Very Basic image analysis

Sample image and/or code

  • Upload an original image file here directly or share via a link to a file-sharing site (such as Dropbox) – (make sure however that you are allowed to share the image data publicly under the conditions of this forum).
  • Share a minimal working example of your macro code.


Simple area analysis of voids in epoxy under a quartz die

Analysis goals

Need percentage of voids per unit area


I’ve used the image threshold tools to highlight the void areas. I just don’t know what analysis tools I need to use to be able to give me a % number of the selected area. Basically I simply need to know how much area the void represents.

Hi Darren,

Welcome to the Forum.

If you are new to ImageJ, I would suggest having a look at some of the tutorials and manuals around, to help you familiarise yourself with the program, which will probably save you a lot of time. For example:

Analyze -> Measure should do what you want.
You can set what you want to measure by ticking the appropriate settings in Analyze -> Set Measurements that includes an option for Area Fraction.
There is a short video here that illustrates this:

Hope this helps,

Hi Volko,

Actually that YouTube video explained exactly what I needed…thank you!!