How to change the Processing Options to generate fewer 3D Points

Depending on the quality of the dataset and the available processing resources, some issues may be encountered.

Changing the processing options in order to generate less 3D points is useful:

  • When having a computer with low resources.
  • To increase the processing speed.
  • When there are errors while processing a large dataset acquired with one or multiple flights. 
 
Warning: Generating less 3D points may lead to lower quality results.
 
Tip: Adding more RAM allows to fit more 3D points simultaneously in memory, and therefore:
  • Reduce probability of processing errors.
  • Increase the processing speed.
  • Process larger datasets.
  • Use better processing options allowing better results.

The software and hardware requirements are related to the mapping area, flight plan, image resolution, etc. For indications about minimum and recommended Hardware and Software: 202557289.

For recommendations about a high performance Hardware and Software: 202559159.

To reduce the number of 3D points:

1. Open the project.
2. On the Menu bar, click Process > Processing Options...
3. Select the processing step 1. Initial Processing.
4. Select the tab General.
5. In the section Keypoints Image Scale, select Custom, then in the drop-down list Image Scale, select 1/2 (Half image size).
6. Select the tab Calibration.
7. In the section Rematch, select Custom and deactivate Rematch.

8. Select the processing step 2. Point Cloud and Mesh.
9. Select the tab Point Cloud.
10. In the section Point Cloud Densification, in the drop-down list Image Scale, select 1/4 (Quarter image size, Fast).

11. Deactivate Multiscale.
12. In the drop-down list Point Density, select Low (Fast).
13. Select the processing step 3. DSM, Orthomosaic and Index.
14. Select the tab DSM and Orthomosaic.
15. In the section Resolution, select Automatic and insert 4.
16. Click OK.
17. On the Menu bar, click View > Processing.
18. Start processing again, one step at a time.

 

If the software becomes unstable in Step 1 of the processing:

1. Open the project.
2. On the Menu bar, click Process > Processing Options...
3. Select the processing step 1. Initial Processing.
4. Select the tab General.
5. In the section Keypoints Image Scale, select Custom, then in the drop-down list Image Scale, select 1/2 (Half image size).
6. Select the tab Calibration.
7. In the section Rematch, select Custom and deactivate Rematch.

8. Click OK.
9. On the Menu bar, click View > Processing.

10. Start step 1. Initial Processing again.

 
Note: This will reduce the number of extracted features and thus reduce the number of initial 3D points. This is required if the software becomes unstable during the first step of processing. However, this solution might lead to a lower number of calibrated images.

11. If processing still fails, try to reduce the Key Point Image Scale to 1/4 (Quarter image size).
12. If it still does not work, split the project into sub-projects and process them separately or merge them. For step by step instructions: 202558579.

If the software becomes unstable in Step 2 of the processing

1. Open the project.
2. On the Menu bar, click Process > Processing Options...
3. Select the processing step 2. Point Cloud and Mesh.
4. Select the tab Point Cloud.
5. In the section Point Cloud Densification, in the drop-down list Image Scale, select 1/4 (Quarter image size, Fast).

6. Click OK.
7. On the Menu bar, click View > Processing.
8. Start step 2. Point Cloud and Mesh again.

9. If processing still fails, try to reduce the Image Scale to 1/8 (Eighth image size, Tolerant).
10. If it still does not work, reduce the Point Density to Low (Fast)
11. If it still does not work, split the project into sub-projects and process them separately or merge them. For step by step instructions: 202558579.

If the software becomes unstable in Step 3 of the processing:

1. Open the project.
2. On the Menu bar, click Process > Processing Options...
3. Select the processing step 2. Point Cloud and Mesh.
4. Select the tab Point Cloud.
5. In the section Point Cloud Densification, in the drop-down list Image Scale, select 1/4 (Quarter image size, Fast).
6. Select the processing step 3. DSM, Orthomosaic and Index.
7. Select the tab DSM and Orthomosaic.
8. In the section Resolution, select Automatic and insert 4.
9. On the Menu bar, click View > Processing.
10. Start step 2. Point Cloud and Mesh and step 3. DSM, Orthomosaic and Index again.

11. If processing still fails, try to reduce the Image Scale to 1/8 (Eighth image size, Tolerant).
12. If it still does not work, reduce the Point Density to Low (Fast).
13. If it still does not work, skip the whole second step by not running it (if the second step has results, delete or store them in a separate folder them before running the third step).
14. If it still does not work, split the project into sub-projects and process them separately or merge them. For step by step instructions: 202558579.

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