[PD] pix_multiblob and tracking multiple objects

[Antoine Villeret]

i tried CCV one time but i had some driver and performance issues
moreover, i can't find an easy way to tune the processing chain
pd is more flexible but, i agree, could be harder

--
do it yourself
http://antoine.villeret.free.fr


2013/4/18 John Harrison <john.harrison at alum.mit.edu>

> I'm not totally clear on the big picture here but it could be you might
> save yourself a lot of time and effort doing your blob tracking with
> Community Core Vision (CCV) then sending the blob data to Pd through OSC.
> After initially doing my blob tracking in Pd only (which did work), I
> switched to this CCV --> Pd approach and got better results because of all
> of the built-in filtering etc. that is provided with that open-source
> cross-platform software.
>
> -John
>
>
> On Thu, Apr 18, 2013 at 5:22 AM, Ska Frenz <skafrenz at gmail.com> wrote:
>
>> Hi, thank you for the suggestions, I'll check openCv. Can you explain how
>> to use "morphological filters" to clear up the noise in the image? Are
>> there examples around? Also, could you please explain me better what do you
>> mean with "adaptive background subtraction method"?
>>
>> Thank you for your time :)
>>
>> francesco
>>
>>
>> 2013/4/17 Antoine Villeret <antoine.villeret at gmail.com>
>>
>>> hi,
>>>
>>> the segmentation method (how you extract what is your interest from the
>>> rest of the image) is very critical in video tracking
>>> background subtraction is a basic way to extract blob and it works only
>>> in certain conditions of light (if you want to track something outdoor, you
>>> should use an adaptive background subtraction method)
>>> moreover, there is no general method to do video tracking, it depends on
>>> what you want to track and how it is filmed
>>>
>>> so, the first thing is to have a good image, with not too much lighting
>>> changes, good contrast between background and features to track
>>> then you can start thinking about segmentation, and the
>>> segmentation accuracy depends on the quality of the video
>>> you may need to do something more than just background subtraction, for
>>> example, you could apply some morphological filter to remove noise
>>> after that, you can start tracking
>>> you could also apply a threshold on the blob size to not track very
>>> small blob
>>> blob of interest are often surrounded by very small blobs due to
>>> segmentation noise
>>>
>>> but you can have a look at pix_opencv objects,
>>> there is [pix_opencv_blobtrack] which implements a whole processing
>>> chain, including foreground extractor, blob detector, blob tracker and
>>> follower
>>> I'm not sure it's included in pd-extended, but you can find some
>>> binaries on build server
>>>
>>> hope this help
>>>
>>> antoine
>>>
>>>
>>> --
>>> do it yourself
>>> http://antoine.villeret.free.fr
>>>
>>>
>>> 2013/4/17 Ska Frenz <skafrenz at gmail.com>
>>>
>>>>  Hi everyone, this is my first time on the pd-list so I hope I won't
>>>> do anything wrong.
>>>> I'm writing here to get some help about pd tracking objects
>>>> (pix_blob..). I'm using the background subtraction method, to track objects
>>>> and I need help to understand how I can track multiple objects with
>>>> multiples different blobs. I'm trying the pix_multiblob and yes, it show 2
>>>> blobs..but they track the same object. Then basically I do not understand
>>>> how can I make the first blob to follow just one object for all the time
>>>> that specific object is inside the webcam rectangle, and the second blob to
>>>> track another separate object. I cannot find any material that clearly
>>>> talks about this.I attached the patch I'm working on. I'd love to see some
>>>> well-explained examples if you know where to get them.
>>>> Thank you very much for your help :)
>>>>
>>>> Francesco
>>>>
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>>>
>>
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