Agisoft Metashape
Agisoft Metashape => General => Topic started by: Domingo on October 30, 2018, 06:11:04 PM
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Hello partners:
I am trying to process a set of photographs taken with the Phantom 4 RTK.
The photographs have in their metadata the precisions in XYZ with which they were made.
When I upload the photos in the PhotoScan 1.4.3 does not recognize that data, it gives me the precision that PhotoScan has by default. 10 meters.
I have tried to load the same photos in Pix4D, if you load the precisions of XYZ (attached photograph).
Can someone tell me the workflow to process the photos taken with the Phantom 4 RTK?
Thank you very much for your cooperation and sorry for my English.
Greetings.
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Where can I download photos taken by phantom 4 rtk?
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I can give it also a try, If you can share the fotos.
Be sure that you have checked (under PhotoScan settings) "load xmp Data..."
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Where can I download photos taken by phantom 4 rtk?
Attached link to download the file with 18 photographs taken with the Phantom 4 RTK, as well as, all the files generated by the drone.
https://we.tl/t-fQ3g2XPNRG
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I can give it also a try, If you can share the fotos.
Be sure that you have checked (under PhotoScan settings) "load xmp Data..."
Yes, I have the "load xmp Data ..." option activated
But when I add the photos, the precision it gives me is 10 meters, the standard configuration of Photoscan (attached image)
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Can you post your configured import window?
If I remember correctly, there is also a an option in the Preferences for loading the accuracy from file.
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Can you post your configured import window?
If I remember correctly, there is also a an option in the Preferences for loading the accuracy from file.
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Hi Domingo,
Try to write the EXIF information of your imagery into an external CSV file using EXIFTOOL.
Follow this instruction: https://medium.com/@hunchly/bulk-extracting-exif-metadata-with-hunchly-and-exiftool-164d67c8d7e2
When you have generated the exif.csv file, open PhotoScan, load your images and click on the IMPORT icon in the reference pane (first icon from left). It will allow you to import camera locations (and orientations), not just GCP/marker information. Just make sure that the name in the label column matches the filename of your images.
If you can share your imagery again then I'll test it for you.
All the best.
Regards,
SAV
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Hi Domingo,
Try to write the EXIF information of your imagery into an external CSV file using EXIFTOOL.
Follow this instruction: https://medium.com/@hunchly/bulk-extracting-exif-metadata-with-hunchly-and-exiftool-164d67c8d7e2
When you have generated the exif.csv file, open PhotoScan, load your images and click on the IMPORT icon in the reference pane (first icon from left). It will allow you to import camera locations (and orientations), not just GCP/marker information. Just make sure that the name in the label column matches the filename of your images.
If you can share your imagery again then I'll test it for you.
All the best.
Regards,
SAV
Thank you very much for your answer SAV
I'm doing the same as you, but from the file with extension * .RMK, generated by the Phantom 4 RTK.
In that file are the EXIF data of all the photographs, I edit it to keep only the data I need and import it following the same method.
My intention is to make PhotoScan automatically read the data of the accuracy of the coordinates as the Pix4d mapper does.
To avoid having to do a previous process before adding the photos in PhotoScan.
I would also like to know if to process some photographs with precision of 1 or 2 cm photocenters, taken with a Phantom 4 RTK, it would be necessary to modify the type parameters that I am using to process the photographs of a Phantom 4 PRO
Receives a warm greeting.
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Hello to all! :-)
We have also invested in the DJI P4RTK with hopes of a successfull process with Photoscan but unfortunatly it is a disapointment in regards of camera/lens calibration.
With the DJI P4P we experienced large problems with Photoscan in the optimize process after alignment. To get good surveying data with GCPs all cam stations had to be unchecked and then GPCs clicked, before optimize.
Now we have done several tests with P4RTK and photoscan can NOT process pictures from P4RTK. We have surveyed the same area several times with and without camera distortion, with and without adaptive camera model fitting when aligning.
But compared with earlier DSMs and GCPs we get about 30-50cm off.
Will Photoscan ever fix DJI P4RTK pictures?
Or what have we missed in the process?
Regards
Johan
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I have taken a look at the data and noticed a few other things.
When opening the first image via exif tool, it seems as if the location is listed twice in the metadata. Once in the EXIF section (Red in photo) and once in the XMP section (Blue in photo). Agisoft seems to be loading the EXIF data. This is important as the EXIF data rounds the final 2 digits. This results in ~2cm error.
Another thing to notice is that accuracy figures (RtkStdLon... etc) are for each axis, whereas Agisoft only has a place for one generalized accuracy value. Perhaps these values need to be combined to one general value for Agisoft to use them?
Location data as visible in Exiftool GUI:
(https://cdn.pbrd.co/images/HN0WKYQ.png)
Location data as visible in Photoscan:
(https://cdn.pbrd.co/images/HN0Yf1Ls.png)
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Is it possible to send an example of such image from DJI with the accuracy values embed to the XMP meta data? It seems that the namespace where the values are written to is not supported, but it should be possible to implement the support for it quickly.
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We have also invested in the DJI P4RTK with hopes of a successfull process with Photoscan but unfortunatly it is a disapointment in regards of camera/lens calibration.
With the DJI P4P we experienced large problems with Photoscan in the optimize process after alignment. To get good surveying data with GCPs all cam stations had to be unchecked and then GPCs clicked, before optimize.
Now we have done several tests with P4RTK and photoscan can NOT process pictures from P4RTK. We have surveyed the same area several times with and without camera distortion, with and without adaptive camera model fitting when aligning.
But compared with earlier DSMs and GCPs we get about 30-50cm off.
Will Photoscan ever fix DJI P4RTK pictures?
Or what have we missed in the process?
Hello Johan,
If you have some problems with the data processing, maybe you can share the problematic image set with support@agisoft.com, so that we can try to reproduce the issue?
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Is it possible to send an example of such image from DJI with the accuracy values embed to the XMP meta data? It seems that the namespace where the values are written to is not supported, but it should be possible to implement the support for it quickly.
Attached link to download the file with 18 photographs taken with the Phantom 4 RTK, as well as, all the files generated by the drone.
https://www.dropbox.com/s/b38by1vpj68n0g4/Phantom%204%20RTK.rar?dl=0
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Thank you, Domingo, I have missed the previously shared link.
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Following this as we may be getting a demo model soon and we are eager to learn more about the exact processing methodology in Photoscan!
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You can use the Inertial Explorer 8.70 or GrafNet 8.70 post-processing software to do PPP or PPK calculations as POS.
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DJI recommend to change the accuracy of the camera location to 0.1m. I have just processed your images with these setting and got these results. Just waiting for the delivery of my P4RTK. Looks promising, but would need some check points for true accuracy.
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In the latest pre-release of the version 1.5.0 (build 7205) we have added the support for the GPS accuracy tags load from XMP meta data to the Reference pane (corresponding flag should be enabled in the Advanced preferences tab).
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In the latest pre-release of the version 1.5.0 (build 7205) we have added the support for the GPS accuracy tags load from XMP meta data to the Reference pane (corresponding flag should be enabled in the Advanced preferences tab).
That's absolutely great to hear, superb and quick handling by the dev team! Will it also be able to handle/import the camera calibration data?
More importantly however, at least for us, when will users of Agisoft Photogrammetric Kit be able to utilize this functionality? We have already been waiting for the first build of Metashape for over six weeks, let alone how much longer build 7205 will take..
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Is anyone, perhaps, capable of clarifying the values encircled in green in the attachment? It depicts three seperate metadata/XMP files extracted from three different Phantom 4 RTK's.
The values in blue most certainly relate to the various interior parameters that were distilled during the a priory camera calibration procedure seemingly conducted by DJI. The latter five likely embody radial (k1-k3) and tangential (p1-p2) coefficients, but I'm not entirely sure. The same goes for the first series of values; they may be related to the focal length or principal point coordinates (cy, cy), but they seem to be expressed in a different unit compared to how they ought to be inputted in Photoscan's camera calibration dialog. As I'm eager to import these parameters as fixed I really need to know what the values exactly represent, any help is much appreciated!
Ps. The middle example doesn't contain any camera calibration parameters. This was likely due to the option 'Distortion Correction' being activated in the DJI app which causes the calibration parameters to be omitted.
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Hi,
yes I think you are right, the last 5 correspond to k1,k2,k3 and p1, p2 distorsion parameters... the 3rd and 4 th parameters seem to correspond to Principal point position in pixels. In screen capture, I show calibration done on P4RTK set corresponding to first example. In this case no dewarp parameters were applied and camera exhibits high radial distorsion… In this calibration, I have also a r4 radial parameter estimated....The first 2 parameters are more difficult to explain, they seem to correspond to something like focal length in pixels ( 2 values for affinity^?) but are far from 3663 value estimated in PS.... DJI should give more information on this especially since it puts in EXIF calibrated focal and PP at:
Calibrated Focal Length : 3666.666504
Calibrated Optical Center X : 2736.000000
Calibrated Optical Center Y : 1824.000000
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Hi,
yes I think you are right, the last 5 correspond to k1,k2,k3 and p1, p2 distorsion parameters... the 3rd and 4 th parameters seem to correspond to Principal point position in pixels. In screen capture, I show calibration done on P4RTK set corresponding to first example. In this case no dewarp parameters were applied and camera exhibits high radial distorsion… In this calibration, I have also a r4 radial parameter estimated....The first 2 parameters are more difficult to explain, they seem to correspond to something like focal length in pixels ( 2 values for affinity^?) but are far from 3663 value estimated in PS.... DJI should give more information on this especially since it puts in EXIF calibrated focal and PP at:
Calibrated Focal Length : 3666.666504
Calibrated Optical Center X : 2736.000000
Calibrated Optical Center Y : 1824.000000
High Paulo,
Not exactly sure what you mean but do you mean that you processed your data letting Photoscan estimate/optimize all camera parameters, OR did you import the values provided by DJI as fixed parameters?
In the meantime I've received official word from DJI on the meaning of the nine consecutive values in the DeWarpData field:
calibrate_date;fx,fy,cx,cy,k1,k2,p1,p2,k3
Where fx;fy is the focal length in the pixe and where cx;cy is the optical center expressed in pixel coordinate (Origin point as the center of the imager).
Now that leaves me wondering what settings we should use in Photoscan's camera calibration dialog as there's only one field for focal length, whereas the XMP metadata provides us with two (horizontally and vertically). I also reckon we should go via the Convert Calibration setting (within the Camera Calibration pane) and change the value in the Type-field, which is set to Photomodeller by default, to Pix4D Perspective. This would be due to Photomodeller expressing both focal length and principal points in millimeters (mm), whereas the P4RTK's XMP metadata expresses these values in pixel (pix) units and this is allowed when changing the Type-field within Convert Calibration to Pix4D Perspective.
Again I'm not sure and still guessing on some details, it'd be great of some of the developers could tune in to this!
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BobvdMeij ,
thanks for the update… makes more sense now...
Yes I did a new calibration in PS without entering Dewarp Data parameters...
However the big difference between fx and fy (affinity) is not reflected in the PS adjustment as b1 is very small.....
By the way in PS calibration f = fy and b1 = fx-fy
My only doubt is p1, p2 parameters as in Pix4D they are inverted wrt PS... so maybe support can confirm how to treat p1, p2 from DJI Dewarp parameters for use in PS ….
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Hello
Attached 4 photographs of information provided by the DJI technical service.
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I had problems uploading the photographs.
Attachment 2 more.
Greetings.
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Nice to meet you, everyone.
As Dragline says, accuracy is poor if you do not capture the last 8 digits of the coordinates.
In the build 7205, meaning that you added the reading of the GPS accuracy tag is lost.
Thank you.
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Postscript.
Paste the image link for reference.
(It is where you highlight the text blue.)
Thank you.
https://drive.google.com/file/d/10hATO3k08TcW7W0TnwbkD_9G99QhxP2_/view?usp=sharing (https://drive.google.com/file/d/10hATO3k08TcW7W0TnwbkD_9G99QhxP2_/view?usp=sharing)
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Hey everyone.
As i understand it you recommend to turn of the Distortion Correction in the DJI Flight Software? And then do a manual calibration where you import the .mrk file into Metashape?
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Hi there we are currently trying to process some P4 Pro RTK data through Agisoft but we are having some issues getting it to read in the accuracies from the metadata - can anyone that has it working please share their workflow ? @Alexey Pasumansky is this working in 1.5.0 release ?
Any help is appreciated
Regards
Steve McMurray
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Hello Steve,
The accuracy values for the coordinates should be properly read from XMP, providing that you have enabled "Load camera location accuracy from XMP meta data" in the Advanced preferences tab.
If it doesn't happen, please provide any example of the image that you are using (either via forum or via email to support@agisoft.com).
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Hello Steve,
The accuracy values for the coordinates should be properly read from XMP, providing that you have enabled "Load camera location accuracy from XMP meta data" in the Advanced preferences tab.
If it doesn't happen, please provide any example of the image that you are using (either via forum or via email to support@agisoft.com).
Does anyone know if the data in the Timestamp.mrk file are calibrated between the antenna position and center sensor camera?
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Hello partners:
I am trying to process a set of photographs taken with the Phantom 4 RTK.
The photographs have in their metadata the precisions in XYZ with which they were made.
When I upload the photos in the PhotoScan 1.4.3 does not recognize that data, it gives me the precision that PhotoScan has by default. 10 meters.
I have tried to load the same photos in Pix4D, if you load the precisions of XYZ (attached photograph).
Can someone tell me the workflow to process the photos taken with the Phantom 4 RTK?
Thank you very much for your cooperation and sorry for my English.
Greetings.
Domingo,
here you have the link: (https://mega.nz/#!0h4g3SSb!z9x0wQSzrwfybQdr_qRZSefbt8cLh5CNcWSmNcyJKro), where I've processed your project without any problem in Agisoft Metashape (no problem at all importing RTK images, aligning photos, point cloud processing, 3d mesh, DSM Orthophoto, Report).
Cheers mate. ;)
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Hello Steve,
The accuracy values for the coordinates should be properly read from XMP, providing that you have enabled "Load camera location accuracy from XMP meta data" in the Advanced preferences tab.
If it doesn't happen, please provide any example of the image that you are using (either via forum or via email to support@agisoft.com).
What about camera calibration information Alexey? We have enabled 'Load camera calibration from XMP meta data' but the Initial tab within the Camera Calibration pane remains empty, except for f which is set to 3648 by default. Strangely enough this number is nowhere to be found in either the metadata or the XMP file. On the contrary all other fields (cx, xy, k1-k3, p1-p2, etc.) remain empty/are set to 0.
The XMP data, however, does contain values for most of these parameters stored within a parameter called 'drone-dji:DewarpData='. It seems that the image's Northing/Easting/Altitude are correctly imported from the XMP file, but the camera calibration parameters are not (although both options are enabled under preferences).
Ps. I'm well aware of your doubts on the accuracy, applicability and environment-independent calibration parameters provided by DJI for a consumer grade camera. But as we're witnessing a structural shift in our outputted models, particularly in the z-axis, we are willing to give these a priori calibration parameters a try to see if this fixes the problem.
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I found this thread and hoping you guys can help. The new P4 Pro RTK adds the following tags to the metadata.
(With sample data from an RTK photo)
Rtk Flag : 16
Rtk Std Lon : 2.70368
Rtk Std Lat : 1.53912
Rtk Std Hgt : 3.68277
I have an external Emlid Reach M+ GPS on my regular phantom 4 Pro. I am post processing the flight data and events in EZsurv. I export the data shown above for all images into a CSV file and I need to import that into the metadata of the images. Then they will be processed just like the P4P RTK images.
My problem has been finding an EXIF editor that I can figure out to import these XMP tags into the images. My CSV file will contain
Image File name
Post Processed Lat
Post Processed Lon
Post Processed Alt
Lat Standard Deviation
Lon Standard Deviation
Alt Standard Deviation
For the updated GPS data, I will simply overwrite the coordinates currently in the EXIF data. Then I need to add the new XMP tag data for the Standard Deviation.
Any help on the best program to use and how to do it will be appreciated. I have played around with multiple exif editors and so far I have not found one where I can successfully add the custom data.
Thanks again for any help you can provide.
Tim
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maybe you need this program
ttps://topodrone.org/reviews/toposetter/
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Hello Tim,
If you have the CSV file with the coordinates and accuracy information for them, you can import these values to Metashape Pro via Import CSV dialog - it would overwrite (in the project) the values derived from the image EXIF.
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maybe you need this program
ttps://topodrone.org/reviews/toposetter/
Hi Alex, Thanks for the link. I already have a PPK solution for my Phantom 4 Pro, my only issue is updating the Image EXIF XMP data from a CSV file (which contains the PPK data). It can be done. I just have to figure out how. The ExifTool program by Paul Harvey will most likely take care of it. I will have to learn how to do it from the command line which is not my specialty.
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Hello Tim,
If you have the CSV file with the coordinates and accuracy information for them, you can import these values to Metashape Pro via Import CSV dialog - it would overwrite (in the project) the values derived from the image EXIF.
Hi Alexey, I want to be upfront here. I currently use a different processing platform but there seemed to be cross platform issues relating to the Image EXIF data. So that is why I posted here as this particular thread had more activity concerning the P4P RTK EXIF data than any other thread. The software package that I use does not accept the Accuracy data without the user providing the phi, omega, and kappa values :(
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I have been doing some testing with the new P4R and getting some good results. I can't seem to enter the DJI dewarp Xmp data so that it means anything to Metashape, has anyone else yet? The auto adjusted camera parameters seem to been getting pretty good accuracy without GCP and even better just using 1 GCP.
Was flown with D-RTK2 base over known point shot with Trimble R10, lens correction turned off in RTK app. Ground control also shot with R10.
Coordinates converted to OSGB1936 in metashape before alignment and loading GCP.
I have tried to do a lens calibration with the chessboard in metashape but get very different parameters than what I see after a flight and optimisation. Anyone else been able to calibrate the P4R lens successfully with metashape?
Without running the optimisation the Z error is over 21cm but down to 6cm after. Using just one GCP tightens things up further to less than 3cm.
See reports https://drive.google.com/drive/folders/1LekTi82gf9Vq4cYkg_4s79YTnccYmgrr?usp=sharing
Let me know your thoughts.
Cheers
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I have been doing some testing with the new P4R and getting some good results. I can't seem to enter the DJI dewarp Xmp data so that it means anything to Metashape, has anyone else yet? The auto adjusted camera parameters seem to been getting pretty good accuracy without GCP and even better just using 1 GCP.
Was flown with D-RTK2 base over known point shot with Trimble R10, lens correction turned off in RTK app. Ground control also shot with R10.
Coordinates converted to OSGB1936 in metashape before alignment and loading GCP.
I have tried to do a lens calibration with the chessboard in metashape but get very different parameters than what I see after a flight and optimisation. Anyone else been able to calibrate the P4R lens successfully with metashape?
Without running the optimisation the Z error is over 21cm but down to 6cm after. Using just one GCP tightens things up further to less than 3cm.
See reports https://drive.google.com/drive/folders/1LekTi82gf9Vq4cYkg_4s79YTnccYmgrr?usp=sharing
Let me know your thoughts.
Cheers
Have you verified the correctness of the transformation parameters in Photoscan/Metashape for transforming coordinates from WGS84 to OSGB1936. We've found that the parameters in Photoscan for going from WGS84 to our Dutch National CRS are incomplete and partly outdated, resulting in a couple cm of deviations in all axis. Hence we're transforming the data outside of Photoscan first before importing into it for further processing.
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Have you verified the correctness of the transformation parameters in Photoscan/Metashape for transforming coordinates from WGS84 to OSGB1936. We've found that the parameters in Photoscan for going from WGS84 to our Dutch National CRS are incomplete and partly outdated, resulting in a couple cm of deviations in all axis. Hence we're transforming the data outside of Photoscan first before importing into it for further processing.
I have just ran the same survey without the transformation to OSGB1936, so keeping to WGS84 with GCP converted outside of Metashape and results are very close. So happy that using the OSGM15 geoid and transformation within Metashape seems to be working well, this speeds up the workflow. I have uploaded the accuracy reports to the same link before if you want to have a look.
Anyone found the best way to precalibrate the P4R lens for repeatable results?
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This is how I use the dewarp data in the XMP tags to calibrate the camera in Metashape:
<drone-dji:DewarpData> 2018-10-23;3662.110000000000,3655.160000000000,5.850000000000,-31.610000000000,-0.268279000000,0.110783000000,0.000693505000,-0.000105054000,-0.031359200000</drone-dji:DewarpData>
Date: 2018-10-23
fx: 3662.110000000000
fy: 3655.160000000000
cx: 5.850000000000
cy: -31.610000000000
k1: -0.268279000000
k2: 0.110783000000
p1: 0.000693505000
p2: -0.000105054000
k3: -0.031359200000
Where:
• fx, fy - focal length
• cx, cy - principal point coordinates
• K1, K2, K3, P1, P2 - radial distortion coefficients
As the camera calibration dialog in Metashape only supports and single value for f, I use the calibrated focal length tag from the XMP data;
<drone-dji:CalibratedFocalLength>3666.666504</drone-dji:CalibratedFocalLength>
In terms of the conversion to OSGB36 with the OSGM15 geoid inside Metashape, I've found it to do an excellent job. We recently did a survey that had to tie in with an existing traditionally surveyed area. We did use several check points surveyed using post processed solutions from a Reach RS+ then converted to OSGB36 using the OS Net online conversion tool, the resultant errors were around 2cm RMSE XY and 3cm RMSE Z. which was well within the tolerance.
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This is how I use the dewarp data in the XMP tags to calibrate the camera in Metashape:
<drone-dji:DewarpData> 2018-10-23;3662.110000000000,3655.160000000000,5.850000000000,-31.610000000000,-0.268279000000,0.110783000000,0.000693505000,-0.000105054000,-0.031359200000</drone-dji:DewarpData>
Date: 2018-10-23
fx: 3662.110000000000
fy: 3655.160000000000
cx: 5.850000000000
cy: -31.610000000000
k1: -0.268279000000
k2: 0.110783000000
p1: 0.000693505000
p2: -0.000105054000
k3: -0.031359200000
Where:
• fx, fy - focal length
• cx, cy - principal point coordinates
• K1, K2, K3, P1, P2 - radial distortion coefficients
As the camera calibration dialog in Metashape only supports and single value for f, I use the calibrated focal length tag from the XMP data;
<drone-dji:CalibratedFocalLength>3666.666504</drone-dji:CalibratedFocalLength>
In terms of the conversion to OSGB36 with the OSGM15 geoid inside Metashape, I've found it to do an excellent job. We recently did a survey that had to tie in with an existing traditionally surveyed area. We did use several check points surveyed using post processed solutions from a Reach RS+ then converted to OSGB36 using the OS Net online conversion tool, the resultant errors were around 2cm RMSE XY and 3cm RMSE Z. which was well within the tolerance.
Was the 2cm and 3cm RMSE from using the DJI Dewarp calibration figures and fixing them? I have just ran the same dataset with my P4R Dewarp parameters fixed in the lens calibration and get massive errors on check points ~30 and 40cm. If I allow Metashape to adjust the precalibrated values the check point accuracy is back to ~4 and 3cm RMSE. My Xmp CalibratedFocalLength is also 3666.666504 and I'm not sure this is correct as the adjusted figure that gives the lower error is very different, more like 3630.
@Agisoft Does supplying precalibrated lens data that isn't fixed get taken into account when optimising alignment, or should we just allow Metashape to optimise the lens parameters from the start?
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Hello rmowbs,
If the pre-calibrated data is used that is not fixed, such un-fixed parameters will be only used as Initial step for the autocalibration procedure.
If you fix the parameters before starting the alignment, then they wouldn't be adjusted during the alignment/optimization procedure.
I'm a bit skeptical regarding built-in parameters stored in the meta-information, and assume that autocalibration should be more effective. Or even performing regular "in-field calibration" over the area with GCPs and estimating the IO parameters based on both cameras and markers coordinates. Then re-using this information in the actual flights.
But such pre-calibration should be performed rather regularly. For example, once a month or even more frequent, depending on the number of flights, as the lens parameters could change due to mechanical reasons (during take-off/landing) or even temperature factor.
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Thanks Alexey, will stick with regular "in-field calibration" as you say. I have already reused this data returning good results.
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We buy Phantom 4 RTK to use PPK option in our works.
We have reached accuracy of 2 times the pixel size in elevation, compared to GCP.
For this we have used external calibration from a work with GCP in similar height conditions. (150 meters) calibration in field. However, we have always agreed to put some CPG to review our quality of work.
In the case of road surveys, using "corridor", we put a GCP every 500 meters.
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I have been doing some testing with the new P4R and getting some good results. I can't seem to enter the DJI dewarp Xmp data so that it means anything to Metashape, has anyone else yet? The auto adjusted camera parameters seem to been getting pretty good accuracy without GCP and even better just using 1 GCP.
Was flown with D-RTK2 base over known point shot with Trimble R10, lens correction turned off in RTK app. Ground control also shot with R10.
Coordinates converted to OSGB1936 in metashape before alignment and loading GCP.
I have tried to do a lens calibration with the chessboard in metashape but get very different parameters than what I see after a flight and optimisation. Anyone else been able to calibrate the P4R lens successfully with metashape?
Without running the optimisation the Z error is over 21cm but down to 6cm after. Using just one GCP tightens things up further to less than 3cm.
See reports https://drive.google.com/drive/folders/1LekTi82gf9Vq4cYkg_4s79YTnccYmgrr?usp=sharing
Let me know your thoughts.
Cheers
Why did you use all coefficients except p3 and p4 when optimising? What is the general rule of thumb when choosing them?
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Hello xabierr,
For general cases we do not suggest to optimize (and actually use) p3 and p4 coefficients. THis recommendation is based on our experience with various project types and user's feedback.
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Hello xabierr,
For general cases we do not suggest to optimize (and actually use) p3 and p4 coefficients. THis recommendation is based on our experience with various project types and user's feedback.
My experience now with a few Phantom 4 Pro/Adv cameras is that they have some quickly changing radial lens distortions that need P3 and P4 solved for in order to best model them. Also the alignment process seems more accurate when tested against PPK if the corners of the photos are masked out from keypoint detection. It is my opinion that nothing good comes from these corners of P4P JPGs.
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So is there any more clarification on settings / workflow for P4RTK ? After reading through the whole thread, doesn't seem to be a consensus on proper workflow.
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I am also very interested in a complete workflow for P4RTK.
Cheers,
B
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so am I :-)
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Has there been a complete workflow in Agisoft for this? Like a step by step thing??
Thank you in advancee