I need to find out what is the pore size of this image



Original TIFF image: download


Hi @Kamran, and welcome to the forum!

This forum is all about quantitative image analysis, but not everyone here is familiar with the kind of images you posted.
There’s a rule of thumb that when writing a forum question, you should spend at least the amount of time that you’d expect others to spend with answering it. So, here are a few additional questions to get you started:

  • What have you tried already? Did you encounter any specific difficulties?
  • How do you (or literature in your field) define pore size?

Also have a look at other topics about pore size here on the forum.


I have tried on ImageJ software but was unable to get the pore size of the image, i found the void fraction that is 31% but i need to find the pore size and its distribution. And I mean from the pore size : the space or volume of the coating that is covered with the solid particles or agglomerates, In this image silica nanoparticles are coated on glass substrate with introduction of porasity to helps in reducing the Refractive index of the silica and also it helps in self cleaning ability.


Good day,

please read carefully what Jan tried to explain.

I think we are still not able to understand what is what in your image.
Here is an enlarged excerpt of your image:

Please indicate what you consider being a pore and what is what you call void.




I am guessing you are asking this question not because you ran into a problem trying to extract the value but because you just don’t know how. For pore size, I use the Local Thickness plugin which is commonly added to ImageJ via the BoneJ plugin. If you are using Fiji instead of vanilla ImageJ, I believe the plugin is already installed. Note that the results are provided as radii in pixels, not scaled units.


That is awesome @Andrew_Shum. The local thickness result looks very interesting. How do you use the histogram data to determine other properties ?


That’s great @yempski. I really appreciate it. Thanks alot, now how can we find the pore size? I mean the size of blackish part, or porous part?


Hi @Kamran, the histogram has a large peak at zero, so my guess is this represents black pixels. You could take the ratio of this to the total count to determine a percentage. However, I really doubt this is an accurate measure of porosity. Wait for some feedback from @Andrew_Shum


You still didn’t answer the question posed in my earlier post. As long as we don’t know how you define pores, we cannot help. Please refer to the before posted enlarged portion of your image and indicate what you consider being a pore.




Thanks alot for asking question and helping. The white spots shows the nano-particles, while the blackish area shows pores means empty spaces, I want to calculate average size of these pores, or size range in nano-meters. As the nano-particle size is about 10-25 nm, what is pore size or diameter.


Good day!

The white spots shows the nano-particles, while the blackish area shows pores means empty spaces

Please tell us how you define black and white!

Here is the gray-value histogram of the excerpt Histogram%20of%20Excerpt of your image:

It shows the number of pixels having a certain gray-value with black to white from left to right. As you can see, the image shows a continuum of gray-values with negligible amounts of pure black and white. Your image shows dark and light “clouds” but they are not black and white!

So what do you call black and white?

Furthermore and related, I can’t find any boundary between what you may call nano-particles and pores.

As long as you can’t provide a formal, (mathematical) definition for nano-particles and pores, there is no way for a machine to do what you want.

Please draw boundaries of nano-particles and pores onto the image excerpt that I’ve posted earlier and post it here.