[PD] multiblob tracking in Gem while objects keep their IDs

[Max]

Am 27.05.2013 um 01:00 schrieb Jack <jack at rybn.org>:
> Le 26/05/2013 20:56, Max a écrit :
>> hi list, a student of mine, Jakob Gomoll, did solve how to track multiple blobs while every blob keeps its ID.
>> Here is where i scratch my head: It works fine until you render the output of the multiblob tracker to a rectangle.
>> I'd like to understand why this is.
>> 
>> Is it a bug or a feature?
>> connect the tracker to the pix_texture (where the red line is) and it will mess up the result:
>> 
> 
> Hello Max,
> This could be interesting for you :
> http://www.mail-archive.com/pd-list@iem.at/msg42343.html

Thanks Jack,
I know – I have posted on this thread too. We solved this problem differently. Because our application was microscopy and we had specimen who were stopping their movement for a while before moving on, the continuity approach wasn't working. Since we based the blob detection on frame differences [pix_movement] rather than background subtraction from a reference frame [pix_background] blobs who were resting for a few frames simply disappeared and got a new ID assigned.
Our approach is to set a time-out after we declare a blob dead. If it starts moving in the same region (size is settable too) again before the time-out, we pick up the old ID. So rather than using movement vectors as reference we used proximity. All data is stored in tables.

The patch works beautifully without any externals. Have you tried?

So this problem is already solved - my question was rather a Gem thing: why does is stop working when I want to render the image behind it? Do you know this?

Max