Posted by
Matthew Moore on
URL: http://imagej.273.s1.nabble.com/Improving-Particle-Analyzer-accuracy-tp4999626p4999635.html
On 01/08/12 11:22, Gabriel Landini wrote:
> On Wednesday 01 Aug 2012 10:35:03 Matthew Moore wrote:
>> On low DPI images, saved straight to jpg, imagej consistently comes well
>> under manual counts. On high DPI images, saved to tiff and then
>> converted (on max settings) to jpgs (so imagej can load them), imagej
>> consistently counts higher than the manual counts.
> Shouldn't the amount of ram to hold the loaded image be the same regardless of
> the format that is stored in?
> But you can improve accuracy in the representation of your image data by not
> using lossy formats (like lossy jpeg).
The loading issue was that imagej wouldn't read the tiff created by
xsane (which I'm using for the scanning). I've converted the tiffs from
xsane into a tif with no compression and imagej loads them fine now.
> Do you see where the the differences are? for example do you detect too many 1
> pixel regions? Is that noise or data? Have you tried different segmentation
> methods? Do they converge?
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.
>> Does anyone have any ideas as to how I can improve accuracy? I've spent
>> a while trying different pixel^2 and circularity settings. I'm using
>> the version of imagej from the ubuntu repositories (1.44i).
> Without more details it is difficult to know what is going on, but I would be
> willing to bet it is not the particle analyzer accuracy, but the segmentation
> approach used.
>
> You would benefit from the constant bug fixing. Latest ij.jar is 1.47b6 (the
> daily build).
I'm sorry, but I've no idea what segmentation approach I'm using. Not
entirely sure what you mean there (and not been able to figure it out
from the docs). The dots are quite obvious really, it's a plain white
piece of paper with black blobs on it.
I'll certainly try the latest daily.
Thanks,
--
Matthew Moore
Surgical Materials Testing Laboratory
System Administrator
Telephone: +44 (0)1656 752165
Email:
[hidden email]
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