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Author Topic: Reuse depth maps - generate if not exist  (Read 1546 times)

andyroo

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Reuse depth maps - generate if not exist
« on: December 04, 2020, 05:29:37 AM »
Not sure about how other folks use this, but I often disable a subset of aligned images, generate a dense cloud, then enable some/disable some images, and generate another dense cloud.

"reuse depth maps" defaults to "checked" in the dialog box (advanced settings, hidden by default) (probably defaults to checked because of my "keep depth maps" setting), but if depth maps don't exist I get a "zero resolution" error, rather than (1) depth maps being created for images that don't have them, or (2) a prompt saying they don't exist.

I would prefer that when I have "keep depth maps" selected in advanced options, "reuse depth maps" does not automatically regenerate existing depth maps, but DOES generate depth maps that don't exist.

Also a quick note - Thank you Agisoft developers for being so responsive to user questions/requests/comments. It makes for a very nice user experience, and I think that it generally shows in the helpfulness and enthusiasm of the user community.

Alexey Pasumansky

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Re: Reuse depth maps - generate if not exist
« Reply #1 on: December 04, 2020, 11:48:03 AM »
Hello andyroo,

If you add more images to the set with pre-calculated depth maps, then you would need not only to generate the depth for the cameras which have been just added, but also to update (re-calculate) the old depth maps, which are related to the cameras overlapping with the newly added images. Otherwise the information from old (pre-calculated) and new depth maps would not match and most likely the resulting surface (dense cloud, mesh or DEM) would be affected and will contain the artifacts in the areas related to the newly added images.
So the suggested scenario seems to be leading to the unwanted and confusing results.

However, we'll see if it would be possible to give any warning when "reuse depth maps" is enabled, but there are no enabled and aligned cameras with the pre-calculated depth maps.
Best regards,
Alexey Pasumansky,
Agisoft LLC

andyroo

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Re: Reuse depth maps - generate if not exist
« Reply #2 on: December 06, 2020, 11:11:45 PM »
Thank you for those details Alexey.

The most common scenario for me with this is with multiple flights of the same area. In that case, careful post-processing after alignment can remove bad (spurious) matches where features that have changed between flights are poorly matched, but keep good matches - improving flight-to-flight alignment and reducing systematic errors in flight-to-flight comparison (especially in the case of no aerial positions and only GCPs).

After aligning two flights together, I will often disable one flight, generate the dense cloud, uncheck "default", disable the other flight, and generate a second dense cloud.