point cloud find center

I have a very large point cloud (42 million points), and I need to find the center of this cloud.

Answer 1

[Star Strider]

The centre (or more accurately in this example, ‘centroid’) is the mean of the individual x, y, and z coordinates for the cloud. So if each row of the matrix defining them is an individual point, and the columns define the position of each point, the coordinates of the centroid are the mean of the matrix.

Answer 2

[Image Analyst]

Why can't you just average all of the components?

[Evan]

First off, Thank you Image Analyst. I have tried simply taking the avg of the x y z values, but the results are not quite right, so I figured I would inquire in hope that there is a pre-built Matlab tool that I was missing.

[Image Analyst]

Why do you say it's not right? I know there may be some reasons (and I can think of some) but I want to hear your reason.

[Walter Roberson]

What is the range of values? With 42 million of them, I would be concerned about exceeding (required precision)/eps when they are totaled

[Image Analyst]

Good point. Might be able to get pretty much the same centroid just by taking a subset of them.