GB2222880A - Method of determining areal coverage of primary colours in measuring segments of multi-coloured print originals in an offset printing - Google Patents
Method of determining areal coverage of primary colours in measuring segments of multi-coloured print originals in an offset printing Download PDFInfo
- Publication number
- GB2222880A GB2222880A GB8917897A GB8917897A GB2222880A GB 2222880 A GB2222880 A GB 2222880A GB 8917897 A GB8917897 A GB 8917897A GB 8917897 A GB8917897 A GB 8917897A GB 2222880 A GB2222880 A GB 2222880A
- Authority
- GB
- United Kingdom
- Prior art keywords
- colour
- image
- printing
- areal coverage
- images
- 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
Links
- 238000000034 method Methods 0.000 title claims description 22
- 239000003086 colorant Substances 0.000 title claims description 21
- 238000007645 offset printing Methods 0.000 title claims description 6
- 238000007639 printing Methods 0.000 claims description 43
- 238000005259 measurement Methods 0.000 claims description 17
- 239000000976 ink Substances 0.000 claims description 15
- 238000010191 image analysis Methods 0.000 claims description 12
- 230000005484 gravity Effects 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 7
- 238000004040 coloring Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000004458 analytical method Methods 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000005286 illumination Methods 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 238000010252 digital analysis Methods 0.000 claims description 2
- 238000012360 testing method Methods 0.000 claims 4
- 230000003595 spectral effect Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000011496 digital image analysis Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000003703 image analysis method Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41F—PRINTING MACHINES OR PRESSES
- B41F33/00—Indicating, counting, warning, control or safety devices
- B41F33/0027—Devices for scanning originals, printing formes or the like for determining or presetting the ink supply
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/46—Measurement of colour; Colour measuring devices, e.g. colorimeters
- G01J3/50—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors
- G01J3/51—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors using colour filters
- G01J3/513—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors using colour filters having fixed filter-detector pairs
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/59—Transmissivity
- G01N21/5907—Densitometers
- G01N2021/5915—Processing scan data in densitometry
- G01N2021/5942—Processing scan data in densitometry for dot area ratio in printing applications
Description
METHOD OF DETERMINING AREAL COVERAGE OF PRIMARY COLOURS IN MEASURING
SEGMENTS OF MULTI-COLOURED PRINT ORIGINALS IN AN OFFSET PRINTING MACHINE
The present invention relates to a method of and apparatus for determining areal coverage of primary colours in measuring segments, for example selected segments of small area, of multi-coloured print originals, especially four-colour printed sheets, in an offset printing machine. By means of such a method, the printed proportions of the primary colours, the so-called areal coverage, therein may be able to be determined with the object of providing a change in inking on a departure of the colour proportions from target values.
The judgement of the printing quality and regulation of the inking usually take place by densitometric evaluation of a colour check strip at the edge of the printed sheet. In that case, the evaluation can take place off-line at a densitometer measuring statically or on-line with the aid of a machine densitometer. It is disadvantageous in this procedure that a colour check strip must also be printed, which is frequently not possible for reasons of format and which means an additional consumption of material.In addition to a number of publications relating to quality control of multi-coloured print originals without the use of colour check strips (for example, US-PS 3 958 509 and GB-PS 2 115 145) with low accuracy and reliability, of note are
EP 0 142 469, EP 0 142 470 and EP 0 143 744 which describe a method and apparatus for judgement of printing quality and for regulation of inking in an offset printing machine without the use of a colour check strip. In that case, the printed sheet is divided into image elements of 0.5 x 0.5 mm2 to 20 x 20 mm2 and the reflectance in four spectral ranges (infrared for black, red for cyan, green for magenta and blue for yellow) is measured photo-electronically in each image element. The reflectance values are then converted by calculation with the aid of the Neugebauer equation into degrees of areal coverage of the primary colours.The Neugebauer equation is an established system of equations which sets the colour components of the printing inks quantitatively into relation with colour-selectively measured reflectances, wherein the reflectance value for the material to be printed on and for the full tones of the printing inks are presupposed as known.
By comparison of the actual areal coverage with the areal coverages of a sheet correctly printed in colour and grey tint, the so-called OKsheet or the areal coverages measured at the printing place, signals are derived for the control of the inking. For this purpose, a weighting factor for each printing colour is associated with each image element and indicates the degree of certainty with which the areal coverage of this colour can be determined in this image element. These factors take into consideration the areal coverage dependence, the environmental dependence and the external colour dependence of the measurement values. A disadvantage of this method is the prerequisite that black must, in the infrared spectral range, have typical reflectance values which make it distinguishable from magenta, cyan and yellow.
However, this prerequisite is fulfilled for only a proportion of the black inks used in the printing industry, so that equipping printing machines with corresponding devices is not sensible.
It is also disadvantageous that in the case of more than four colours the method is usable only for linearly independent colours, since the system of the Neugebauer equations is indefinite and thereby not solvable in the case of a dependence.
There is therefore a need for a method of determining areal coverage in multi-colour printing without use of a check strip for printing inks with any desired reflectance characteristics, so as to permit quality judgement of the print originals and/or regulation of the inking means.
According to a first aspect of the present invention there is provided a method of determining areal coverage of primary printing colours in measuring segments of multi-coloured print originals in an offset printing machine through integral photo-electronic reflectance measurement, comprising the steps of carrying out integral photoelectronic reflectance measurement of only those printing inks having a reflectance characteristic differing from that of any desired superposed printing combination of the remaining printing inks, and determining the areal coverage of any desired other printing inks by producing additional digitalised colour extract images from the respective measuring segment and carrying out digital analysis of such images.
According to a second aspect of the present invention there is provided apparatus for carrying out the method of the first aspect of the invention, the apparatus comprising an objective and a colourmeasuring head for reflectance measurement at a measuring segment, a first beam splitter for division of the light beam from the objective and transmission of part thereof to the measuring head, a second beam splitter for receiving the other part of the beam and having three light exit surfaces respectively provided with red, green and blue filters, respective colour-selective sensors arranged at said light exit surfaces for the production of colour extract images, and image analysis means connected to output means of the sensors for determination of the degree of areal coverage.
In a preferred example of the invention merely the degree of areal coverage of the three colouring inks, which are distinguishable by colour measurement as secondary or tertiary colours also in superposed printing, is determined by integral photo-electronic measurement of the reflectances in a measuring segment of several square millimetres in area, whilst the areal coverage of the remaining colours, in particular of the colour black, is determined by digital image analysis.
For this purpose the measuring segment is covered by an image raster and multi-spectral images are produced in the given raster field. The image recording preferably takes place by cameras with colour-selective sensor fields. The geometric resolution of the image raster field is higher than that of the printing raster, so that its raster width amounts to a multiple of the image point spacing. The grey value resolution is dependent on the required measurement accuracy of the colour proportions.
From the obtained three digitalised colour extract images, in the case of the four-colour printing, the areal coverage of the colour not measurable by its reflectance in superposed printing is determined with the aid of image-analytic methods. This value is then inserted for the corresponding unknown in the Neugebauer equation system. This equation system is now solvable according to the remaining unknowns for the proportions of the colouring inks.
In a preferred embodiment of apparatus for determination of the areal coverage by means of image analysis, the three colour extract images from the same measuring segment are set up with the aid of colour-selective sensor fields as for the photo-electronic reflectance measurement. For this purpose, a first beam splitter is arranged behind the objective and resolves the light reflected from the segment by way of the objective into two parts, wherein the first part is passed to a colour-measuring head for reflectance measurement and the second part to a second beam splitter, at the three light exit surfaces, provided with corresponding red, green and blue filters, of which the colour-selective sensor fields are arranged, the outputs of which are connected with an image analysis system.The three colour extract images are made binary each time with a threshold which corresponds to the most frequently occurring grey value of the colour to be measured by image analysis. The three arising binary images are now logically interlinked in such a manner that an image point in the resultant image receives the value "1" exactly when the same image points in the three images to be interlinked also have the value "1". The thus determined image points with the value "1" contain the colour to be determined by image analysis or superpositions with this colour without these image points having to overlap the entire raster points of this colour. By means of an object isolation method, a marking of the individual objects in this binary image and the computation of their centres of gravity take place.Subsequently, all image points are checked in concentric rings around these centres of gravity, on the a priori assumption of circularly shaped printing raster points, as to whether their grey tints in the three colour extract images are smaller than preset limit values. These limit values identify the grey tone transition between the colour raster point of the colour to be determined by image analysis and the material to be printed on.
The algorithm checks sequentially starting from the inner image point ring and counts all image points up to the first time infringement of the stated conditions, wherein all image points of the ring, in which the infringement is ascertained, are also counted.
This number represents the sought area from which the degree of areal coverage is calculated in-percent by reason of the known geometry of the colour raster point arrangement. This takes place for all centres of gravity and the computed area values are averaged. This mean value is inserted as a constant into the Neugebauer equation.
By the now possible solving of this equation system according to the degrees of areal coverage of the remaining primary colours, regulating signals for a change in inking can be produced by a comparison of the actual areal coverages with the areal coverages of an OK-sheet or the areal coverages measured at the printing plates. The following presumptions are tied to the selection of the measuring segment: - colour homogeneity is assumed within the measuring segment and
within a neighbourhood, since averaging is carried out over all
colour raster points in the measuring segment and slight displace
ments of the measuring segment on the original may not have any
influence on the measurement, and - the colour raster points of the colour to be measured are isolated
from each other in the image, which is achieved by a degree of
areal coverage of less than 50%.
These presumptions require that the image is checked only in selected measuring segments, but at least once in each printing zone.
The use of image analysis enables the method to be used equally well for any desired special printing colours (house colours) in five-colour, six-colour or seven-colour printing. Since these colours are usually printed separately, i.e. not in superposed printing, the image analysis processing is simpler.
The determination of the areal coverage takes place at the moved sheet preferably on-line immediately after the last colour printing in that the duration of the flash illumination is matched to the speed of movement of the sheet, so that the resolution of the images in direction of movement does not measurably differ from that perpendicular to the direction of movement.
An example of the method and an embodiment of the apparatus of the present invention will now be more particularly described with reference to the accompanying drawing, the single figure of which is a block diagram of apparatus embodying the invention.
The apparatus illustrated in Fig. 1 serves for the monitoring of the printing quality of multi-coloured print originals through.
determination of the colour proportion of the primary colours cyan, magenta, yellow and black participating in the printing. In this case, the Neugebauer equation, which describes the relationship between the degrees of areal covera9eoccyanso(ma9entas (yellow and black and the reflectances x, y and z in the three spectral ranges blue, green and red, has the form:: x xB y = (1-αcyan) (1-αmagenta) (1-αyellow) (1-αblack) yB+ z ZB
XC cyan(1-αmagenta) (1-αyellow) (1-αblack) yC
ZC
XM (1-αcyan) αmagenta (1-αyellow) (1-αblack) ZM
xCM αcyan αmagenta (1-αyellow) (1-αblack) yCM+==+
zCM
xCMGS αcyan αmagenta αyellow α;black yCMGS
ZCMGS (x, y, z) - Reflectances in the measuring segment (xB, yg, zB) - Reflectances of the material to be printed on (xC, YCs zC) - Reflectances of the full tones of cyan, magenta,
yellow and black (x5, y5, zs) (XCM, yCM, zCM) - Reflectances of the full tone of the superposed
printing of cyan and magenta and the remaining
five possible superposed printings of two
colours (xMG, yMG, zMG) (XCMG, YCMGX ZCMG) - Reflectances of the full tone of the superposed
printing of cyan, magenta and yellow and the
remaining possible superpositions of three
colours (xGMS, YGMss zGMS) - Reflectances of the full tone of the superposed
printing of the four colours of cyan, magenta,
yellow and black.
The reflectances of the full tone are independent of the sequence of printing and are determined - empirically by photo-electronic measurement or taken from colour tables in case of known full tone density before the monitoring phase. The measurement of the actual reflectance (x, y, z) in the measuring segment 1 on the web 2 of material to be printed on takes place photo-electronically by the colour-measuring head 3 by way of the objective 4. The measuring segment has a size of 2.5 x 2.5 mm2. Since the Neugebauer equation system of three equations with four unknowns is not solvable, the degree of areal coverageCbl,,k of the colour black is determined by means of an image analysis method andblack is thereby eliminated.For this purpose, three colour extract images are set up with the use of a colour-selective sensor 7 from the same measuring segment 1 by way of beam splitters 5 and 6, wherein the light exit surfaces of the beam splitter 6 are provided with appropriate red, green and blue filters. The sensor 7 is so constructed that a sharp image is produced on the sensor field for each colour extract.
Scanning takes place with a geometric resolution of 20 micrometres per image point, which is about 10 times as high as the printing raster resolution and a grey value resolution of 64 grey steps. A flash lamp having a standard light mode C or similar characteristic with a flash duration of 1 to 5 microseconds according to a speed of the printed sheet of 2 to 10 metres per second serves for illumination.
The filtering must occur in the typical spectral absorption ranges for the three colouring inks. In the ideal case, the transmission curve of the filter corresponds to the absorption curve of the respective colouring ink.
The determination of the degree of areal coverage of the colour black takes place in two image analysis steps through processing of the three colour extract images in an image analysis system 8. The system 8 is controlled by a host computer 9. For demonstration, the individual processing steps can be represented on an image screen monitor 10. In the first step, a list of the centres of gravity is determined by making the colour extract images binary and logical interlinking thereof. In that case, an object isolation process can be used, in which - during marking of the individual objects in the image - their co-ordinates of the circumscribing rectangle and their area are also.computed.
The co-ordinates of the circumscribing rectangle permit estimation of the centres of gravity with sufficient accuracy. In a second step, all image points pg in concentric image point rings around these centres of gravity are checked in the three colour extract images g and i (blue, green, red) for the fulfilment of the conditions P9blue (i, j) tblue green (i, j) = tgreen P9red (i, j) ~ tred The thresholds tblue, tgreen and tred identify the grey value transition between the black colour raster point and the material to be printed on.
The algorithm checks the image points from the inner to the outer ring sequentially and counts all image points up to the first time infringement of one of the above conditions, wherein all image points of the ring in which this infringement is ascertained are also counted. This number represents the- sought area, from which the degree of areal coverage in percent can be calculated by reason of the known geometry of the colour raster point arrangement. The algorithm is denoted as conditional territorial growth following the known segmentation algorithms by means of territorial growth, since due to the conditions the algorithm breaks off before complete segmentation of the image.
Subsequently, the area contents of all black colour raster points situated in the measuring segment are averaged. All necessary thresholds are derived from the respective grey value histogram.
By the now possible solution of the Neugebauer equation system according to the degrees of areal coverage of the remaining three primary colours, ining change signals 12 are produced in a comparison unit 11 by comparison of the actual areal coverages with the areal coverages of an OK-sheet or the areal coverages measured at the printing plates.
Claims (8)
1. A method of determining areal coverage of primary printing colours in measuring segments of multi-coloured print originals in an offset printing machine through integral photo-electronic reflectance measurement, comprising the steps of carrying out integral photoelectronic reflectance measurement of only those printing inks having a reflectance characteristic differing from that of any desired superposed printing combination of the remaining printing inks, and determining the areal coverage of any desired other printing inks by producing additional digitalised colour extract images from the respective measuring segment and carrying out digital analysis of such images.
2. A method as claimed in claim 1, wherein the step of reflectance measurement is carried out in respect of the three colouring inks and the step of image production and analysis is carried out in respect of the colour black.
3. A method as claimed in claim 2, wherein the step of image production and analysis comprises producing three binary colour extract images with a threshold corresponding to the most frequently occurring grey value of the colour to be measured in image analysis, logically interlinking the three binary images by assigning the value "1" to an image point in the resultant image exactly when the same image points in the three images have the value "1" so that the thus determined image points with this value contain the colour to be measured and superpositions of this colour without these image points having to overlap the entire colour raster points of this colour, marking the individual objects and computing their centres of gravity in the resultant image by means of an object isolating process, testing all image points in concentric rings around these centres of gravity to ascertain whether their grey tints in the three colour extract images are smaller than preset limit values representing the grey tint transition between the colour raster point of the colour to be determined and the material to be printed on, and carrying out further image point testing starting from the inner image point ring with counting of the image points to the first time infringement of the test condition, wherein all image points of the ring in which the infringement is ascertained are also counted so that this number after repetition of the testing for all centres of gravity and report of the measured number represents the sought areal coverage.
4. A method as claimed in any one of the preceding claims, wherein the determination of the areal coverage takes place on-line at the sheet, during movement thereof and immediately after the last colour printing, by matching the duration of the flash illumination to the speed of movement of the sheet so tkat the resolution of the images in the direction of movement does not differ measurably from thatperpendicular to the direction of movement.
5. A method as claimed in any one of the preceding claims, wherein monitoring of printing quality takes place in selected measuring segments but in at least one measuring segment for each printing zone, in which segments colour homogeneity is present in the sense of the required measurement accuracy and the degree of areal coverage of the primary colours is less than 50%.
6. A method as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawing.
7. Apparatus for carrying out the method claimed in claim 1, comprising an objective and a colour-measuring head for reflectance measurement at a measuring segment, a first beam splitter for division of the.light beam from the objective and transmission of part thereof to the measuring head, a second beam splitter for receiving the other part of the beam and having three light exit surfaces respectively provided with red, green and blue filters, respective colour-selective sensors arranged at said light exit surfaces for the production of colour extract images and image analysis means connected to output means of the sensors for determination of the degree of areal coverage.
8. Apparatus substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DD88318856A DD274787A1 (en) | 1988-08-11 | 1988-08-11 | METHOD AND ARRANGEMENT FOR DETERMINING THE FLUID COVERAGE OF PRIMARY COLORS IN MEASUREMENT SEGMENTS OF MULTICOLORED PRINTING TEMPLATES OF AN OFFSET PRINTING MACHINE |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8917897D0 GB8917897D0 (en) | 1989-09-20 |
| GB2222880A true GB2222880A (en) | 1990-03-21 |
| GB2222880B GB2222880B (en) | 1993-04-07 |
Family
ID=5601682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8917897A Expired - Fee Related GB2222880B (en) | 1988-08-11 | 1989-08-04 | Method of determining areal coverage of primary colours in measuring segments of multi-coloured print originals in an offset printing machine |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH02167438A (en) |
| CN (1) | CN1040344A (en) |
| DD (1) | DD274787A1 (en) |
| DE (1) | DE3925012A1 (en) |
| GB (1) | GB2222880B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5530656A (en) * | 1993-10-21 | 1996-06-25 | Man Roland Druckmaschinen Ag | Method for controlling the ink feed of a printing machine for half-tone printing |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4122794A1 (en) * | 1991-07-10 | 1993-01-14 | Roland Man Druckmasch | METHOD FOR MONITORING AND REGULATING THE PRINTING PROCESS, ESPECIALLY ON OFFSET PRINTING MACHINES |
| JP2905049B2 (en) * | 1993-08-04 | 1999-06-14 | アルプス電気株式会社 | Printing control method |
| US20040213436A1 (en) * | 2003-04-25 | 2004-10-28 | Quad/Tech, Inc. | System and method for measuring color on a printing press |
| DE102005041179A1 (en) * | 2005-08-31 | 2007-03-01 | Man Roland Druckmaschinen Ag | Typographic process e.g. color registering, regulating method for printing machine, involves determining pre-press based target value from pre-press data and under consideration of data about characteristic of sensor |
| CN104597056B (en) * | 2015-02-06 | 2017-04-19 | 北京中科纳新印刷技术有限公司 | Method for detecting ink-jet printing ink dot positioning accuracy |
| CN104742516B (en) * | 2015-03-12 | 2017-01-25 | 周广伟 | High-power image dot coverage rate digital measuring method suitable for whole printing process |
| CN105572080B (en) * | 2015-12-18 | 2018-03-09 | 河南理工大学 | Contactless float glass tin surface automatic identification equipment and method |
| JP7400617B2 (en) * | 2020-05-08 | 2023-12-19 | コニカミノルタ株式会社 | Coverage detection device, image forming device, coverage detection method, and coverage detection program |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1436638A (en) * | 1972-05-13 | 1976-05-19 | Morat Gmbh Franz | Method of and device for identifying colours |
| GB2040038A (en) * | 1978-11-28 | 1980-08-20 | Hell R Dr Ing Gmbh | Methods and circuit for the recognition of colours |
| EP0069572A1 (en) * | 1981-07-06 | 1983-01-12 | Philip Emanuel Tobias | Method and apparatus for use in connection with the adjustment of printing presses |
| GB2115145A (en) * | 1981-07-29 | 1983-09-01 | Dainippon Printing Co Ltd | Method and device for inspecting printed matter |
| EP0142469A1 (en) * | 1983-11-04 | 1985-05-22 | GRETAG Aktiengesellschaft | Method and device for controlling the ink supply in an offset printing machine, and offset printing machine provided with such a device |
| GB2202939A (en) * | 1987-03-25 | 1988-10-05 | Kollmorgen Corp | Densitometer method and system |
-
1988
- 1988-08-11 DD DD88318856A patent/DD274787A1/en not_active IP Right Cessation
-
1989
- 1989-07-28 DE DE3925012A patent/DE3925012A1/en not_active Withdrawn
- 1989-08-04 GB GB8917897A patent/GB2222880B/en not_active Expired - Fee Related
- 1989-08-08 JP JP1205540A patent/JPH02167438A/en active Pending
- 1989-08-11 CN CN89106382A patent/CN1040344A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1436638A (en) * | 1972-05-13 | 1976-05-19 | Morat Gmbh Franz | Method of and device for identifying colours |
| GB2040038A (en) * | 1978-11-28 | 1980-08-20 | Hell R Dr Ing Gmbh | Methods and circuit for the recognition of colours |
| EP0069572A1 (en) * | 1981-07-06 | 1983-01-12 | Philip Emanuel Tobias | Method and apparatus for use in connection with the adjustment of printing presses |
| GB2115145A (en) * | 1981-07-29 | 1983-09-01 | Dainippon Printing Co Ltd | Method and device for inspecting printed matter |
| EP0142469A1 (en) * | 1983-11-04 | 1985-05-22 | GRETAG Aktiengesellschaft | Method and device for controlling the ink supply in an offset printing machine, and offset printing machine provided with such a device |
| EP0142470B1 (en) * | 1983-11-04 | 1988-01-07 | GRETAG Aktiengesellschaft | Method and device for judging the printing quality of a printed object, preferably printed by an offset printing machine, and offset printing machine provided with such a device |
| GB2202939A (en) * | 1987-03-25 | 1988-10-05 | Kollmorgen Corp | Densitometer method and system |
Non-Patent Citations (1)
| Title |
|---|
| GB1436638 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5530656A (en) * | 1993-10-21 | 1996-06-25 | Man Roland Druckmaschinen Ag | Method for controlling the ink feed of a printing machine for half-tone printing |
Also Published As
| Publication number | Publication date |
|---|---|
| DD274787A1 (en) | 1990-01-03 |
| CN1040344A (en) | 1990-03-14 |
| DE3925012A1 (en) | 1990-05-17 |
| GB2222880B (en) | 1993-04-07 |
| JPH02167438A (en) | 1990-06-27 |
| GB8917897D0 (en) | 1989-09-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2540485B2 (en) | Hue identification method, color identification method, and hue identification circuit | |
| US10262409B2 (en) | System and method for generating images for inspection | |
| US4583116A (en) | Method and apparatus for eliminating defects in images in polychromatic printing due to faulty registration of superimposed printing of color separations | |
| US5181257A (en) | Method and apparatus for determining register differences from a multi-color printed image | |
| US5530656A (en) | Method for controlling the ink feed of a printing machine for half-tone printing | |
| US4884130A (en) | Method of describing a color in a triaxial planar vector color space | |
| JPH0322117B2 (en) | ||
| EP1215538A2 (en) | Method for measuring color registration and determining registration error in a marking platform | |
| US7307755B2 (en) | Method for correcting unadjusted printing data on the basis of colormetrically measured reference sheet | |
| KR20040053110A (en) | Printing method, printed matter, and printing controller | |
| WO2001025737A1 (en) | Method for colour matching by means of an electronic imaging device | |
| JPH0345373B2 (en) | ||
| GB2222112A (en) | Monitoring print quality in multi-colour offset printing machines. | |
| GB2222880A (en) | Method of determining areal coverage of primary colours in measuring segments of multi-coloured print originals in an offset printing | |
| GB1594569A (en) | Arrangement for indicating over-correction in electronic colour correction | |
| WO1997027700A1 (en) | Method and system for automatically monitoring the colors of an object at a vision station | |
| US4637728A (en) | Method for colorimetrically evaluating a sheet printed on both sides thereof | |
| NL7908907A (en) | METHOD FOR PRODUCING COLOR PARTICULARS | |
| US5761327A (en) | Group of measured fields for determining color data of a printed product | |
| CN111095907B (en) | Adjusting colors in an image | |
| JP2918386B2 (en) | How to measure the print area ratio of printed originals, especially plates | |
| CN110146509B (en) | Battery detection method and battery detection equipment | |
| US5778088A (en) | Procedure for producing a reference model intended to be used for automatically checking the printing quality of an image on paper | |
| US6012390A (en) | Method for controlling the inking of a printing press by determining color value gradients | |
| CN109605964A (en) | A kind of standardized printing control method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20020804 |