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Section 10: Processing astronomical images
The MallinCam Universe is capable of producing high-quality astronomical images with little or
no subsequent image processing required. However, image processing techniques can enhance
your images even further, bringing out all the subtle detail that the camera can capture.
A full discussion of image processing is well beyond the scope of this guide, but there are a few
suggestions we can make to help you along.
Using 16-bit TIF and RAW files
The MallinCam image capture application offers two methods of saving the image files with
maximum color resolution: the 16-bit TIF file and the RAW file.
In an 8-bit file format such as BMP, the data in each color channel (Red, Green, and Blue) is
divided into 256 different levels of intensity. Such files are also referred to as 24-bit RGB files,
since each color channel is 8-bits and there are three channels. However, in a 16-bit file, each
color channel contains 65,536 levels. This is equivalent to dividing a single level in an 8-bit file
into 256 sub-levels. This finer graduation of the color information allows for much more
intensive image processing and the ability to bring out subtle details not possible when using
8-bit files. Such 16-bit files are also referred to as 48-bit RGB files, since each color channel is
16-bits and again, there are three channels.
The 16-bit TIF file is the preferred format for processing images in programs such as Adobe
TM
Photoshop
. Select the 16 Bit checkbox to produce 16-bit files. Note that some other image
processing applications cannot read this richer TIF format. But other programs are also available
that can read the 16-bit files and convert them to 8-bit.
TIP: It's better to save the 16-bit files since you can always convert them to 8-bit files, if
required. You can't convert an original 8-bit file to 16-bit at a later date, because that additional
was never recorded – it's lost. Keeping an original image that contains the full 16-bit per channel
data just makes good sense, though of course, it'll cost you some extra hard drive space.
The RAW format also contains the full 16-bit per channel data. The MallinCam RAW files can
be converted using the ImageJ program. ImageJ is a free, public domain, Java-based image
processing program. It can read and process many different file formats at various bit depths and
then convert them to other formats such as BMP, JPG, or even FITS files.
The ImageJ program can be downloaded from:
http://rsbweb.nih.gov/ij/
If you want to download a free plug-in for ImageJ that will convert your RAW files to the
popular astronomical imaging FITS format, this can be found at:
http://www.umanitoba.ca/faculties/science/astronomy/jwest/plugins.html
MallinCam Universe - User's Guide v1.05
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