Patent ID: 8279414

Claim:
A device adapted for monitoring a delimited area in order to detect if an undesired object is present within the area, comprising: at least a first laser, which is adapted to emit a laser pulse of a determined wavelength over the area, at least a first photo sensor, which is arranged to receive a reflected part of the laser pulse, an evaluation unit, which is connected to the laser and the photo sensor, wherein the evaluation unit is arranged to measure the reflected part of the laser pulse during an adjustable time period after the pulse has been emitted from the laser, to generate a signal having an energy and depending on the measured reflected part, and to process the generated signal in order to determine if an undesired object is present within the area, and wherein the evaluation unit is arranged to compare the generated signal with a reference signal having an energy, and to establish that an object is present within the area if the energy of the generated signal exhibits a deviation from the energy of the reference signal with a minimum predetermined value.