DOCUMENT VIDEO DIGITIZER

Abstract: A high speed document manipulator providing high resolution digital video-signal output. A document transport (10) moves the documents (2) at a high speed for entrance (1) flip-over (31) and exit (30), and at about one-fifth that speed for video scanning while moving for producing the video signal. Servo control (43) provides a forward and back initial motion to obtain top to bottom scanning. The servo circuit is electrically protected (70). The video sensor (18) is firmly coupled to the optical system (17). An elongated light source (20) elliptical reflector (21) and "cool" mirror (22) provide an elongated transverse illuminated area on the document as it moves through.

Description: "DOCUMENT VIDEO DIGITIZER" - BACKGROUND OF THE INVENTION This invention pertains to producing digitized video signals from documents. U.S. patent No. 3,988,062 discloses a photographic microfilm or microfiche document recorder that automatically moves documents for photographing and selectively may turn them over for copying both sides. Non-responsive logic is employed. A state-counter determines the steps in the operation of the machine. Magnetically actuated clutches and brakes control the motions of belts that carry the documents. U.S. patent No. 4,027,870 discloses a modification of the structure of the above patent in which the turn-over mechanism is at right angles to the main translation path of the documents. The documents are turned end-fcr-end rather than side for side. Clutches and brakes are used. U.S. patent No. 3,677,159 discloses a photographic micro- film camera that employs a servo system loop to control film motion in combination with a pair of idler arms. A digital control circuit reduces the velocity of the film in steps for decelerating the film. The digital circuit has nothing to do with digitizing video signals. 1 SUMMARY OF THE INVENTION 2 A microprocessor controls a servo system to move each 3 document so that a digital video signal is produced according 4 to the writings upon the document. 5 • A desirably high throughput of 3,000 document images per g hour is attained fay utilizing a high speed for moving the documents and a slow speed for video scanning the same. 3 ' The document is moved forward from the loading position 9 at a high speed to beyond the video scanning area, is stopped, Q and then moved backward at low speed for video scanning. H Then the document may be continued backward to the flip-over 12 device, emerging therefrom moving forward at high speed until 13 it reaches the video scanning area, after which it moves further 4 forward at low speed for video scanning the second side of the 15 document. Thereafter, it moves still further forward at high S speed to exit the apparatus as a whole. 17 The microprocessor control can be altered by the operator 13 to accomplish the above manipulation, except that the document 1 9 moves exclusively at high speed after leaving the flip-over 2 device and the second side of the document, if any, is not i scanned. 2 Further, the microprocessor cαn-croi can be altered to scan 2 one side of the document and then exit -it without flip-over. 4 The power amplifier of the servo system is protected by a 25 diode to prevent catastrophic burn-out thereof upon a power Q semiconductor means thereof failing. 2 The power amplifier of the servo system is operated at a low 8 dissipation loss by a plural diode clamp circuit there connected. 9 A document skew detection sensor coacts with the micrα- 30 processor to provide dynamic skew detection. OM? 1 BRIEF DESCRIPTION OP THE DRAWINGS 2 Fig. 1 is a simplified side elevation view of the document 3 video digitizer machine. 4 Fig. 2 is a block diagram of the whole electrical system. 3 • Fig. 3 is a block-schematic, diagram of the servo system. g Fig. 4 is the initial part of the flow diagram for the 7 microprocessor of Fig. 2. 3 • Fig. 5 is the remaining part of the flow diagram for the 9 microprocessor of Fig. 2. 10 11 12 DESCRIPTION OF THE PREFERRED EMBODIMENTS 3 In Fig. 1, numeral 1 identifies the feed table, upon which 4 the operator (not shown) places a document 2 for the purpose 13. of converting the text thereof to video-signals. The apparatus 3 can be constructed for documents of any size, but a typical 1 document size would be 23. centimeters (cm) by 21.6 cm; i.e. 3 11" x 8*5", with a minimum size for the same apparatus αf about 1 9 half this size. The document is preferably placed upon table 0 1 with a long side parallel to the length of the tabl and with the head of the document pointed to- the right in Fig. 1. The document is actually placed upon a plurality of spaced 3 belts 3, which overlie the table and are held taut by rollers 4 4 and 5, the latter being mechanically connected to a motor 5 "M" of Fig. 3 by belt 6. Vacuum chamber 7 lies beneath belts 3. 3 When motor M shall be energized and when a vacuum shall be- 7 established in chamber 7 is determined by controlling ' micro- 8 processor 40 of Fig. 2 , according to the flow chart of Fig. 4. 9 Accordingly, the functioning of the apparatus will be detailed 0 in the consideration of Fig. 4 and 5. OMP 1 Sensor 8 senses that a document is, or is not, at the feed 2 station on table 1. Sensor 8 may be actuated by the stoppage 3 of the air flow through it upon a document being placed over it. 4 5 Certain conditions having been met, belts 10 on main ' table S 11 are put in motion, also belts 3 of the feed table. 7 This results in document 2 being rapidly translated to the 3 left, in Fig. 1,. say at 254 cm per second. 9 This continues until sensor 14 is intercepted, which is 0 substantially the whole length of main table 1Q. On the way, the document passes sensor(s) 15, which detect ske of the document, if any, in a dynamic manner. Two aligne sensor elements are employed. If the document is not skewed, both elements are influenced at the same time. If the document is skewed, one element might be influenced 3 one millisecond before the other. This time interval corres- ponds to a large skew, say 15 degrees. Smaller skews are detectable. g When skew is detected the microprocessor controls che table belts to return the document to the operator at feed table 1 for re-positioning correctly and start translating the document t° sensor 14 again. Having reached sensor 14 in good order and giving the "host" I/O 45 of Fig. 2 an opportunity to affirm that video scanning of the document is desired, belts 10 are reversed at a slow speed, say 56 cm/sec, and the scanning takes place. Ca era- scanner IS is electronically activated to accomplish this. The slow mo-ion of the document provides the vertical component of the video scansion, while an elongated multiple ligfrc- 1 sensitive element in the camera provides the horizontal 2 component along each ^ (television) line of the scansion. 3 While the term ' "slow" is used herein, that speed of scanning 4 a document is fast with, espect to known art. 5 . . . g It is necessary that the document be illuminated along a narrow transverse area that i's imaged by objective lens 17 g upon light-sensitive element 18 within the camera. 9 The preferred embodiment utilizes a high light intensity 10 as a consequence of the reasonably rapid translation of the 11 document at 5β cm/sec and the nominal sensitivity of the light- 12 sensiti-ve element 13. The light intensity is approximately 13 300,000 Lux, being of uniform intensity across the width of 14 the document and extending about 0.β cm in the direction of 13 translation. 1 3 In order to meet the requirements of this apparatus the . 17 optical system has certain unusual characteristics. 1 3 Some documents, such as color brochures, have a "shiny" ig (specular reflective) surface to the paper. Should the optical- 20 system direct light ' vertically down upon such a document only 2 a blank image would be obtained. The light must be directed 2 at approximately 45° to the vertical for the printing and/or 3 other indicia to be properly imaged in the vertical optical 4 peth to light-sensitive element 18. 3 A linear light source 20, such as a quartz-halogen incan- 6 descent lamp, approximately 28 cm long and of 1,000 watts 7 ra-ing is situated at one focus of elliptical mirror 21. 3 The other focus is at the document. Canta.t ray 23 depicts 9 ' cha optical path from source 20 to plane mirror 22, to the 0 document and then upwards to lens 17. Most of the light 1 illuminating the document is reflected from the sides of 2 elliptical mirror 21. 3 "Cold" mirror 22 is employed to pass away the infra-red 4 radiant energy (heat) from the lamp, and to reflect only the 3 visible energy. This keeps the document and translating belts 3 10 desirably cool and also prevents spurious optical results 7 from certain inks that are infra-red reflective. The mirror 3 is' available in the optical trade. 9 Light-sensitive element 18 as normally embodied is sensitive 10 to infra-red as well as visible light energy. This is an H important reason as to why the infra-red -energy must be removed 12 from the light that it receives. 13 14 Heat sink 24 is located near behind cold mirror 22 and 13 accepts the infra-red energy. This is manifest as heat and so 1 3 the several cooling fins are integral with the heat sink. 7 The sink is cooled by a brisk flow of air along the fins, 3 which flow is also directed at lamp 20 for the cooling thereof. ig This air is provided by a fan-blower and ducts according to 2Q known practice and so these have not been shown. 21 22 While the document is on main table 11, vacuum chambers 23 26,27 and 23 are evacuated, as was chamber 7. 24 3 the time the trailing edge of the document has passed 25 sensor 15 on the slow video-signal-generating translation 2S backwards, a switch-manipulated decision previously made by 27 the operator, or handled by a program from the Host I/O 46, 23 determines whether or not the document shall be discharged 29 from the apparatus; shall be turned over and then discharged; 30 . or turned over, the second side scanned to produce video 1 signals, and then discharged. Foot switch intervention by 2 the operator may be arranged into the interface control board 3 42 of Fig. 2? i.e., should the preset program call for only 4 one side scanning, then actuation of the foot switch will 5 arrange for scanning both sides, and vice versa. S 7 Should the choice be to discharge the document after side 3 one is scanned, then belts 10 go into fast forward and the 9 document passes into catch tray 30. 0 Should the choice be to turn the document over, "flipper" 1 31 is energized, belts 10 go into fast reverse, the vacuum in 2 chamber 27 is withdrawn and vacuum is established in flipper 3 chambers 32 and 33. In passing underneath the flipper the 4 document is drawn slightly upward by the vacuum in chamber 32 5 onto plural spaced parallel belts 34, which run on-large roller S 35 and small roller 36. These rollers are preferably driven 7 by a separate motor that is controlled by microprocessor 40 3 and its interface circuits. 9 The document passes around large roller 35 and downward 0 toward small roller 36.. Vacuum is re-established in chamber 1 28 and is withdrawn from chamber 33. This allows the rapidly 2 moving document to leave the flipper mechanism and to again 3 be vacuum-secured to belts 10. The document passes over 4 sensor 37 as ' it naars roller 36. 5 If the document is than to be discharged it progresses at s high speed to catch tray 30, as before. 7 3 If the second side is to be scanned, then belts 10 move 9 forward at slow speed from the time sensor 15 is reached, 0 camera Iβ is energized, and the second side is scanned as it moves from sensor 15 to sensor 14. Thereafter, it is moved further forward at high speed into the catch tray. The video signal thus produced is 180° out of phase with respect to that of side one. An electronic buffer in inter- face 42 acting as a shift register inverts the data to compensate for this phase reversal. Camera-scanner 16 is rigidly supported to the rest of the apparatus, in part, by cylindrical tube 38. The distance from the documents on belts 10 and lens 17 may be 55 cm; the lens having a 60 millimeter focal length. Light-sensitive element 18 is preferably a CCD linear array, such as the Fairchild 143. It is spring mounted against the rear mount of lens 17, so that focus will be maintained. The depth of focus is about 1/10th millimeter. The several electronic circuits of the camera-scanner; such as timing, electrical clamp, switching for A & 3 pixels αf the CCD, automatic gain centrol of the video signal, gamma correction aperture correction, and threshold, are according to the Video- scan camera. Model VS2200, of the Terminal Data Corp., Woodland Hills, California. Additionally, the circuits and information of the Fairchild 143 CCD instruction manual may be used. The threshold cirσui-c constitutes the analog to digital converter in the camera-scanner. the overall block diagram of the apparatus of Fig . 2 , microprocessor 40 is the basic elamen- . It may be a 3C3 30/10 board , having an 8080A microprocessor . An RS232C interface is resident upon the microprocessor ' circuit board, to which a monitor 41 can be connected for 3 running diagnostic tests, should there be circuit trouble. 4 " 5 Interface control board 42 connects via a multibus to g microprocessor 40 and similarly to the other elements of γ major importance in the apparatus. g ' An input/output set of connections from control board 42 g passes to Feed Table /Transport Servo entity 43. Therefrom Q are connections to feed table motor 44 and separately to 1 transport table motor 45, for the control of these motors. At 46, the Host input/output, information to and commands 3 from the "Host", or external microcomputer entity, with which 4 this apparatus is to work in a typical case. This aspect is 3 treated further in the consideration of. the flow charts of Q Figs. 4 and 5. 7 Document camera-scanner 16 is connected for input/output 3 functioning by an RS422 interface; aiso, an enable scanner 9 connection 47, which puts this device in operating condition when a page of document is to be scanned to produce video signals. At other times the camera is inoperative, since spurious video signals would otherwise be created. Fig. 3 is a block-schematic diagram of the servo system; block 43 in Fig. 2. There are two separata systems according to Fig. 3; one for activating belts 3 of the feed table by energizing motor 44 of Fig. 2, and another for activating belts 10 of the main transport table by energizing motor 45 of Fig. , 3oth sys-sms are the same; thus, the motor in Fig. 3 is identified as "44 or 45"-. O PI 1 Input terminal 50 receives reverse the belts commands, either fast or slow, as the case may be. These pass into 3 inverting amplifier 51 in order to provide the inverse of the 4 forward commands to the error amplifier. g Input terminal 52 receives forward commands, either fast g or slow, and is connected directly to error ampli ier 53. γ Input terminal 54 receives an output from tachometers that 3 are separately connected, to each of the belt systems, as the g case may be. 10 The commands from either terminals 50 or 52 are from 1 microprocessor ' 40 (Fig. 2) , are continuously applied as long 12 as a forward or a reverse command is to be executed by the 13 belts involved. The voltage level that represents the command 1 has a constant value and represents the true value for ig determining the speed of translation of -the belts involved. ig The input from the tachometer involved, at terminal 54, 1~ represents the ac-cual speed of translation of the corresponding i a belts. 1„ Tachometer filter 55 reduces the speed of response of the 2 Q ' system so that high frequency oscillations, as caused by the , motor-tachometer coupling resonance, cannot occur. 2« Error amplifier 53 gives an output corresponding to the 2 - difference between the voltage level at either terminal 50 or 24 52 and that at terminal 54. 25 The amplitude and the polarity of the output from amplifier 23 53 gives the remainder of the elements of Fig. 3 electrically 27 represented information as to whether motor 44 or 45 is to 23 rotate faster or slower, forward or reverse. 29 30 Amplifier 56, of the differential type, simultaneously 31 performs several f nctions, according to the designation ' 1 thereof as "volts to amperes converter and pulse-width 2 modulator generator". 3 Pseudo-triangle wave generator produces- n approximate 4 triangular wave, such as shown by the small waveform adjacent 5 to the output of generator 57. This may be a square wave 3 oscillator, the known triangular wave output of which is 7 utilized. This waveform enters the +• terminal of amplifier 56. 3 ' The D.C. output from error amplifier 53 enters the - terminal 9 of amplifier 56 through an isolating resistor. Also through 0 an isolating resistor the current sensed as flowing through 1 motor 44 or 45 as a voltage appearing across a small resistance 2 value resistor 49-, which is connected between the motor and 3 ground return. 4 When the motor is running, the error amplifier provides a 5 continuous voltage output as a result of- any error developed S between the command voltage and the tachometer voltage. 7 This output is then applied to pulse width modulator 56, 3 which adjusts the square-wave duty cycle accordingly. This 9 duty cycle translates into an increase or decrease in current 0 to the motor. 1 Amplifier 56 and its peripherals thus performs three functions 2 D converts a D.C. voltage input to motor current output, 3 2) converts a D.C. voltage to a pulse-width modulated square- 4 wave (along -wi-th— enerator 57) , and 3) provides motor current limiting (with resistor 49) . 3 The output of amplifier 56 becomes the input to voltage amplifier 58, and the output thereof passes to the amittar- follower cascade consisting of transistors 59, 63 and 64. 1 Diodes 61 and 65 are used to speed the transition between "on" and "off" of the subsequent circuits in switching amplifier fashion, thereby reducing the energy loss and consequently 4 reducing the heating of the output circuit semiconductors. 5 . g Driver transistor 63 increases the power level to adequately 7 drive parallel output boosters 64, the latter also being properly g characterized as a push-pull switching type power amplifier. 9 1 The base input of transistor 59 is also connected to a supply 1 voltage, say 50 volts, through a series of similarly poled ' diodes 12 constituting clamp 66. With this clamp absent, the V Cj≥ 1 (voltage across collector to emitter junction) of ou u booster 1 S is 2.6 volts. This gives a power dissipation of 130 15 watts, with the 50 volt supply. With the clamp present, the i voltages in the transistor circuits are adjusted so that the 17 is only 0.25 volt and the dissipation is only 12.5 watts. IS 19 Diode 67, inserted at the output emitter of transistor 63 20 and the input to boosters 64, is a protection diode. 21 Typically, output boosters 64 is comprised of four power 22 transistors, of the silicon power type. Should one of these 23 fail in use, the failure is invariably a fusion of the collector, 24 emitter and base into one short-circuit conductor. This allows 25 the " +50 volts" power supply for these boosters to revert 23 back to the emitter resistor of driver transistor 63. This 27 destroys the resistor and the heat or fire resulting destroys 23 the circuit board at that location, so that a new circui board 29 is required as a replacement. 30 Diode 67 prevents this. In the normal functioning of 1 this part of the circuit diode 67 is forward biased and acts 2 like a conductor. When a booster failure occurs diode 67 is 3 back biased and the circuit is opened. Current flow to the 4 resistor of transistor 63 is thus prevented and there is no 5 damage. 3 Considering this matter further, it is usual that only one 7 power transistor fails. hen this occurs and it becomes a 8 short circuit, this de-energizes the other transistors in 9 parallel therewith, and the other transistors dα not fail. 0 1 The power output from boosters 64 is connected to motor 44 2 or 45 by conductor 68. This output may be a current of 50 3 amperes at a voltage of 50 volts in a preferred embodiment of 4 this apparatus. 5 Diode 69 allows a fast recovery with . respect to current S - changes by negating the inductance of the motor. 7 3 Short circuit protect entity 70 is a transistor that senses 9 too great current in the booster and turns off the drive at 0 transistor 59 under such conditions. 1 Elongated rectangle 71, labeled "negative complement (mirror 3 image) " is schematic nomenclature for identifying a duplication 4 of all of the elements from 59 through 70 that are shown in 5 ?i « 3. e The square waveform below motor " " represents a voltage 7 output waveform of -(-50 volts. That is contributed by the s circuit elements 59-70 that are shown in Fig. 3. The voltage g of -50 volts is contributed by the negative complement 71. 0 The double-pointed arrows signify that the pulse width may be OMF V modulated to increase or decrease the current, as has been describe . Motors 44 and 45 are direct current mβ-cors. ' In the flow diagram of Fig. 4, "Start", identified by numeral 75, indicates that the apparatus has been turned on and is in operating condition. The first activity is dependent upon there being a "Document at feed station" 76. Until that occurs the "Wait" return path is taken and the apparatus remains waiting for the document. The document is placed at the feed station by a human operator, or an automatic document feed apparatus. As soon as the document is present "Enable feed- station vacuum" 77 occurs; i.e., in vacuum chamber 7 in Fig. 1. The next activity is "Set fast forward transport" 78; i.e., belts 10 in fast forward on the main table, Fig. 1. That activity allows acceptance of the document upon the main table once it moves off of the feed table. The next activity is "Set feed table transport in fast forward" 79. This situation carries on until "Document trailing edge detected" 80 decision point is a "Yes" answer. Prior thereto the instruction is "Wait". The edge is detected by sensor 8. The document now being on the main transport table the next activity is "Set feed table stop and disable- feed 1 station vacuum" 31. This allows the next document to be placed 2 on the feed table by the operator. 3 4 "Scan line approach sensor 15 active" 82 decision point is 5 next, with "Wait" until that occurs. hen reached, a finding 3 as to whether or not the document is skewed is provided by the 7 pair of sensors at 15. 3 This finding is accomplished at the next decision point, 9 "Document skewed" 83. 0 If the answer is "Yes", then the activity is to return the 1 document to the operator. 2 The first activity thereafter is "Set fast reverse transport" 3 84; i.e., reverse belts 10 at the fast speed. 4 The second activity is "Illuminate skew error indicator" 5 85. This is a lamp upon the control panel of the apparatus S that is a part of Interface control board 42 of Fig. 2. 7 The next activity is "Wait H second" 86 decision point, 3 which is interposed to allow the document to return to the 9 operator. Thereafter, "Set 'stop' transport" ' 87 is activated Q and the microprocessor returns to the "Start" 75 condition. i The operator is to properly position the document and to start the above-recited sequence over again. In order to extinguish the skew error indicator lamp the operato'r must depress the "Reset" button on the control panel. 5 The "Reset" is connected to interface 42 in Fig. 2. 3 If the skew answer is "No" at decision point 83, then the activity passes on to "Scan line sensor 14 active" 83. If necessary, there is a "Wait" until this occurs; i.e., the time raαuirad for the document to move from sensor 15 to -£ fRE O PI 1 sensor 14 at the fast speed of translation. This is a small 2 fraction of a second. 3 The next activity is "Scan line sensor 14 inactive" 89. 4 This means that the document has gone beyond that sensor, 5. which is to be expected on a fast forward translation of the 3 document. Thereafter, "Set slow reverse transport" 90, 7 becomes active to slowly bring the document back at the slow 3 speed, of transport for video scanning. The next activity is 9 to "Enable scanner, side 1" 91; i.e., to activate camera- 0 scanner 16 of Fig. 1. 1 Next, is to "Notify Host 'scanner ready'" 92; i.e., the apparatus is ready to produce video signals from the document that is in the apparatus. In effect,"Do you wish to have this occur?" The "Host" is a control microcomputer", minicomputer, or 3 equivalent, that determines overall strategy for the document 7 video digitizer apparatus of this invention, likely in concert S with other apparatus that makes use of the digitized video 9 signals. Herein, it is the equivalent to a very fast acting 0 "operator", or agency that establishes what the operative 1 plan shall be. 2 3 Next, "Scan line sensor 14 active" 93 decision point holds 4 off video scanning until the answer is given that this should 5 occur. 3 The next decision poin-c is "Host acknowledges 'scanner ready'" 7 94. If that answer is "Yes", the document is scanned. 3 If the answer is "No", the document is returned to the 9 human operator; i.e., "Set fast reverse transport" 95. 0 The "Illuminate I/O error indicator" 96 occurs. After this, the operator must depress the reset switch to extinguish the I/O error lamp. This return of the document follows the sequence of the prior skew error return. It enters the prior sequence at the begin- ning of the "Waif second" 86 decision point, then through "Stop" 87 and back to "Start" 75. ' On the other hand, if the "Scanner ready" is acknowledged as "Yes" at 94, the activity goes to the "Yes" of Fig. 5, the remaining part of the flow diagram started in Fig. 4. Inherent in the "Yes" response at 94 is the empowering of "Set slow reverse transport" 90 and the other preparedness functions of items 91 through 93. Thus, the document is scanned by camera 16. When this is completed "Scan line sensor 14 i active". 97.occurs. At this point a decision is to be made as to whether or not the scanned document is to be turned over. ' This is "Document flip command active" 98. " If the answer is "No", then the activity is to "Set fast forward transport" 9 . This results in the document exiting the apparatus and being deposited in catch tray 30 of Fig. 1. The microprocessor returns to "Start" 75 of Fig. 4. On the other hand, if the flip command at 98 is "Yes", then the activity is to "Enable flipper vacuum" 100, and after that "Set fast reverse transport" 101. This transports the document under flipper 31. With the flipper vacuum "on" the document adheres to flipper belts 34 and is carried around the clipper to turn the document over. See Fig. 1. /*& OMP1, ~ ' ~ 1 Next, "Flipper sensor 37 active" 102 decision point calls 2 for a "Wait" until this occurs. When it does it signifies that 3 the document is on the opper inclined surface of the flipper. 4 This calls for activity "Set fast forward transport" 103; 5 i.e., start belts moving rapidly forward. 3 Again, "Flipper sensor 37 inactive" 104 implies that the 7 document has left the flipper and is largely upon belts 10 of 3 the main transport table. 9 0 Next, "Scan side 2 command active" 105 decision point is 1 involved. Typically, this decision has previously been made by the operator manipulating a switch on the control panel. 3 Assume that the answer is "No". 4 Then "Scan line approach sensor 15 active" 106 decision point 5 is involved, with a "Wait" far the approach-to sensor 15. S Thereafter,"Disable flipper vacuum" 107 is accomplished. 7 Since the "Fast forward transport" had been set at 103, the 3 document exits the apparatus to catch tray 30 of Fig. 1 and 9 the microprocessor returns to "Start" 75 of Fig. 4. This 0 routine is employed if some of the documents have been scanned 1 on both sides and it is desired that all of the documents in 2 catch tray 30 lie with corresponding sides upward. 3 4 Now, assume that the decision at decision point 105 is "Yes". 5 Then, with the document just coming off of the flipper belts, s the "Set slow forward transport" 108 occurs. After that 7 "Scan line approach sensor 15 active" 109 decision point is 3 reached. There is a "Wait" until that occu- . g Next, "Disable flipper vacuum" 110 occurs so that such 0 vacuum will not confuse the next traverse of the next document 1 in the apparatus. 2 "Document skewed" 111 decision point is next reached. 3 If * the answer is "Yes", then the "(1)" indicates that the actio 4 goes back to the same "(1)" after the "Document skewed" 83 5 decision point of Fig. 4, and the document is returned to β "Start" 75, as-before. 7 if the 111 answer is "No", then "Notify Host 'scanner 3 ready'" 112 occurs by action of the microprocessor. Thereafter, 9 "Scan line sensor 14 active" 113 decision point is reached 10 and holds further action until that is true. 11 The next decision point "Host acknowledges 'scanner ready'_" 12 114, parallels the considerations of items 92 to 94 previously 13 explained. 14. If the answer at this item 114 is "No", "(2)" indicates that 13 the action goes back to the same "(2)" after item 94 of Fig. 4. IS The action and the document goes back to "Start" 75, as before. 17 3 on the other hand, if the scanner ready is acknowledged as 9 "Yes" at 114, the next activity is "Enable camera-scanner 0 side 2" 115, and the scanning of side 2 takes place at the 1 necessary slow transport speed that had already been set at 108. 2 Next, "Scan line approach sensor 14 i active" 116 is 3 involved. The microcomputer waits until this is true, which 4 means that the document has been scanned on side 2. 5 Thereafter, "Set fast forward transport" 117 occurs, which 3 exits the document to catch tray 30 of Fig. 1. 7 3 This concludes scanning the document on two- sides, with 9 side 1 being scanned while the document is moving backward 0 at the slow rate and side 2 beinσ scanned while the document 1 is moving-forward at the slow rate. This results in both 2 sides of the document being scanned from top to bottom. 3 The microprocessor goes back to "Start" 75 to be ready to 4 handle the next document. 5 3 7 In addition to the flow chart of Figs. 4 and 5, there is 3 here presented' the architecture relating to microprocessor 40. 9 The program thereof primarily controls the document transpor 0 system. The software handles control of the movement of the 1 documents through the system, including; error warning, position sensing, operator command and diagnostic routines. 3 " The control section of the program resides in the RAM at 4 3D00H and may not extend beyond the stack, which starts at 3 400OH and is approximately 32 Bytes long. During power up 5 the program is mo.ved from its origin in the ROM at 0800H to the RAM at 03D00H. 3 The system utilities reside at 400H, and include port set 9 (.set) and reset (.res) routines, a pause (.delay) routine, 0 and a bipolar status check routine (.newmait). Bits on the two input (sense) ports statl and stat2, are 2 active "low" to the software. Statl devotes 5 of its 8 bits to the document position sensors. Bits 2, 3 s 7 are not used. 4 Stat2 uses the low order nibble (4 bits) to describe system 3 conditions and errors. The "hi" order nibble represents the s current operator command. Stat3 is not implemented. 7 The two output (command) ports, com! and com2, direct system s nctions. Coml sends ready, enable and error commands to the g system. Cαm2 directs the motion and speed of the transport and 0 enables the feed table vacuum and motion. Com3 is not used. S UBS j fi Ϊ TUTE SHEET Logic polarity is described by the following signal levels. 2 The input ports, statl (0E4H) and stat2 (OSSH) are active when. 3 low. They will rest hi (1) and become low (0) only in their 4 true (active) state. The output ports, coml (0E3H) and com2 (0E9H) are more s complex. On the output ports the logic is active when hi. 7 That is, a given command signal, such as flipper .vacuum, 3 rests at a zero or low level, hen the program wishes to g enable that particular command signal, it is turned on, i.e., 0 hi, (1) . The active hi command port outputs are inverted to active when low on the apparatus side of interface 42 of Pig. 2. Further, all of the individual output command signals, and all of the individual input sense signals, are defined as active hi signals. This is to facilitate readability. The logic still ultimately handles these signals as described above; sense signal logic is active when low and command signal logic is active when hi. It is seen that coaction of the microprocessor, electrical, optical and mechanical aspects of the apparatus are required for the operation thereof, along with other aspects relating to safety and reliability in order to provide a commercially viable apparatus.

Claims: We claim: 1. Document video-manipulative means, comprising; (A) video means (iβ) to accept an image of a document (2) , (B) belt means (10) to selectively reversibly translate a document, (C) servo means (43) to translate said belt means, mechanically connected thereto, (D) microprocessor means (40) to control said servo means, electrically connected thereto, to; (a) move said document forward at high speed, (b) stop said document, (c) move said document backward at low speed, and (d) activate said video means during the backward motion of said document to form a video signal corresponding to the image of said document. 2. The document video-manipulative means of claim 1, in which said microprocessor means (40) additionally controls said servo means (43) to; (a) move said document forward at high speed after the previously recited movements to exit the document from the manipulative means. OMPI 3. The document video-manipulative means of claim 1, which additionally includes; . (A) further belt means (31) having a curvilinear path, thereby to turn said document over, and (B) said microprocessor means additionally controls said servo means, to; (a) move said, document backward at high speed, around ' said further belt means at high speed, and thereafter forward at high speed, (b) thereafter move said document forward- at low speed, (c) activate said video means during the move forward at low speed, to form a video signal corresponding to the image of the second side of said document, and (d) move said document forward at high speed to exit the document from the manipulative means. 4. The document video-manipulative means of claim 1, which additionally includes; (A) further belt means (31) having a curvilinear path, thereby to turn said document over, and (3) said microprocessor means additionally controls said servo means, to; (a) move said document backward at high speed, around said further belt means at high speed, and forward at high speed to exit the document from, the manipulative means. O FI 5. The document video-manipulative means of claim 1, in which said microprocessor means (40) further includes; (a) plural sensors (15) in the path of translation of the document (2) by said belt means (10) , said sensors electrically connected to said micro¬ processor-means (40) through interface means (42) , (b) means in said microprocessor means to detect ' the time of arrival of an edge of said document at each of said plural sensors, and (c) error warning means in said interface means active upon a response from said microprocessor means to respond with an error warning when the time of arrival differs by an interval in excess of that corresponding to a few angular degrees of skew of said document. β. The document video-manipulative means of claim 1, in which said servo means further includes; (a) plural semiconductor means connected in parallel, (b) other semiconductor means connected to 5 electrically drive said plural semiconductor means, and (c) a diode poled to prevent electrical energy from passing from said plural semiconductor means to said other semiconductor means upon an electrical short occurring in at least one of said plural Q semiconductor means. 7. The document video-manipulative means of claim 1, in which said servo means (43) further includes; (a) means (56,57) to convert a d.c. input from the microprocessor (40) to a pulse-width modulated square wave, (b) means (58-64) to convert said pulse- width modulated square wave to motor current output, and (σ) means (56) to limit the motor current. 3. The document video-manipulative means of claim 7, in which said means (53-64) to convert said pulse- width modulated square wave to motor current output further includes; (a) plural series-connected diodes forming a clamp (66) in the circuit from said means (53) to convert said pulse-width modulated square wave to motor current output to a power voltage source . (+5Qv) , to neutralize plural semiconductor voltage drops to significantly reduce the collector to emitter potential drop in a semiconductor element (63) and so the dissipative current thereof. OMPI 9. The document video-manipulative means of claim 1, which further includes; (a) an elliptical reflector of elongated transverse extent, (b) an elongated source of illumination disposed at a focus of said elliptical reflector, and (c) a mirror disposed away from said source of illumination to reflect substantially only the visible spectrum emitted by said source of illumination to a relatively narrow area of light transverse of said belt means to illuminate a said document. 10. The document video-manipulative means of claim 1, which further includes; (a) a tubular support surmounting said belt means where the belts move at low speed, (b) an objective lens having a rear mounting attached to said tubular support away from said belt means, and (c) CCD means spring-mounted to press upon said rear mounting to receive an image of said document. ' SUBSTITUTE SHEET OM

Inventors: OLIVER THOMAS W, ROLLER THOMAS W, ROTHBART MICHAEL, THERIEN ROBERT D, WILLIAMS ROBERT D, OLIVER, THOMAS, W., ROLLER, THOMAS, W., ROTHBART, MICHAEL, THERIEN, ROBERT, D., WILLIAMS, ROBERT, D.
Applicants: TERMINAL DATA CORP, TERMINAL DATA CORPORATION
Application year: 1983
Main classification: H04N1
IPC codes: H04N1