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DOI-USGS / ISIS3

Integrated Software for Imagers and Spectrometers v3. ISIS3 is a digital image processing software package to manipulate imagery collected by current and past NASA and International planetary missions.
https://isis.astrogeology.usgs.gov
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Map projection occlusion bug #1980

Closed ascbot closed 5 years ago

ascbot commented 5 years ago

Author Name: Kenneth Edmundson (Kenneth Edmundson)

Original Assignee: Tyler Wilson

Incorrect pixel values are used when map projecting in an occluded region. Probably happening in general, but quite noticable when projecting highly oblique images.

The necessity to properly map project Apollo Metric oblique images prompted this ticket.

This paper discusses the problem...

http://info.asprs.org/publications/pers/2007journal/april/2007_apr_403-411.pdf

ascbot commented 5 years ago

Original Redmine Comment Author Name: Kenneth Edmundson (Kenneth Edmundson) Original Date: 2015-02-12T19:38:03Z

Attached images illustrate the problem.

In the Level 2 image, incorrect pixels are projected into the occluded area of the crater.

ascbot commented 5 years ago

Original Redmine Comment Author Name: Tyler Wilson (Tyler Wilson) Original Date: 2016-10-11T20:38:17Z

A description of the work that has already been done on this bug can be found in the LPSC abstract attached to this ticket, as well as the README.txt file in /work/projects/isis/latest/m02224.

Future work should involve implementing a traditional zbuffer method to compare with the current method. I have been working with the XForm functions in the cam2map class. Implementations of the zbuffer method might involve looking at higher level classes (such as Projection/TProjection).

The second attached paper by Habib, et al. also has an excellent overview of this problem, as well as a good description of the zbuffer method and I recommend it to anyone pursuing future research on this issue.