I am using pix_blob with with pix_film. according to the help file, pix_blob outputs x and y coordinates of the 'center of gravity' through the second and third outputs, respectively. I've tried several movies, using all of pix_blobs' channel selections (Gray, R,G,B,A) but have not seen either of these outputs reach above 0.5. What exactly do these numbers represent? Is it the scaled range of the window (i.e. 0 is the far left/top and 1 is the far right/bottom)?

Also, whenever I set the blob analysis channel to alpha, output freezes at max values. What's up with this thing yo?

maybe the example sketch from the gem/4.pix directory might help a little.(attached)

i think this object is crap! too hard (impossible) to get in working and get any use from it.

any disagrees? somebody here, who got it working properly?

http://www.pdpatchrepo.info/hurleur/23.gravity.pd

In my experience [pix_blob] works really well but probably it requires one to spend some time on it.
I found out that [pix_data] is much more flexible and responsive for simple luminance/movement detection both with live stream and movie players.

Hi, I use [pix_blob] a lot with my students to work on presence detection and localization in a defined area. The limitation of the object is that it is completely dependant on the way light is captured by the cam in the room. To get usefull informations from the object, you have to take care of the light diffusion. It is necessary to use a spotlight in the detection area in order for the object to "see" luminance changes. Of course, you have to put a [pix_background] object just before to cancel the background.
Best

FDo