Grabs a background image at a point in time and subtracts this from the incoming image. The operator works in two modes, "adaptive" and "one time". In one time mode, a bang in the first inlet grabs the next image as the background. In adaptive mode, four parameters determine how the imcoming images is incorporated into the background image.

Inlets & Arguments:

#	Name	Arg	Description
1	image	n/a	Eyes Image, standard operator messages see: eyes messages
2	adaptive background on/off	a	Turns adaptive backgrounding on and off. 0=off 1=on.
3	preserve	p	Attempts to preserve the image intensity values. (Doesn't work well in practice)
4	cycle	c	Number of frames used to integrate in order to obtain a background. c = (f[0] + f[1] + ... + f[n])/n. Where c is the integrated background and f[x] is a frame in time, and n is the number of frames to integrate.
5	percent	%	Once frames are integrated, this is the percentage of that image that is integrated into the current background. b = b*(1-%) + c*%. Where b is the current background, % is the percentage value, and c is the new data obtained from the background integration.
6	skip	s	Skip this number of frames between cycles. This is the number of frames where no adaptation information is calculated between each point in time where background information is calculated. c[0] = (f[0] + f[1] + ... + f[n])/n The next integration is c[1] = (f[s] + f[s+1] + ... + f[s+n])/n etc. Same as formula in cycle, s is the number of frames to skip.

Outlets:

#	Name	Description
1	background subtracted image	Image with the background subtracted.

Messages:

bang

A bang in the first inlet grabs the current image as the background.

Standard messages

Accepts all messages sent to the eyes object. See eyes messages.

Argument messages

Accepts all inlet arguments as messages: ab, p, c, %, and s.

Example: