GB1591447A

GB1591447A - Optical character recognition system

Info

Publication number: GB1591447A
Application number: GB49621/77A
Authority: GB
Original assignee: Recognition Equipment Inc
Current assignee: Recognition Equipment Inc
Priority date: 1976-12-27
Filing date: 1977-11-29
Publication date: 1981-06-24
Also published as: NO774431L; JPS5858659U; JPS5840434Y2; NL7713609A; JPS5389628A; JPS5840435Y2; JPS5858658U; DE2757495A1; SE7714672L; FR2375666B1; DK575977A; FR2375666A1

Description

(54) OPTICAL CHARACTER RECOGNITION SYSTEM (71) We, RECOGNITION EQUIPMENT INCORPORATED, a corporation organised under the laws of the State of Delaware, United States of America, and of 2701 E.

Grauwyler, Irving, Dallas County, Texas, United States of America, do hereby declare the invention foi which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to optical character recognition equipment and more particularly to a total data entry system utilized in a hand-held optical character reader.

A small hand-held optical character recognition unit capable of manual scanning of alphanumeric characters is disclosed in U.K. Patent Application No. 1525479. An optical character recognition unit that can be used in a portable system is disclosed in U.S. Patent Application No. 1498221. The hand-held unit disclosed in the above patent application has been utilized in a portable optical character recognition system which is disclosed in U.K.

Patent Application No. 40155/77 (Serial No. 1582020). The portable system disclosed in the last mentioned patent application is light weight and may be carried from one point to another for such purposes as taking inventory of merchandise or reading labels on stored goods in order to determine the number of goods on hand. One disadvantage of the system is that it is in the form of an attache case and the user must generally stop and place the case on a table or floor while using the wand, if it is desirable to enter data in the system manually by the keyboard in instances where the data on the document or label is such that it cannot be read by the optical character reader. Also, it is inconvenient to view the information which is displayed on the console display unless it is residing flat on a table or other surface.

The present invention provides an optical character recognition system comprising a hand wand which is remote from, but linked to, a portable signal processor by a transmission path; said wand having an optical scanner for receiving and scanning a data image to supply a respective information signal to said transmission path, said wand including a display and a keyboard for entering data by hand instead of via the optical scanner whereby a respective information signal is supplied to the transmission path, the latter data being readable on the display; said signal processor being provided to receive said information signals, to derive data recognition signals therefrom and to operate the display.

For portability, a preferred embodiment of the invention is battery operated and it may be carried by a shoulder strap. Preferably, the wand has a head portion which can be rotated through 1800 so that it can be used in either in the right, or the left hand. In the preferred embodiment, the head portion is lifted and rotated and then allowed to be seated against the top of a case on which the keyboard and display are mounted. When the transmission path comprises electrical wires, connecting the wand to the portable signal processor, a strain relieved, rotational connection is included in the wand so that the head portion may be rotated through 1800 without undue wear or harm to the connection between the electronic components.

Suitably, the wand is provided with lamps in a nose portion for illuminating data which is read by the optical scanner. Preferably, the wand includes a document sensing device for switching on the power supply from the battery to the system when a document is placed adjacent the optical scanner. For example, the wand may include an infrared light source, a light guide or pipe for transmitting light from the source to the document, and a photosensor for receiving light reflected from the document and transmitted again through the light guide or pipe. The light guide or pipe is preferably provided in the nose portion of the wand to avoid providing electrical connections which may be disturbed when removing the nose portion to change said lamps. Without a light guide or pipe, the light-source and photosensor may need to be built into the nose portion, thereby requiring electrical connections with components in the body of the wand. Preferably, the light guide or pipe is of integral constructions and is made of injection moulded, acrylic plastics material.

If the optical scanner cannot be used to read-data, for example, on an item which is torn or smudged, the keyboard can be used to enter data which is verified by the display. Preferably, a cassette tape recorder is included in the portable signal processor so as to record correctly entered information signals and to store said signals for later processing. Suitably, the signal processor includes a character recognition unit for recognising the data which is read by the optical scanner. After recognition, signals are provided which are recorded on tape. The tape can then be used, at a later stage, by feeding it into a computer or some other data processing system to utilise the recognised data which was read by the scanner, processed and then recorded on the tape.

The transmission path may be a radio link instead of a wired connection between the wand and the portable signal processor.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an optical character recognition system in accordance with the invention which comprises a hand wand and a portable signal processor.

Figure 2 is a plan view of the hand wand.

Figure 3 is a block diagram schematically illustrating the circuitry within a head portion of the hand wand.

Figure 4 is a block diagram of circuitry used with a keyboard and display in the hand wand.

Figures 5 and 6 are sectional views, on different elevations of the hand wand.

Figure 7 illustrates a part of the wand to enable rotational movement of a head portion relative to a body portion.

Figure 8 is a perspective view of a light pipe used in the wand.

Figures 9a and 9b are top and side views of the light pipe of Figure 8.

In Figure 1 is illustrated one embodiment of a total data entry optical character recognition wand and data entry unit according to the present invention. The hand-held unit is attached to the recognition electronics unit 2 by cable 3. The unit includes a provision for a magnetic tape cassette at 4. Switches 5 and 6 are used to turn the units on and to control other functions of the system. The unit 2 may be provided with a strap connected to connectors 7, one of which is illustrated.

A more detailed drawing of the hand-held unit 1 is shown in Figure 2. The unit consists of the read head 13 having a nose portion 14 which is attached by the rotating screw 15. Data is entered on keyboard 11 by keys 16. Information input into the system is displayed on the display 12. When the unit is in the process of reading or processing data, the display light 17 turns on showing that the system is busy.

The read head electronics 13 is illustrated in more detail in Figure 3. The read head includes a 12 by 38 self scanning electronic array onto which is focused, by the lens, information read from the media which may be in the form of a document, or any printed material such as price tags, labels, etc. Lamps DS1 and DS2 illuminate the document for reading. In order to conserve energy and to turn off the power to most of the system while the read head is not actually reading a document, a control circuit is used. The emitter-sensor for the control circuit is illustrated at 19. An infrared signal is emitted from the unit 19, transmitted through the light pipe 18 to the document and reflected back through light pipe to the unit 19 if a document is being read. However, if no document is in the immediate vicinity of the read head, the infrared signal is not reflected, and the unit is not turned on. Such a control system is disclosed in UK Patent Application No.40155/77.

During a read cycle, the array is continually scanned and driven by the cell clock driver and the row clock driver through the x andy registers. To synchronize the system, an end of frame signal and an end of line signal goes into a buffer sync logic unit and are sent back to the recognition electronic unit. The video output from the array is also sent back to the recognition unit. The status lamp LED 17 is on when the system is in use and data is being processed.

The transmit signal line and the receive signal lines are connected to the transmit-receive unit 19 in order to transmit signals and receive reflections thereof to tell the unit to turn on when a document is being read or comes within the vicinity of the nose of the read unit.

The keyboard and display circuitry is illustrated in block form in figure 4. A 4 bit microprocessor is used to take the infqrmation keyed in from the keyboard and relay it back to the recognition unit electronics and in turn relay to the display the information which has been entered into the keyboard, read by the read head and processed by the recognition unit.

Five lines are needed to go into the keyboard display unit. Battery power, ground and three lines which communicate between the 4 bit microprocessor and the electronics in the recognition unit.

The display and keyboard are standard available units which are commonly used in, for example, hand-held calculation. The four bit microprocessor may be, for example, a Texas Instruments TMS 1200 microprocessor chip.

Communication between the keyboard and display and the recognition unit 2 is accomplished with a serial message format. Recognition unit 2 includes a Fairchild F-8 microprocessor as disclosed in UK Patent Application No. 40155/77 (Serial No. 1582020). The transfer of data from the recognition unit to the Keyboard Display Unit is initiated by raising the data lines to a logic "one". The TMS 1200 located in the Keyboard Display Unit generates eight clock pulses which have a 6 millisecond period to strobe data from the recognition unit to the Keyboard Display Unit. Table 1 list the message codes which are transmitted to the TMS 1200.

Key stroke data is transmitted in an interrupt mode to the recognition unit with the MSB (most significant bit) being transmitted first. The "ATTN" key code is all "ones" and is used to "wakeup" the system during power-save cycles. The Interrupt Strobe initiates a power ON cycle which maintains power for two seconds after the last keystroke. Table 2 list the various key codes which are transmitted to the recognition unit.

To provide a universal hand-held unit which can be operated with either hand, the read head 13 can be rotated 180 degrees so that it will point in either direction, left as shown in Figure 5 or right (not illustrated). In order to provide a flexible connection between the keyboard display unit and the rotational shaft through which the cable 3 passes to intercon neck the read head with the recognition unit, it is necessary that the interconnection between the rotational unit be flexible to survive the rotation of 180 degrees. This is accomplished by having a plug 22 connected to a receptacle 28 (Figure 7) on the rotational shaft in the recessed portion thereof. Wires 23 are connected to the plug 22, loop around the rotational shaft and are connected with terminals on the circuit board on which the keyboard and display components are mounted. Five wires are required for the battery connection, (positive and ground) and the 3 wire input/output and clock data lines which are used to communicate between the keyboard display and the recognition unit 2. On the uppermost portion of the rotational unit of shaft 3 is a spring which holds the read head 13 in contact with the top portion of the body 20. In order to rotate the read head, the read head is pulled away from the body 20 and rotated. Once the rotation is complete the spring will pull the read hea back into place and hold it against the body 20. Accidental rotation of the read head is prevented by the display housing which extends up against one side of the read head when the read head is in its lower position. The read head must be pulled above the display before it can be rotated.

Serial Message Format F-8 to TMS 1200 Character/Function MSB LSB 0 1000 0000 1 1000 0001 2 1000 0010 3 1000 0011 4 1000 0100 5 1000 0101 6 1000 0110 7 1000 0111 8 1000 1000 9 1000 1001 1000 1010 A 1000 1011 F 1000 1100 E 1000 1101 C 1000 1110 (Blank) 1000 1111 End of Message 1001 XXXX Recall 1 1010 XXXX Recall 2 1010 XXXX Hold Message in TMS 1200 1100 1111 Release Hold 1100 0000 Force Attn Key 1101 1111 Release "Attn" Key Force 1101 0000 Blink Display 1110 XXXX Clear Display 1111 XXXX X = Don't Care Table 1 Serial Message Format From TMS 1200 to F-8 Key Number MSB LSB 1 0000 0000 2 0000 0001 3 0000 0010 4 0000 0011 5 0000 0100 6 0000 0101 7 0000 0110 8 0000 0111 9 0000 1000 10 0000 1001 11 0000 1010 12 0000 1011 13 0000 1100 14 0000 1101 15 0000 1110 ATTN 1111 1111 2ndLevel 1111 1110 3rd Level 1111 1101 Table 2 A more detailed view of the rotational unit is illustrated in figure 7 wherein the plug 22 is shown to mate with the connector 28 in recess 30. The spring, not illustrated, resides around the shaft at 25, the lead wires 27 extend up into the read head are interconnected to the electronics therein and extend out the other end for connecting with the recognition unit 2 through the cable 3 and plug 26.

It is possible that the cable 3 could be replaced with a receive/transmit unit and in the handheld unit and the recognition control unit. Small data relay transmit/receive units are well known and need not be covered in detail.

A more detailed view of the light pipe used in conjunction with turn on/off circuit is illustrated in figures 8 and 9. Figure 8 is a pictorial view of the light pipe and Figures 9a and 9b are side and top views.

Normally in light pipes of this nature, multifiber optical bundles are used. However, such a light pipe does not lend itself to high volume low cost production. The light pipe illustrated is made by injection molding with acrylic plastic. The light pipe is a homogenous material as opposed to individual glass fibers. In order to impart a mirror finish to the sides of the light pipe the mold has a 16 microinch finish or better. One advantage of this type of light pipe is that only one inexpensive part is needed to perform the function.

The surfaces of the light pipe are highly polished providing essentially total internal reflection. Therefore, light energy in the pipe is conducted from input to output with relatively low loss. Referring to Figures 3 and 5, energy from the emitter/ receiver sensor 19 is conducted through the light pipe to the document and reflected energy is transmitted back through the light pipe to the sensor. The sensor is mounted on the main read head frame while the light pipe is in the nose cone. The pipe permits removal of the nose without any electrical connection between the nose and the main read head body. The pipe may be used with any non-coherent light where the energy source or receiver is remotely located.

In order to mount the light pipe without the exterior walls coming into contact with a surface which may interfere with the internal reflectivity of wall, mounts 29 are formed on the sides of the light pipe and are used to prevent undesirable contact of the walls with surrounding structures.

The above described embodiment relates to a total data entry hand held unit which optically reads data. When the data cannot be read optically, the same unit having a keyboard thereon is used to encode data into the system. The encoded data is displayed for verification.

In order to provide for either left hand or right hand use of the unit, the read head may be rotated through 180 degrees so that it points either to the right or left of the keyboard display body. A rotational strain relief unit is provided within the body to permit internal connections with the keyboard and display without damaging the interconnections.

WHAT WE CLAIM IS: 1. An optical character recognition system comprising a hand wand which is remote from, but linked to, a portable signal processor by a transmission path; said wand having an optical scanner for receiving and scanning a data image to supply a respective information signal to said transmission path, said wand including a display and a keyboard for entering data by hand instead of via the optical scanner whereby a respective information signal is supplied to the transmission path, the latter data being readable on the display; said signal processor being provided to receive said information signals, to derive data recognition signals therefrom, and to operate the display.

2. A system according to claim 1 in which said wand houses a microprocessor for receiving the data entered by the keyboard and for providing the information signal to the transmission path.

3. A system according to claim 1 or 2 wherein the wand includes a head portion provided with an optical scanning window, and a body portion to be held in the hand.

4. A system according to claim 3 wherein the body portion is provided with the keyboard and the display.

5. A system according to claim 3 or 4 wherein said head portion is rotatably mounted on said body portion by means of a tubular member which is secured to one of said portions and extending through the other of said portions, and a biasing member which co-operates with said tubular member to hold said bodies in an abutting relationship.

6. A system according to claim 5 wherein said tubular member is provided with a circumferential ridge to abut one end of said biasing member.

7. A system according to claim 5 or 6 wherein the transmission path comprises electrical wires extending between said wand and said portable signal processor, said wires extending through said tubular member into each of said portions in such a manner as to permit rotation of one of said portions relative to the other.

8. A system according to claim 7 wherein said tubular member has a circumferential

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. A more detailed view of the rotational unit is illustrated in figure 7 wherein the plug 22 is shown to mate with the connector 28 in recess 30. The spring, not illustrated, resides around the shaft at 25, the lead wires 27 extend up into the read head are interconnected to the electronics therein and extend out the other end for connecting with the recognition unit 2 through the cable 3 and plug 26. It is possible that the cable 3 could be replaced with a receive/transmit unit and in the handheld unit and the recognition control unit. Small data relay transmit/receive units are well known and need not be covered in detail. A more detailed view of the light pipe used in conjunction with turn on/off circuit is illustrated in figures 8 and 9. Figure 8 is a pictorial view of the light pipe and Figures 9a and 9b are side and top views. Normally in light pipes of this nature, multifiber optical bundles are used. However, such a light pipe does not lend itself to high volume low cost production. The light pipe illustrated is made by injection molding with acrylic plastic. The light pipe is a homogenous material as opposed to individual glass fibers. In order to impart a mirror finish to the sides of the light pipe the mold has a 16 microinch finish or better. One advantage of this type of light pipe is that only one inexpensive part is needed to perform the function. The surfaces of the light pipe are highly polished providing essentially total internal reflection. Therefore, light energy in the pipe is conducted from input to output with relatively low loss. Referring to Figures 3 and 5, energy from the emitter/ receiver sensor 19 is conducted through the light pipe to the document and reflected energy is transmitted back through the light pipe to the sensor. The sensor is mounted on the main read head frame while the light pipe is in the nose cone. The pipe permits removal of the nose without any electrical connection between the nose and the main read head body. The pipe may be used with any non-coherent light where the energy source or receiver is remotely located. In order to mount the light pipe without the exterior walls coming into contact with a surface which may interfere with the internal reflectivity of wall, mounts 29 are formed on the sides of the light pipe and are used to prevent undesirable contact of the walls with surrounding structures. The above described embodiment relates to a total data entry hand held unit which optically reads data. When the data cannot be read optically, the same unit having a keyboard thereon is used to encode data into the system. The encoded data is displayed for verification. In order to provide for either left hand or right hand use of the unit, the read head may be rotated through 180 degrees so that it points either to the right or left of the keyboard display body. A rotational strain relief unit is provided within the body to permit internal connections with the keyboard and display without damaging the interconnections. WHAT WE CLAIM IS:

1. An optical character recognition system comprising a hand wand which is remote from, but linked to, a portable signal processor by a transmission path; said wand having an optical scanner for receiving and scanning a data image to supply a respective information signal to said transmission path, said wand including a display and a keyboard for entering data by hand instead of via the optical scanner whereby a respective information signal is supplied to the transmission path, the latter data being readable on the display; said signal processor being provided to receive said information signals, to derive data recognition signals therefrom, and to operate the display.

portion removed to accommodate an electrical connector for said wires.

9. A system according to claim 8 wherein said wires are looped around the tubular member.

10. A system according to any one of claims 1-6 wherein the transmission path is a radio link.

11. A system according to any one of the preceding claims including a document sensing device and a control circuit for connecting the power supply to the system when a document is read by said optical scanner.

12. A system according to claim 11 wherein the document sensing device comprises, within the wand, a light guide, a light source, and a photosensor whereby, in use, light from the source is transmitted through the light guide and is reflected from a document positioned adjacent the optical scanner, is transmitted again through the light guide and is received by the photosensor.

13. A system according to claim 12 wherein the light guide is an integral body of homogeneous plastics material, said body having polished sides for reflecting light transmitted through the guide and having projections to prevent objects from contacting said sides.

14. A system according to claim 13 wherein said projections are part-spherical.

15. A system according to claim 13 or 14 wherein said body has a generally rectangular cross section.

16. A system according to any one of claims 13 - 15 wherein said body is made of injection moulded, acrylic plastics material.

17. An optical character recognition system substantially as herein described with reference to the accompanying drawings.