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Author Topic: photos aligned but without depth map?  (Read 17769 times)

RalfH

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photos aligned but without depth map?
« on: January 24, 2013, 06:10:35 PM »
I have a project with 114 photos, all of which are aligned, and refined camera calibration values look good (i.e., close to the initial values and with only small changes between photos). Building a model from the sparse point cloud also works well.

However, when I want to build a model using lowest, low or medium (haven't yet tried high and ultra), most photos are skipped and depth maps are build for only 21 cameras. What could be the reason for this?


Alexey Pasumansky

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Re: photos aligned but without depth map?
« Reply #1 on: January 24, 2013, 06:22:51 PM »
Hello RalfH,

Pairs for depth maps reconstruction will be skipped if one camera observes the camera position for another photo.
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Alexey Pasumansky,
Agisoft LLC

RalfH

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Re: photos aligned but without depth map?
« Reply #2 on: January 24, 2013, 06:31:55 PM »
Hello Alexey,

but wouldn't it improve model quality if all depth maps were calculated? There are 114 aligned photos, but the model is build from only 21 depth maps?

P.S.: I have now tried to force PhotoScan to build the missing depth maps (right-clicking on a photo --> "export depth" forces the depth map to be build for export even if that depth map exists already), but I got the message "can't export depth". The missing depth maps result in large flat areas in the model even though these areas have valid points in the sparse point cloud. Is there a way to improve this?
« Last Edit: January 24, 2013, 08:57:38 PM by RalfH »

Alexey Pasumansky

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Re: photos aligned but without depth map?
« Reply #3 on: January 25, 2013, 03:29:28 PM »
Hello RalfH,

This restriction is based on algorithm specifics. But knowing that you can arrange further capturing scenarios in more PhotoScan-acceptable way. Or let us know if such kind of shooting (when one camera observes a lot of others) is required and can not be changed.
« Last Edit: January 25, 2013, 03:32:37 PM by Alexey Pasumansky »
Best regards,
Alexey Pasumansky,
Agisoft LLC

RalfH

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Re: photos aligned but without depth map?
« Reply #4 on: January 25, 2013, 03:41:35 PM »
Hello Alexey,

when you say "one camera observes the camera position for another photo", do you mean that a camera position is within the line of sight of another camera? For example, when you take a roughly linear series of pictures at different distances of an object? Or a situation where there are overview as well as closeup pictures?
« Last Edit: January 25, 2013, 03:50:32 PM by RalfH »

Alexey Pasumansky

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Re: photos aligned but without depth map?
« Reply #5 on: January 25, 2013, 03:54:14 PM »
Foe example, when the camera is moving along the corridor and is looking in the movement direction while pictures are taken.
Best regards,
Alexey Pasumansky,
Agisoft LLC

RalfH

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Re: photos aligned but without depth map?
« Reply #6 on: January 25, 2013, 04:03:44 PM »
Hello Alexey,

yes, that is exactly the situation in this project. It is a linear series of oblique images, and model quality suffers a lot from these constraints, because only a few depth maps are build and used. It would be a very good idea to have an option button with which to activate/de-activate this behaviour of PhotoScan. Perhaps already in 0.9.1?

FoodMan

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Re: photos aligned but without depth map?
« Reply #7 on: January 25, 2013, 04:57:10 PM »
oups, wrong thread... :)

f/
« Last Edit: January 25, 2013, 05:22:30 PM by FoodMan »

TDJ109

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Re: photos aligned but without depth map?
« Reply #8 on: May 27, 2013, 11:34:52 PM »
This is a real problem for me as well. Even worse, I am dealing with photo sets of 15-20 cameras. Photoscan only wants to use 4-5 to create my meshes. The surfaces which Photoscan DOES recreate are very useful. If I could only get the program to compute the data from the missing cameras, I would have what I need. Anyone find a work around for this problem?