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

• US 6,160,479 A
• Filed: 02/19/1999
• Issued: 12/12/2000
• Est. Priority Date: 05/07/1996
• Status: Expired due to Term

• Current Assignee: Assa Abloy IP AB (Assa Abloy AB)
• Original Assignee: Besam AB (Assa Abloy AB)
• Inventors: Carlsson, Olof, .ANG.hlen, Hans
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/180,349
• Time in Patent Office: 662 Days
• Field of Search: 340/545.1, 340/545.3, 340/555, 340/556, 340/557, 340/686.1, 340/686.2, 340/686.6
• US Class Current: 340/555
• CPC Class Codes: G01C 3/10 using a parallactic triangle with variable angles and a base of fixed length in the observation station, e.g. in the instrument
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves

Abstract

A method of determining distances and angular positions of stationary and moving objects (3), for example in an area to be monitored in connection with for instance swing doors. The determination is done by means of triangulation where light, which in the main part is collimated, is transmitted (1) into the area at different angles and in a certain sequence. The reflected light is correspondingly registered on a position-sensitive sensor (5) which is positioned at a certain distance from the transmitter (1). The position (5a, 5b), where the reflected light falls on the sensor (5), represents the distance, and the moment when the light is received represents the angular position of the detected object. The values are compared to stored reference values which change when the angle of the door'"'"'s opening is changed.

Claims

1. 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.

2. A method according to claim 1, wherein the substantially collimated light is transmitted by means of at least one light source, the different angle sectors are different vertical and horizontal angular sectors, each angular sector is illuminated by the at least one light source and the angular sectors are illuminated sequentially in accordance with the certain predetermined sequence.

3. A method according to claim 2, wherein the predetermined sequence depends on previous detections.

4. A method according to claim 1, wherein the output signals from the position-sensitive sensor correspond to an amount of the substantially collimated light and a position of the substantially collimated light on the position-sensitive sensor and the stored reference signals, to which the output signals are compared, are changed based on at least one parameter of the door.

5. A method according to claim 4, wherein the at least one parameter is selected from a group consisting of an opening angle of the door, speed of the door and direction of movement of the door.

6. A method according to claim 5, wherein the reference signals for different angles of opening are updated automatically and gradually during normal operation of the door.

7. A method according to claim 1, further including the step of generating a signal to a driving device of the door for braking, stopping and changing of direction of the door.

8. A method according to claim 1, further comprising the step of inputting and storing the reference signals.

9. A method according to claim 1, wherein the transmitter has a transmitter optic system of an anamorphic type having x and y axes with different scales for reproduction of images.

10. A method according to claim 1, wherein the position-sensitive sensor has a receiver optic system consisting of an array of lenses where each lens reproduces an image of a small angular area of the area being monitored.

11. A method according to claim 10, wherein the lenses are Fresnel lenses.

12. A method according to claim 1, wherein a receiver optic system is positioned in front of the position-sensitive sensor, the receiver optic system comprising diffractive optics.

13. A method according to claim 12, wherein the receiver optic system comprises at least one kino form, each kino form reproduces images of several different and separate angular areas.