CA1162309A - Character recognition system - Google Patents
Character recognition systemInfo
- Publication number
- CA1162309A CA1162309A CA000376943A CA376943A CA1162309A CA 1162309 A CA1162309 A CA 1162309A CA 000376943 A CA000376943 A CA 000376943A CA 376943 A CA376943 A CA 376943A CA 1162309 A CA1162309 A CA 1162309A
- Authority
- CA
- Canada
- Prior art keywords
- delay
- timing
- character
- signals
- peak
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V30/00—Character recognition; Recognising digital ink; Document-oriented image-based pattern recognition
- G06V30/10—Character recognition
- G06V30/22—Character recognition characterised by the type of writing
- G06V30/224—Character recognition characterised by the type of writing of printed characters having additional code marks or containing code marks
- G06V30/2253—Recognition of characters printed with magnetic ink
Abstract
CHARACTER RECOGNITION SYSTEM
Abstract A character recognition system including a timing subsystem, comprising a base oscillator or clock, and timing circuits driven by the base clock to provide a plurality of timing pulses for timing the operation of the entire system. The timing circuits are governed in part by delay circuits which are in turn controlled by the amplitude and location of peak signals derived from scanning earlier pulses.
Abstract A character recognition system including a timing subsystem, comprising a base oscillator or clock, and timing circuits driven by the base clock to provide a plurality of timing pulses for timing the operation of the entire system. The timing circuits are governed in part by delay circuits which are in turn controlled by the amplitude and location of peak signals derived from scanning earlier pulses.
Description
3.~
I
.
CHAR7~CTER RECOGNITI~N SYSl'E~
Background of the Invention l. Field of the Invention This invention relates to character recognition S systems and particularly single gap magnetic ink char-acter recognition systems utilizing an adaptive timing system. More particulary, the invention relates to an adaptive timirlg system which will compensate for printing defects in the characters to be recognized by the system.
I
.
CHAR7~CTER RECOGNITI~N SYSl'E~
Background of the Invention l. Field of the Invention This invention relates to character recognition S systems and particularly single gap magnetic ink char-acter recognition systems utilizing an adaptive timing system. More particulary, the invention relates to an adaptive timirlg system which will compensate for printing defects in the characters to be recognized by the system.
2. Description of the Prior Art There are a large number of prior art character recognition systems of the so-called "single gap"
type. U.S. Patent~ 3,119,980; 3,541,508; 3,629,829;
type. U.S. Patent~ 3,119,980; 3,541,508; 3,629,829;
3,645,392; 3,879,707 and 4,148,010 are directed to systems of this type. They do not contemplate, however, a timing system which is adaptive to changes in the location of peaks in the analog signals used in the system.
~20 Summary o~ the Invention It is accordingly a principal object of the present invention to provide an improved single gap character recognition system.
An object of this invention is to provide an improved system of the type described in which the operation of the system timing circuits is altered in accordance with the location of peaks in the input waveform.
Arlotiler object o~ tl~is :invol-lt:ion is to provkle a ~.
~ ~6230g improved character recognition system in which the timing of the system is adApted to compensate for faulty printing.
Yet another object of this invention is to provide an improved character recognition system in which the timing of the peak detection circuits is governed by the location of the-next two previous peaks.
A further object of this invention is to provide an improved system of the type described in which the resetting time of the integrators used in the system is varied to compensate for printing imperfections.
Briefly described, a single gap character recognition system of a type well ]cnown in the art is provided with a subsystem of timing circuits which are governed by the location and amp~itude of the next two previous peaks in the analog signals derived from scanning the character. The peak detecting circuitry governs the supply of signals from the basic system clock to a delay time-out counter, which in turn governs the resetting of time zone integrators which éxamine the integrated value of the signal in each of the plurality - of time zones which divide or partition the input signal. Where necessary, an extended time zone integration is performed in order to be sure that a delayed peak signal will be properly detected. An inhibit delay trigger is also provided to distinguish a narrow line character. When conditions are met, this trigger will disable the adaptive timing for that character.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings~
1 ~6Z3~9 --3~
Brief Description of the ~rawings Fig. 1 is a schematic block diagram of a single-gap character recognition system of a type already known in the art.
Fig. 2 is illustrative of waveforms encountered in the system of Fig. 1, when scanning a defective character.
Fig. 3 is a schematic general block diagram of the system shown in Fig. 1, modified to use the adaptive timing system in accordance with the invention.
Fig. 4A-4D illustrates the waveforms encountered in the system of Fig. 3 when scanning a defective character as shown in Fig. 4A.
Fig. 5 is a schematic block diagram showing the circuitry of the adaptive timing system in greater detail.
Si~nilar reference characters refer to similar parts ~-in each of the several views.
Description of Preferred Embodiment , Referring to Fig. l, there is shown a schematic diagram of a single gap magnetic ink character reading system of the type already known in the art. Signals from magnetized characters are generated by passing a read head l across the character wherein the changes in the magnetic flux induce voltages in the head winding which are supplied to the input of a pre-amplifier 3, and then through a low pass filter 5,which serves to extract noise from the signal, to the input o a voltage controlled amplifier 7, the output of which is connected to the input of a power amplifier 9. The output of amplifier 7 is also supplied to the input of a peak detector circuit 11, which has one .. , .. .
3 0 ~
-I , output connected back to the yain control input of amplifier 7. The other output of peak detector 11 is supplied as a timing control signal to the input of an oscillator 13, which supplies timing signals ~or the remainder of the system.
The output of amplifier 9 is connected to the inputs of a plurality of time zone integrators 15, in the present case 8 time zones being provided. The integrators are all reset by a common reset control signal supplied over a line 17 from the oscillator 13. The output of integrators 15 are supplied to the input of a plurality of correlation networks 19, one such correlation network being provided for each of the characters to be recognized, in this instance 14 characters. The 14 outputs of correlation networks 19 are supplied to the corresponding inputs,of a plurality of maximum le`vel detectors 21, also equal to the nu~ber of characters to be recognized, namely _ 14. The outputs of the maximum level detectors are supplied to a corresponding plurality of character latches 23, which store the output signals representing the character which has been read.
- ~ourteen output lines are provided from the character latches 23. Checking for proper operation of the system includes logic circuits for indicating whether or not there has been a correlation error, in which case tllere is an output generated by the logic bloc~ 25 designated "not 1 and only 1 character."
This logic block will provide an output to an OR
circuit 27, if the character latches 23 indicate that more than one character latch has been set, thereby indicating a conflict or uncertainty in the reading of the character. ~dditional circuitry is provided to indicate whether or not there has been an error in EN97~027 ~, ~ ~ 6~30 g detecting,th'e peaks in the character and thls ls provided by circuitry designated as peak and signal in time zone detectors 29 ! provided with inputs from the output of amplifier 9, and two signal lines 31 and 33 from the oscillator 13. Line 31 provides signals indicating sample time between time zones and line 33 provides signals indicating a sample during a time zone. The detectors 2g determine whether or not the signals occur at the proper intervals, and are translated by a logic block 35, designated as "character peak in error logic." This logic block provides an output to OR circuit 27 when an error occurs in detecting the peak or peaks in a chaxacter. The output of OR circuit 27 appears on a line 37 which when active indicates that a character error has occurred and therefore the output of the character latches 23 should not be util-ized.
The foregoing describes the arrangement for a single gap magnetic ink character reader as already known in the art. This particular arrangement works very well on magnetic ink characters which have been printed within the rigid specifications set for such printing but some printing defects which can occur and are often found in the actual check environment can cause considerable rejects to occur in systems of the type just described. A large portion of the out-of-spec or inferior printing that causes rejects on systems of this type are those involving time displace-ment of the most important signal information points of the characte~rs. Such printing defects are generally caused by embossing of the character edges, the non-uniformity of ink deposits, the character edge defi-ciencies and variations in character dimensions.
Displacement of the prime signal points in the character wave forms affect the prior single gap recog-, .
1 162~09 , ~ 6--nition system :ln two difEerent ways. First, it causes errors in the correlation networks utilized in the system and second, peaks are located at inappropriate areas within the character waveform. Both of these S conditions are caused by the fact that the prior system sets time boundaries throughout the character analysis determined only by the location of the first positive peak of the character. An example of a printing defect causing an error in both the correlation circuitry and in the peak in error circuitry is shown in Fig. 2. In this instance, the character "6" shown at the top of the figure has a left hand border which cornprises an embossed edge shown by the heavy line instead of the normal trailing edge indicated by the dotted vertical line. The character signal waveform resulting from the scanning of the character, as shown, provides an output as indicated in the -topmost waveform shown in Fig. Z. The dotted waveform shown in zone 6 represents the normal waveform which would be seen if the character were properly formed, while the solid line shows the distorted portion of the waveform extending into zone 7 resulting from the heavy embossed edge. The next two waveforms show the integrator signals for zones 6 and 7 and the resulting time zone correlation results in a conflict between the character "6" which is the correct character shown and a syrnbol "SS3" which is caused by the malformed portion of character 6. A test for a signal existing between time zone 6 and time zone 7 provides a peak in error signal at the boundary between lines 6 and 7 and also provides a peak in error signal in time zone 7 which should not exist.
In the present invention, the adaptive timing system corrects the timing boundary according to the information relating to peaks and wave amplitudes found in the previous two peaks. I~ a peak is detected r ~ 3a~7 late within the fixed time boundaries and the previous peak does not signify that the system is dealiny with a narrow line, the following boundary is displaced in time. The time displacement is determined by absolute location of the previous peak and is controlled to make the peak appear as if located in the center of the time zone. Following boundaries are not affected unless the associated signal is also distorted.
Additional information is used in the beginning third ~o of the character to determine if correction is needed.
This circuit, known as the inhibit delay trigger, looks for particular peak sequencés such as the character described as "SS3". Normally, this character does not need displaced boundaries to separate it from the other 13 characters in the usual font to be recogni~ed. This system according to the present invention is also capable of correcting a peak of the curve just after the fi~ed time boundary by resetting the associated integrator. This circuit is known as the force integrator TZX extenslon.
FIG. 3 of the drawings shows a single gap magnetic ink character recognition system similar to that shown in FIG. 1, but including the adaptive timiny circuits which comprise the present invention. This showing is in a broad schematic form and is used to illustrate the manner in which tne adaptive timing circuits are included in the recognition circuit of the type already known in the àrt. It can be seen that the adaptive timing circuits 39 are essentially introduced between the timing control oscillator 13 and the remainder of the recognition system. The control line to the integrator resets, 17 as well the lines 31 and 33 to the peak signal and time zone detectors now emanate from the adaptive timing circuits 39 rather than from the timing control 13. Also, the adaptive timing control utilizes a Eull wave rectiEied ~ signal plus peak levels supplied from the detector EN97~027 I ~L6~3V9 , .
circuits 29 and utilizes an input in ~he timiny cir-cuits 39. The output of peak detector 11 is supplied to the timing circuits 39 via the timiny contro'l oscillator 13 as in the arrangement shown in FIG. 1.
FIGS. 4A, 4s, 4C, and 4D are diagrammatic views of waveforms encountered at various points in the system, illustrating the manner in which the adaptive timing circuits operate.
FIG. 4A shows a character "6" in which the shaded area shows an embossed portion which represents defec-tive printing and which in the usual instance would cause a mistaken reading by prior known systems.
FIG. 4B shows a waveform'of the induced MICR
signal resulting from scanning an idealized character 6, illustrating the rel~ationships of the va~ious portions of the scan signal with the basic time zones designated 0 through 8 as manifest from the drawing. '~'~
FIG. 4C shows the time zones as adjusted by the ' adaptive timing system, with the delayed-'peaks shown in their relationship to the time zones 1 and ~.
FIG. 4D shows the relationship between the induced MICR signals resulting from scanning a defective char-acter 6 such as shown in FIG. 4A, and the relationship of that waveform to the various signals developed in the system utilizing the adaptive timing arrangement.
Note that the two negative going peaks in time zones 1 and 7 are displaced from their normal position.
The waveform designated as Control ]., reEerence character 41, is a square wave having equal on and off times ànd extending over the duration of the basic time zone, such as, for example, the time zone TZl. Next, there is shown the waveform for the basic .. ... .... ... . . ... .. . .. . . . . .. ... .. .. .... . .. .... . ...
~ ~L6230~
_9_ sample time zones and the sample time zone signals L~5 when the adaptive timing system is provided. It will be noted that a delay time is added to the off time of the first cycle, as desi~nated in the drawing by the legend "sample TZ delay."
The next pair of waveforms are the siynals de-scribed as sample between TZ, and comprised of waveforms 47 and 49. Again, it will be noted that the sample between time zone signal is altered by the amount of the delay designated by the legend BTZ Delay and shown in the drawing.
The next pair of waveforms are the resetting signals for zone 2, designated by reference characters 51 and 53 in which the reset signal is delayed by an amount indicated by the legend INTG TZ Delay as shown in the drawing. The next pair of sig~als are the 'reset integrator signals for zone 7, designated by reference characters 55 and 57. Note that an output pulse 59 is provided on the waveform 57, and is designated as Force INTG TZX Extension. The waveforms 6] and 63 show the signals gene'rated by the integrator ~or time zone 7 without and with the adaptive timing system respectively. 'It can be seen that the integrated curve 63 is reset by the additional pulse 59 and the waveform 57.
.
Fig. 5 is a more detailed schematic block diagram of the adaptive timing circuits shown generally by the block 39 of Fig. 3. The input signals are mainly supplied from the system clock or o'scillator 13 of Fig. 3, and to simplify the drawing, the source of each signal is indicated on the drawing as conventional manually operated switches, rather than the logical circuits which would be actually employed. Su~Eice it to $ay that when the switches shown are closecl the signals indicated by the accompanying legend are supplied ....
~ 1~23()~
as inputs to the circuit elements shown in the drawings The amplified analog signals are full-wave recti-fied and supplied to the peak detection and discriminator .circuit 69, and are supplied as one input to an AND
circuit 71. A second input to this AND circuit is a peak level signal controlled by switch 73, and a third input is supplied via a switch 75, and comprises the timing signals for the 8 time zones, designated by the legend TZ timing. The output of the circuit 71 con-stitutes the set input for a delay trigger 77. Thistrigger sets the delay timing into operation. This trigger is reset by terminating conditions which result in a reset signal being supplied from an OR circuit 79.
The first criteria for resetting the trigger 77 is detection of a narrow li.ne i.n the character. Switches 81 and 83 control the positive and negative level inputs to a narrow line~detector 85, which is also rendered effective by an "on" output from trigger 77, on line 103. The output of detector 85 on line 8~
comprises one inpu.t to OR circuit 79. A second re-setting circuit is provided by the inhibit delay trigger ., .
output on a line 87. Inputs to trigger 89 are governed by switches 91, 93 and 95, governing the supply of signals "peak level", "Intg TZ", and TZ Timing" respec-tively. The remaining reset signal to trigger 77 issupplied by the delay time-out element 97. This e].ement which may comprise, for example, an appropriate counter or cascaded single-shot multivibrator provides a plurality of timed.output pulses at intervals deter-mined by signals from the base oscillator, governed byswitch 101. The delay time-out cycle is initiated by a signal on the output line 103 of trigger 77 and the final time-out si.gnal on line 105 is supplied to OR
circuit 79, to thereby reset trigger 77.
The Force Integrator ri'z~ Extension Circuit 106 combines off signals from the delay trlgcJer 77, on linc 3 (~ 9 107 and the inhibit delay trigger 89, on line 109.
lso supplied to this circuit, via switches 11]., 113, and 115 are the signals peak level, INTG TZ signals and TZ timing signals, as shown. These siynals are com-bined by the logic in element 106 to provide an outputon line 117, designated INTG TZ RST, that is, "Inte-grator Time Zone Reset". This signal along with the outputs from the delay time-out 97, designated as BTZ
DLY, INTG TZ DI.Y and Sample TZ DLY, on lines 119, 121 and 123, are supplied as control inputs to the Delay and Reset Control 125. This combination of logic circuits interposes delays in the basic timing signals supplied from the system clock, i.e. the integrator - reset control, the sample time between zones, and the sample time zones on multiple lines 127, 129, and 131, and supplies the delayed signals on the lines 133, 135 and 137. ~hese signals affect the delay operations illustrated in Figs. 4B,4D.
If a peak is located in the second half o~ the time zone and none of the lnhibit delay condltlons is met withln the character, the delay trigger latch ls set to drive the delay time-out counter at the speed of the base;oscillator frequency rate. This delay time-out counter determines the amount of time delay on the between TZ sampling pulses, on the sample TZ sampling pulses, as well as on the extension of the Inty Zne X
reset. An example of how these important sampling pulses and integrator resets get changed on embossed character 6 with the MICR adaptive timing system, is shown in Fig. 4.
The delays will be terminated as soon as the delay time-out explres or when a "narrow line condltlon" is detected and the lnduced MICR signal swings across the reference level.
.. .
; ~, 2 3 () 9 , ;~
The ~lrorce Intg TZx llxtension" circuit looks for a very strong negative peak, which is within the first division of the six segments of the TZX-~l, together with the previous information that also indicates it is a possible delayed peak. This forces a TZx-~l integrator reset pulse at the third divison of the six segrnents of TZx~l to remove the enexgy which-has already been accumulated from integrator TZ~+l. It is essentially the same as extending TZx boundary l/2 time zone further for the peak of that character to the integrating and correlating networks. An example of how the "Force Intg TZx Extension" circuit works on a distorted signal of character six is shown in Fig. 4 by generating an extra reset pulse for Intg Zne 7 to remove the incorrect energy away from Intg 7.
The "inhibit delay trlgger" circuit is designed to differentiate the narrow line SS3 character'from the rest. It is looking for certain conditions between the TZ2 al1d TZ3 boundary. When the conditions are met, the adaptive timing logic will be disabled.
While the invention has been particularly shown and described with reference to a preferred~embodiment thereof, it will be understood by those skilled in the ~ ar~t that various changes in form and details may be ; ~25 ~ made without departing from the spirit and scope of the inventlon.
: : ~
EN97~027
~20 Summary o~ the Invention It is accordingly a principal object of the present invention to provide an improved single gap character recognition system.
An object of this invention is to provide an improved system of the type described in which the operation of the system timing circuits is altered in accordance with the location of peaks in the input waveform.
Arlotiler object o~ tl~is :invol-lt:ion is to provkle a ~.
~ ~6230g improved character recognition system in which the timing of the system is adApted to compensate for faulty printing.
Yet another object of this invention is to provide an improved character recognition system in which the timing of the peak detection circuits is governed by the location of the-next two previous peaks.
A further object of this invention is to provide an improved system of the type described in which the resetting time of the integrators used in the system is varied to compensate for printing imperfections.
Briefly described, a single gap character recognition system of a type well ]cnown in the art is provided with a subsystem of timing circuits which are governed by the location and amp~itude of the next two previous peaks in the analog signals derived from scanning the character. The peak detecting circuitry governs the supply of signals from the basic system clock to a delay time-out counter, which in turn governs the resetting of time zone integrators which éxamine the integrated value of the signal in each of the plurality - of time zones which divide or partition the input signal. Where necessary, an extended time zone integration is performed in order to be sure that a delayed peak signal will be properly detected. An inhibit delay trigger is also provided to distinguish a narrow line character. When conditions are met, this trigger will disable the adaptive timing for that character.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings~
1 ~6Z3~9 --3~
Brief Description of the ~rawings Fig. 1 is a schematic block diagram of a single-gap character recognition system of a type already known in the art.
Fig. 2 is illustrative of waveforms encountered in the system of Fig. 1, when scanning a defective character.
Fig. 3 is a schematic general block diagram of the system shown in Fig. 1, modified to use the adaptive timing system in accordance with the invention.
Fig. 4A-4D illustrates the waveforms encountered in the system of Fig. 3 when scanning a defective character as shown in Fig. 4A.
Fig. 5 is a schematic block diagram showing the circuitry of the adaptive timing system in greater detail.
Si~nilar reference characters refer to similar parts ~-in each of the several views.
Description of Preferred Embodiment , Referring to Fig. l, there is shown a schematic diagram of a single gap magnetic ink character reading system of the type already known in the art. Signals from magnetized characters are generated by passing a read head l across the character wherein the changes in the magnetic flux induce voltages in the head winding which are supplied to the input of a pre-amplifier 3, and then through a low pass filter 5,which serves to extract noise from the signal, to the input o a voltage controlled amplifier 7, the output of which is connected to the input of a power amplifier 9. The output of amplifier 7 is also supplied to the input of a peak detector circuit 11, which has one .. , .. .
3 0 ~
-I , output connected back to the yain control input of amplifier 7. The other output of peak detector 11 is supplied as a timing control signal to the input of an oscillator 13, which supplies timing signals ~or the remainder of the system.
The output of amplifier 9 is connected to the inputs of a plurality of time zone integrators 15, in the present case 8 time zones being provided. The integrators are all reset by a common reset control signal supplied over a line 17 from the oscillator 13. The output of integrators 15 are supplied to the input of a plurality of correlation networks 19, one such correlation network being provided for each of the characters to be recognized, in this instance 14 characters. The 14 outputs of correlation networks 19 are supplied to the corresponding inputs,of a plurality of maximum le`vel detectors 21, also equal to the nu~ber of characters to be recognized, namely _ 14. The outputs of the maximum level detectors are supplied to a corresponding plurality of character latches 23, which store the output signals representing the character which has been read.
- ~ourteen output lines are provided from the character latches 23. Checking for proper operation of the system includes logic circuits for indicating whether or not there has been a correlation error, in which case tllere is an output generated by the logic bloc~ 25 designated "not 1 and only 1 character."
This logic block will provide an output to an OR
circuit 27, if the character latches 23 indicate that more than one character latch has been set, thereby indicating a conflict or uncertainty in the reading of the character. ~dditional circuitry is provided to indicate whether or not there has been an error in EN97~027 ~, ~ ~ 6~30 g detecting,th'e peaks in the character and thls ls provided by circuitry designated as peak and signal in time zone detectors 29 ! provided with inputs from the output of amplifier 9, and two signal lines 31 and 33 from the oscillator 13. Line 31 provides signals indicating sample time between time zones and line 33 provides signals indicating a sample during a time zone. The detectors 2g determine whether or not the signals occur at the proper intervals, and are translated by a logic block 35, designated as "character peak in error logic." This logic block provides an output to OR circuit 27 when an error occurs in detecting the peak or peaks in a chaxacter. The output of OR circuit 27 appears on a line 37 which when active indicates that a character error has occurred and therefore the output of the character latches 23 should not be util-ized.
The foregoing describes the arrangement for a single gap magnetic ink character reader as already known in the art. This particular arrangement works very well on magnetic ink characters which have been printed within the rigid specifications set for such printing but some printing defects which can occur and are often found in the actual check environment can cause considerable rejects to occur in systems of the type just described. A large portion of the out-of-spec or inferior printing that causes rejects on systems of this type are those involving time displace-ment of the most important signal information points of the characte~rs. Such printing defects are generally caused by embossing of the character edges, the non-uniformity of ink deposits, the character edge defi-ciencies and variations in character dimensions.
Displacement of the prime signal points in the character wave forms affect the prior single gap recog-, .
1 162~09 , ~ 6--nition system :ln two difEerent ways. First, it causes errors in the correlation networks utilized in the system and second, peaks are located at inappropriate areas within the character waveform. Both of these S conditions are caused by the fact that the prior system sets time boundaries throughout the character analysis determined only by the location of the first positive peak of the character. An example of a printing defect causing an error in both the correlation circuitry and in the peak in error circuitry is shown in Fig. 2. In this instance, the character "6" shown at the top of the figure has a left hand border which cornprises an embossed edge shown by the heavy line instead of the normal trailing edge indicated by the dotted vertical line. The character signal waveform resulting from the scanning of the character, as shown, provides an output as indicated in the -topmost waveform shown in Fig. Z. The dotted waveform shown in zone 6 represents the normal waveform which would be seen if the character were properly formed, while the solid line shows the distorted portion of the waveform extending into zone 7 resulting from the heavy embossed edge. The next two waveforms show the integrator signals for zones 6 and 7 and the resulting time zone correlation results in a conflict between the character "6" which is the correct character shown and a syrnbol "SS3" which is caused by the malformed portion of character 6. A test for a signal existing between time zone 6 and time zone 7 provides a peak in error signal at the boundary between lines 6 and 7 and also provides a peak in error signal in time zone 7 which should not exist.
In the present invention, the adaptive timing system corrects the timing boundary according to the information relating to peaks and wave amplitudes found in the previous two peaks. I~ a peak is detected r ~ 3a~7 late within the fixed time boundaries and the previous peak does not signify that the system is dealiny with a narrow line, the following boundary is displaced in time. The time displacement is determined by absolute location of the previous peak and is controlled to make the peak appear as if located in the center of the time zone. Following boundaries are not affected unless the associated signal is also distorted.
Additional information is used in the beginning third ~o of the character to determine if correction is needed.
This circuit, known as the inhibit delay trigger, looks for particular peak sequencés such as the character described as "SS3". Normally, this character does not need displaced boundaries to separate it from the other 13 characters in the usual font to be recogni~ed. This system according to the present invention is also capable of correcting a peak of the curve just after the fi~ed time boundary by resetting the associated integrator. This circuit is known as the force integrator TZX extenslon.
FIG. 3 of the drawings shows a single gap magnetic ink character recognition system similar to that shown in FIG. 1, but including the adaptive timiny circuits which comprise the present invention. This showing is in a broad schematic form and is used to illustrate the manner in which tne adaptive timing circuits are included in the recognition circuit of the type already known in the àrt. It can be seen that the adaptive timing circuits 39 are essentially introduced between the timing control oscillator 13 and the remainder of the recognition system. The control line to the integrator resets, 17 as well the lines 31 and 33 to the peak signal and time zone detectors now emanate from the adaptive timing circuits 39 rather than from the timing control 13. Also, the adaptive timing control utilizes a Eull wave rectiEied ~ signal plus peak levels supplied from the detector EN97~027 I ~L6~3V9 , .
circuits 29 and utilizes an input in ~he timiny cir-cuits 39. The output of peak detector 11 is supplied to the timing circuits 39 via the timiny contro'l oscillator 13 as in the arrangement shown in FIG. 1.
FIGS. 4A, 4s, 4C, and 4D are diagrammatic views of waveforms encountered at various points in the system, illustrating the manner in which the adaptive timing circuits operate.
FIG. 4A shows a character "6" in which the shaded area shows an embossed portion which represents defec-tive printing and which in the usual instance would cause a mistaken reading by prior known systems.
FIG. 4B shows a waveform'of the induced MICR
signal resulting from scanning an idealized character 6, illustrating the rel~ationships of the va~ious portions of the scan signal with the basic time zones designated 0 through 8 as manifest from the drawing. '~'~
FIG. 4C shows the time zones as adjusted by the ' adaptive timing system, with the delayed-'peaks shown in their relationship to the time zones 1 and ~.
FIG. 4D shows the relationship between the induced MICR signals resulting from scanning a defective char-acter 6 such as shown in FIG. 4A, and the relationship of that waveform to the various signals developed in the system utilizing the adaptive timing arrangement.
Note that the two negative going peaks in time zones 1 and 7 are displaced from their normal position.
The waveform designated as Control ]., reEerence character 41, is a square wave having equal on and off times ànd extending over the duration of the basic time zone, such as, for example, the time zone TZl. Next, there is shown the waveform for the basic .. ... .... ... . . ... .. . .. . . . . .. ... .. .. .... . .. .... . ...
~ ~L6230~
_9_ sample time zones and the sample time zone signals L~5 when the adaptive timing system is provided. It will be noted that a delay time is added to the off time of the first cycle, as desi~nated in the drawing by the legend "sample TZ delay."
The next pair of waveforms are the siynals de-scribed as sample between TZ, and comprised of waveforms 47 and 49. Again, it will be noted that the sample between time zone signal is altered by the amount of the delay designated by the legend BTZ Delay and shown in the drawing.
The next pair of waveforms are the resetting signals for zone 2, designated by reference characters 51 and 53 in which the reset signal is delayed by an amount indicated by the legend INTG TZ Delay as shown in the drawing. The next pair of sig~als are the 'reset integrator signals for zone 7, designated by reference characters 55 and 57. Note that an output pulse 59 is provided on the waveform 57, and is designated as Force INTG TZX Extension. The waveforms 6] and 63 show the signals gene'rated by the integrator ~or time zone 7 without and with the adaptive timing system respectively. 'It can be seen that the integrated curve 63 is reset by the additional pulse 59 and the waveform 57.
.
Fig. 5 is a more detailed schematic block diagram of the adaptive timing circuits shown generally by the block 39 of Fig. 3. The input signals are mainly supplied from the system clock or o'scillator 13 of Fig. 3, and to simplify the drawing, the source of each signal is indicated on the drawing as conventional manually operated switches, rather than the logical circuits which would be actually employed. Su~Eice it to $ay that when the switches shown are closecl the signals indicated by the accompanying legend are supplied ....
~ 1~23()~
as inputs to the circuit elements shown in the drawings The amplified analog signals are full-wave recti-fied and supplied to the peak detection and discriminator .circuit 69, and are supplied as one input to an AND
circuit 71. A second input to this AND circuit is a peak level signal controlled by switch 73, and a third input is supplied via a switch 75, and comprises the timing signals for the 8 time zones, designated by the legend TZ timing. The output of the circuit 71 con-stitutes the set input for a delay trigger 77. Thistrigger sets the delay timing into operation. This trigger is reset by terminating conditions which result in a reset signal being supplied from an OR circuit 79.
The first criteria for resetting the trigger 77 is detection of a narrow li.ne i.n the character. Switches 81 and 83 control the positive and negative level inputs to a narrow line~detector 85, which is also rendered effective by an "on" output from trigger 77, on line 103. The output of detector 85 on line 8~
comprises one inpu.t to OR circuit 79. A second re-setting circuit is provided by the inhibit delay trigger ., .
output on a line 87. Inputs to trigger 89 are governed by switches 91, 93 and 95, governing the supply of signals "peak level", "Intg TZ", and TZ Timing" respec-tively. The remaining reset signal to trigger 77 issupplied by the delay time-out element 97. This e].ement which may comprise, for example, an appropriate counter or cascaded single-shot multivibrator provides a plurality of timed.output pulses at intervals deter-mined by signals from the base oscillator, governed byswitch 101. The delay time-out cycle is initiated by a signal on the output line 103 of trigger 77 and the final time-out si.gnal on line 105 is supplied to OR
circuit 79, to thereby reset trigger 77.
The Force Integrator ri'z~ Extension Circuit 106 combines off signals from the delay trlgcJer 77, on linc 3 (~ 9 107 and the inhibit delay trigger 89, on line 109.
lso supplied to this circuit, via switches 11]., 113, and 115 are the signals peak level, INTG TZ signals and TZ timing signals, as shown. These siynals are com-bined by the logic in element 106 to provide an outputon line 117, designated INTG TZ RST, that is, "Inte-grator Time Zone Reset". This signal along with the outputs from the delay time-out 97, designated as BTZ
DLY, INTG TZ DI.Y and Sample TZ DLY, on lines 119, 121 and 123, are supplied as control inputs to the Delay and Reset Control 125. This combination of logic circuits interposes delays in the basic timing signals supplied from the system clock, i.e. the integrator - reset control, the sample time between zones, and the sample time zones on multiple lines 127, 129, and 131, and supplies the delayed signals on the lines 133, 135 and 137. ~hese signals affect the delay operations illustrated in Figs. 4B,4D.
If a peak is located in the second half o~ the time zone and none of the lnhibit delay condltlons is met withln the character, the delay trigger latch ls set to drive the delay time-out counter at the speed of the base;oscillator frequency rate. This delay time-out counter determines the amount of time delay on the between TZ sampling pulses, on the sample TZ sampling pulses, as well as on the extension of the Inty Zne X
reset. An example of how these important sampling pulses and integrator resets get changed on embossed character 6 with the MICR adaptive timing system, is shown in Fig. 4.
The delays will be terminated as soon as the delay time-out explres or when a "narrow line condltlon" is detected and the lnduced MICR signal swings across the reference level.
.. .
; ~, 2 3 () 9 , ;~
The ~lrorce Intg TZx llxtension" circuit looks for a very strong negative peak, which is within the first division of the six segments of the TZX-~l, together with the previous information that also indicates it is a possible delayed peak. This forces a TZx-~l integrator reset pulse at the third divison of the six segrnents of TZx~l to remove the enexgy which-has already been accumulated from integrator TZ~+l. It is essentially the same as extending TZx boundary l/2 time zone further for the peak of that character to the integrating and correlating networks. An example of how the "Force Intg TZx Extension" circuit works on a distorted signal of character six is shown in Fig. 4 by generating an extra reset pulse for Intg Zne 7 to remove the incorrect energy away from Intg 7.
The "inhibit delay trlgger" circuit is designed to differentiate the narrow line SS3 character'from the rest. It is looking for certain conditions between the TZ2 al1d TZ3 boundary. When the conditions are met, the adaptive timing logic will be disabled.
While the invention has been particularly shown and described with reference to a preferred~embodiment thereof, it will be understood by those skilled in the ~ ar~t that various changes in form and details may be ; ~25 ~ made without departing from the spirit and scope of the inventlon.
: : ~
EN97~027
Claims (3)
1. A character recognition system comprising, in combination, scanning means for scanning characters to be read, said scanning means providing output signals distinctive for each character, said signals having at least one peak signal having an amplitude and time of occurrence characteristic of the character, peak determining means for determining the magnitude of said peak signal timing means including a base oscillator and means for deriving a plurality of timing signals from the output of said oscillator, and delay means connected to said timing means for delaying said timing signals by predetermined amounts, said delay means being governed by said peak determining means and including a delay control trigger connected to said peak determining means, and to a plurality of delay timing circuits for governing the generation of said delayed timing signals, inhibiting means for inhibiting said delay control trigger when the scanning output signals indicate the scanning of predetermined characters, and circuit means for supplying the delayed signals to said system.
2. A character recognition system as claimed in claim 1 further including a plurality of integrator circuits for integrating said output signals over each of a corresponding plurality of time zones, reset means for resetting said integrators, reset control means for varying the resetting time of said integrators, said reset control means being governed by said delay control trigger to effectively delay said reset time only when said delay control trigger is ineffective to govern said delay timing circuits.
3. A character recognition system as claimed in claim 2, in which said reset control means additionally governs said delay timing circuits.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/163,672 US4356472A (en) | 1980-06-27 | 1980-06-27 | Character recognition system |
| US163,672 | 1980-06-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1162309A true CA1162309A (en) | 1984-02-14 |
Family
ID=22591072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000376943A Expired CA1162309A (en) | 1980-06-27 | 1981-05-06 | Character recognition system |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4356472A (en) |
| EP (1) | EP0042944B1 (en) |
| JP (1) | JPS6034158B2 (en) |
| CA (1) | CA1162309A (en) |
| DE (1) | DE3172748D1 (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0213205B1 (en) * | 1984-12-28 | 1992-12-09 | Micro Co., Ltd. | Method of stacking printed circuit boards |
| US4797938A (en) * | 1985-10-15 | 1989-01-10 | International Business Machines Corporation | Method of identifying magnetic ink (MICR) characters |
| US5054092A (en) * | 1988-03-31 | 1991-10-01 | Checkmate Electronics, Inc. | Hand-operated low cost magnetic character recognition system |
| US5014324A (en) * | 1987-12-21 | 1991-05-07 | Ncr Corporation | MICR character reader using magnetic peaks to update timing clocks |
| US4913182A (en) * | 1989-03-24 | 1990-04-03 | Sloan Valve Company | Plumbing fixture check stop |
| US5305196A (en) * | 1989-05-01 | 1994-04-19 | Credit Verification Corporation | Check transaction processing, database building and marketing method and system utilizing automatic check reading |
| US5237620A (en) * | 1989-05-01 | 1993-08-17 | Credit Verification Corporation | Check reader method and system for reading check MICR code |
| US5644723A (en) | 1989-05-01 | 1997-07-01 | Credit Verification Corporation | Method and system for selective incentive point-of-sale marketing in response to customer shopping histories |
| US5621812A (en) * | 1989-05-01 | 1997-04-15 | Credit Verification Corporation | Method and system for building a database for use with selective incentive marketing in response to customer shopping histories |
| US5687322A (en) | 1989-05-01 | 1997-11-11 | Credit Verification Corporation | Method and system for selective incentive point-of-sale marketing in response to customer shopping histories |
| US5201010A (en) * | 1989-05-01 | 1993-04-06 | Credit Verification Corporation | Method and system for building a database and performing marketing based upon prior shopping history |
| US8700458B2 (en) | 1989-05-01 | 2014-04-15 | Catalina Marketing Corporation | System, method, and database for processing transactions |
| GB2237915B (en) * | 1989-10-24 | 1993-09-29 | Unisys Corp | Character recognition apparatus |
| US5026974A (en) * | 1989-12-27 | 1991-06-25 | Ncr Corporation | Method for recognizing the leading edge of a character in E13B font |
| US5134663A (en) * | 1991-04-19 | 1992-07-28 | Unisys Corporation | Center line magnetic ink character recognition system |
| US6292786B1 (en) | 1992-05-19 | 2001-09-18 | Incentech, Inc. | Method and system for generating incentives based on substantially real-time product purchase information |
| US6609104B1 (en) | 1999-05-26 | 2003-08-19 | Incentech, Inc. | Method and system for accumulating marginal discounts and applying an associated incentive |
| US6993498B1 (en) | 1999-07-15 | 2006-01-31 | Midnight Blue Remote Access, Llc | Point-of-sale server and method |
| US6956962B1 (en) * | 2002-05-07 | 2005-10-18 | Unisys Corporation | System and method of signal processing for use in reading data |
| US7796798B2 (en) * | 2006-05-17 | 2010-09-14 | International Business Machines Corporation | Frequency domain based MICR reader |
| US8023718B1 (en) * | 2007-01-16 | 2011-09-20 | Burroughs Payment Systems, Inc. | Method and system for linking front and rear images in a document reader/imager |
| US8636214B2 (en) | 2011-10-25 | 2014-01-28 | International Business Machines Corporation | Recognition of encoded information on documents |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3192504A (en) * | 1960-06-23 | 1965-06-29 | Gen Electric | Detection of long waveshapes in automatic symbol reader |
| US3535682A (en) * | 1965-12-10 | 1970-10-20 | Lundy Electronics & Syst Inc | Waveform recognition system |
| US3528058A (en) * | 1966-05-27 | 1970-09-08 | Ibm | Character recognition system |
| BE755936A (en) * | 1969-09-09 | 1971-02-15 | Ibm | APPARATUS AND METHOD FOR IDENTIFYING CHARACTERS |
| US3987411A (en) * | 1975-08-11 | 1976-10-19 | Burroughs Corporation | Character recognition system employing extraneous and required peak detection with variable threshold controlled timing |
| US4053737A (en) * | 1976-06-25 | 1977-10-11 | Recognition Equipment Incorporated | Magnetic reader for bar encoded characters |
| US4143355A (en) * | 1977-08-29 | 1979-03-06 | Signature Guardian Systems, Inc. | Character recognition system |
| US4143356A (en) * | 1977-10-31 | 1979-03-06 | Ncr Canada Ltd - Ncr Canada Ltee | Character recognition apparatus |
| US4148010A (en) * | 1977-10-31 | 1979-04-03 | Ncr Canada Ltd. - Ncr Canada Ltee | Magnetic ink character reader system |
| US4277776A (en) * | 1979-10-01 | 1981-07-07 | Ncr Canada Ltd - Ncr Canada Ltee | Magnetic ink character recognition apparatus |
-
1980
- 1980-06-27 US US06/163,672 patent/US4356472A/en not_active Expired - Lifetime
-
1981
- 1981-04-20 JP JP56058704A patent/JPS6034158B2/en not_active Expired
- 1981-05-06 CA CA000376943A patent/CA1162309A/en not_active Expired
- 1981-05-12 DE DE8181103612T patent/DE3172748D1/en not_active Expired
- 1981-05-12 EP EP81103612A patent/EP0042944B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3172748D1 (en) | 1985-12-05 |
| EP0042944A3 (en) | 1982-09-29 |
| EP0042944A2 (en) | 1982-01-06 |
| US4356472A (en) | 1982-10-26 |
| EP0042944B1 (en) | 1985-10-30 |
| JPS5714975A (en) | 1982-01-26 |
| JPS6034158B2 (en) | 1985-08-07 |
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