Low-cost, robust gravimetric system for enhanced security of accesses to public places

Working Principle and Performance of a Scalable Gravimetric System for the Monitoring of Access to Public Places

“…A different field of application for smart floors, footboards and platforms is security [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Herein, the floor is used to monitor the occupancy of surveilled or sensitive areas, possibly to identify the people present inside these areas and, finally, in the novel application field considered in this paper, for the control of access in walk-through gates.…”

“…This is especially true for the application proposed in this paper, i.e., automatic control of accesses in public places through walk-through gates, where a very high throughput is expected, and fast (theoretically on-line) analysis of transit events is needed. The technology proposed to meet the requirements of this specific application is provided by gravimetric systems: in fact, different from sensor matrix-based footboards, gravimetric platforms have a simpler but more robust structure, similar to the one of a common weighing scale, consisting of a rigid plate supported by a small number of force sensors (such as load cells), usually placed at the platform corners [ 17 , 18 ]. Obviously, the platform surface is not an active sensing area; nevertheless, the output of the force sensors besides providing information about the magnitude of the net vertical force applied to the plate, can be used to accurately assess its application point position [ 17 , 18 ] as a function of time.…”

“…The technology proposed to meet the requirements of this specific application is provided by gravimetric systems: in fact, different from sensor matrix-based footboards, gravimetric platforms have a simpler but more robust structure, similar to the one of a common weighing scale, consisting of a rigid plate supported by a small number of force sensors (such as load cells), usually placed at the platform corners [ 17 , 18 ]. Obviously, the platform surface is not an active sensing area; nevertheless, the output of the force sensors besides providing information about the magnitude of the net vertical force applied to the plate, can be used to accurately assess its application point position [ 17 , 18 ] as a function of time. When only one person or object is present on the footboard, her/his/its position can be estimated quite simply and accurately, as shown in [ 18 ], where this approach is applied to the localization of a robot.…”

“…When only one person or object is present on the footboard, her/his/its position can be estimated quite simply and accurately, as shown in [ 18 ], where this approach is applied to the localization of a robot. Things get more complicated if more than one person is present on the gravimetric platform, or if one person is pulling a luggage on wheels, or, more generally speaking, if there are other application points of the vertical forces beyond the feet of a single person [ 17 ]. Indeed, the force information is integrated over the relatively large area of the plate and this limits the capability of spotting any type of irregularities.…”

“…Here, we analyze the working principle and the performance of a scalable smart gravimetric system, described in a previous paper by the same authors [ 17 ], which is specifically designed for the control of walk-through accesses to public places with the aim of detecting simultaneous passages of more than one person. The system is based on a gravimetric footboard composed of a small array of traditional gravimetric platforms [ 17 ]. The proposed system is conceived to operate together with other deployed systems, such as surveillance cameras, metal detectors and Radio Frequency Identification (RFID) readers.…”