GB2093179A - Measuring opacity and detecting holes in sheet - Google Patents

Measuring opacity and detecting holes in sheet Download PDF

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Publication number
GB2093179A
GB2093179A GB8104872A GB8104872A GB2093179A GB 2093179 A GB2093179 A GB 2093179A GB 8104872 A GB8104872 A GB 8104872A GB 8104872 A GB8104872 A GB 8104872A GB 2093179 A GB2093179 A GB 2093179A
Authority
GB
United Kingdom
Prior art keywords
sheet
area
opacity
apparatus
photocell
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.)
Granted
Application number
GB8104872A
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GB2093179B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
de la RUE SYST
de la Rue Systems Ltd
Original Assignee
DE LA RUE SYST
de la Rue Systems Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by DE LA RUE SYST, de la Rue Systems Ltd filed Critical DE LA RUE SYST
Priority to GB8104872A priority Critical patent/GB2093179B/en
Publication of GB2093179A publication Critical patent/GB2093179A/en
Application granted granted Critical
Publication of GB2093179B publication Critical patent/GB2093179B/en
Application status is Expired legal-status Critical

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using infra-red, visible or ultra-violet light
    • G01N21/84Systems specially adapted for particular applications
    • G01N21/88Investigating the presence of flaws or contamination
    • G01N21/89Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/892Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the flaw, defect or object feature examined
    • G01N21/894Pinholes
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using infra-red, visible or ultra-violet light
    • G01N21/84Systems specially adapted for particular applications
    • G01N21/88Investigating the presence of flaws or contamination
    • G01N21/89Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07DHANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/06Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
    • G07D7/12Visible light, infra-red or ultraviolet radiation
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07DHANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/06Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
    • G07D7/12Visible light, infra-red or ultraviolet radiation
    • G07D7/121Apparatus characterised by sensor details
    • GPHYSICS
    • G07CHECKING-DEVICES
    • G07DHANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/181Testing mechanical properties or condition, e.g. wear or tear
    • G07D7/185Detecting holes or pores

Abstract

For detecting the presence of holes or tears in a sheet (for example a banknote) and for measuring the opacity of the sheet, an area (A) of the sheet is illuminated by a source (S), a lens (L2) focuses undeflected, parallel light from the whole of this area onto a photocell (P1) to indicate the presence of holes or tears within the illuminated area, light diverging from the illuminated area passes through the said lens, through a transparent plate (TP) on which the first photocell (P1) is mounted and is then focused by a further lens (L3) onto a second photocell or matrix of photocells (P2) to measure the opacity of the area (A) of the sheet. Lenses L2 and L3 together form an image of the area (A) at P2; lenses L1 and L2 form an image of the light source (S) at P1. These two imaging systems are independent, and the advantage is that the measurement of opacity and the detection of holes or tears are therefore performed independently. <IMAGE>

Description

SPECIFICATION Apparatus for detecting the condition of a sheet This invention relates to apparatus for detecting the presence of holes or tears in a sheet and for measuring the opacity of a sheet. It is particularly useful in the sorting of banknotes according to whether they are worn, torn or dirty, or according to their denomination.

Apparatus according to the invention, for detecting the presence of holes or tears in a sheet and for measuring the opacity of the sheet, comprises an optical system having on one side of the sheet a light source and a first converging lens for directing a beam of light on to an area of the sheet, and on the other side of the sheet a second converging lens which receives light transmitted through the said area of the sheet, a first photoelectric device on to which parallel light from the illuminated area of the sheet is focused by the second converging lens, the output of the first photoelectric device producing an indication of the presence of a hole or tear in the said area, a third converging lens for receiving light from the second convering lens and a second photoelectric device on to which an image of at least a portion of the illuminated area of the sheet is focused by the third converging lens, the output of the second photoelectic device providing an indication of the opacity of the said portion of the area.

Preferably, the first, second and third converging lenses are aligned with one another, and the first photoelectric device is a photocell supported on the optical axis of the converging lenses between the second and the third lenses, for example by means of a transparent plate. Also, in the preferred form of apparatus used as a banknote scanner, a line of such detectors extends transversely to the direction of movement of the banknotes, the individual areas nearly touching each other, so that most of the banknote area is scanned for the presence of holes or tears, and a number of parallel strips are scanned for opacity measurement. The invention permits a very compact construction for the hole-detection and opacity-measuring apparatus, particularly in the form in which the lenses are aligned.In this apparatus, for detecting holes or tears in the sheet, parallel light which has been transmitted through the sheet substantially undeviated is focused on to the photocell; and, in contrast, for measuring the opacity of a part of the sheet, an image of the illuminated area is viewed by a photodetector. Thus the hole or tear detection measurement is substantially independent of the note opacity, and the opacity measurement is substantially independent of the presence of a hole or tear. Opacity measurement may be required, for example, to determine the colour of the printing ink or to detect the amount of grease absorbed into the paper. The light source may be an LED or projector lamp.

In order that the invention may be more fully understood, one embodiment of it will now be described with reference to the accompanying drawings, in which: Figure 1 shows a banknote being analysed as it passes through an apparatus embodying the invention with a linear array of optical systems; and Figure 2 is a sketch of part of the apparatus shown in Figure 1.

The preferred embodiment comprises a transparent screen on each side of the note (see Figure 2), and a linear array of 32 optical systems spanning the length of the note (see Figure 1). The note is moved past the array, as shown by the arrows in Figure 1, and the optical systems scan the note at 32 different areas of its surface.

Electronic apparatus (not shown) then responds to the scanning signals from the optical systems to compute for example whether there is a hole or tear or a grease spot, or whether the banknote is of one denomination or another.

The system is shown in some detail in Figure 2.

A compact source S, on one side of the note, may be a single LED or at the end of an optical fibre from a source of light common to many identical optical systems. Light is collimated or condensed in a first converging lens L1, whence it passes as a parallel beam through a glass screen S1,through an area A of the banknote, and then through another glass screen S2.

Parallel light from the whole of the area A of the note is focused on to a photocell P 1 by a second converging lens L2. If there is a hole or a tear in or extending into area A of the banknote, a part of area A will appear to photocell P 1 to be entirely transparent, and the photocell P 1 will give a greater response than if there is no such defect on that part of the note.

The photocell P1 is supported on a transparent plate TP. The opacity of the banknote is measured by a second photocell or a matrix of photocells P2 behind the plate TP. For this purpose, light diverging from portions, e.g. B, C, of the area A which was not directed onto the first photocell P 1 by the second converging lens L2 is allowed to pass through the transparent plate TP and is further converged by a third lens L3 to form corresponding images B', C' on the second photocells(s) P2.

By using the whole of the area A of the note, which is nearly as great as the area of the lenses, the maximum available brightness is used.

By supporting the first photocell P 1 in the centre of the transparent plate TP on the optical axis, the two imaging systems are combined into one system, with very little interference one with the other.

The array of photocells P 1 and P2 is connected to electronic circuitry (not shown) which determines the condition and perhaps the denomination of the banknote.

1. Apparatus for detecting the presence of holes or tears in a sheet and for measuring the opacity of the sheet comprising: an optical system having on one side of the sheet a light source and

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Apparatus for detecting the condition of a sheet This invention relates to apparatus for detecting the presence of holes or tears in a sheet and for measuring the opacity of a sheet. It is particularly useful in the sorting of banknotes according to whether they are worn, torn or dirty, or according to their denomination. Apparatus according to the invention, for detecting the presence of holes or tears in a sheet and for measuring the opacity of the sheet, comprises an optical system having on one side of the sheet a light source and a first converging lens for directing a beam of light on to an area of the sheet, and on the other side of the sheet a second converging lens which receives light transmitted through the said area of the sheet, a first photoelectric device on to which parallel light from the illuminated area of the sheet is focused by the second converging lens, the output of the first photoelectric device producing an indication of the presence of a hole or tear in the said area, a third converging lens for receiving light from the second convering lens and a second photoelectric device on to which an image of at least a portion of the illuminated area of the sheet is focused by the third converging lens, the output of the second photoelectic device providing an indication of the opacity of the said portion of the area. Preferably, the first, second and third converging lenses are aligned with one another, and the first photoelectric device is a photocell supported on the optical axis of the converging lenses between the second and the third lenses, for example by means of a transparent plate. Also, in the preferred form of apparatus used as a banknote scanner, a line of such detectors extends transversely to the direction of movement of the banknotes, the individual areas nearly touching each other, so that most of the banknote area is scanned for the presence of holes or tears, and a number of parallel strips are scanned for opacity measurement. The invention permits a very compact construction for the hole-detection and opacity-measuring apparatus, particularly in the form in which the lenses are aligned.In this apparatus, for detecting holes or tears in the sheet, parallel light which has been transmitted through the sheet substantially undeviated is focused on to the photocell; and, in contrast, for measuring the opacity of a part of the sheet, an image of the illuminated area is viewed by a photodetector. Thus the hole or tear detection measurement is substantially independent of the note opacity, and the opacity measurement is substantially independent of the presence of a hole or tear. Opacity measurement may be required, for example, to determine the colour of the printing ink or to detect the amount of grease absorbed into the paper. The light source may be an LED or projector lamp. In order that the invention may be more fully understood, one embodiment of it will now be described with reference to the accompanying drawings, in which: Figure 1 shows a banknote being analysed as it passes through an apparatus embodying the invention with a linear array of optical systems; and Figure 2 is a sketch of part of the apparatus shown in Figure 1. The preferred embodiment comprises a transparent screen on each side of the note (see Figure 2), and a linear array of 32 optical systems spanning the length of the note (see Figure 1). The note is moved past the array, as shown by the arrows in Figure 1, and the optical systems scan the note at 32 different areas of its surface. Electronic apparatus (not shown) then responds to the scanning signals from the optical systems to compute for example whether there is a hole or tear or a grease spot, or whether the banknote is of one denomination or another. The system is shown in some detail in Figure 2. A compact source S, on one side of the note, may be a single LED or at the end of an optical fibre from a source of light common to many identical optical systems. Light is collimated or condensed in a first converging lens L1, whence it passes as a parallel beam through a glass screen S1,through an area A of the banknote, and then through another glass screen S2. Parallel light from the whole of the area A of the note is focused on to a photocell P 1 by a second converging lens L2. If there is a hole or a tear in or extending into area A of the banknote, a part of area A will appear to photocell P 1 to be entirely transparent, and the photocell P 1 will give a greater response than if there is no such defect on that part of the note. The photocell P1 is supported on a transparent plate TP. The opacity of the banknote is measured by a second photocell or a matrix of photocells P2 behind the plate TP. For this purpose, light diverging from portions, e.g. B, C, of the area A which was not directed onto the first photocell P 1 by the second converging lens L2 is allowed to pass through the transparent plate TP and is further converged by a third lens L3 to form corresponding images B', C' on the second photocells(s) P2. By using the whole of the area A of the note, which is nearly as great as the area of the lenses, the maximum available brightness is used. By supporting the first photocell P 1 in the centre of the transparent plate TP on the optical axis, the two imaging systems are combined into one system, with very little interference one with the other. The array of photocells P 1 and P2 is connected to electronic circuitry (not shown) which determines the condition and perhaps the denomination of the banknote. CLAIMS
1. Apparatus for detecting the presence of holes or tears in a sheet and for measuring the opacity of the sheet comprising: an optical system having on one side of the sheet a light source and a first converging lens for directing a beam of light on to an area of the sheet, and on the other side of the sheet a second converging lens which receives light transmitted through the said area of the sheet, a first photoelectric device on to which parallel light from the illuminated area of the sheet is focused by the second converging lens, the output of the first photoelectric device providing an indication of the presence of a hole or tear in the said area, a third converging lens for receiving light from the second converging lens and a second photoeiectric device on to which an image of at least a portion of the illuminated area of the sheet is focused by the third converting lens, the output of the second photoelectric device providing an indication of the opacity of the said portion of the area.
2. Apparatus according to claim 1, wherein the first, second and third converging lenses are aligned with one another, the first photoelectric device being supported on the optical axis of the converting lenses between the second and third lenses.
3. Apparatus in accordance with claim 2, wherein the first photoelectric device is a photocell supported on a transparent plate disposed between the second and third converging lenses.
4. Apparatus in accordance with claim 1, 2 or 3, comprising a pair of parallel transparent screens between which the sheet is located and which separate the sheet from the said light source, lenses and photoelectric devices.
5. Apparatus in accordance with claim 1, 2, 3 or 4, wherein the second photoelectric device comprises a matrix of photocells each of which receives an image of a different portion of the illuminated area; and whose outputs are combined to provide an indication of the opacity of the whole area.
6. Verifying apparatus for detecting the presence of holes or tears in any part of a sheet and for measuring the opacity along a number of lines on the sheet, comprising a number of units of apparatus in accordance with any one of claims 1 to 5, arranged parallel to one another and side by side to form a row, and means for moving the sheet in a direction which is transverse with respect to the axis of the first converging lens and which lies in the plane of the sheet.
GB8104872A 1981-02-17 1981-02-17 Measuring opacity and detecting holes in sheet Expired GB2093179B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8104872A GB2093179B (en) 1981-02-17 1981-02-17 Measuring opacity and detecting holes in sheet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8104872A GB2093179B (en) 1981-02-17 1981-02-17 Measuring opacity and detecting holes in sheet

Publications (2)

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GB2093179A true GB2093179A (en) 1982-08-25
GB2093179B GB2093179B (en) 1984-09-19

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2149092A (en) * 1983-08-25 1985-06-05 Mundet Tipping Limited Paper perforation monitor
WO2000049582A1 (en) * 1999-02-17 2000-08-24 Cashcode Company Inc. Optical sensor with planar wall
US6163034A (en) * 1999-02-17 2000-12-19 Cashcode Company Inc. Optical sensor with planar wall
US6797976B2 (en) 2001-08-13 2004-09-28 Giesecke & Devrient Method and apparatus for examining defects in or on sheet material
WO2004104948A1 (en) * 2003-05-23 2004-12-02 Giesecke & Devrient Gmbh Device for checking banknotes
US8331643B2 (en) 2007-07-17 2012-12-11 Cummins-Allison Corp. Currency bill sensor arrangement
US8401268B1 (en) 2007-03-09 2013-03-19 Cummins-Allison Corp. Optical imaging sensor for a document processing device
ITMI20130417A1 (en) * 2013-03-19 2014-09-20 Plug In S R L A device for the recognition of negotiable documents.

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2149092A (en) * 1983-08-25 1985-06-05 Mundet Tipping Limited Paper perforation monitor
WO2000049582A1 (en) * 1999-02-17 2000-08-24 Cashcode Company Inc. Optical sensor with planar wall
US6163034A (en) * 1999-02-17 2000-12-19 Cashcode Company Inc. Optical sensor with planar wall
AU772395B2 (en) * 1999-02-17 2004-04-29 Crane Canada Co. Optical sensor with planar wall
US6797976B2 (en) 2001-08-13 2004-09-28 Giesecke & Devrient Method and apparatus for examining defects in or on sheet material
WO2004104948A1 (en) * 2003-05-23 2004-12-02 Giesecke & Devrient Gmbh Device for checking banknotes
US7414710B2 (en) 2003-05-23 2008-08-19 Giesecke & Devrient Gmbh Device for checking banknotes
AU2004241493B2 (en) * 2003-05-23 2008-10-16 Giesecke+Devrient Currency Technology Gmbh Device for checking banknotes
US8401268B1 (en) 2007-03-09 2013-03-19 Cummins-Allison Corp. Optical imaging sensor for a document processing device
US8781206B1 (en) 2007-03-09 2014-07-15 Cummins-Allison Corp. Optical imaging sensor for a document processing device
US8331643B2 (en) 2007-07-17 2012-12-11 Cummins-Allison Corp. Currency bill sensor arrangement
ITMI20130417A1 (en) * 2013-03-19 2014-09-20 Plug In S R L A device for the recognition of negotiable documents.

Also Published As

Publication number Publication date
GB2093179B (en) 1984-09-19

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