Aligned Images in PhotoScan
In order to extract three dimensional points from two dimensional images, it is necessary to perform a triangulation with at least two images (a stereo pair). When more than two images are used in a triangulation, we refer to the group of images as a ‘block’. To perform a triangulation, we must measure a sufficient number of tie, control, and/or check points throughout the block. Constraints may also be placed on certain sets of points to enforce angular, linear, and/or planar properties. Once a triangulation is successful, image exterior orientation parameters (along with estimate for accuracy) should be available to the user. These are important pieces of information for downstream deliverables and should be documented. The table below describes the appropriate documentation for this process. Download a printable form in PDF format here or in a spreadsheet (.xlsx) format here.
| Entry | Description |
| For each block: | |
| Name and version of the software | Include all details of the software name, manufacturer, version, and build used for image processing and file format conversions. |
| Description of image processing | Describe and image processing and/or file format conversions performed and the settings used. |
| Name and version of the software | Include all details of the software name, manufacturer, version, and build used for triangulation. |
| RMSE values | Root Mean Square Error (RMSE) for control and check point measurements, indicating whether the RMSE is for control points only, check points only, or all points. |
| Constraints on object points | List of constraints used during processing. |
| For each point: | |
| Point ID | ID or name used for the point. |
| Point type | Tie, Control, or Check point. |
| XYZ priori and a priori | If available, provide the XYZ coordinates before and after bundle adjustment (control and check points only). |
| Covariance matrix a priori | If available, provide the covariance matrix. |
| Image coordinates and residuals | A list of images on which the point is indicated. For each image on the list, provide the uv coordiates and residual. |
| For each image: | |
| Exterior orientation | List exterior orientation parameters for each image. |