v.noisegate v.noisegate sets all pixels with brightnesses < noise threshold to zero. v.noisegate sets all pixels with brightnesses < noise threshold to zero. The operation can be set to work on pseudo-signed streams (meaning that 128 is assumed to represent 0, and values that are less than noise threshold away from zero (either above or below) are set to 128	from the library : softVNS Format : External Environment : jitter / max commercial Max 4.x http://homepage.mac.com/davidrokeby/softVNS.html