detection systems adapted to hand held devices require touching a screen a gesture detection system is disclosed herein that requires no contact with a screen and that is relatively simple and robust for use in a hand held device such a system may be based on the operation principle of a finger mouse the imaging surface of the conventional finger mouse is however omitted whereby the user 39 s hand or a pointer object may move at an arbitrary distance from the sensor the depth of field of the lens or optical system of the sensor may be sufficient to discriminate motion of the pointer object over a wide range of distances from the sensor however the size of the image captured by the sensor varies with the distance of the object from the sensor whereby the motion information produced by the sensor is not representative of the actual motion of the object to overcome this difficulty a distance sensor may be associated with the image sensor to measure the distance between the object and the sensor and to correct the motion information output by the motion sensor an exemplary mechanical configuration of such a system is schematically illustrated in fig1 the distance sensor may be an optical time of flight sensor including on a substrate 8 an infrared radiation source 10 emitting photons 12 substantially perpendicularly to the substrate a photon detector 14 is arranged on the substrate close to the emitter 10 for receiving photons reflected from a pointer object 16 moving over the substrate 8 the detector 14 may be based on.