IMG2PNG, PDS/FITS to PNG conversion Options

[Bjorn Jonsson]

I decided to create a special thread for this topic. Previously information on IMG2PNG was scattered across various threads here.

I new version of IMG2PNG is now available. For those that don't know, this is a command line uitility that can convert various PDS formatted files to PNGs (8 or 16 bits per pixel depending on the input files).

This utility should work for lots of different PDS files, e.g. MER, Pathfinder, Voyager, Galileo, Cassini, Stardust, various Mars orbiters, Mariner 9/10 (!), Viking Orbiter, Viking Lander, Magellan, Clementine, Messenger, New Horizons etc.

The major new feature in the new version is the ability to convert FITS files.

IMG2PNG can be downloaded by visiting http://www.mmedia.is/bjj/utils/img2png

Any information on possible bugs welcome.

[Bjorn Jonsson]

A new IMG2PNG version is now available at the usual site:

http://bjj.mmedia.is/utils/img2png/index.html

The biggest change in this version is that it is now possible to debayer (also known as demosaicking) the input images. This is applicable for images from e.g. Chang'e 3. There are three new command line options associated with this:

-debayer
-debayer_ash
-debayer_exp

-debayer is used to debayer the input images using a default algorithm (Adaptive Smooth Hue) and -debayer_ash can be used to explicitly select this algorithm. This is the same algorithm as the one that can be selected in the "Debayer Image" ImageJ plugin; it has been used by Damia to process Curiosity images with great results (see e.g. here). -debayer_exp is used for experimental stuff, currently the Directionally Weighted Gradient Based Interpolation algorithm where I have been experimenting with post-processing the debayered images to suppress color artifacts (currently this involves selectively median filtering the hue using a 3x3 neighborhood for each pixel - this may change in future versions). -debayer_exp seems to work slightly better than -debayer_ash for some of the Chang'e 3 images but it is likely to work worse than debayer_ash for some images too (if anyone finds images where this is the case I'd like to know).
The color filter arrangement can be specified, e.g. -debayer:RGGB (which is the default arrangement and the one used by Chang'e 3).

Some bugs have also been fixed, mainly in the conversion of Chang'e 3 and LROC images and I also fixed some nasty bugs in the thumbnail generation code (for one thing, the automatic contrast stretch was far too severe). Also the header was sometimes missing from the metadata table that can be created with -metadata_table and there is now a Chang'e 3-specific version of this table.

See the IMG2PNG webpage for more details.