Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1988-04-21
1989-07-11
Westin, Edward P.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250342, 340567, 377 6, 377 53, G08B 1318
Patent
active
048474851
DESCRIPTION:
BRIEF SUMMARY
The invention relates to an arrangement for determining the number of persons and a direction within a space to be monitored according to the preamble of claim 1.
In the prior art, it is attempted to achieve the so-called "singling-out" in the known control systems in that firstly the so-called sluice room or pass-through is maintained structurally narrow or tightly limited, and secondly, that the pass-through is closed off by means of two mutually locked doors, or in that the undesirable simultaneous admission of a second person is prevented by means of weight testing. In the first named case, the so-called rotatable locking turnstiles are known which are only made functional after an identification card check by an identification reader. Instead of identification cards, for example at large sporting events, the entry ticket is inserted into the reader slot. By carrying a second person on the shoulders, such singling-out devices may be easily deceived. Estimates indicate that between 14 and 18% unauthorized persons enter in this manner.
If the singling-out arrangement involves a closed narrow sluice room or pass-through, then claustrophobia results for a large number of visitors, so that an arrangement which functions in this manner is already rejected by the company personnel counselor.
The situation is similar for the known narrow pass-throughs which are closed by two doors, whereby after the entry door has been closed, the exit door automatically opens. Here, the difficulty additionally arises that the narrow sluice room or pass-through becomes a "prison" during functional troubles which, for example, arise due to power failure, etc., and therefore, additional emergency call arrangements, door opening devices which become active during a power failure, and the like become necessary.
If, however, in the above mentioned instances the sluice room or pass-through is made wider, then the simultaneous entry of two people is no problem, and the security arrangement is very easy to overcome.
In the embodiment in which the singling-out is carried out by means of a weight control via tread boards, etc, an outsmarting by two persons is similarly relatively easy because the prescribed weight tolerance must be maintained very high so that it is no problem, for example, that two slender women can enter simultaneously, or an adult person and a youth. Besides that, in all of the above mentioned cases the technical effort and expense is very considerable.
German Patent Publication (DE-OS) 2,542,594 discloses an arrangement for determining the number and direction of persons within a space to be monitored or a pass-through, especially the double door of a vehicle, in which at least two IR-sensors and an evaluating unit are used for determining the number of persons passing through. An active system is used for the detection, namely, a light barrier system with transmitters and receivers. This has the advantage that the space region being monitored is exactly defined by the transmitting region and is therefore relatively easily circumventable, or must be held small enough by mechanical boundaries, which is however, not a problem in the described range of applications.
It is the object of the present invention to embody the known arrangements for determining the number and direction of persons in such a manner that an increased security against the fradulent entry by persons is achieved, without requiring that the monitoring region be excessively narrowed by means of walls.
This object is achieved by means of the measures defined in the characterizing clause of claim 1. Advantageous embodiments are set forth in the dependent claims, and example embodiments are dealt with in the following description and are shown schematically in the figures of the drawing, wherein:
FIG. 1a is a top view onto a wide passage of which the door is opened by an identification reader arranged on both sides;
FIG. 1b is a top view onto a wide corridor which possesses a sluice room or pass-through closed by two doors and each door is opened by an
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Fasse W. G.
Kane, Jr. D. H.
Westin Edward P.
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