Greetings, I have been using PD for audio for a number of years, but now I am boldly exploring the multimedia side of it. So I need a bit of help with my patch.

I am interested in using GEM with live camera to get the information on the moving object on the camera.
More specifically, are the moving objects (changes) present in four quadrants of the image, and what is the minimal distance from the center of the image 'r', as depicted in the image below.

Using the pix_background it is easy to extract only the changes on an image and extract moving objects, but how do I detect in which quadrant of the image are these objects present, and what is the minimum distance from the center of the image?

In the case of the illustration, the objects are in the quadrant 1 & 4, and the minimum distance from the center is 'r'.

@happilylazy You should investigate TUIO .... https://www.tuio.org/
and you will find quite a lot of information about how it can be used with Pd here....... https://www.google.co.uk/search?q=pdpatchrepo+tuio+site:forum.pdpatchrepo.info&complete=0&hl=en&sa=X&ved=2ahUKEwjzvL6VuOreAhWixoUKHR8fBk8QrQIoBDAAegQIBRAM&biw=1440&bih=844
Most of the posts are about problems of course, but there are a lot of links and plenty of info.
and here......https://github.com/teo523/pd-reactivision-wekinator
The communications can be done in pure vanilla (without mrpeach) using newer objects.
It will give you x and y position in the image, and angle (orientation of the blob)..
It is built to recognise and identify fiducials, but I remember that it can also return data for "blob"s.
David.

Wow, thanks a lot for these specific implementation. They look like exactly what I need.
I will try to use them and see how far I can get.

But, I was still wondering if masking, or pixel analysis could solve my problem using pure GEM. Simply.