Image Processing and Centroid Determination

Hi,

I'm currently processing images to track objects and I want to determine the location of the object in pixels. I used the matlab function centroid to do this and it works perfect.

My question is I am getting numbers with decimals. ie(232.34,456.72) How are the extra significant figures being determined and can I trust these values?

Thanks in advance!

Answer 1

[Image Analyst]

Let's say the pixels are considered to be at the center of the number. So with this image

[0, 1, 1, 0]

There is a pixel at 2, and one at 3. So the centroid would be at 2.5. If the image is

[0, 1, 1, 1, 1, 0
 0, 1, 1, 1, 1, 0]

The xCentroid is at 3.5 and the y centroid is at 1.5. As you can imagine, as you get lots more pixels, the centroid could be at some other fractional location. Does that explain it?

[Brandon]

Yes, that makes complete sense! I don't know why I didn't think about it that way. I always tend to over think things!

Thank you!