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https://issues.apache.org/jira/browse/IMAGING-251?focusedWorklogId=420208&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-420208
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ASF GitHub Bot logged work on IMAGING-251:
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Author: ASF GitHub Bot
Created on: 10/Apr/20 13:03
Start Date: 10/Apr/20 13:03
Worklog Time Spent: 10m
Work Description: gwlucastrig commented on issue #72: IMAGING-251 support
for TIFF floating-point formats
URL: https://github.com/apache/commons-imaging/pull/72#issuecomment-612019069
I think I will be able to improve the coverage as soon as I can get some
test images to exercise the sections of code that are not currently being
covered. I'm a bit confused by Coverall's results because in the last update I
made no code changes, but added additional unit tests to cover more of the
code. The coverage rating went down.
No luck in my search for relevant test images, so I am trying to figure out
how to use the Commons Imaging API to write TIFF files that carry
floating-point data. That way the project will be able to generate its own test
images with the different combination of options. Most of the pieces are
already present in the API. The original authors put a remarkable amount of
work into the code... But figuring out how to use the API is not always easy.
At least at first, I will not create test files that use the
predictor/compressors for floating-point data. The predictors have a lot of
nuances and I wouldn't trust my code to produce "valid" TIFF for those
combinations of options where I don't have standard samples to test against.
All the samples I have so far are 32-bit tile-based files. I've found hundreds
of those from the US Geological Survey. But I haven't found any strip-based
files.
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Issue Time Tracking
-------------------
Worklog Id: (was: 420208)
Time Spent: 3h 20m (was: 3h 10m)
> Support TIFF standard floating point data
> -----------------------------------------
>
> Key: IMAGING-251
> URL: https://issues.apache.org/jira/browse/IMAGING-251
> Project: Commons Imaging
> Issue Type: New Feature
> Components: Format: TIFF
> Affects Versions: 1.x
> Reporter: Gary Lucas
> Priority: Major
> Fix For: 1.x
>
> Attachments: Imaging252_USGS_n38w077.jpg
>
> Time Spent: 3h 20m
> Remaining Estimate: 0h
>
> Commons Imaging does not support the floating-point format included in the
> TIFF specification. There are prominent data sources that issue products in
> this format. The ability to support this information would open up new
> application areas for Commons Imaging.
> TIFF is often used as a mechanism for distributing data from geophysical
> applications in the form of GeoTIFF files. Some of this is not imagery, but
> data. For example, the US Geological Survey is currently releasing
> high-resolution elevation data grids for the 3DEP program under the name
> Cloud-Optimized GeoTIFF (COG). It is a substantial data set with significant
> potential commercial and academic applications.
> To access this data means modifying the TIFF DataReaderStrips and
> DataReaderTile classes to recognize floating point data (which is typically
> indicated using TIFF tag #339, SampleFormat). Also, returning the data in the
> form of a BufferedImage makes no sense at all, so the API on the
> TiffImageParser and supporting classes would need additional methods to
> return arrays of floats. The good news here is that that requirement would
> mean adding new methods to the classes rather than making significant changes
> to existing classes. So the probability of unintended consequences or new
> bugs in existing code would be minimized.
> Specification details for floating-point are given in the main TIFF-6
> documentations and Adobe Photoshop TIFF Technical Note 3.
>
> I am willing to volunteer to make these changes provided that there is
> interest and a high probability that my contributions would be evaluated and,
> if suitable, integrated into the Commons Imaging code base.
> Thank you for your attention in this matter.
>
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