Device and Method for Decoding Magnetic Patterns

Abstract

A device for decoding magnetic patterns printed on documents comprising a reading head (12) having: a reader (20) arranged to read first magnetic signals belonging to the magnetic patterns and to electromagnetic noise due to sources internal and/or external to the device. The device further comprises: a further reader (40), arranged to read second magnetic signals belonging to the electromagnetic noise, an adder component (25) arranged to algebraically subtract the amplified second magnetic signals from the amplified first magnetic signals, and a converter (16) arranged to convert the resulting signal into a digital signal representing the read magnetic patterns. A method for decoding magnetic patterns is also disclosed.

Claims

1. A device for decoding magnetic patterns printed on documents, comprising a reading head (12) having a first reader (20, 112) arranged to read first magnetic signals, said first magnetic signals being related to the magnetic patterns and to electromagnetic noise due to sources internal and/or external to the device; characterized by a further reader (40, 140) arranged to read second magnetic signals related to the electromagnetic noise; an adder component (25, 125) arranged to algebraically subtract said second magnetic signals from said first magnetic signals; and a converter (16) arranged to convert the resulting signal into a digital signal representing the read magnetic patterns.

2. The device for decoding magnetic patterns according to claim 1 further comprising a first amplifier (15a) connected to the reading head (12) and arranged to amplify said first magnetic signals read by said first reader (20, 120); and a second amplifier (15b) connected to the further reader (40, 140) and arranged to amplify said second magnetic signals read by said further reader (40, 140).

3. The device according to claim 1, wherein said reading head (12) further comprises said further reader (40).

4. The device according to claim 1, wherein said reading head (12) is a movable head arranged to move along the documents (11) in order to read the magnetic patterns.

5. The device according to claim 1, wherein said reading head (112) is a stationary head and the document (11) and the associated patterns are moved in front of the stationary head (112).

6. The device according to claim 5, wherein said further reader (140) is a stationary reader positioned in a position different from that of the stationary reading head (112) and arranged to read the electromagnetic noise coming from noise sources internal or external to the device.

7. A system for reading and decoding magnetic patterns printed on documents compnsing at least one driving motor (119) arranged to move a reading head (12) or a document (11) to be read by the reading head (112), characterised in that it further comprises a device as claimed in claim 1.

8. A method for decoding magnetic patterns printed on documents comprising the steps of: reading first magnetic signals by means of a first reader, said first magnetic signals belonging to the magnetic patterns and to electromagnetic noise due to internal and/or external sources; read second magnetic signals by means of a second reader, said second magnetic signals belonging to the electromagnetic noise; algebraically subtracting said second magnetic signals from said first magnetic signals; and obtaining a third magnetic signal corresponding to the magnetic patterns, said third magnetic signal having a signal-to-noise ratio higher than that of the first magnetic signal.

9. The method of claim 8 wherein said step of reading first magnetic signal comprises the step of amplifying said first magnetic signal; and said step of reading second magnetic signals comprises the step of amplifying said second magnetic signals.

10. The method according to claim 8, wherein said step of reading said first magnetic signals is made by moving the document (11) and the associated patterns in front of a stationary reading head (112).

11. The method according to claim 8, wherein said steps of reading said first magnetic signals and of reading said second magnetic signals is operated through one head including both a first reader (20, 120) arranged to read said first magnetic signals; and a second reader (40, 140) arranged to read said second magnetic signals.

12. The method according to claim 8, wherein said step of reading said first magnetic signals and said second magnetic signals is made by moving a reading head (12) along the document (11) and the associated patterns.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0030] These and further features and advantages of the present invention will appear more clearly from the following detailed description of preferred embodiments, provided by way of non-limiting examples with reference to the attached drawings, in which components designated by same or similar reference numerals indicate components having same or similar functionality and construction and wherein:

[0031] FIG. 1 schematically shows a block diagram of a device according to prior art;

[0032] FIG. 2 schematically shows a block diagram of a device made according to a first embodiment of the present invention;

[0033] FIG. 3 schematically shows a reading head made according to the first embodiment of the invention;

[0034] FIG. 4 shows an electric circuit embodied into the head made according to the first embodiment of the invention;

[0035] FIG. 5 schematically shows a block diagram of a device made according to a second embodiment of the present invention; and

[0036] FIG. 6 schematically shows a mode of operation of the device made according to the second embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

[0037] A first embodiment of the present invention is disclosed with reference to FIG. 2.

[0038] According to such first embodiment a device 10 for decoding magnetic patterns printed on documents 11 comprises a plurality of components arranged to read and reproduce magnetic patterns, such as, for instance, magnetic characters printed on bank cheques.

[0039] Preferably, such device 10 comprises a first and a second amplifier, 15a and 15b, respectively connected in output, through a component operating as an algebraic adder 25, to a converter 16, for instance an A/D converter, and a control unit (CPU) 18, known per se, connected to the above components, and arranged to control operation thereof.

[0040] Preferably, the device 10 comprises a reading head (head) 12, having a first magnetic reader 20 (FIG. 2 and FIG. 3) comprising a first magnetic core 23 and a first coil 21, connected to the first amplifier 15a, and arranged to read field magnetic signals coming from the magnetic patterns printed on the documents. The magnetic reader 20 is also sensitive to the electromagnetic noise coming from noise sources internal or external to the device.

[0041] For instance, the electric circuit of the first coil 21 has, as schematically shown in FIG. 4, an inductance value of 0.7 H and an equivalent resistance value of 1 K.

[0042] Preferably, in cases where the head 12, (FIG. 2, FIG. 3) is a movable head arranged to move along the documents 11 in order to read them, the head 12 further comprises, according to the first embodiment, a second magnetic reader or a dummy magnetic reader 40, comprising a second magnetic core 43 and a second coil 41, connected to the second amplifier 15b and arranged to read the electromagnetic noise coming from noise sources internal or external to the device.

[0043] According to this embodiment, the second magnetic reader 40 is mounted on the head, for instance inside or externally, so as to be magnetically decoupled from first magnetic reader 20 and in a position such as not to sense the magnetic field generated by the magnetic characters.

[0044] Applicant has experimentally verified that a rule for obtaining a decoupling of the second magnetic reader 40 from the first magnetic reader 20 is to install the second magnetic reader 40 at a distance of about 1-3 mm from the first magnetic reader 20 and from the characters. For instance, the electric circuit of the second coil 41 has, as schematically shown in FIG. 4, an inductance value of 0.07 H and an equivalent resistance value of 100 Ohms.

[0045] Preferably the two coils 21 and 41 have the same time constant (=R/L) in both the magnetic readers so as to grant the same quality of the signals collected therefrom.

[0046] The above structure can also be changed by connecting the two coils 21 and 41 to the algebraic adder 25 and one amplifier in output to the adder 25. Such a second configuration does not change the general structure of the first embodiment, therefore the following description discloses in detail the first configuration of the first embodiment.

[0047] The operation of the device 10 according to the first configuration of the first embodiment is as follows.

[0048] In a first step the head 12, moving along the document including magnetic patterns, is arranged to read, by means of the first magnetic reader 20, the magnetic signals belonging to the magnetic patterns and the electromagnetic noise (first magnetic signals).

[0049] At the same time, according to the disclosed architecture, the second magnetic reader 40 is arranged to read magnetic signals belonging only to the electromagnetic noise (second magnetic signals).

[0050] In a second step the first magnetic signal and the second magnetic signal are separately amplified by the respective first and second amplifier, 15a and 15b, and then, by means of the adder component 25, algebraically added by subtracting the amplified second magnetic signal from the amplified first magnetic signal in order to obtain a new amplified magnetic signal or resulting magnetic signal representing the read magnetic pattern.

[0051] Following the second step, the new magnetic signal substantially comprises a magnetic signal corresponding to the read pattern and having, thanks to the algebraic subtraction of the two amplified magnetic signals, a signal-to-noise ratio higher than that of the first magnetic signal.

[0052] In a third step the new magnetic signal is sampled and converted, in a known way, by the converter 16 into a digital signal and processed by the CPU 18 so as to represent the read magnetic patterns or characters.

[0053] A second embodiment of the present invention is disclosed with reference to FIG. 5, wherein a device for decoding magnetic patterns (device) 110 is shown.

[0054] Such embodiment is, preferably, applicable in cases where the document 11 and the associated patterns are moved in front of a stationary head 112.

[0055] According to such second embodiment the device 110 comprises, similarly to the first embodiment, a first and a second amplifier, 115a and 115b (FIG. 5, FIG. 6), respectively connected in output, through a component operating as an algebraic adder 125, to a converter 116, for instance an A/D converter, and a control unit (CPU) 118, known per se, connected to the above components 115a, 115b, 116, and 125, and arranged to control operation thereof, said components being all of known type.

[0056] Preferably, the device 110 comprises a reading head (head) 112 having a first magnetic reader (FIG. 5 and FIG. 6) with a structure and an electric circuit substantially similar to those disclosed with reference to the first magnetic reader 20 of the first embodiment.

[0057] According to the second embodiment the device 110 further comprises a second magnetic reader 140, having, preferably, a fixed position, and a structure and an electric circuit substantially similar to those disclosed with reference to the second magnetic reader 40 of the first embodiment.

[0058] Such second magnetic reader 140 is positioned in proximity of the stationary reading head 112 so as to be magnetically decoupled from the stationary reading head 112 and in a position such as not to sense the magnetic field generated by the magnetic characters.

[0059] In particular the second magnetic reader 140 is arranged to read only the electromagnetic noise coming from noise sources internal or external to the device.

[0060] Applicant has experimentally verified that a rule for obtaining a decoupling of the second magnetic reader 140 from the stationary reading head 112 is to install the second magnetic reader 140 at a distance from the stationary reading head 112 in a range of 3-15 millimeters.

[0061] Preferably, the second magnetic reader 140 comprises a coil mounted in proximity to the stationary head 112, for instance in front of the head 112 as schematically shown in FIG. 6.

[0062] However, any position of the second magnetic reader 140 in proximity to the head, but such as not to read magnetic patters printed on documents 11, can be used.

[0063] The second embodiment, as clearly apparent to a person skilled in the art, does not need to modify the reading head and therefore has, in general, a cost lower than that of the first embodiment.

[0064] The above structure can also be changed by connecting the head 112 and second magnetic reader 140 to the algebraic adder 125 and only one amplifier in output to the adder 125.

[0065] Such a second configuration does not change the general structure of the second embodiment, therefore the following description discloses in detail the first configuration of the second embodiment.

[0066] The operation of the device 110 according to the first configuration of the second embodiment is as follows.

[0067] In a first step document 11 is moved, for instance, step-by-step according to a certain speed, in front of the stationary head 112 that is arranged to read, by means of the first magnetic reader 112, the magnetic signals belonging to the magnetic patterns and to the electromagnetic noise (first magnetic signals).

[0068] At the same time, according to the disclosed architecture, the second magnetic reader 140 located in proximity to the stationary head 112 is arranged to read only the electromagnetic noise (second magnetic signals).

[0069] In a second step the first magnetic signal and the second magnetic signal are separately amplified by the respective first and second amplifier, 115a and 115b, and then, by means of the adder 125, algebraically added by subtracting the amplified second magnetic signal from the amplified first magnetic signal so as to obtain a new amplified magnetic signal or resulting magnetic signal representing the read magnetic pattern.

[0070] Following the second step, the new magnetic signal substantially comprises magnetic signals corresponding to the read pattern and having, thanks to the algebraic subtraction of the two amplified magnetic signals, a signal-to-noise ratio higher than that of the first magnetic signal.

[0071] In a third step the new magnetic signal is sampled and converted, in a known way, by the converter 116 into a digital signal and processed by the CPU 118 so as to represent the read magnetic patterns or characters.

[0072] Preferably, the device 10 configured according to the first embodiment is recommended in case of a movable reading head and the device 110 configured according to the second embodiment is recommended in case of a stationary reading head and movable documents.

[0073] However nothing can prevent to use the reading head 12 as disclosed according to the first embodiment in case of devices 110 provided with a stationary head or to use the reading head 112 and the stationary external noise detector 140 in case of devices arranged to read stationary documents.

[0074] Advantageously, the device according to both the embodiments, by not requiring shields or other components for shielding electromagnetic noise, is structurally very compact.

[0075] More advantageously, a system including the device 10 according to the first embodiment or the device 110 according to the second embodiment, and driving motors 119 (FIG. 6) arranged to move the head 12 or the documents 11 may be configured so that the motors 119 can be placed very close to the respective reading heads.

[0076] As a matter of fact, the electromagnetic noise read by the head 12 or 112 and by the second magnetic reader, respectively 40 or 140, can be cancelled by means of the algebraic adders 25 or 125.

[0077] Moreover, advantageously, by adopting the device according to the invention, the design and production costs can be reduced, for instance, by avoiding any shielding for cutting electronic noise generated by noising components.

[0078] In addition, advantageously, being the quality of the final magnetic signal very high, also the reliability of the read patterns is very high.

[0079] Of course, without prejudice to the basic principles of the invention, the details and embodiments may vary, also significantly, with respect to what has been described herein by way of examples only, without departing from the scope of the invention as defined by the claims that follow.