Posted by
Michael Schmid on
Jun 20, 2011; 12:19pm
URL: http://imagej.273.s1.nabble.com/Area-measurements-for-50-particles-on-one-image-image-attached-tp3684189p3684194.html
Hi Kumara,
your example looks very difficult to analyze. Some shadows are too
sharp to distinguish them from true particles, and shadows have
different orientations, so one can't get rid of the shadows. Why not
use better illumination? Probably very diffuse illumination from all
sides, mainly around the camera, would be best. Also, a background
with a color clearly different from that of any particles would help
a lot. On a very dark (black) background, the shadows won't be a
problem.
Michael
________________________________________________________________
On 20 Jun 2011, at 12:48, janaka kumara wrote:
> Dear all,
>
> In this image, there are 50 particles. I want to measure areas for
> each particles but when I do using ImageJ toolbar, I don't get area
> measurements for all particles (50). I do analyses as follows,
>
> - Analyze, then Set Scale (to set a scale)
> - Rectangle shape selection (to remove ruler on the image)
> - Edit, then clear outside (now only particles remained on the image)
> - Process, then Find Edges
> - Process, then Binary, then Make Binary
> - Process, then Binary, then Dilate (as images are not very clear)
> - Analyze, then Analyze particles, there
> size (mm2): 5-infinity
> circularity: 0-1.00
> show: outlines
>
> Then, on the result sheet, I cannot see data for exactly 50 particles.
>
> Could you please advice me on this matter?
>
> Note: due to limitation for size, image attached was resized. If
> you want the original image, I can give you it if you will send me
> your email address.
>
> Thank you.
>
> Yours sincerely,
> Kumara
>
> PhD candidate
> Geotechnical Engineering Laboratory
> Department of Civil Engineering
> Yokohama National University, Japan<gravels - PSD.jpg>