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Author Topic: how to find bad alligned photos  (Read 5420 times)

frank.stremke

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how to find bad alligned photos
« on: April 30, 2013, 07:16:21 PM »
when looking at my sparse point cloud i can see a whole bunch of wrong points. the seem to form a second Chostsrface floating over the actual one. when building geometry i get a mushrom like shape bloming on tom in arbitraty mode and in high field many spikes....
so i would like to get rid of thes points but gradual selection and manual deleting does not work so i would like to find out which cameras are responsible for these pionts without having to realign all pictures is there a way to know from wich camera these points came or to speed up testing.
frank

Alexey Pasumansky

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Re: how to find bad alligned photos
« Reply #1 on: April 30, 2013, 07:25:41 PM »
Hello Frank,

You can select point and use Filter by Points option in the Photos pane to check only photos with the selected points.
Also you can use Reset View option for suspicious photos, comparing the point cloud from the reset point of view with the image. In case of obvious incorrespondence camera alignment could be reset.
Best regards,
Alexey Pasumansky,
Agisoft LLC

frank.stremke

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Re: how to find bad alligned photos
« Reply #2 on: April 30, 2013, 09:44:38 PM »
thanks thats the tool i need but unfortunaly id did not realy do the job. because of me taking the photographs wrong.
because if i select some of the wrong points i get lods of photos from the filter. i think the problem is: while walking around the mountain i was walking a bit then taking a series of photos to cover the whole mountainface from this location so now camera locations are very close together. i try now with selecting only one photo of every location maybee that wil help. is there any function to sett a minimum distance between camereas or a filter wich can help me?
frank

Alexey Pasumansky

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Re: how to find bad alligned photos
« Reply #3 on: April 30, 2013, 10:47:43 PM »
Hello Frank,

Actually you are right and taking photos from exactly the same point is not good for PhotoScan.
Generally we recommend to have minimal stereo base (the distance between two neighboring photos) about 10% from distance to object, but I suppose that in terms of mountain it could be a big value, however, it should be quite big, otherwise the images whould be nearly identical.
Best regards,
Alexey Pasumansky,
Agisoft LLC

frank.stremke

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Re: how to find bad alligned photos
« Reply #4 on: May 01, 2013, 11:35:45 PM »
another problem with alligning i came around just now..
i alligned 118 pictures and got 109 alligned automaticly however i decided to turn the project into  a chunk of a larger project and there i just get 84 alligned automaticly using the same settings.
does anybody have an idea why this could be the case...
frank

RalfH

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Re: how to find bad alligned photos
« Reply #5 on: May 02, 2013, 01:06:14 AM »
I sometimes have projects in which a different number of images aligns (or the resulting alignments differ) if I reapeat the whole process with the same settings - there seems to be a random element in there. Copying images from one chunk to another (e.g. drag and drop) seemed to be a bad idea a while ago because some of the image parameters get lost along the way; I'm not sure if this is fixed in the most recent build of Photoscan.