Patent ID: 7907061

Claim:
A method for use in monitoring the proximity of an object, comprising: (a) controlling a light source; (b) during one or more time period, detecting an intensity of both ambient light and light produced by the light source that is reflected off the object; (c) during one or more further time period while the light source is not producing light, detecting the intensity of the ambient light; and (d) producing, based on the intensities detected at steps (b) and (c), an output indicative of the intensity of the detected light produced by the light source that is reflected off the object, and that compensates for the ambient light including transient changes thereto so that an affect of the ambient light on the output is substantially removed; wherein because the affect of the ambient light on the output is substantially removed, the output produced at step (d) can be used to produce one or more estimate of the proximity of the object that is/are substantially unaffected by the ambient light.