Tips for making masking easier?

[james___Uk]

Okay so I can't get someone to hold a green screen behind everything I photograph, I plan to photograph a lot out in the world and I was wondering if using shallow DOF past the object I'm photographing would be a good idea to help make masking easier? I figured you'd have your object fully in focus and have a sharp outline around it making it easier for the magic wand/marker tools.

If this isn't the case I was wondering if anyone did have any tips or tricks for this? And help is very appreciated!

Regards,
James F

[driftertravel]

A: If you're "out in the world" you shouldn't have to mask most of the time, you can use the background to help in the alignment, then use the selection tools in the dense cloud step to delete the points representing what you don't want in the final model. You would want to mask only when you have to rotate the item physically to see the back side or something.
B. Green sucks as a backdrop for most things, as it casts a green hue on your object which is difficult to impossible to remove. Yes it's easy to remove with masking software, but I'd take one thick white and one thick black sheet to use as a backdrop if/when you need it. Choose the one that has the most contrast vs. the object that you're photographing and lay it down on the ground or something if you're taking pictures of something you need to flip over to see the back of.
C. Use the masking tools in after effects or use a plugin like primatte in photoshop to automate the masking process. They both work pretty well.

[james___Uk]

Oh cool, I thought you had to mask just to get a better sparse cloud but thinking about it that doesn't entirely make sense XD That's very good to hear though! I think I got confused because the first thing I scanned was done before I even knew I could delete points in photoscan (don't know why i didn't think this wouldn't be possible really).

I'm wary about green screen spill since I saw it in some VFX tutorial I once watched so I just have the backdrop far enough away and not so overly bright to be a problem, plus it has a blue side too. Glad to hear I'm not the only person to have used white as an acceptable backdrop (I come from a 3D graphics background so I'm more used to green/blue screens). I'll have to check out primatte, before I've done a masking job in photoshop and recorded it as an action so I literally just select and hit play for each layer and then save it.

Thankyou very much for your post, it's given me a much better idea about it now 

[bigben]

Masking tools would be worth exploring.  I have a set of Photoshop masks I use for masking out the sky to remove a lot of white noise in the point cloud. I normally shoot on cloudy days and expose so that the sky is as blown out as possible without over-exposing the subject.

Typically combinations of colour range selections, creating, adding and subtracting from the alpha channel.  I pick out images that don't have white in the subject and run those as a batch. For the others I open the images and make a selection excluding the white in the subject and then run the actions.  If there is a lot of variation in the sky (dark clouds/blue sky etc...) I change the colour range selection to allow user input for adding the extra areas.

https://skfb.ly/CPpn Removing the white sky showing through the tree canopy made a big reduction in noise, as well as cleaning up the roof line.

[james___Uk]

Thanks for the reply, I tried initially using filters on a copied layer for a selection but your method sounds far more professional XD Results speak for themselves. Good idea on over exposing, I did just get a sturdy new tripod too.