Artifacts and ghosting

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menszerman
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Artifacts and ghosting

Unread postby menszerman » 11.07.2017 03:44

JohnMenszer (1 of 1).jpg
Stacked image shows artifacts in background and ghosting around objects
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After stacking 14 images then using Helicon Rendering B factory settings the resulting image shows artifacts (light circles) in background and ghosting around objects like halos. Am using latest version of Helicon.

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Stas Yatsenko
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Re: Artifacts and ghosting

Unread postby Stas Yatsenko » 12.07.2017 14:52

Please upload your stack to our server (as described at http://www.heliconsoft.com/ftp-server/) and we will see what is happening.
If you are user of GoogleDrive, DropBox, OneDrive or other cloud service, you can upload your files there and send us a link.

menszerman
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Re: Artifacts and ghosting

Unread postby menszerman » 27.07.2017 23:20

Here is a link to my dropbox: https://www.dropbox.com/sh/wxl9ewcgcssk69g/AAAjmsErunBlMhG3sbEepKJBa?dl=0
The folder contains the stacked tiff and the Nikon raw files (d800) that were used to create it. There are a series of artifacts, white dots, that corrupt the stacked tiff. Thank you.

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Stas Yatsenko
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Re: Artifacts and ghosting

Unread postby Stas Yatsenko » 30.07.2017 11:50

Usually this kind of artifacts appears when lightening of source layers is different and program is not able to fully compensate this because background and foreground are exposed non-uniformly. In your case it is better to disable this option (Preferences\Autoadjustment\Brightness). Or you can use retouching brush to copy background from any of the source images. With color tolerance of 30% the brush will affect only background.

menszerman
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Re: Artifacts and ghosting

Unread postby menszerman » 06.08.2017 00:09

I posted new files to my dropbox: https://www.dropbox.com/sh/wxl9ewcgcssk69g/AAAjmsErunBlMhG3sbEepKJBa?dl=0

Please see folder: Helicon Artifact Problem Update 1. You will see 2 Helicon folders.

I tried focus stacking the statues using your suggestion of leaving Brightness off. The resulting tiff is in the folder: Adjust Brightness Unchecked. The artifact problem was worse. There were halo's around the subjects as well as the spots in the background.

I tried a new shot of a Rifle Grenade Purse. There is an artifact problem in the middle of the handle. The edge of the rifle grenade is overlapped and fuzzy. I had Adjust Brightness Checked per default. In the folder: Rifle Grenade Purse are the raw Nikon d800 shots and the Focus Stacked Tiff.

Please advise.
Thank you.

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Stas Yatsenko
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Re: Artifacts and ghosting

Unread postby Stas Yatsenko » 16.08.2017 14:36

We checked your stack again. It looks like these artifacts appear because of black area at the bottom of some images. This shadow is taken into account when the program calculates average image brightness. Because of this, layers are not properly adjusted and you see the halos in the resulting image. Workarounds: the image *0350000.nef differs the most. Exclude it from the stack and process it again. Another method: crop all images so that shadow at the bottom is not visible any more.

menszerman
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Re: Artifacts and ghosting

Unread postby menszerman » 17.08.2017 22:09

Thank you for your reply. I would like to show you our latest work "Scrap Book" which has ghosting around the edges with 5 or more duplications. It can be found at:
https://www.dropbox.com/sh/72c56povvw63i74/AAA8vIc6ybls440EbJQi36OOa?dl=0 (The stacked images are filed as tiffs and also as converted to jpgs as some browsers could not open tiffs) We did a stack of 22 images and a short stack of the first 16 images. Both had problems.

Our technique is to use a Nikon d800 with 200mm micro lens at f10, flash. The camera is on a track. It is focused on the front of the subject and rolled forward in 1 cm increments for as many as 25 frames. We are using Helicon on a Mac.

As to your reply to our last post, the rifle-grenade purse. I don't see the black area you are finding in our images. Do you mean the shadow under the purse? I cant find the Nikon raw image that corresponds to the number 0350000.

Please advise. Thanks.

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Stas Yatsenko
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Re: Artifacts and ghosting

Unread postby Stas Yatsenko » 19.08.2017 10:32

Current version is not able to properly align this stack. This is mostly due to major shift between 24 and 25 images. We will send you a newer beta for tests. And even with new version, please set larger auto adjustment limits (5%,3%,2degrees,5%) in the Preferences.


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