Messages

31

General / Re: Incorrect Show image with calibration with k4

« on: March 15, 2024, 06:48:23 AM »

Dave,

strange you should get plots available for ll options even if plot is white .... Something is wrong...

Yes I fly with dewarp off as I want MS to estimate its own calibration parameters...

32

General / Re: Incorrect Show image with calibration with k4

« on: March 14, 2024, 06:21:17 PM »

Hello Dave ,

yes the k4 less calibration is certainly adequate. But given the significant radial distorsion in this wide angle lens, I decided to compare  a 5 cm GSD calibration flight, optimizing with and without k4 checked. And I got slightly better results in terms of reprojection error (error promedio de reproyeccion) and tie points variance (Precision promedia de puntos) but a little worse in GCPs error using k4  compared to nok4... Following results with k4 first then without...

Code: [Select]

---------------------------------------------------------------------------
    Reporte Puntos de amarre - Calib_110_140_pr_Optk4_gradsel_RU_PA_RE - Calib_5cm.psx version 2.0.2.16334
 ---------------------------------------------------------------------------
 Sigma0: 0.998
 Precision de puntos de amarre (pix): 0.13
 Numero de puntos de amarre: 93610
 Numero de proyecciones: 315302
 Promedio de proyecciones (TiePts) por foto: 1480
 Numero de fotos alineadas: 213
 Numero de puntos iniciales: 456675
 Numero de proyecciones iniciales: 2210367
 Error promedio de reproyeccion (pix): 0.276
 Error maxima de reproyeccion (pix): 1.529
 Error medio cuadratico (RMS) de reproyeccion (pix): 0.330
 Precision promedia de puntos (cm):3.988 sX, 3.499 sY, 6.579 sZ, 8.452 sTotal
 Tamano promedio de punto (pix): 2.352
 Multiplicidad promedia de punto de amarre: 3.368
 Multiplicidad promedia de punto de amarre (todos): 4.840
 ---------------------------------------------------------------------------
 Script finished in 2 seconds.

Total error GCPs:
    Control points 0.015 0.019 0.019
    Check point 0.025   0.029 0.048
   
---------------------------------------------------------------------------
    Reporte Puntos de amarre - Calib_110_140_pr_Nok4_gradsel_RU_PA_RE - Calib_5cm.psx version 2.0.2.16334
 ---------------------------------------------------------------------------
 Sigma0: 1.008
 Precision de puntos de amarre (pix): 0.18
 Numero de puntos de amarre: 93610
 Numero de proyecciones: 315302
 Promedio de proyecciones (TiePts) por foto: 1480
 Numero de fotos alineadas: 213
 Numero de puntos iniciales: 456675
 Numero de proyecciones iniciales: 2210367
 Error promedio de reproyeccion (pix): 0.384
 Error maxima de reproyeccion (pix): 3.199
 Error medio cuadratico (RMS) de reproyeccion (pix): 0.465
 Precision promedia de puntos (cm): 6.094 sX, 5.460 sY, 9.940 sZ, 12.875 sTotal
 Tamano promedio de punto (pix): 2.352
 Multiplicidad promedia de punto de amarre: 3.368
 Multiplicidad promedia de punto de amarre (todos): 4.840
 ---------------------------------------------------------------------------
 Script finished in 2 seconds.

Total Error GCPs:
    Control points 0.016 0.018 0.017
    Check point 0.005 0.025 0.002

All in all there is no significant difference.... I think

Attached is camera calibration comparison (no k4 - k4). Clearly image residuals are smaller  with k4....

33

General / Re: Incorrect Show image with calibration with k4

« on: March 13, 2024, 06:05:44 PM »

Thanks Alexey,

this what i found when I tried using reverse projection and iterative approximation. At top right corner the iterative approximation does not converge rather diverges towards infinity...

34

General / Re: Incorrect Show image with calibration with k4

« on: March 13, 2024, 09:25:28 AM »

I think the difference between initial calibration (no k4) and adjusted gives strong values in corners...ie. the reason for problematic projection on model....

Definitely with k4 adjustment the camera.unproject at corners gives wrong values as calculation does not seem to converge... thus getting greater and greater values...to infinity
as seen in  Excel extract starting from image top right u,v = 5279,0 pixel, I get undistorted pixel position that is huge as the iterative corrections do not converge to 0...

35

General / Re: Incorrect Show image with calibration with k4

« on: March 12, 2024, 10:40:34 PM »

Hi olihar,

yes your distorsion plot looks fine... However if you can activate Show Images in model view to see how  an image looks when projected onto model?

36

General / Re: RTK survey with one check point

« on: March 12, 2024, 03:34:46 PM »

Classic error in surveying...not considering antenna ht reduction!

Good to know it is working 

37

General / Re: RTK survey with one check point

« on: March 12, 2024, 03:21:49 PM »

Hello xyzm,

can you share the prj definition of your MSL based CS? What geoid is it referenced to?. The  GCP how was it determined? ARE you sure it is the same CS?


A little bit more info could help...or if you can share  this small data (just RGB images + GCP data) , I could have a look at it....

38

General / Re: Alignment error when processing chunk of images with GCPs along one axis only.

« on: March 12, 2024, 03:16:56 PM »

Hi March,

in case the misaligned tilted part only has GCPs along a line. then tilted nature can be explained by this pattern. My suggestion is to create at least 3 GCPs (not on same line) in correct chunk that overlap with tilted chunk. And identify and measure these same markers in tilted chunk. Then align chunks using marker based method...

Should work...

39

General / Re: Incorrect Show image with calibration with k4

« on: March 11, 2024, 07:02:18 PM »

Hello Alexey,

if I change the sign of k4, I get something that is not correct like barrel distorsion....

I think there is a bug when k4 is adjusted during optimization in the projection of image/camera...

If I optimize with just k1,k2,k3, th projection of image on model is correct.... see 2nd attachment

40

General / Re: RTK survey with one check point

« on: March 11, 2024, 12:24:38 PM »

hi xyzm,

Normally the camera positions are in WGS84 with elipsoidal height and it does seem that you GCP in in MSL height... That is you must transform your camera positions to MSL height using a geoid (either global or local depending where you are situated)...

The difference between the 2 Vertical systems (elipsoidal and MSL) is around 18 m (34 -16)....

41

General / Incorrect Show image with calibration with k4

« on: March 11, 2024, 05:54:59 AM »

Hello all,

i have a project where my images (M3E) were adjusted using k1,k2,k3,k4 radial parameters in camera calibration. But when I do show Images in model view, the corners of projected image on model are chopped off when I would expect to have a pointed pattern (push pin). AS you can see in following the top left corner of projected  image is chopped off... in radial distorsion plot it is clear that in corners, there is up to 670 pixel distorsion....

Any explanation for this behavior? This does not occur if I calibrate with just k1,k2,k3 radial distorsion...

42

Python and Java API / Re: Metashape model.pickPoint issue in version 2.1

« on: March 08, 2024, 06:21:17 PM »

Hello,

I think that the view_mode must be set to Model Data outside loop so to load mesh only once (probably your default view_mode is set to Tie_points Data). See:

Code: [Select]

Metashape.app.model_view.view_mode = Metashape.DataSource.ModelData
2024-03-08 09:54:41 loaded mesh in 1.215 sec

for i in range(10):
    p = chunk.model.pickPoint(camera.center, camera.unproject([i*100,i*100]))
    print(p)
   
2024-03-08 09:55:36 Vector([-4.059615135192871, -2.7640161514282227, -9.319589614868164])
2024-03-08 09:55:36 Vector([-4.249917030334473, -2.972996950149536, -9.520050048828125])
2024-03-08 09:55:36 Vector([-4.044933319091797, -2.8117287158966064, -9.369665145874023])
2024-03-08 09:55:36 Vector([-3.8784561157226562, -2.687345504760742, -9.251367568969727])
2024-03-08 09:55:36 Vector([-3.7242331504821777, -2.5761122703552246, -9.141517639160156])
2024-03-08 09:55:36 Vector([-3.5773491859436035, -2.4710636138916016, -9.038172721862793])
2024-03-08 09:55:36 Vector([-3.4366350173950195, -2.3685312271118164, -8.9429931640625])
2024-03-08 09:55:36 Vector([-3.2960205078125, -2.271303653717041, -8.842096328735352])
2024-03-08 09:55:36 Vector([-3.0704894065856934, -2.2703800201416016, -8.480890274047852])
2024-03-08 09:55:36 Vector([-2.958159923553467, -2.164015054702759, -8.438690185546875])


43

General / Re: RTK survey with one check point

« on: March 08, 2024, 05:12:16 PM »

Hello,

15 m looks very suspicious. What is your flying height? Where are you flying? Maybe your GCP is in a different vertical datum? i.e. MSL instead of ellipsoidal height for camera positions...

44

General / Re: Transform Coordinates from WGS84 to LV95/LN02

« on: March 05, 2024, 07:46:48 PM »

Bonjour jerm,

I redid the calculation but this time not supposing 500 m elevation for all points as this  is false. Since the datum transformation is 3d the correct elevations should be taken into account. So I extracted them from Aster DEM  and used them instead of 500 everywhere. After transforming to WGS84 with Reframe and then to LV95 LN02 with Agisoft... I get a smaller difference (min -16 mm, max 13 mm. And most (68%) within -4 mm and 2mm.... see attached screen capture and corresponding file...

La difference restante peut être expliquée par différents types d'interpolation  utilisées par Reframe et Agisoft...?

En fait en fouillant la documentation sur Reframe, il semble que la dernière version inclut une transformation différente de celle donnée juste par le fichier chgeo2004_htrans_LV95.agr.. voir extrait du document :

Transformation d’altitudes usuelles en altitudes orthométriques Une transformation d’altitudes usuelles (NF02) en altitudes orthométriques (RAN95) n’est possible que de manière approchée, en raison des distorsions locales en NF02 ainsi que des différences dans la correction de l'influence du champ de pesanteur. Elle s’effectue sur la base d’une interpolation planimétrique pondérée d’une part, d’un facteur d’échelle altimétrique obtenu par interpolation biquadratique dans une grille de 1x1 km d’autre part. La précision moyenne de cette transformation est meilleure que le cm sur le plateau et le long des lignes de nivellement national, mais peut être supérieure à 10 cm dans les Alpes. Cette fonctionnalité de REFRAME remplace le programme HTRANS.

ceci devrait expliquer la différence rencontrée...

45

General / Re: Can't load local geoid model into metashape

« on: March 01, 2024, 02:13:10 PM »

Hi again,

I think I found how to correct the file. The columns and rows numbers were inverted....

Now I created a Tif for MyGeoid 2004 and just copy into your Agisoft Geoids file.

Attached is tif file and screen capture showing geoid with 2 points on sea side with their geoid values...

You can also use following compound prj file:

Code: [Select]

COMPD_CS["GDM2000 + MyGeoid 2004 height",
GEOGCS["WGS 84",
DATUM["World Geodetic System 1984 ensemble",
SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],
TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],
UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9102"]],AUTHORITY["EPSG","4326"]],
VERT_CS["MyGeoid04 height",
VERT_DATUM["Malaysia 2004",2005],
UNIT["metre",1,AUTHORITY["EPSG","9001"]]]]
I hope it works for you,