[PD-dev] GridFlow/#labeling

Mathieu Bouchard matju at artengine.ca
Thu Aug 13 18:57:16 CEST 2009

On Thu, 13 Aug 2009, sisil mehta wrote:

> I found a patch called pix-multiblob-help.pd in PD-extended. is it 
> similar to the multiblob-for-gridflow patch that u had written?

Well... yes and no. If you compared the help file with what I've told you 
about [#labeling], you would see that several features don't match: with 
[#labeling] you're supposed to do the threshold yourself (with [# >=] or 
anything else); [#labeling] does not give you the min/max (bounding box) 
but [pix_multiblob] does not give you the variance. In my opinion the 
variance is a very useful measurement, but then that's why I wrote 
[#labeling] the way I did.

Also, [#labeling] gives you the data in little pieces instead of a big 
table like [pix_multiblob] does. You'd think it would be more in 
GridFlow's style to put data in big chunks (which is the normal way to do 
things in GridFlow) but I made this an exception to make it easy to filter 
out unwanted blobs using [spigot]. For example, in multiblob.png you can 
see that it only keeps blobs that have at least 25 pixels.

You could make any other filters you want: for example, you could keep 
only blobs that spread on a large amount of space (regardless of actual 
area of the blob); or you could keep directional blobs (long and narrow), 
which would keep narrow ovals and narrow rectangles, to reject circles and 
squares (which are as long as they are wide).

I don't know what the iemmatrix offers for processing [pix_multiblob]'s 
output. Perhaps Johannes can give some examples.

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| Mathieu Bouchard - tél:+1.514.383.3801, Montréal, Québec

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