Posted by
Matthew Moore on
URL: http://imagej.273.s1.nabble.com/Improving-Particle-Analyzer-accuracy-tp4999626p4999642.html
On 02/08/12 11:06, Gabriel Landini wrote:
>> The main problem is that the 'Make binary' that you have to use before
>> running the particle analyzer introduces lots of noise into the image,
>> so it picks up lots of false positives.
> In that case you could process the image before thresholding or after.
>
> <snip>
>
> You need to be aware that by any of that processing, you are changing the
> original data.
Thanks for the pointers. I've been trying various combinations of them
out, not got better than about +/- 20% so far. The flag to ignore dots
on the edge of the image has been the most useful so far, as that's
nearly always noise.
>> The dots are quite obvious really, it's a plain white
>> piece of paper with black blobs on it.
> I guess that probably the dots are not the problem, but the image or
> background is not completely white, and the thresholding level that you are
> using picks some of that intensity variation as "object".
Exactly. As you and Volker correctly guessed part of the problem is
that when scanning dust is picked up (which looks similar to the
smallest blobs) and when the image processing is done for the counting,
noise from the paper is picked up (shade from where the paper wasn't
totally flat is a main culprit).
If I had access to a clean room to do the splatter and scanning then I
reckon I could get a reasonable level of accuracy, but as it is I'm not
sure it's going to be possible.
Many thanks for the suggestions and advice.
--
Matthew Moore
Surgical Materials Testing Laboratory
System Administrator
Telephone: +44 (0)1656 752165
Email:
[hidden email]
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