Data processing: measuring – calibrating – or testing – Measurement system – Article count or size distribution
Reexamination Certificate
1998-11-09
2001-12-04
Shah, Kamini (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system
Article count or size distribution
C377S005000, C377S006000, C377S045000
Reexamination Certificate
active
06327547
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method and system for estimating an number of objects effecting dynamic contact with a confined area of floor space. In particular, the invention finds application for estimating the number of occupants in a confined area such as a store, public transport and the like.
BACKGROUND OF THE INVENTION
Various prior art proposals exist for estimating a number of occupants in a confined spaces such as, for example, an elevator, store and so on. For example, in International Publication No. WO 97/02474, there is proposed an improved method based on the use of a matrix of pressure contacts for estimating an actual occupied area of floor in a confined space. Pressure contact points are clustered so as to form composite areas of floor which are occupied and a boundary is provided around each of these areas in order to allow for minimum breathing space between adjacent passengers. On this basis, the total occupied area may be estimated. However, such a method still does not give an accurate estimation of the actual number of passengers in the elevator because the footprints of two passengers standing in very close proximity will be so close that they are clustered together and, to all intents and purposes, are treated as a single footprint. This, of course, does not matter when only occupied or free area in a confined space is of interest. However, it is critical when an actual number of occupants is to be estimated.
This having been said, there is a fundamental difference between, on the one hand, the situation where people are static in a confined space and, on the other hand, when people are moving across a confined space so as to effect dynamic contact therewith. In the static case, for example in an elevator car, as more people are confined into the limited space thereof, their feet inevitably are brought into ever closer proximity. Eventually, it becomes impossible to determine whether adjacent pressure contact points belong to the same footprint or to the adjacent footprints of two people standing almost on top of one another. As noted, this does not matter where an estimation of occupied floor space is all that is required, but it clearly militates against an accurate estimation of the number of occupants.
However, in the second, dynamic case, where people are constantly on the move and where they effect only transient contact with the sensor, the likelihood that two different people in close proximity will exert pressure on the sensor simultaneously is so slim as to be safely negligible. This means that, contrary to the static case discussed above, each distinct cluster of pressure points may be identified with a unique instance of a person making his way across the sensor.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method and system for estimating a number of objects effecting transient contact with a floor area.
According to a broad aspect of the invention there is provided a method for counting a number of objects passing through an entry threshold, the method comprising:
(a) disposing a sensor having a matrix of sensing points in an area of the entry threshold,
(b) identifying successive complete footprints of the same object on said sensor, and
(c) distinguishing between different footprints using clustering.
Thus, in accordance with the invention a sensor is employed for registering objects entering and leaving an entry threshold it being assumed, as noted above, that two or more people will not be so close on the trail of one another that their respective footprints make virtually simultaneous and contiguous contact with the sensor.
The method according to the invention also allows for wheeled objects such as baby carriages and wheel chairs to be counted as well as objects dragged across the sensor such as, for instance, a piece of luggage and the like.
REFERENCES:
patent: 4223887 (1980-09-01), Holtz
patent: 4303851 (1981-12-01), Mottier
patent: 5656801 (1997-08-01), Goren et al.
patent: 9702474 (1997-01-01), None
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