http://imagej.273.s1.nabble.com/thresholding-and-detection-issues-when-analyzing-particles-to-obtain-object-counts-in-a-petri-dish-tp5015178p5015186.html
scanners. (Interpolated resolution is for selling not for science.)
> Thank you Ben and Aryeh. At this point, total egg counts is the main
> objective, but eventually we would like to use the area and perimeter
> information from analyze particles to estimate egg size. Do you have any
> additional information that could lead to me still utilizing the analyze
> particles function?
>
> Thanks again,
>
> Rich
>
> On Tue, Dec 8, 2015 at 11:28 PM, Aryeh Weiss <
[hidden email]> wrote:
>
>> On 08/12/2015 10:57 PM, Rich Pendleton wrote:
>>
>>> Hey all,
>>>
>>>
>>>
>>> I was wondering if someone might be able to provide some insight similar
>>> to
>>> a question that was posted last month. I am trying to use the analyze
>>> particles function to count fish eggs in a petri dish. Some eggs are more
>>> mature than others and the smaller less mature eggs are rather
>>> transparent. Therefore when trying to adjust the threshold to detect the
>>> less mature eggs, I get clumping of mature eggs that are in close
>>> proximity
>>> to one another. Despite using the watershed function in attempt to
>>> separate eggs that are close, I still have many large clumps that have
>>> numerous eggs that are being counted as one unit. As a result, the counts
>>> are always much less than the true count (often over 1000 eggs less). If I
>>> adjust the threshold in the other direction, I am unable to detect the
>>> less
>>> mature eggs. It is quite difficult to prevent eggs from clumping when the
>>> petri dish is first scanned therefore was hoping I might be able to get
>>> around it within ImageJ. I have attached a few pictures (from top to
>>> bottom) 1) original image set to 8 bit, 2) after thresholding, 3) after
>>> watershed, 4) outlines of counted particles. The original image was
>>> scanned in as a jpeg with 1200 dpi. Any help that you may be able to
>>> provide would be greatly appreciated.
>>>
>>>
>> Try Process>Find Maxima..
>> For your image, a threshold of about 15 seems to work.
>> Process>Subtract Background may also help if you want to threshold, but I
>> dont think Find Maxima needs it.
>>
>> However, I suggest that you not acquire your images as jpg -- use a format
>> that is not lossy ( or acquire uncompressed).
>> You resolution is currently about 20 micron/dot (1200 dots in 25.4 mm).
>> You might do better if you can get a higher resolution scan.
>>
>> --aryeh
>>
>> --
>> Aryeh Weiss
>> Faculty of Engineering
>> Bar Ilan University
>> Ramat Gan 52900 Israel
>>
>> Ph: 972-3-5317638
>> FAX: 972-3-7384051