Hi guys, I'm fairly new to max and currently I'm working on a project for an interactive sound installation.

I want to track the position of two people (walking and standing still) in front of a camera. The width-range the camera can see will be about 5 meters. I want to know the position of the two people, the distance between them can then be obtained from that.

A simple way to track a person I though was to use grayscale live video with a width resolution of 12 pixels and slice that into 12 slices with jit.scissors. Now I can see the brightness of each of the 12 pieces individually, and attached them to a jit.cellblock.

Currently I only use 1 pixel height resolution so in the cellblock I only have one row, and the 12 columns for each grayscale 0-255 value. What I want to know now is the column in which value is the lowest (that represents where one person is standing)

I've tried some stuff and looked around but coundn't find a (preferably simple) solution yet.

I hope you understand my question, thanks!

Hi guys, I'm fairly new to max and currently I'm working on a project for an interactive sound installation. 

I hope you understand my question, thanks!


select-highest-value-from-jit-cellblock

There are external objects available that solve this problem in a 

simple way. These will also give you information about the position 

at a finer resolution than your approach. Try my 2up.jit.centroids 

object at 2uptech.com or the cv.jit.centroids object in the cv.jit 

On Jan 16, 2009, at 12:50 PM, Mischa Daams wrote:

> Hi guys, I'm fairly new to max and currently I'm working on a 

> project for an interactive sound installation.

> I want to track the position of two people (walking and standing 

> still) in front of a camera. The width-range the camera can see will 

> be about 5 meters. I want to know the position of the two people, 

> the distance between them can then be obtained from that.

> A simple way to track a person I though was to use grayscale live 

> video with a width resolution of 12 pixels and slice that into 12 

> slices with jit.scissors. Now I can see the brightness of each of 

> the 12 pieces individually, and attached them to a jit.cellblock.

> Currently I only use 1 pixel height resolution so in the cellblock I 

> only have one row, and the 12 columns for each grayscale 0-255 

> value. What I want to know now is the column in which value is the 

> lowest (that represents where one person is standing)

> I've tried some stuff and looked around but coundn't find a 

> I hope you understand my question, thanks!

There are external objects available that solve this problem in a  
simple way.  These will also give you information about the position  
at a finer resolution than your approach.  Try my 2up.jit.centroids  
object at 2uptech.com or the cv.jit.centroids object in the cv.jit  
package.

>
> Hi guys, I'm fairly new to max and currently I'm working on a  
> project for an interactive sound installation.
>
> I want to track the position of two people (walking and standing  
> still) in front of a camera. The width-range the camera can see will  
> be about 5 meters. I want to know the position of the two people,  
> the distance between them can then be obtained from that.
>
> A simple way to track a person I though was to use grayscale live  
> video with a width resolution of 12 pixels and slice that into 12  
> slices with jit.scissors. Now I can see the brightness of each of  
> the 12 pieces individually, and attached them to a jit.cellblock.
>
> Currently I only use 1 pixel height resolution so in the cellblock I  
> only have one row, and the 12 columns for each grayscale 0-255  
> value. What I want to know now is the column in which value is the  
> lowest (that represents where one person is standing)
>
> I've tried some stuff and looked around but coundn't find a  
> (preferably simple) solution yet.
>
> I hope you understand my question, thanks!
>


Thanks for your quick reply Randy, i'm definitely going to try / use the centroids object, probably in combination with an 'empty' background to compare difference.

But I would find it pretty cool if there was a way find the lowest value from a row in a cellblock.. Because its really simple and fast. I found the minimum object but the problem is when I unpack the cellblock object and place them in a coll an I sort them from small to big I can't get an automated way to get the column number from the smallest value..

Do you or someone else know a easy way to output the column number with the lowest value?

I tried some things (like to put them in a coll) you can see in the patch but nothing gave me the column(index) number with the lowest data value.

Btw great achievement with the multitouch prototype!

Jit.3m is the object you want. The other objects under "Jitter 

Analysis" in the New Object List may also help.

Jit.cellblock is just a GUI object, so I wouldn't put it between your 

On Jan 16, 2009, at 3:13 PM, Mischa Daams wrote:

> Thanks for your quick reply Randy, i'm definitely going to try / use 

> the centroids object, probably in combination with an 'empty' 

> But I would find it pretty cool if there was a way find the lowest 

> value from a row in a cellblock.. Because its really simple and 

> fast. I found the minimum object but the problem is when I unpack 

> the cellblock object and place them in a coll an I sort them from 

> small to big I can't get an automated way to get the column number 

> Do you or someone else know a easy way to output the column number 

> I tried some things (like to put them in a coll) you can see in the 

> patch but nothing gave me the column(index) number with the lowest 

> Btw great achievement with the multitouch prototype!

Jit.3m is the object you want.  The other objects under "Jitter  
Analysis" in the New Object List may also help.

Jit.cellblock is just a GUI object, so I wouldn't put it between your  
video and your data output.

> Thanks for your quick reply Randy, i'm definitely going to try / use  
> the centroids object, probably in combination with an 'empty'  
> background to compare difference.
>
> But I would find it pretty cool if there was a way find the lowest  
> value from a row in a cellblock.. Because its really simple and  
> fast. I found the minimum object but the problem is when I unpack  
> the cellblock object and place them in a coll an I sort them from  
> small to big I can't get an automated way to get the column number  
> from the smallest value..
>
> Do you or someone else know a easy way to output the column number  
> with the lowest value?
>
> I tried some things (like to put them in a coll) you can see in the  
> patch but nothing gave me the column(index) number with the lowest  
> data value.
>
>
> Btw great achievement with the multitouch prototype!
>


Select highest value from jit.cellblock