Hi all,
I am a newbie in MATLAB. I am trying to do particle analysis on an image in MATLAB.I work with
nanocrystals of varying sizes and contrast. Basically what I am trying to do is count the
number of cells  in the image  by setting thresholds and make measurements like area,
perimeter, radius. The challenge with this work is that the nano crystals change both in
contrast and circularity from image to image.
Has anybody worked on this before? Does anybody know what algorithm works best in this case.
Please let me know. It will really help me.

Thanks,
Sandhya

I guess you must be using regionprops to calculate the area, perimeter etc.
You can know the count of number of cells crossing the threshold by using
the
statement [L,num]=bwlabel(matrix) before you do regionprops which you need
to do anyways to convert the matrix to a binary value. the variable num
gives the number of cells identified or ones which crossed the threshold.
This is to be done after you apply the condition for threshold.
On 27 May 2008 22:00:49 -0000, sandhya nageswaren <s...@rediffmail.com>
wrote:
> Hi all,
> I am a newbie in MATLAB. I am trying to do particle analysis on an image in
> MATLAB.I work with nanocrystals of varying sizes and contrast. Basically
> what I am trying to do is count the number of cells in the image by setting
> thresholds and make measurements like area, perimeter, radius. The challenge
> with this work is that the nano crystals change both in contrast and
> circularity from image to image.
> Has anybody worked on this before? Does anybody know what algorithm works
> best in this case.
> Please let me know. It will really help me.
>
> Thanks,
> Sandhya