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Occasional Contributor
Posts: 11
Registered: ‎05-18-2020

Scans with look like a duplicate on an image Question. HELP ?

 

Maybe somebody in here  can help me with my  question I may have here...

 

I got these image from an external hard drive that my agency got from a contractor, it is a black and white ungeoreferenced raw scanned images that I have to orthorectification here on my national forest.

 

I have the original picture and another image that had the error. Somebody drew a red circles that is showing me  duplicates on them on the right side of the bright and to the left from the line of the dark and bright line . It looked like there is a duplicate there.

 

Do you think somebody may have mixed up with the scans that looked like a duplicate within a scan ? or was it the plane that may have cause it the film to slipped a bit ?

This is my second profile.
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Technical Evangelist
Posts: 976
Registered: ‎10-01-2015

Re: Scans with look like a duplicate on an image Question. HELP ?

That does look like a double-exposure doesn't it, now that you point out the "ghosting" effect. Which would explain why the one section is much brighter than the other , if it's been exposed twice.

 

Perhaps there are some old-time aerial photographers on here that could comment on if that was something that could happen with film-based survey cameras. It does seem plausible that the film didn't advance correctly between frames and so there's overlap between exposures.

 

But even if it was, there's not a lot you can do with those sections of the image. You're probably best off simply subsetting the data to remove the over-exposed sections and just trying to work with the "good" bits. Although that's going to make orthorectification difficult if you were trying to rely on measuring fiducials, etc. Something like IMAGINE Autosync might work though.

 

Are all the frames like this, or just some of them?

 

Cheers

 

Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
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Occasional Contributor
Posts: 11
Registered: ‎05-18-2020

Re: Scans with look like a duplicate on an image Question. HELP ?

Thank you for this explantion and it gave me an understanding about it...

 

 

 

 

This is my second profile.
Highlighted
Occasional Contributor
Posts: 11
Registered: ‎05-18-2020

Re: Scans with look like a duplicate on an image Question. HELP ?

Are there any terminology for this kind of thing ?

 

Are there any journals that have about this sort of thing ?

This is my second profile.