Posted by
Robert Baer on
URL: http://imagej.273.s1.nabble.com/Infrared-filter-on-RGB-image-tp5001401p5001403.html
On 1/14/2013 11:40 AM, Nisha Shah wrote:
> Dear ImageJ Experts,
>
> If I have sent this message twice please pardon me, because my first post
> has "This post has NOT been accepted by the mailing list yet." on the top.
>
> I want to apply an IR filter on a color image. And so was exploring
> different tools to accomplish this task. I am new to ImageJ and have very
> less knowledge about the programming possibilities.
>
> I would like to know whether it is possible to apply an IR filter of a
> specific wavelength on a RGB image or some other desired wavelength filter
> (from the visible spectrum) on a RGB image? If so, please guide me.
>
> Thanks in advance! :)
>
> Best Regards,
> Nisha
>
> --
> ImageJ mailing list:
http://imagej.nih.gov/ij/list.htmlFirst, this is a more complicated question than I think you probably
appreciate. Second, filtering, per se, is typically done at capture
time using "hardware" filters. You can do some "software filtering"
when you have extremely well defined spectral conditions, but this is
rarely the case. Finally, there is the mixed situation where you want
to use multiple images with and without a hardware filter to separate a
part of a signal. ImageJ has utility in this latter instance.
Digital RGB representations of images are typical done either by using a
monochrome camera taking pictures using a spectral filter placed in
front of the camera to limit the wavelengths captured, or by using a
color camera in which case the channels are most often separated by what
is know as a Bayer filter. The spectral sensitivity of the monochrome
chip can vary in either case.
Some cameras have the ability to turn on and turn off an "IR " filter,
and if you have such a camera, you might be able to determine the IR
contribution to the image by image subtraction. ImageJ could help you
with this task depending on whether the IR filter is a lowpass or
bandpass filter. ImageJ certainly can do mathematical operations on
sets of images like image subtractions.
You do not tell us enough about the hardware part of your task to tell
you much more about how ImageJ might help.
Rob Baer
--
__________________
Robert W. Baer, Ph.D.
Professor of Physiology
Kirksille College of Osteopathic Medicine
A. T. Still University of Health Sciences
Kirksville, MO 63501 USA
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