Communications: electrical – Digital comparator systems
Patent
1979-08-06
1982-12-07
Strecker, Gerard R.
Communications: electrical
Digital comparator systems
178 19, 324228, G06K 900, G08C 2100, G01R 3300
Patent
active
043630235
DESCRIPTION:
BRIEF SUMMARY
SPECIFICATION
FIELD OF THE INVENTION
This invention relates to a device for dynamic analysis of handwriting.
BACKGROUND OF THE INVENTION
Handwriting has already been studied in a static manner by graphology. However there are cases in which graphological analysis is inadequate or liable to mistakes and a dynamic analysis of the writing must be used. This requirement is increasingly necessary in order to authenticate signatures during the endorsement or issue of a cheque for example, or for payments or withdrawals of money by means of credit cards or travellers' checks which are being used more frequently.
Various solutions have already been proposed for dynamic analysis of writing, in particular for comparing two apparently similar signatures in order to ascertain whether they have been produced by the same person.
It has already been proposed for this purpose to measure the contact pressure of the pen on the writing support, and the lateral friction between the pen and the writing support. The drawback of these two proposals is that they are strongly influenced by the type of instrument used for writing as well as by the type of writing support, so that the information obtained by these methods may show wide variations between the analysis of two signatures made by the same person under different material conditions.
It has also been proposed to measure the successive accelerations during writing by means of accelerometers fixed to the writing instrument. The drawback of this solution is due to its dependence on the spatial arrangement of the accelerometers. In effect, as the writing instrument is generally of a cylindrical form, the accelerometers may be in any position about the axis when the instrument is picked up. Consequently, the accelerations recorded may vary considerably between two signatures made by the same person.
OBJECT OF THE INVENTION
The object of the present invention is to remedy, at least partially, the above drawbacks.
SUMMARY OF THE INVENTION
For this purpose, the present invention relates to a device for measuring characteristic features of the speed of handwriting which comprises, on one hand, two superposed windings of electrical conductors lying under the surface constituting the writing support, the two ends of each winding terminating in two measuring terminals, each of these windings having a portion in which its conductors are rectilinear, the portion of rectilinear conductors of one winding being at right angles to the rectilinear portion conductors of the other winding, the respective lengths of these portions of rectilinear conductors defining the surface area of the surface of the said writing support, and, on the other hand, a magnet adjacent to the writing tip of the writing instrument, the magnetization orientation of which is generally parallel to the longitudinal axis of the said instrument and symmetrical about this axis, so that when the tip of the instrument is displaced at least in the immediate proximity of the surface of the said support, voltages are induced in these windings, as a function of the rate of variation of the field with respect to these two portions of rectilinear conductors.
BRIEF DESCRIPTION OF THE DRAWING
The attached drawing is a very diagrammatic illustration, by way of example, of devices according to the present invention. In the drawing:
FIG. 1 is a diagram intended to explain the principle on which the device is based;
FIG. 2 is a plan view of the sensor element according to this embodiment;
FIG. 3 is an axial cross-section of a writing instrument designed to cooperate with this sensing element;
FIGS. 4a, 4b, 5a and 5b show diagrams corresponding to the voltages recorded at the terminals of the sensor element following two signatures by the same person;
FIGS. 6a and 6b show two further diagrams relating to the signature of another person;
FIG. 7 illustrates a variant of FIG. 2;
FIG. 8 is an explanatory diagram of the operation of this variant; and
FIG. 9 is a diagram of a circuit for processing the signal sensed by this v
REFERENCES:
patent: 3962679 (1976-06-01), Engelbrecht
Inokuchi et al., "A New Magnetic Device for Graphic Input" Systems-Computers-Controls vol. 4, No. 1, 1973, pp. 56-60.
Battelle (Memorial Institute)
Ross Karl F.
Snow Walter E.
Strecker Gerard R.
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