Topics

1

General / Camera matching and points not seeming to align?

« on: April 05, 2016, 04:36:34 PM »

Hi all,

I quite like modelling cars in 3D.

I've taken photos of my car on a Ricoh GR and let Photoscan do it's work to get camera alignments really nice.


I then undistort and export images too for use in the background.

I export the model (patchy but usable for quick reference) to 3DS Max via FBX or 3DS format.



But for some reason points I place don't seem to line up so great.

Things towards the centre of the images usually line up ok over several images, but elements towards the edges of the shot seem to drift out by a few centimetres. Ie, a part near the centre of the car looks ok in several shots but as the camera distance increases from that point it can drift.

Is this normal?

Surely for Photoscan to work correctly these points should be perfectly aligned?

Is there any way to check inside Photoscan how accurate a camera position is? I usually use gradual selection and make sure reprojection error tie points over 0.25 or 0.5 or so are deleted (if this helps?)

Am I better shooting the checkerboard to get a lens profile to use from Lens, since currently I've just used the automatic Photoscan camera calibration detection.


Any help would be much appreciated since this workflow 'should' work, but I can't figure out why it's not.


Many thanks

Dave

2

General / Clarification on feature, GPS in standard Photoscan?

« on: July 19, 2015, 04:08:06 PM »

Hi all,

I've been looking high and low on the website and documentation (and 'searching' the manual), but I can't find out if the standard version of Photoscan uses GPS EXIF data to help in aligning the image inputs.

Is this an automatic feature, or something I have to set specifically, or not even in the standard version.


I've seen it mentioned before and I was certain it was a standard feature but perhaps I'm just misremembering?



Clarification on the version features page might be useful for others if it is indeed not present in the standard version.


Thanks

Dave

3

General / Photoscan non-pro, alignment of cloud methods?

« on: June 12, 2014, 07:37:45 PM »

I was certain in testing that if I aligned my initial camera image (first one in the imported images, or number 1) to be flat that I could then use that as a guide for rotations or corrections of the cloud to be completely accurate.

Ie, in 3DS Max just use the point cloud and rotate the point cloud object say 90deg or whatever to get it aligned properly.

I'm certain I did this with about 3 test reconstructions and assumed it was a good working feature.




But now I'm really struggling to get this behaviour. Quite often it's just one of the random cameras in the set that the scene seems to be aligned with, and it's not easy to get the numerical transformation of that camera from the know camera in the scene.

Using the manual scene rotation feature is just not very useful at all as it's not accurate enough.


Is it possible, or worth adding as a feature, so you can just choose a camera in the list and align the cloud to that camera? You could then easily adjust as necessary with simple transforms (90deg) rather than arbitrary adjustments.


I'll keep having a test as I'm certain this was working before, with camera 1 always being square to the reconstruction.... hmmmmm.


Thanks for any help/advice/thoughts!


Dave