Re: Counting color pixels

Posted by W. Chan on Sep 12, 2009; 11:12pm
URL: http://imagej.273.s1.nabble.com/Counting-color-pixels-tp3691188p3691190.html

What is the format of your doppler images?  If it is just 8-bit index
color e.g., NWS radar images, then it would be really easy.  Select an
area of interest.  Do Analyze | Histogram, then click on List.  The first
column is the color index and the second column is the pixel count.  Now
you just need to find out what color is represented by which index value.
You can zoom in and position the cursor on the pixel with the color you
want to count and read it off on the status bar of ImageJ.  It would be up
to you to define what red or blue are e.g., range of dBZ you're interested
in.  Hope this help.

On Sat, 12 Sep 2009, Smileyy1585 wrote:

> I am new to this forum but I'm having some difficulty with the ImageJ
> program. My goal is to take color doppler images and to count the colored
> pixels within a certain area. The main colors I am looking for are red and
> blue, but the color ranges from light to dark red and blue. What makes
> things difficult is that the background is black, light and dark grey.
> Basically I want to count the colored pixels and divide it by the total
> number of pixels of a chosen area.
>
> I keep seeing that this is possible with Image J, but I have not been able
> to make this work. Any help would be appreciated. Thank you!

--
Pang (Wai Pang Chan, [hidden email], PAB A087, 206-685-1519)
The Biology Imaging Facility (http://depts.washington.edu/if/)