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Author Topic: Is masking useful?  (Read 2933 times)

cbnewham

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Is masking useful?
« on: February 10, 2014, 05:15:44 PM »
I ask because, at first glance it looks like a good thing - you don't have to process anything in the pictures except the subject.

However, on many examples over the past few months I've found that masking produces inferior results. It seems to be fairly obvious why: when the image has extensive masking it means that points are only being used in a small area of the image, and therefore the position of the cameras will not be as accurate. e.g.: if the pictures are masked so that only a small central section is available, then the angles between extreme points in each picture will be less and thus the camera positioning error will be greater along the line connecting the camera and the subject.

So, it seems reasonable to not mask for creating the initial point cloud. However, masking does not appear to be used for the dense cloud (why is that?) and I wonder whether it is useful at the texturing phase?

Thoughts anyone?

James

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Re: Is masking useful?
« Reply #1 on: February 10, 2014, 05:55:06 PM »
Yes it's useful.

Like you suggest, I often do not use masks for image alignment stage, letting photoscan use all the available image information.

Dense cloud and texturing do both pay attention to masks. If you mask object X in all photos then that object will not be included in the dense cloud or texture map.

If you only mask object X in some photos, then it may still be reconstructed and textured from photos where it is not masked.

cbnewham

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Re: Is masking useful?
« Reply #2 on: February 10, 2014, 07:49:50 PM »
Interesting.

I wasn't sure if mask were used for the dense cloud because there isn't an option to switch them on or off like there is with the sparse cloud.

I had suspected that the masks were used for texturing as I've noticed cleaner results when I have masked.