# Using density slice to analyze attrition

I am very new to ImageJ and image analysis. I have a few SEM images of a dental bur before and after use, and I want to measure how much wear has occurred.

The best example would be if you took a piece of chalk, and drew a hundred circles, how much of the chalk still remains? It’s as if I would be looking at the chalk if it was standing straight up from a bird’s eye view

I have been told density slicing can help but am unsure where to start. Any help would be appreciated!

I guess would saying that I am measuring the depth of something be more accurate?

Welcome to the forum, @DJAT!

We could probably help you more easily if you post some representative sample images.

Good point!

So the diamond particles that are sticking out should be in theory, a little worn down after use. I want to see how much worn down they are compared to a brand new one. Any thoughts?

Can you image the burs “on end” so that the diamond particles stick out radially from the central column? This would be much easier to measure computationally.

So you mean just to focus on the diamond particles on the edge? Yes, that is something I have thought about. However, I was thinking it might be better statistically to somehow select a huge area on the “front face” of the bur and somehow analyze it that way.

For example, if you go to google earth, and take a snapshot of the Rockies Mountains, is there a way to easily analyze how high each peak or hill was?

From the top down? This strikes me as very tricky at best.

Taking the photograph on edge means you can simply measure the length of a line from the perimeter of the circle to the edge of each particle. Right?

So you mean just to focus on the diamond particles on the edge?

Is there a good way to analyze the percent change for a group of selected diamond particles?
Or do I have to analyze each individual particle?

Aren’t all the particles “on the edge”? As in: around the circumference of the drill column? Or do I misunderstand something here?

I think you could measure in aggregate, because you’d have: A) a circle defining the column itself, and B) a larger fitted circle around the outer column of diamond particles. The distance between the inner and outer circles would be the average particle length.

But again, I am naive in these matters. Maybe what I propose is not ideal for some reason. How do other people in your field measure this?