Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1999-02-19
2000-12-12
Trieu, Van
Communications: electrical
Condition responsive indicating system
Specific condition
340556, 340557, G08B 1318
Patent
active
061604798
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to a method and device for determining the distance and position of stationary and moving objects, for example within an area to be monitored in connection with, for instance swing doors.
2. Description of the Prior Art
It is known to use sensors for detecting objects, such as people, in close vicinity to, for example swing doors which open automatically. One common sensor is a pressure-sensitive mat placed in front of the door where the form and size on the mat is adapted to current rules and criteria. The disadvantage with such mats is that they quickly become worn out, they are expensive since they must often be recessed on the ground level and that they are sensitive to sharp objects such as heels and stones. Another known sensor is based on the capacitive function but the disadvantage with this sensor is that it is sensitive to disturbances from the temperature, dampness and so on. In addition, it is difficult with this sensor to distinguish between stationary objects that are close to each other. For moving objects, it is known to use sensors based on microwave and the Doppler effect technology. Using passive infra-red technology is also known but the disadvantage of this is the difficulty in detecting objects which have the same temperature as their surroundings. Finally, it is also known to use active infra-red technology in sensors but these known devices often have the disadvantage of the object's size and properties of reflection greatly affecting the distance of detection and sensitivity. For sensors of the above types, it is necessary that they fulfill certain stipulated requirements, for example the requirements on the size and form of the security area, the capacity to be able to distinguish between several objects in the area, response time, noise tolerance and so on.
The method according to this invention provides a solution to the above given problems.
SUMMARY OF THE INVENTION
The objective of the invention is to provide a method for determining the degree of the angular position and distance to stationary and moving objects which are found to be within the area to be monitored in connection with, for example swing doors or the like. The determination takes place with triangulation, that is the optical measurement of distance with help of the measurement of the angle in a triangle with a known base. The purpose of this measurement is to detect whether any object appears within the door's so called "security area" and, in such case to send a signal to the door's driving device to not close/open the door or to change the door's movement. Another purpose is to initiate the opening of the door if someone approaches the activation area of the doors.
Amongst other things, the invention is characterized by light, which is mainly collimated, being transmitted to the area to be monitored in a certain sequence and at different angles. The reflected light is then registered in a position-sensitive detector located at a certain distance from the transmitter. As soon as the distance to the object changes, the point of registration on the detector changes. Consequently such a sensor's primary output becomes the distance to an object and in which angular section the object appears.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view showing the optical path of light transmission to a sensor according to the invention.
FIG. 2 is a perspective view of an embodiment of the path of light transmission according to the invention.
FIG. 3 is a flow chart of the detection process according to the invention.
DESCRIPTION OF EMBODIMENTS
FIG. 1 shows the path of light transmission to a sensor used to determine distance and position according to the invention, and where 1 (FIG. 2) represents one or more sources of light (1a, 1b, 1c), for example IR light sources in a transmitter. These light sources are arranged in a special pattern and by such the transmitted light can be collimated by means of a transmitter optic system, 2, and se
REFERENCES:
patent: 4319332 (1982-03-01), Mehnert
patent: 4628496 (1986-12-01), Lee
patent: 4760381 (1988-07-01), Haag
patent: 4879461 (1989-11-01), Philipp
patent: 4967083 (1990-10-01), Kornbrekke et al.
patent: 5357309 (1994-10-01), Seki
patent: 5739523 (1998-04-01), Tsutsumi et al.
patent: 5973594 (1999-10-01), Baldwin et al.
.ANG.hlen Hans
Carlsson Olof
Besam AB
Trieu Van
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