Method for the determination of the distance and the angular position of an object

A method of determining distances and angular positions of stationary and moving objects within an area being monitored in connect ion with a swinging door, the method comprising the following steps:

• (a) utilizing a transmitter to transmit substantially collimated light in the area being monitored in different angle sectors in a certain predetermined sequence so that the different angle sectors receive the substantially collimated light at different moments;
• (b) utilizing a position-sensitive sensor to detect the substantially collimated light as reflected by a possible object in the area being monitored, the position-sensitive sensor being positioned a certain distance from the transmitter and receiving the substantially collimated light as reflected by a possible object in the area being monitored from the different angle sectors in a corresponding sequence, the substantially collimated light as reflected by a possible object in the area being monitored produces a point of registration on the position-sensitive sensor, the point of registration on the position-sensitive sensor changes when the distance to a possible object in the area being monitored changes;
• (c) generating output signals from the position-sensitive sensor which are representative of both distance and angular position of the possible object in the area being monitored;
• and
• (d) comparing the output signals from the position-sensitive sensor to stored reference signals.