Every ArcGIS Drone2Map project includes a detailed processing report that displays the results of the block adjustment. Block adjustment is the process of computing an adjustment or transformation based on the internal relationship between overlapping images, control points, a camera or sensor model, and a digital elevation model (DEM). After performing a block adjustment, it is necessary to review the results of the adjustment and assess the quality of the control points (ground control points [GCPs], tie points, and checkpoints) used in the adjustment.
To access the report once the initial processing step is completed, on the Home tab, in the Processing section, click Report. You can also access the processing report at any time in the project folder in PDF and HTML format. The processing report includes the following sections.
Project Summary
The Project Summary table provides an overview of general project settings. The fields in the Project Summary table are described below:
| Field name | Description |
|---|---|
Project Name | Name of the ArcGIS Drone2Map project. |
Processed On | Date and time the report was generated. |
Camera Model | Drone camera model used in processing. |
Images | Number of images used in the block adjustment. |
Project Area | Size of the project area used in processing. |
Ground Resolution (unit/pixel) | Average ground resolution for all images in the image collection. The units are listed in the field heading and can be feet or meters. |
Processing Time | Total time elapsed to process the project. |
Adjust Images
The Adjust Images section provides a synopsis of the settings used for the block adjustment process and the quality of the adjustment.
Summary
The adjust images Summary table provides a synopsis of your most recent block adjustment. The fields in the adjust images Summary are described below:
| Field name | Description |
|---|---|
Number of Tie Points | Number of tie points used to perform the block adjustment. |
Number of Solution Points | Number of solution points generated in the block adjustment. |
Mean Reprojection Error / Sigma Naught (Pixel) | The root mean square error (RMSE) of the reprojection across all adjusted images. The units are pixels. Each computed 3D point has initially been detected on the images (2D keypoint). On each image, the detected 2D keypoint has a specific position. When the computed 3D point is projected back to the images, it has a reprojected position. The distance between the initial position and the reprojected one gives the reprojection error for the tie point. |
Ground Control Points RMSE | The root mean square error (RMSE) of each ground control point or check point used in the adjustment. The units can be feet or meters. |
Initial Processing Time | Amount of time to complete the initial processing step. |
Processing Options
The Processing Options table in the Adjust Images section lists the user-defined settings used in the adjustment process. The fields in Processing Options are described below:
| Field name | Description |
|---|---|
Initial Image Scale | The image scale used to extract feature points for adjustment |
Refine Adjustment Scale | The image scale used when the refine adjustment option is enabled |
Matching Neighborhood | Size of the neighborhood used to find tie points during adjustment |
Internal Camera Parameters
The Internal Camera Parameters table lists the camera calibration information for the adjustment. The information is derived from the camera database when you load project imagery. The camera calibration parameters can be modified in the Edit Camera Parameters pane by using the Edit Camera button on the Flight Data ribbon.
The Internal Camera Parameters table is split into two fields: initial camera parameters that are used for adjustment and the optimized camera parameters that are calculated after the block adjustment completes.
The fields in the Internal Camera Parameters table are described below:
| Field name | Description |
|---|---|
Focal Length (mm) | Camera lens focal length in millimeters. |
Principal Point X (mm) | The principal point is a point on the image plane where a line from perspective center (camera lens), perpendicular to the image plane, intersects the image plane. The X direction is parallel to the direction of image rows. |
Principal Point Y (mm) | The principal point is a point on the image plane where a line from perspective center (camera lens), perpendicular to the image plane, intersects the image plane. The Y direction is parallel to the direction of image columns. |
K1, K2, K3, P1, P2 | Lens distortion parameters, defined by the Brown-Conrady Model. Reference: Qi, J. et al., 1994, "A modified soil vegetation adjusted index," Remote Sensing of Environment, Vol. 48, No. 2, 119–126. |
Tie Points Per Image
For every adjusted image, a number of tie points were used to perform the adjustment. The fields in the Tie Points Per Image table are described below:
| Field name | Description |
|---|---|
Min | Minimum number of tie points used in an image adjustment for the image collection |
Max | Maximum number of tie points used in an image adjustment for the image collection |
Median | Median number of tie points used per image adjustment for the image collection |
Average | Average number of tie points used per image adjustment for the image collection |
Total | Total number of tie points used in the image adjustment for the image collection |
Tie Point Projection Error
This table lists the various reprojection error statistics for tie points generated from the project imagery. The fields in the Tie Point Projection Error table are described below:
| Field name | Description |
|---|---|
Min (Pixels) | Image with the lowest tie point reprojection error. The image file name is listed and units are in pixels. |
Max (Pixels) | Image with the highest tie point reprojection error. The image file name is listed and units are in pixels. |
Median (Pixels) | Median reprojection error for tie points across all project imagery. The units are pixels. |
Average (Pixels) | Average reprojection error for tie points across all project imagery. The units are pixels. |
Standard Deviations of Exterior Orientation
This table lists the maximum and minimum standard deviation of the exterior orientations (X, Y, Z, Omega, Phi, Kappa) that were computed for project images after the Adjust Images step. The standard deviation gives an indication of the reliability of the optimized parameter. Typically, the quality of the adjustment increases as the standard deviation approaches zero. A value of zero is expected when the parameter is fixed in processing options. The fields in the Standard Deviations of Exterior Orientation table are described below:
| Field name | Description |
|---|---|
X | Solution point shift in the X direction. The units are feet or meters. |
Y | Image shift in the Y direction from the initial position. The units are feet or meters. |
Z | Image shift in the Z direction from the initial position. The units are feet or meters. |
Omega (degrees) | Image rotational angle shift of the camera's x-axis. The units are decimal degrees. |
Phi (degrees) | Image rotational angle shift of the camera's y-axis. The units are decimal degrees. |
Kappa (degrees) | Image rotational angle shift of the camera's z-axis. The units are decimal degrees. |
Adjusted Image Positions
The Adjusted Image Positions graphic shows a representation of the GPS deviations for each image before and after block adjustment. Blue points indicate the initial position of the images from the GPS, and green points indicate the GPS location as a result of adjustment. The vectors are exaggerated for visualization. When viewing this graphic, assess the directional shift of the images in your image collection to evaluate systematic error in the adjustment.
Overlap Map graphic
The Overlap Map graphic is a static map of the overlap between images. Higher numbers of overlapping images produce higher accuracy for three-dimensional ortho products. You can use this graphic to identify areas in your image collection that may require additional overlap, or to better understand the accuracy of your adjustment.
Cross Matches graphic
The Cross Matches graphic indicates the level of connection between images. A link with a dark color indicates a larger number of tie point sets and a stronger connectivity between the images. Identify areas in your image collection where tie points are sufficient or lacking, and use this information to add control points or overlapping images if necessary.
Solution Points table
Tie points connecting two or more image links are essential for aerial triangulation. The Solution Points table lists the number of times a solution point is detected and linked in other images. The 2 Images field represents the number of solution points that connect at least two overlapping images. Similarly, the 3 Images field represents the number of solution points that connect three overlapping images, and so on. Adjustment quality is better when there is a large number of solution points that have high overlap between images.
Geolocation Details
The Geolocation Details section of the processing report provides adjustment details on any ground control points that were used in the project.
Ground Control Points
The Ground Control Points table shows an overall summary of the GCPs used in the block adjustment. It is only listed in the report if you used GCPs in the adjustment. Each ground control point is listed in the table as its own field along with adjustment statistics for the point. The fields in the Ground Control Points table are described below:
| Field name | Description |
|---|---|
<Ground Control Point name> | Name of the ground control point used in the adjustment. Statistics for each point include its shift after adjustment from its initial X (dX), Y (dY), and Z (dZ) position in meters. Projection error for each point is listed in pixels. Status lists the number of valid versus total image links used for that ground control point. |
RMSE | The root mean square error (RMSE) of all ground control points used in the adjustment. Values are provided for the points' X (dX), Y (dY), and Z (dZ) position and units are in feet or meters. |
Min | The minimum amount of shift in either X (dX), Y (dY), or Z (dZ) position between all ground control points. Units are in feet or meters. |
Max | The maximum amount of shift in either X (dX), Y (dY), or Z (dZ) position between all ground control points. Units are in feet or meters. |
Median | The median amount of shift in either X (dX), Y (dY), or Z (dZ) position between all ground control points. Units are in feet or meters. |
Average | The average amount of shift in either X (dX), Y (dY), or Z (dZ) position between all ground control points. Units are in feet or meters. |
Dense Matching
The Dense Matching section of the processing report provides information about point cloud settings and generation.
Summary
This table lists the point cloud settings used in the project to derive the level of geometric detail of the resulting reconstruction. The fields in the Summary table are described below:
| Field name | Description |
|---|---|
Point Cloud Density | The level of density of the point cloud used in the project |
Number of Tiles | Number of tiles the point cloud was divided into when generated |
Processing Time | Total time to run the Dense processing step |
Project settings
The project settings section of the processing report includes information about the system the project was processed on, coordinate systems used in the project, project resolution, and whether any preprocessing was used. These sections are described further below.
System information
System hardware and operating system information are listed for each project. Hardware information is displayed as the system's CPU, RAM, and GPU. For more information about supported hardware in ArcGIS Drone2Map, see ArcGIS Drone2Map system requirements.
Coordinate information
Coordinate systems used in the project are listed in this section. The table is divided into the coordinate system used for the images, project, and ground control points. If there are no ground control points in the project, that field will not appear.
Project resolution
The project resolution used to process all projects. This is defined in the processing options and defaults to different levels depending on the template in use.
Preprocessing
The preprocessing table provides an answer to whether preprocessing adjustments were used in processing of the project. A Yes or No is provided for each of the preprocessing options.
2D products
The 2D products section of the processing report provides a summary of product processing times and 2D processing options enabled on the project.
Summary
The 2D Products Summary table lists each of the products that were enabled for processing and the total time it took to generate them. A field for a 2D product only appears if it is enabled when processing completes.
Processing Options
The 2D Products Processing Options table lists the 2D products and options available and whether they were enabled or disabled for processing. A Yes or No is provided for each of the processing options.
3D products
The 3D products section of the processing report provides a summary of 3D processing options enabled on the project.
Processing Options
The 3D Products Processing Options table lists the 3D products and options available and whether they were enabled or disabled for processing. A Yes or No is provided for each of the processing options.