point in the alignment
  • RMS of Reprojection Errors or —The mean value of all reprojection errors for each automatic or manual tie point in the alignment