Messages

1

General / Re: Insta360 double Fisheye DNG's

« on: May 08, 2024, 11:48:26 AM »

I'm just starting out with the same camera. I see you have a functioning workflow splitting the images, but I was wondering if you'd compared the output from this with output using the rectilinear images processed by Insta360 Studio please?

2

General / Current best 360 camera?

« on: February 28, 2024, 01:18:36 PM »

I'm looking to buy a 360 degree camera, which will be used for both videos and photogrammetry. What is the current best available consumer or prosumer 360 camera please, in terms of photogrammetry? They could be up to $5000, but preferably less than $1000 (USD). It'd be used both indoors (lower light) and outdoors on high poles (where cases where drones are prohibited).

Many thanks in advance.

3

Feature Requests / Ability to input more parameters from Camera Calibration Reports/Certificates

« on: June 13, 2023, 07:06:52 PM »

Currently Metashape will accept the following camera calibration parameters (note those in bold):

f - Focal length measured in pixels (in pixels).
cx, cy - Principal point coordinates, i.e. coordinates of lens optical axis interception with sensor plane (in pixels).
b1, b2 - Affinity and non-orthogonality (skew) coefficients (in pixels).
k1, k2, k3, k4 - Radial distortion coefficients (dimensionless).
p1, p2 - Tangential distortion coefficients (dimensionless).

It is also possible to input the coordinates of any fiducial marks in mm, and also to input the focal length in mm.

Many archive (historical) aerial photographs (airphotos) come with Camera Calibration Reports/Certificates. The calibrated focal lengths and coordinates of the fiducial marks can readily be input. Where there are many airphotos in a strip or block these are usually sufficient initial conditions, which can readily be improved upon (i.e. the other parameters can be reliably estimated). However, it would still be useful to be able to add the many other calibration parameters available in certificates/reports, and especially in instances where very few photos are available (e.g. just 2 to 4) and thus the estimates for the other parameters listed above are less reliable.

One of the barriers to this is the units used. For instance, most certificates/reports list the coordinates of the principle point in mm (whereas Metashape only accepts pixels). This can be estimated manually, if one knows the fiducial coordinates in mm and the number of rows/columns between them... but it would be much better to have the additional option of adding Principal point coordinates in mm please.

In a similar way radial distortion is usually listed in the certificates/reports, but in um in relation to degrees. It would be great to have the ability to optionally add the distortion in such units please.

In some cases certificates/reports include calibrated distances between (i.e. across) pairs of fiducials (in mm). It would be great to have the option to add these also please.

Finally, some certificates/reports include uncertainties (in mm) for the estimate of the calibrated focal length. It would be great to be able to add these too, for use in constraining the SCBA.

Below is an example Camera Calibration Report/Certificate listed the parameter and units I mention.

Many thanks indeed.

4

General / Migrating data: Can't Read from Source File or Disk Error

« on: April 12, 2023, 02:41:03 PM »

I'm migrating data and products from a smaller drive to a larger drive on my Windows 10 PC (all drivers etc. up to date). I'm migrating all kinds of data, from lots of different sources, and products from lots of different image processing and GIS packages. Everything has gone well, apart from several Agisoft Metashape files, which stubbornly will not copy across due to the error "Can't Read from Source File or Disk Error".

At first I thought this was a problem with the small drive (e.g. bad sectors, mis-matched formats etc), but CHKDSK and other checks show all is well. I also restarted several times and tried copying to different drives instead. It was then that I noticed Metashape files were the ONLY files which had this problem... no other files from any other source, no matter what the size or format, suffered this issue. Further, it seems to be specific file types, such as:

images*.zip (e.g. images0.zip, images1. zip)
dense_cloud.oc3

Any help in fixing this would be much appreciated 

5

Feature Requests / Orient model using "scale bar"

« on: January 12, 2023, 12:13:49 AM »

I have an unreferenced model (no targets used during or after image capture). I've scaled the model using several "scale bars" created from pairs of markers. I've tried manually rotating/orienting the model such that it is the right way up and facing the correct direction, but this is very difficult to do accurately. I know that the marker pairs, and therefore the scale bars which join them, happen to be aligned with the axes of the object in real life (for instance at least one scale bar is parallel to X, another is parallel to Y and another to Z, in real life). Therefore is  there any means by which I can use the scale bars to orient the model of my object to the real-world X, Y and Z axes please?

If not, could this be added as a Feature Request please.

Many thanks

Andy

6

General / Re: Using Leica DMC III images

« on: August 10, 2021, 05:49:28 PM »

I woud fix all parameters.....

I'm returning to this processing again and just want to triple check that the focal length, pixel sizes and principal point coordinates are fixed to those from the [synthetic] camera calibration, and all other values are also fixed, presumably at zero?

If so, once erroneous sparse points are removed and Cameras Optimised (i.e. final bundle adjustment) only the exterior orientation (i.e. camera stations/poses) are adjusted? If this is correct, I'm curious to know what kind of Accuracy you used for the camera locations (m) and orientations (degrees) please? Did you import values from a table of ephemeris data for the flight (I have SD for locations, via dGNSS, and orientations, via IMU), or did you set Accuracy values the same for all photos? If the latter is the case, did you use small/tight values (e.g. fractions of a metre and fractions of a degree) or larger/looser values (e.g. a metre or more and a degree or more)?

Many thanks again! 

7

General / Re: Using Leica DMC III images

« on: August 03, 2021, 12:48:42 PM »

Here is my Camera Calibration GUI. I believe the only difference with yours is I have fixed f

8

General / Re: Using Leica DMC III images

« on: August 03, 2021, 11:58:44 AM »

Many thanks for your reply Paul 

I have a PDF which contains the info in the same format as you presented. For anonymity I've removed the Serial Number, but everything else is just a copy & paste:

Code: [Select]

Geometric Calibration
The output image geometry is based on the Pan Camera head (reference head =
master camera). All other camera heads are registered and aligned to this head.
Aerial triangulation checks overall system performance based on.
Output image
Reference Camera PAN
Serial Number NNNNNNNN
Number of rows/columns [pixels] 25728 x 14592
Pixel Size [um] 3.900 x 3.900
Image Size [mm] 100.3392 x 56.9088
Focal Length [mm] 92.0000 mm + /- 0.002 mm
Principal Point [mm] X= 0.0000 mm, Y= 0.0000 mm + /- 0.002 mm
The “SYNTHETIC” geometric calibration is based on a simulated mathematical lens distortion calculation based on the detailed optical design data of the lens.

9

General / Using Leica DMC III images

« on: August 02, 2021, 06:23:26 PM »

I would like to use some stereo, vertical Leica DMC I and DMC III aerial imagery, provided as RGB in TIFF format. I have exterior orientation metadata as text, together with some interior orientation metadata (e.g. calibrated focal length, pixel size etc). I can import said data and metadata.

I have started by working with a block of >70 DMC III images and Align Photos to create a sparse cloud.

Unless I deliberately fix the focal length it ends up changing dramatically (>34000 mm vs. the calibrated 92mm). When I then use Model > Gradual Selection and progressively select points in the sparse cloud according to Reconstruction Uncertainty I get distinct structures forming:





When I fix the focal length the sparse point cloud appears thus:



These structures suggest systematic errors. I sense there is something wrong with the camera model? Is there something extra I should be doing to import Leica DMC images? Might the systematic errors be related to the fact DMC use multiple 2D arrays?

10

General / Re: historic aerial frames, same pixel dimensions, fiducials slightly different

« on: March 27, 2020, 02:15:26 PM »

First, which country, agency/company and camera? I have some archive camera calibration reports and you never know, they might match...!

Second, the variations you report (0.2 and 0.5 mm)... are these with reference to the [assumed] principal point?

Andy

11

Camera Calibration / Clarification regarding Calibrate Fiducials

« on: March 20, 2020, 01:08:12 AM »

Am I correct in guessing that Calibrate Fiducials assumes the fiducial marks are symmetrical (equidistant from the principle point) and uses the given scan resolution to calculate their approximate coordinates? Is this done on a per-image basis, or use means (or some other statistic) if multiple images are selected together (therefore more representative coordinates)? I'm just seeking some clarification please. 

If this is correct it'd be great to add such to the manual for future reference.

Many thanks

Andy

12

Feature Requests / Calibrate Fiducials: um & dpi options

« on: March 20, 2020, 12:56:23 AM »

When using Calibrate Fiducials it would be wonderful to have the options to input the scan resolution in um (microns) and dpi please.

Many thanks

Andy

13

Feature Requests / 2D/horizontal (x,y) vs. 1D/vertical (z) markers and accuracy

« on: June 19, 2019, 05:38:04 PM »

There may be a way of doing this which I haven't yet discovered (please provide instructions if there is) but we really need a means creating 2D (i.e. horizontal) markers... i.e where only x,y coordinates were able to be measured. Also, where 3D markers are used (i.e. the only kind of marker I'm aware of in the current version) it would be very useful indeed to differentiate between 2D/horizontal (x,y) and 1D/vertical (z) marker accuracy, as the two are often very different indeed (e.g. when using GNSS to survey marker locations). Using just one overall Accuracy for each marker is very limiting when it comes to bundle adjustment with markers surveyed by different means or in different conditions.

14

General / Re: Patches of high/low areas in point cloud of terrain

« on: March 02, 2018, 07:36:21 PM »

I can't export as XML, when when I import the same XML nothing appears (there are no error messages either)...

15

General / Re: Patches of high/low areas in point cloud of terrain

« on: March 02, 2018, 04:56:36 PM »

Here it is: http://www.mediafire.com/file/lb3luqhv8gf54rb/Report%20for%20OS%201982%20vertical%20aerial%20photographs%20March%202018.pdf