MAGNETIC INK CHARACTER RECOGNITION SYSTEM

• US 3,605,092 A
• Filed: 01/19/1970
• Issued: 09/14/1971
• Est. Priority Date: 01/19/1970
• Status: Expired due to Term

• Current Assignee: Harold S. Richard
• Original Assignee: Harold S. Richard
• Inventors: Richard, Harold S.
• Primary Examiner(s): Robinson, Thomas A.
• Application Number:
  US05/003,689
• Time in Patent Office: 603 Days
• Field of Search: 333/29 250/219CR 340/146.3
• US Class Current: 382/208
• CPC Class Codes: G06V 30/2253 Recognition of characters printed with magnetic ink G06V30/2247 takes precedence

Abstract

A triggering circuit is provided with an MICR character reader which enables the character recognition circuits during the time the analog waveform provided by a transducer reading head is properly positioned in a tapped delay line. The triggering circuit is responsive to the signals appearing at certain of the tapped outputs of the delay line, and a comparator included therein allows the character recognition circuits to be enabled when the voltage at the most delayed tap is a certain percent of the highest voltage appearing at the other taps coupled to the triggering circuit.

Claims

1. A magnetic ink character recognition system comprising:

means for scanning an article having at least one magnetized ink character thereon and for providing an analog signal corresponding to the said character;

a delay line having a plurality of tapped outputs, there being a delayed version of a signal applied to said delay line at each of said tapped outputs, said signals at said tapped outputs being delayed by differing amounts;

means for applying said analog signal to said delay line;

character recognition means responsive to the signals appearing at first selected ones of said tapped outputs for recognizing said character during a given time in which an enabling signal is applied thereto;

gating means responsive to the signals appearing at second selected ones of said tapped outputs for providing a signal having a magnitude equal to the largest of the magnitudes of the signals appearing at said second selected tapped outputs, said second selected outputs having signals thereat which are delayed by an amount more than the majority of the signals at said first selected outputs;

comparing means for comparing the magnitude of the signal appearing at one of said first selected tapped outputs with said gating means signal and for providing said enabling signal whenever the ratio of the magnitude of the signal appearing at said one tapped output to the magnitude of said gating means signal exceeds a preselected value, said signal at said one tapped output being delayed more than the signals at said second selected tapped outputs; and

means for applying said enabling signal to said character recognition means.

2. The invention according to claim 1 wherein each of said tapped outputs of said delay line is positioned to cause each succeeding tapped output signal to be delayed from the immediately preceding tapped output signal;

and wherein said second selected ones of said tapped outputs include at least two adjacent ones of said tapped outputs, one of which is positioned adjacent to said one tapped output, the signal appearing at said one tapped output being delayed by a greater amount than the signals at said one of said two adjacent tapped outputs.

3. The invention according to claim 2 wherein said comparing means includes a triggerable monostable multivibrator which, once triggered, provides a signal having a fixed duration, said multivibrator being triggered when said ratio exceeds said predetermined value.

4. The invention according to claim 2 wherein said enabling signal is provided for a fixed duration after said ratio exceeds said predetermined value.

5. The invention according to claim 2 wherein coarse timing means are further provided for providing a coarse timing signal whenever the magnitude of the signal appearing at said one of said tapped outputs exceeds a given value, said enabling signal being able to occur only while said coarse timing signal occurs.

6. The invention according to claim 5 wherein said comparing means includes a triggerable monostable multivibrator which, when triggered, provides a signal having a fixed duration, said multivibrator being triggered when said ratio exceeds said predetermined value.

7. The invention according to claim 2 wherein said comparing means includes:

an operational amplifier haVing two inputs and an output;

first coupling means including a first resistor for coupling the gating means signal to one of said operational amplifier inputs; and

second coupling means including a second resistor for coupling the signal from said one tapped output to the other input of said operational amplifier, the ratio of said second resistor to said first resistor determining the ratio between said compared signals necessary to cause said comparing means signal to be provided.

8. The invention according to claim 7 wherein the signals applied to said two operational amplifier inputs have opposite polarities.

9. In combination:

utilization means;

means for providing a plurality of signals which are successively delayed versions of one another;

means for providing first selected ones of said signals to said utilization means;

gating means responsive to second selected ones of said plurality of signals for providing a signal having a magnitude equal to the largest of the then-existing magnitudes of said signals, at least two of the signals of said second selected signals not being included as part of said first selected signals; and

comparing means for comparing said gating means signal with another one of said plurality of signals and for providing a signal when the ratio of said compared signals arrives at a predetermined value.

10. The invention according to claim 9 wherein said another one of said plurality of signals is delayed by an amount at least as great as each of said selected ones of said plurality of signals.

11. The invention according to claim 9 wherein said second selected ones of said plurality of signals exclude said another one of said plurality of signals.

12. The invention according to claim 9 wherein said second selected ones of said plurality of signals exclude said another one of said plurality of signals;

and wherein said another one of said plurality of signals is delayed by an amount greater than each of said second selected ones of said plurality of signals.

13. The invention according to claim 9 wherein said comparing means signal lasts for a fixed time.

14. The invention according to claim 9 wherein said combination further includes course timing means for providing a signal whenever the magnitude of said another one of said plurality of signals exceeds a given value;

and wherein said comparing means signal can occur only during the time said course timing means signal is provided.

15. The invention according to claim 14 wherein said comparing means signal lasts for a fixed time.