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Author Topic: Masking All source photos  (Read 5724 times)

alivebyphotoscan

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Masking All source photos
« on: February 12, 2016, 04:02:50 PM »
Hello
Fairly new to Photoscan, like the software a lot so far...Starting out with the online tutorials & have begun the masking process.  In my research of various software I came across a workflow where only half a dozen or so source photos were needed to create a model, would this be the case with Photoscan or do all source photos need to be masked?

As a newbie if anyone has suggestions for step-by-step online video tutorials or other mediums that would be Great  :)

Thank you in advance to those who responded..greatly appreciated..
« Last Edit: February 12, 2016, 08:04:40 PM by alivebyphotoscan »

Kiesel

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Re: Masking All source photos(newbie)
« Reply #1 on: February 12, 2016, 05:53:24 PM »
As allways it depends from how and what you want to model!

Normally you don't need masking.

You need it when:
- you don't want to model something in your images.
- Photoscan has trouble with parts of your images (e.g. reflections, ....).
- changing background (e.g. moving objects, ...)
- ...

When you use a turntable the background is static but your object is moving, so if PhotoScan is using the background for image alignment it can't align your images properly, all images seems to be shot from one position (as they are in reality) instead of a circle around your object. Here you can use for example masking from (empty) background image to generate masks for all images but others have also good success with an uniform (overexposed or black) background, where PhotoScan can't find tiepoints, without masking .

For a turntable tutorial with masking see: https://www.youtube.com/watch?v=9_F-b2hxP_o

Karsten

alivebyphotoscan

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Re: Masking All source photos
« Reply #2 on: February 12, 2016, 08:20:32 PM »
Thank you kindly Karsten for your response...

Primarily I will be modeling various, individual static objects, big and small (i.e mechanical parts, a car etc.)  In some case I can utilize a turntable, but in those I can't does Photoscan still require all photo sources to be masked to create a model?


Thank You Again

Matt

Kiesel

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Re: Masking All source photos
« Reply #3 on: February 13, 2016, 01:17:27 AM »
Hello Matt,

Quote
In some case I can utilize a turntable, but in those I can't does Photoscan still require all photo sources to be masked to create a model?

No, normally masking is not needed. Just go around your object and shot enough photos.
Mechanical parts and especially cars might be difficult to model because of reflections and low texture, some special techniques are needed here for photogrammetry (and for laser scanning also).

Karsten

alivebyphotoscan

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Re: Masking All source photos
« Reply #4 on: February 15, 2016, 06:48:19 PM »
Thank You Karsten

Being new to photogrammetry do you have a source or suggestion of where to learn these specialized techniques?

Appreciate your feedback...
Regards
Matt

Kiesel

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Re: Masking All source photos
« Reply #5 on: February 20, 2016, 09:38:12 PM »
Hi Matt,

another tutorial you might be interested in where an active photogrammetry method with pattern projection and masking is used:

http://www.pi3dscan.com/index.php/instructions/item/agisoft-how-to-process-a-scan-with-projection

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Primarily I will be modeling various, individual static objects, big and small (i.e mechanical parts, a car etc.)

For reverse engeneering I would recommend SLS (Structured Light Scanning which is also photogrammetry with  pattern projection with a series of pattern) instead of passive stereo photogrammetry. Or you test active stereo photogrammetry first.
A good SLS to start with is David Laserscanner (nevertheless in SLS no laser is used  ;)) http://www.david-3d.com/en/.


Karsten
« Last Edit: February 21, 2016, 02:07:41 AM by Kiesel »