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Pix4dmatic is very slow and consume a lot of hard space!

Hello to all

I have a big project with 11,800 images. I surveyed the area with Wingtraone drone in 16 flights. Processing one zone by Pix4Dmapper was easy, but for the large area it is very slow. So, I activated Pix4Dmatic for one month, and now trying to process the whole area once. I noticed that Pix4Dmatic consumes a lot of hard space, and it is very slow in the final steps.
My PC specifications:
Processor: AMD Ryzen Threadripper 3960x 24-core double thread
Ram: 128 GB
Graphic: 12 GB
Is there any option to make it processing faster and consume less space?
Is it possible to process it by Pix4Dmapper?

Kind Regards,

Ako from Geometry Bureau

Hi Ako,

Thanks for reaching out. As you mentioned, it’s recommended to use PIX4Dmatic for project of this size.

Could you give more information on how long it took to process the dataset?

What were the processing options that you used? If you used “high” settings then this could explain why it took longer to process.

Can you also export the quality report and share it with us?

More information about hardware requirements and usage

Best,

Thanks Blaz,

Now I am processing the whole area by matic. The 1st step (calibration) finished, I chose 1/2 image scale. Then I imported 30 GCPs then calibrated again; that step also finished. Now running the Densify with default settings:
Algorithm: HW accelerated
Density: Optimal
Min matches: 3
in 12 hours 35% of this step finished. I also checked the quality report, which will be done after the densification, and I will send you.

Regards,

Ako

Dear @Blaz

I installed an 8 TB SSD hard to my PC then run the model. All steps went well, but the last step, orthomosaic, is very slow. In 2 days the total percentage is 10% and the ortho creation is 30%; is that normal?

Regards,

Ako

Could you upload the log file of the processing and we will have a look.

You can upload it here. Please let me know once the files are available.

@Blaz
I uploaded it, please have a look.

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Thank you for the files, Ako.

We had a look and noticed the Deghosting option is enabled which increases the processing time and memory consumption.

If the processing still did not finish, we recommend canceling and saving the project. After upgrading to the latest version of PIX4Dmatic, disable the Deghosting option and process the Orthomosaic step once more. There is no need to reprocess the other steps.

Let me know how it goes,

@Blaz
Thank you so much Blaz
Before processing I noticed that Deghosting will consume time, but I think it is necessary. The area I am processing had many moving cars.

I understand better now.

If you decide to wait for it to process with the Deghosting enabled, please let us know how long it took.

The orthomosaic that you try to generate is very large (204800x200704 pixels) and it can take a while to generate it. Next time you can consider increasing the Resolution value or disabling the Deghosting.

You can refer to the PIX4Dmatic FAQ to get an idea about how long it takes to process a project. Note that most of the dataset in the graphs are done with ≈20MP camera while yours is 42MP.

Yes I have 11,850 images taken by 42 Mpix camera. All images are more than 200 GB.
The required resolution is 5 cm, I set on that. After finishing this I will rerun the last step with deactivating the Deghosting.

Another question: required to produce an accurate DTM; which software is better for DTM generation? Auto DTM is not accurate, in Pix4dmapper I deleted objects manually, but took long time for small projects even. Is Pix4Dsurvey practical for this purpose? Or importing the Las file to ArcGIS Pro?

Thank you

Ako

I also have a Wingtra. I use ArcGIS Pro to create a DTM. First create a las dataset from the individual las files. Then run the automated ground classification tool in Pro. There are several options to choose from. Once you are satisfied with the automated classification, use the las dataset to raster tool to generate a raster DTM. Then you can use the pixel editor to cleanup the DTM, as necessary.

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You can also try out PIX4Dsurvey which can classify point clouds into terrain and non-terrain classes and generate a representation of the ground surface by only using the terrain points. The workflow is the following:

  • Terrain filter to classify selected input point clouds into terrain and non-terrain points.
  • Grid of points to automate the creation of spot elevations. Using the Smart type creates points only where changes in terrain occur.
  • TIN is a seamless set of triangles that represent a surface. When using only terrain points the generated surface is a DTM .

The TIN can be exported as a surface in LandXML file format which is fully compatible with CAD software.

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Thank you @Andrew_Milanes
Pix4dmapper creates a number of las files; but the matic created 1 large las file (95 GB). Can GIS pro run the file of that size? And I am using GIS for other purposes, haven’t used in photogrammetry, is there any YouTube tutorial about that?

Regards

Is there manual edit for the DTM? Point classification is not that accurate for real DTM creation, in the Pix4dmapper I created it manually.

I would assume Pro could handle it. It doesn’t load the whole point cloud on screen anyways. Just create a las dataset from the las file. Then do the ground classification. Your workstation should have no problem with this. I just completed a project with 20,000 42mp images. Pro classified the las dataset in less than 30 minutes. Be sure to set a DTM resolution when you perform the classification. 1 foot resolution is plenty good enough for a DTM.

The las dataset is created from the las file in GIS Pro?

Yes

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You can manually edit the classification in PIX4Dsurvey by selection points and assigning them to the desired class.

Note that only a rectangular selection tool is available at the moment. To use it, you need to hold CTRL and left click to select points.