Black marks in an orthophoto

[gatsri]

I got some problems in Orthomosaic:
specialy in forest area I got holes in Orthophoto - see image.
is there any workaround to fill / blend these holes.
I know it is cause the area isn't on any image. bit may be I can do something expect of a new flight...

[Jaume]

Hi everyone,

I'm wondering where is a problem with my orthophoto. After exporting I've got the orthophoto with small random black strains that are placed around trees.

I'm attaching this ortho below.

How can I avoid this problem in the future?  What factors does the problem with a orthophoto depend on?

[James]

I believe these black areas are parts of the mesh that are not visible in any photo due to:

1. being masked out
2. being occluded by the mesh from every camera angle
3. outside the field of view of any camera

If you export the orthophoto as TIF or PNG, rather than JPG, then the black areas will be transparent.

In this case i think it is most likely issue #2 above, and you probably have a noisy mesh in this area. You might do better by either smoothing the mesh (Tools->Mesh->Smooth Mesh - but save first as you can not undo this operation) so there are fewer lumps and bumps occluding certain areas, or just build the mesh from the sparse cloud so it is lovely and smooth to start with.

Have you tried the ground point classification tools? They might also help avoid a lumpy mesh caused by meshing things like trees etc that protrude above the ground and cause occlusion.

[ju]

Hi,
since last update to version 1.2.4 there are black holes in the orthophotos. I just produced the same orthophoto with version 1.1 and there are no black holes in the photo. Is there any workaround to avoid those black holes in the orthophotos exported from version 1.2.4?

Best regards

[BenjaminB]

Hey,

try to "Close Holes" in the mesh and run the orthophoto again.

[lenamat]

Hi,

I am having the same issue with the orthophoto export in v 1.2.4. What bothers me is that neither the DSM nor the mesh have any holes, they appear only in the orthophoto...
I have tried building the ortho from both the mesh and the DSM : the holes are almost identical with both methods.
I've also tried smoothing the model and then rebuilding the ortho : the holes are slightly less numerous but they are still visible (plus the smoothing modifies the shape of sharp objects).

Is there any explication / solution for this problem ??

Thanks

[Alexey Pasumansky]

The holes in the orthomosaic on all the provided examples look to be related unseen from any camera position. It may be a result of the noisy surface when the tree tops are not reconstructed correctly and there are some zones of the incorrect elevation. So i can suggest to check the dense cloud prior to the mesh/DEM generation for such areas and manually remove the obvious outliers (like points beneath the ground level).

In the next version update, however, we will improve the hole-filling for the orthomosaic generation process.

[AlexZ]

I have the same problem now. Older projekts with no black marks in orthofotos have black marks after re-generating orthofotos... (black marks are in trees)

[Unknownid]

Hey I am having an issue with the new version and holes in my ortho. I don't remember this being an issue in the older versions but I can't figure out how to close holes in my ortho (the close holes in mesh doesn't help).

I've attached some photos to help explain what I mean. I have pretty good photo coverage, i'd just like to to slightly blur the areas by blending vs a white hole...

Any ideas? I just can't seem to find an option to close holes on ortho export anywhere....

Thanks

[Alexey Pasumansky]

Hello Unknownid,

Have you rebuilt orthomosaic in the version 1.2.5 build 2735?

[Unknownid]

Hey Alexey,

I re ran the orthomosaic using the latest version which seemed to help a little bit.

Im still getting holes near the edges and a little closer in. I assume this is to do with photo coverage but I could have sworn older versions had the option of blurring the ortho vs leaving white holes?

Thanks for the help.