Measuring distance between 2 point clouds

[Adam]

Hello,

I'm having difficulties to measure the distance between 2 point clouds. Here I have used vertical distance. I want to be able to tell this is the vertical distance (height difference ) between them. Can you please look at the attached images and help me to figure out what is the average distance (my units are in mm). I'm expecting small-scale topographic changes. I have attached the histogram too but I don't understand the mean value and std (what they represent)?
I really need your help with this as I have no one to help me!

Many thanks

[daniel]

I never understand what you want... The average = mean = sum of all values divided by the number of values?!

And I believe I already told you that the average is not interesting alone (you have to consider the standard deviation in addition at least).

[Adam]

Hi,

I would like to know the distance values.
For example, I would like to write it like this> ''the map of surface change shows a very large range of detected absolute changes from 6 mm to 6.96 m' Dimitri Lague, 2013

So what is this number in my case? I'm looking at the height difference between the two clouds as a measure of surface change.

Thanks