Posted by
Jeremy Adler on
Jun 02, 2014; 2:49pm
URL: http://imagej.273.s1.nabble.com/Generating-random-points-and-tallying-proportion-of-points-that-fall-within-object-tp5007988.html
From your description the images are effectively binary - objects black, background white
You may want to ensure they are binary by using Process/Binary/Make binary
Checking 1000 random points is a traditional approach for finding the fraction of the image that is occupied - it asks the user to decide point by point, it is still useful if it is hard to decide on whether the point hits an object or not.
But you have binary images, so all you need to do is find the mean intensity of each image - in the ImageJ version of binary there are two values 0 and 255.
The fraction of the image that is white (255) is simply the mean intensity of the whole image divided by 255.
The mean intensity comes from Analyze/Measure. You can chose what is measured using Analyze/Set measurements.
To measure the 300 images,
Process/Batch/Measure - the software asks where the file containing the images is, and then prints out the results, which you can save and import into Excel or wherever.
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From: ImageJ Interest Group [mailto:
[hidden email]] On Behalf Of atawewe
Sent: den 2 juni 2014 15:55
To:
[hidden email]
Subject: Generating random points and tallying proportion of points that fall within object
I have over 300 images I need to process to obtain an unbiased estimate of the proportion of each image that is occupied by the object of interest. For each image, the objects of interest are black in color, mostly spherical in shape, but range in sizes, while the background of the image is white. The challenge for me is that I need to generate 1000 random points on each image, and determine the proportion of points that fall within the objects of interest in the image. I will appreciate information on how to achieve this using imageJ. After searching online, I really couldn't find any tips on where to start from or how to go about generating random points on an image and estimating whether they fall within the object of interest or not in imageJ.
Thanks in advance.
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