I've imported photos from a DJI Phantom 3 and performed an AT on them, it works OK except for a bit of radial distortion.
I then bring in and mark my ground control and do another AT using the setting 'Use control points for adjustment', but after AT the number of photos the control points are marked in drops hugely. The ones that still have 3 or more photos have great RMS, but visually the tie points look terrible.
The tie points are many metres from the lost ground control points. The tie points are kind of broken up into groups like there has been a massive earthquake fracturing the ground.
What has happened? Why are the GCPs marked in less (sometimes no photos) after the AT?
Also where can I see the camera parameter calibration from AT?
Cheers
Caleb
Before aerotriangulation
After aerotriangulation
Name
Category
Check point
Horizontal accuracy [m]
Vertical accuracy [m]
Number of photos
RMS of reprojection errors [px]
RMS of distances to rays [m]
RMS of 3D errors [m]
RMS of horizontal errors [m]
RMS of vertical errors [m]
GCP1
Full
0.010
4
411.43
6.454
23.397
6.367
-22.514
3
0.05
0.001
0.000
-0.000
GCP2
409.86
16.151
19.969
11.436
16.370
0
GCP3
344.30
6.666
8.643
7.970
-3.343
0.06
0.002
-0.002
GCP4
486.97
13.751
15.279
13.327
-7.472
GCP6
870.70
16.239
55.824
14.866
-53.808
1
0.02
GCP7
5
707.84
11.629
77.088
11.304
-76.255
0.03
GCP8
788.30
15.943
93.513
15.990
-92.135
GCP9
1139.95
16.914
88.363
19.911
-86.091
0.15
GCP10
1377.93
15.238
64.111
3.744
-64.002
GCP12
8690.62
28.058
63.225
17.662
-60.708
GCP13
712.22
18.720
29.252
18.038
-23.028
0.07
0.004
-0.004
GCP14
598.11
31.025
44.139
14.349
41.741
0.04
-0.001
GCP15
539.34
21.726
23.843
17.301
16.407
0.003
-0.003
GCP19
20387.28
24.567
87.654
15.807
-86.217
0.01
GCP20
2914.25
43.308
117.417
10.980
-116.902
GCP21
2368.89
42.859
98.524
8.557
-98.152
Block_1 - part 1 - AT - Control - export.zip
Don't use all GCP at first, set at first half of them as check-points. Maybe some points are not accurate and that causes block to break.
Also if it nadir flight only it is best to use preexisting calibration - communities.bentley.com/.../how-to-calibrate-your-camera-using-contextcapture
Answer Verified By: Caleb Baildon
Thanks Otto. I did figure out what was going on, it was a misidentified GCP. I've been a long time Pix4D user and only started using Context Capture in the last 6 months. I'm still learning how it does things, because it does some things quite differently to Pix4D.