Hi, all


ttc. readpresence instead of motion.txt

Several people have had problems with the ttc routines requiring constant motion in order to activate.  For example, Jessica wanted the section of the image to continue to fill in as long as you stand in the same place.  There is a somewhat easy fix to this if your camera is looking on a scene that does not change - for example, if you can grab an image of the empty room and nothing will change except people moving around it.  Sometimes you can't do this - for example if people are moving against a changing video projection.  If you have a situation that is static then this fix may work.

If you are using the checknewchange template, notice the last line starting with remember.  This line uses the last grabbed image as a new template.  It constantly calibrates the scene, which is great if you have a changing scene.  The unfortunate consequence is that if a person moves into an area and just stands there, the changes are read as they move in but once they are static, it uses their last static image as the template and it looks like there is no change.

You can overcome this by taking a reference frame near the beginning before people walk in and not again.  This won't work in situations that have changing light - for example outside with sun and shadow movement.  It has to be activated after ttc sets up.  Here's how to modify what you have:

1. comment out the last line in the routine starting with remember
  --  remember(trackobj,0)--&&  -- remember the last grab to prepare for next check

2. arrange to take a grab when the room is empty.  If you copied the whole routine, you can find something called takeref.  If you didn't bring it in, it is listed below.  Put it on the movie level.

3. You could just activate it by typing it in the message box before people come in.  You could try putting it into the end of your startmovie routine but sometimes things have not settled down by that time so it gets garbage.  Maybe some timer before it is activated?



on checknewchange
  global foundlist, trackobj,vidrect  -- basic changed pixels checking routine
  
  -- define rect to track - in this come in 10 px on all sides - avoid noise
  -- need to coordinate what rect with the size of frame being captured ? vidrect
  frect=rect(10,10,310,230) --&&
  foundlist=[] -- empty found list
  -- how sensitive 0-100// 100 really very picky/ 10 very tolerant/ adjust for situations
  sen = 10
  GrabOneframe(trackObj)
  -- GrabSomeFrames(TrackObj, 1, 2)  -- grab 2 frames using the method 1 averaging
  GrabToCast(TrackObj,[vidrect,29])  -- put it into cast so can see it if sprite on stage
  BlobList = [sen,frect] -- make blob list out of sensitivity and rect to be tracked
  trackchangeblobs(trackobj,[BlobList] )  -- activate command
  set foundList = the result[1]  -- the routine returns rects of change in the result - set to foundlist
  --put  foundlist  --&&  print out what found as debugger - omit in real program
  remember(trackobj,0)--&&  -- remember the last grab to prepare for next check
end



on takeRef
  global TrackObj
  --set searchRect = rect(10,10,VideoWidth-10,VideoHeight-10) 
  grabOneframe(TrackObj)
  Remember(TrackObj,0)  -- 0 means live feed , other numbers refer to cast members for quicktime monitor
end