Background masking

[james_blonde]

I am evaluating different approaches for a large project, and have a lot still to learn.

One of the initial obstacles I have come across is the separation of subject points and background points.

I have taken some photos which I wanted to use with Scannerkiller, but this software seems to create points to fill gaps between the foreground and background. Or perhaps I have a wrong setting somewhere. In any case, the points view in Meshlab of the result looks like this, despite there being a good physical separation between subject and background:

http://forums.rennlist.com/upload/meshlab_points.jpg

If I run the same photos through Photoscan, I get a point cloud like this:

http://forums.rennlist.com/upload/photoscan_points.jpg

Unfortunately it doesn't seem possible to select and delete points in Photoscan, and I can't export the point cloud in the demo version.

What is the simplest way to do this? I was hoping that Scannerkiller, once calibrated, could easily disregard points more than X metres from the cameras - that would be an elegant solution and much preferable to creating a mask.

[Infinite]

Hi Graham, a mask is your best bet.

I recommend shooting against a black background. It then takes literally about 15-20 seconds to make a mask in PS, black and white. You can then use that mask in ZBrush to remove the excess data. Or just re-process through SK. Masking in ZBrush is better though.

[james_blonde]

Hi Lee. Thanks for your reply. However for complicated reasons I won't get into, it isn't possible to shoot against a black background (in a nutshell, there are other things going on with the subject at the same time which already determine the environment). That's why I'm looking for a basic 'distance from camera' based filter.

[Infinite]

Hi Lee. Thanks for your reply. However for complicated reasons I won't get into, it isn't possible to shoot against a black background (in a nutshell, there are other things going on with the subject at the same time which already determine the environment). That's why I'm looking for a basic 'distance from camera' based filter.

Apart from quick masking, or doing it by eye with a lasso. I would recommend posting on the SK forums, or contact them directly with that feature request (if it's not possible already?) as it is a good idea and makes sense to have. I can 2nd it as well with an email. Artec Group scanning software does the same thing on the fly, cuts off by distance. Should be pretty easy to implement I would imagine.

Unless there is a feature already in the Calibration I don't know about.

[james_blonde]

Thanks again. I have already been in touch with Helmut at XYZ RGB about this. It's not currently possible and he didn't seem interested in adding the feature (I guess he gets many bespoke requests and can't add them all).