Is it possible to automatically select ROI's, and then obtain greyscale histograms for these ROIs

[SarahBr]

Hi,

I need to count droplets in an image (an example is attached). Some of these are water droplets and some are ice (these are the ones that look like they have internal structure). I would like to count how many there are of each. I have tried binarising the data in Vision Assistant, but due to the change in light intensity across the image I can't isolate the droplets properly. So i was wondering if it was possible to isolate the droplets in another way and then obtain histograms for each droplet as these should have different patterns for the liquid and ice droplets. However, there are about 100 droplets in each image and I would like to do this for multiple images, so is there any way to automaticlly detect the circles first?

Thanks,

Sarah

[muks]

Have you tried "circle detection"? in vision assistant. I see non-uniformity in the illumination which is going to make it hard in applying a proper threshold. Is there a way you can replace this illumination with say a dome light?

[muks]

You can try something like this

[SarahBr]

Thanks for that vi - it is pretty useful. However, it does not distinguish between the two types of droplet I am interested in. I have tried modifying it slightly, but haven't had any luck so far.

I also tried using the compare example.vi from the example finder to look at the difference between two images, in which more droplets had frozen by the second image. However, none of the different comparison operators seem to be that good for what I need, and the difference between the two images appears to be overlayed over one of the images (see attachment). Is there any way to just get the difference?

Sarah

[muks]

I am not able to open the image as i get "image has errors and cannot be opened"

[muks]

[SarahBr]

This might be better

[muks]

Your image looks to me as if it is burnt/over exposed. what lighting are you using?

[SarahBr]

 The image that I just posted ws produced  using the compare example.vi from the example finder to look at the difference between two images I expect what you are seeing as burn out is the difference between the two images.

[SarahBr]

However, I think I am out of my depth here and the timescale I have to work within is quite short. So I was wondering what the best way to outsource this probelm to a proffesional was