Messages

16

General / Re: Orthomosaic for council tax calculation

« on: March 15, 2018, 04:00:05 PM »

Thank you SAV and selimerguden for your help.

SAV, I am using your workflow with some adjustments on it. I just have a doubt regarding to the processing resources.

I have two machines. The first with 64 CPUs and 240 Gb RAM which I'm thinking to use just for the alignment step. The second one has 12 CPUs and 2 NVIDIA Tesla P100 which I want to use for build the dense cloud. What do you think about it? Am I right with the machines?

Another issue. What is the best flight speed for Phantom 4 Pro and Mavic Pro. I know that the shutter are different in both. But I took photos over the city with the P4P and some are very blurry. I thought that it could be the flight speed. Is there any other cause?

Thanks!

Regards,
B

17

General / Re: Orthomosaic for council tax calculation

« on: March 15, 2018, 12:29:56 AM »

Hello Rene,

Thank you for your reply. As I already work with photogrammetry, I have a workflow for my research works. But that's the first time I get a job like that, generate an orthomosaic for a whole city with 4300 photos.

This is the workflow I'm intending to use. Is that correct?

1. Load photos and uncheck the coordinates

2. Estimate image quality, not consider image quality below 0.7.

3. Align photos (quality: HIGH, pair preselection: REFERENCE, key point limit: 40,000, tie point limit: 4,000, adaptive camare model fitting: YES).

4. Take average reprojection error in pixels from the Reference pane and use this value as Tie Point accuracy (in pixels);

5. Optimize the camera alignment;

6. Add markers' projections and load the coordinates;

7. Take reprojection error for markers from the Reference pane and use this value as Marker Accuracy parameter in the Reference pane settings;

8. Optimize the camera alignment.

9. Clean sparse point cloud (EDIT > GRADUAL SELECTION). Remove all points with high reprojection error (0.5 - 0.9) and high reconstruction uncertainty (what is the best value here?).

10. Adjust the bounding box

11. Optimize camera alignment

12. Build dense cloud (HIGH or MEDIUM???)

13. Build DEM (from dense cloud) - What is the best option: generate the orthomosaic from MESH or DEM?

14. Build Orthomosaic based on DEM

Do you have any comments or suggestions to do regarding to my workflow?

Thank you very much guys.

Cheers,
B

18

General / Orthomosaic for council tax calculation

« on: March 14, 2018, 10:08:05 PM »

Hello folks,

I did a flight over a city in Brazil to estimate the council tax value for each house. So, the idea is to generate a georeferenced orthomosaic of the whole city.

I have about 4300 photos and 140 GCPs got by dGPS. The flight was done using a DJI Phantom 4 Pro.

In that way, I would like suggestions of the best workflow to process all this images and get a precise orthomosaic that will be exported in .TIFF.

Considering the large amount of photos, I'll process everything on the cloud. So, RAM and CPU will not be a restriction.

All the best,
B

19

General / Re: Mavic Pro or Phantom 3 Pro

« on: February 27, 2018, 03:44:03 PM »

Thanks SAV for your kindly reply.

Unfortunately the Phantom 4 Pro is out of my current budget. But I have looked for Phantom 4 ADVANCED and found good prices. For my needs in photogrammetry do you think that there are too many differences between P4P and P4ADV?

I saw that the only difference is in the sensors, but don't know about the camera quality.

Thank you one more time.

All the best,
B

20

General / Mavic Pro or Phantom 3 Pro

« on: February 26, 2018, 03:17:02 PM »

Hi folks,

I'm looking for a drone for photogrammetry. In that way, considering my budget, I am between Mavic Pro and Phantom 3 Pro. I know that the Mavic is designed to be a portable UAV, but I want to know from you experts. What is the best drone for photogrammetry?

Are there too much difference between that models?

Thanks in advance!

Cheers,
B

21

General / Re: Georeferenced point cloud in .txt

« on: July 19, 2017, 06:27:50 PM »

Hi folks, I already figured out how to do it.

Regards,
B

22

General / Georeferenced point cloud in .txt

« on: July 19, 2017, 05:47:25 PM »

Dear,

I'm needing to export the point cloud as a .txt file but with the X, Y and Z columns for each point of the cloud.

Is it possible to do it in Photoscan?

Thanks in advance.

Kind regards,
B

23

General / Re: GPU problem on version 1.3

« on: March 06, 2017, 06:27:30 PM »

Hi Alexey,

You don't suggest to use integrated graphics (Iris Pro) just in v.1.3.0 or in all future versions?

Thanks!
B

24

General / GPU problem on version 1.3 (Mac OS X)

« on: March 02, 2017, 05:45:31 PM »

Hi Alexey!

The new Photoscan version (1.3 build 3772) couldn't recognise the GPUs on my Macbook Pro. On 1.2 they worked well, but now...

Why this is happening?

This is the message that appears on the console:

2017-03-02 11:13:11 Iris Pro: no SPIR support
2017-03-02 11:13:11 AMD Radeon R9 M370X Compute Engine: no SPIR support

Thank you!

Best regards,
B

25

General / How to reduce the marker error (pix)

« on: May 31, 2016, 04:31:52 PM »

Hi folks,

I'm having difficulties in reduce the marker error (pix) and would like to know if somebody can help me with this.

I used Total Station to get the coordinates and I'm using the marker detect tool (cross non-coded) to project them in the images.

My workflow is:

1. Add images and uncheck the cameras
2. Align the photos (Key point = 120.000 and Tie point limit = 0)
3. Delete the reprojection error points with 0.5 and optimize
4. Take average reprojection error in pixels from the Reference pane and use this value as Tie Point accuracy (in pixels);
5. Optimize the camera alignment
6. Add markers' projections automatically through marker detection
7. Load the coordinates
8. Take reprojection error for markers from the Reference pane and use this value as Marker Accuracy parameter in the Reference pane settings;
9. Optimize the camera alignment.

I repeat the optimization based on markers after refining the Marker Accuracy until the optimization results are no longer significant.

Therefore, my results are not so good. I need a precision of millimetres and I'm getting 4 or 5 centimetres.

Somebody can help me?

All the best!

26

General / Re: Validation points

« on: April 06, 2016, 08:05:50 PM »

Thank you for your answer.

So, what's the difference between the errors showed on the check and uncheck markers?

All the best.

27

General / Validation points

« on: April 06, 2016, 07:09:31 PM »

Hi folks,

In my area I have 14 GCPs. I would like to use some points to validate the accuracy. But I don't understand very well how this process works, I just saw in the manual.

So, I know that I have to uncheck the markers to use it as validation points. But how can I know if the validate process was successful processed?

How can I use these validation results in my project?

Thanks.

28

General / Re: Optimize settings

« on: April 01, 2016, 02:44:46 PM »

As default on the Reference Settings we can see the following values:

- marker accuracy at 0.1 pix
- tie point accuracy at 4 pix.

If I understand this correctly than it means than in adjustment image marker measurement  is considred 40 times more accurate than tie point matching measurement...

Why would this be so? I would think computer image matching to be more precise than manual image marker measurement...

29

General / Re: Optimize settings

« on: April 01, 2016, 12:44:14 PM »

Hi JMR,

Thank for your good answer.

So, do you think that doesn't matter what value I have in my Camera and Marker error (pix), I must use a fix value in Marker accuracy (pix), 0.2 or 0.5, and Tie point accuracy (pix), 1 or higher?


All the best!
Bernardo

30

General / Re: request advice: hardware cost / performance, below$2000-2500

« on: March 31, 2016, 11:48:29 PM »

With this budget it's possible to build a good PC or laptop.

I suggest the follow PC specs:

Processor: Intel core i7 6700k
Memory: 64 Gb RAM
Video card: NVIDIA Asus GTX 980 Ti Strix
SSD (PCIe): 512 Gb (Samsung 950 Pro, p.e.)
Motherboard: Asus Z170 (Pro Gaming, p.e.)

If you want a laptop, I would recommend the same processor (i7 6700k), video card NVIDIA GTX 980m or GTX 980 Desktop and the same amount of memory if possible.

In eBay you can find the components separately. But if you are in USA you can find a lot of stores that sell PC or laptops with the above specs.

All the best,
Bernardo