CN104742516B - High-power image dot coverage rate digital measuring method suitable for whole printing process - Google Patents
High-power image dot coverage rate digital measuring method suitable for whole printing process Download PDFInfo
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Abstract
The invention discloses a high-power image dot coverage rate digital measuring method suitable for a whole printing process. The measuring method includes the processes that in the whole printing processes of platemaking, reprinting, filming and the like, a printing image to be measured is selected, screenshot is conducted to obtain color samples by using a high magnified glass, pixel values of the color samples are measured by an image tool software, percentage judgment is conducted by using a general formula, the dot coverage rate is obtained through comparison and correction, the dot coverage rate is measured and corrected reasonably according to a new theory accurately and rapidly, and abnormal reprinting sample making is completed in advance at a time. Dot area rate is measured accurately and rapidly and corrected to replace the coverage rate, errors are corrected automatically, and the accuracy is high. Datamation and automation joint are convenient to conduct. In the printing of a frequency adjustment web and printing dots, edges, shapes and dot spacing are easy to determined, the website of the film or PS edition is clear, the shape is good, and the distinguish accuracy and identification error can be controlled within 1%.
Description
Technical field
The present invention relates to, it is related to the measurement technology of ipc classification b41f printing machinery or the irregular surface of g01b or profile；
Belong to net-point quality control field in printing technology, be more particularly suitable for printing whole high power dot of image coverage rate digitlization survey
Amount method.
Background technology
During modern presswork, measurement monitoring programme has become indispensable important step, realizes digitization, mark
Standardization and standardization more become basic precondition and guarantee.
" printing today " 1998 03 periodical carries a kind of new method of measurement dot area coverage it is believed that color halftoned images
It is by mean of one known target colour code of various primary colors sites combinations matches to reproduce contrast and the color of original copy, from color separation
Film, printing down, draw a design until print image, the substantially conversion transmittance process of dot area coverage.It can be seen that, dot area coverage
Whether measurement is correct with calculating, closely related with the reproduction quality of image.Measurement and calculate laser photocomposing machine output film and
The site shining system on forme is not difficult, but will correctly measure the non-easy thing of coverage rate of the site being imprinted on paper, mainly difficult
Topic is: be 1. transformed into the ink site paper from forme, there is no uniform thickness from center to edge, marginal portion from
Thickness, to thin, can not perceive under microscope, and can not perceive and be not equal to edge.Because paper has absorbency, ink
Can penetrate among the fiber of paper, so site edge does not have clear and definite boundary.As long as 2. ink site is occurred on paper, must
So with the optics enlargement phenomenon of jet nit point.Optics expansion is not the real expansion of ink site spreading area, but by light
Spread the vision enlargement phenomenon causing.Eyes with people are the same, similarly there is this optics enlargement phenomenon, make in optical sensor
Obtain and with optical sensor, the edge of ink site cannot be decided.
Have a kind of method in known technology, estimate the ratio of dot area and blank area with magnifying glass, two sites it
Between if when can be filled into three an equal amount of sites, the site of this size is known as " 1 one-tenth ".If can be filled into two equally big
Little site, then be referred to as " 2 one-tenth ".If one and half an equal amount of sites can be filled into, be referred to as " 3 one-tenth ' ".If 1.25 can be filled into
An equal amount of site, then be referred to as " 4 one-tenth ".Black, white half and half site is " 5 one-tenths ", 5 one-tenth above site one-tenth numbers with noted earlier
Just contrary." method of this survey grid point seems the side's of being applied to point, there is description defect and (put if round and be just not suitable for
), moreover 1-5 become point conventional be all round dot, the area that can put a point between 5 one-tenth points (diagonal) is not just 50%
If, and be less than 50%. same 1 one-tenth, 2 one-tenth, the 3 one-tenth cylinder points becoming with 4 and see in this way and there is also error.
Site size is to be determined by the coverage rate of site, also referred to as Ink Transfer Percentage.Like in general custom with " one-tenth " conduct
Unit of measurement, the site of such as 10% coverage rate is known as " one one-tenth site ", the site of coverage rate 20% is referred to as " two one-tenth sites "
In addition, the site of coverage rate 0% is referred to as " exhausted net ", the site of coverage rate 100% is referred to as " on the spot ".Dot area coverage is exactly black
The area of color site accounts for the ratio of place frame area.The contrast of printed matter is generally divided into three levels: high light, middle tone, dark
Adjust.The dot area coverage of bright part is 10%～30% about；The dot area coverage of middle tone part is 40%～60% left side
Right；Shadow part is then 70%～90%.Absolutely net and be partly in addition division on the spot.The size of screen density determines image
Fine degree, similar to resolution ratio. common line number application includes: the low-quality printing of 10-120 line, the sea of remote viewing
Report, poster homalographic, than larger printed matter, generally use newsprint, offset paper printing, sometimes also using the Asia of low grams
Art printing paper and art paper；The common four-color process of 150 lines typically all adopts this precision, and all kinds of paper have；175-200 line is exquisite to be drawn
Volume, magazine etc., most pictures album using halftone paper printing 250-300 line peak demand etc., majority senior art paper and special type
Paper prints.
The development of high power electronic image technology, makes the image that people obtain microcosmos become a kind of easy thing, high
Times electron microscope has surmounted naked eyes recognition capability, by vertically hung scroll net 150 line not easy to identify for naked eyes, 175 lines, 200 lines, 250 lines
And above even frequency-modulation halftone dot is amplified to tens times, hundred times and thousands of times and mug.
In Traditional Printing Industry, in electric operation break-down before print, or electric partial image is defined by producer's correction, or with computer
Display is defined, and electricity point technical staff adjusts image to printed original, by rule of thumb as it is seen and thinks that printed original seems 50%
Site, is just adjusted by 50% site, and if actually 55% or 48% can be to discriminate between out.
Before printing, plate-making experienced and goes out the film to the technical change of ctp CTP, film net from ctf film setter
The quality control of point uses transmission-type Density Measuring Instrument, and the quality control of forme site uses reflection type density instrument, however, this class instrument
Device not only price all expensive to more than tens thousand of, and, in press, most of printing technology personnel still need by means of 10 times
Magnifying glass see site it is seen that dot area coverage be typically 1%-99%, the master worker typically with rich experiences can separate 50%,
More than 50%, also it is less than 50%, as more accurate such as less than 50%, be 20% or 25%, be substantially difficult to accurately judge
's.Concrete manifestation includes:
Fm screening is that site size is fixed, and shows contrast by the dense degree of network point, according to definition, by net
The intensive impact of point, it is how many that personnel are more difficult to accurately distinguish dot area coverage.Likewise, for printed original electric operation break-down
Professional and technical personnel nor accurately distinguish printing net-point coverage rate.
For plate-making before the film and forme printing, the either film, or forme is if it is possible to meet printing quality,
Typically require printing net-point quality control it is desirable to the site measure error of the film or forme is less than 1%, relatively in 1% error
Accurate reflection type density instrument and reflective forme measuring instrument can meet, but the price of two kinds of Density Measuring Instruments is higher, and
Still need to be aided with artificial experience judgement.Frequency-modulation halftone dot is random network point distribution, if experienced printing master worker's energy
Enough distinguish the amplitude of 10% difference, then frequency-modulation halftone dot is still difficult to differentiate between；General enterprise less demanding to image color
Printing sample is taken to determine color value to chromatogram, if paper and ink and each color density value are also directly perceived close to that this method
Feasible, but substantially impracticable in wider actual production.Electricity separately wins the image taking image color value to be printing industry specialty
Input method, is generally used for the acquisition of picture it is necessary to process toning process color just can relatively again, this process needs
Set up several primary color measuring control points, the value effect of other measuring control points, this mistake will be looked after when adjusting color data
The skill set requirements of the requirement to color measuring for the journey and toning are all higher.
In fact, in the prior art, even if there being precision instrument to assist, arbitrarily printing technician still can not accurately distinguish print
Brush dot area coverage, and under conditions of accurate measurement cannot be realized, estimate or network point coverage rate relies basically on people
Work experience.
Pertinent literature includes:
In a kind of Chinese patent application cn89106382 offset machine multicolor print measured zone, primary colors plane covers
The determination apparatus and method of degree, in the plane that without detector bar, offset press multicolor print is determined in its measured zone with primary colors
Coverage, can determine that the flat cover-degree of any printing color, especially arbitrary black for producing colored color matching variable signal,
And the spectral reflectivity colored with these is unrelated, it is realized in: as being only that three kinds of colored planes cover in four-color process
Degree measures reflectivity by photoelectric method in a known manner and tries to achieve new establishment solution of equations, and black flat cover-degree is using figure
Add after additional scanning being made to three digitlization color separation figures in same measured zone when with albedo measurement of picture analysis method
To determine.
Chinese patent application cn200580014316 is related to a kind of being used in sheet-fed press (1) in the printing process phase
Between detect the method for spectra measurement, density measurement or color measured values on the stock (705) of sheet-fed form, it is special
Levy and be: in motion by upper these measured values and will by means of computer (200) of measuring of the page (705) of printing machine (1)
These measured values are used as control parameter for controlling the printing process of sheet-fed press (1).
A kind of method of Chinese patent application cn200680026148 measurement printing image (12) quality, walks including following
Rapid: the stock (14) thereon with printing image (12) is provided；Obtain part print using image acquiring device (30)
The digital picture of map brushing picture；With the physical characteristic measuring one or more obtained digital pictures to provide printing image
(12) instruction of quality.
Chinese patent application cn200680052440 is used for the equipment of print quality measurements, and system and method are included at least
One scanner (116).Each scanner (116) includes multiple sensors (202,222,242,244,262,264), and
Each sensor (202,222,242,244,262,264) can measure to substrate (106) a part of related one or
Multiple features.This substrate (106) has the printing producing by print system (102).This equipment also include controller (118,
120), this controller can receive at least some measurement from multiple sensors (202,222,242,244,262,264), and
Determine the quality of the upper printing of substrate (106) using the measurement receiving.Substrate (106) can represent paper, and print system
(102) offset printing system can be represented.At least one of sensor (202,222,242,244,262,264) can fixed
In position and/or sensor (202,222,242,244,262,264) at least one surface in substrate (106) a part
Upper removable.The determination quality of printing can include the density printed, and puts area, dot gains, contour acuity, Cheng Shuan, spot, weight
Picture, misregister, stain or the inappropriate positioning of different colours ink.
Chinese patent application cn200810246311 discloses the print of a kind of comprehensive range estimation, Density Detection and colorimetric detection
Swabbing coloured silk quality detecting method, comprises the following steps: (1), on the basis of Traditional control bar, adds spot color color lump, and spot color color
Block is placed on printed matter special secondary school color part corresponding ink keypad；(2) it is printed on the machine；(3) extract printed matter after machine to be printed is stable
Carry out range estimation inspection, take the qualified printed matter of range estimation；(4) with colorimeter measure printed color angle value, with printed color angle value with
The standard that the value of chromatism of sample set-point, digital sample or traditional sample judges as qualification；(5) adopt density in printing process
Detection method carries out measuring density.
Chinese patent application cn102878958a discloses a kind of measuring method of lithographic forme dot area, profit
Shoot dot area and the white space acquisition digital picture on lithographic printing-plate with photomicrography instrument, by dot area numeral
The negative film of image and white space digital picture is overlapped, and eliminates the impact of illumination unevenness, using the method for threshold segmentation
Binaryzation is carried out to image, eliminates noise using the method expanding and corrode, then take out five from the centre position of bianry image
Site, determines the area of grid by calculating the distance between site center, then calculates dot area ratio and obtains this area
The dot area in domain.
Chinese patent application cn201310390230 discloses a kind of measurement of the printed matter ink speck based on gradient of image and gray scale
Method, the method follows the steps below the measurement of printed matter ink speck, carries out the IMAQ of print mottle by scanner,
Size according to measured zone carries out graphical analysis sampling, carries out multilevel wavelet exploded view picture using different wavelet basis, will scheme
As being decomposed into HFS and low frequency part, retain image subject composition, and remove high frequency noise components；Inverse using discrete wavelet
Conversion reduces to ink speck image, obtains print mottle smoothed image, and it is overall to calculate the shade of gray of smooth ink speck image
With the change of local, the i.e. degree of ink speck size.
As improved technology, conclude and include:
It is said that using certain dot meter device, during the whole printing of finished product of working out a draft, can effectively help control
Whether site processed, the ink on printing machine printed matter out and paper bond completely, and accurately whether chromatography, equipment can allow several
Individual master worker sees printed matter, ps version, the site on the same position of film, and analysis judges whether the control of ink and chromatography are accurate
Really.The medium and small printing enterprise of tradition takes the method that common magnifying glass judges, needs the film to draw a design, contrast of drawing a design, this method
Very passive, usually draw a design not as in the case of repeatedly drawn a design again, the cycle of drawing a design is long.The medium and small printing enterprise of tradition adopts
The method taking common magnifying glass to judge, needs film contrast printing sample, though this method has improved, its passivity
It is that will first go out the film contrasts again, just knows that site has been greatly or little, once different that goes out again, the time is waste
?.More advanced also has, and goes out+15-100 times of magnifying glass contrast printing sample of the site film of 1-99% gray value, with gone out
The film is very direct to printed matter, but it is critical only that the applicability of the gray value site film, has such as said the film of 175 lines
The printed matter of 175 lines is possible, but the printed matter to 250 lines is laboriously, solution be 150 lines, 175
The 1-99% gray value site film of line, 200 lines and 250 lines is standby；Also have magnifying glass multiplying power be identification site important because
Element, 10 times of magnifying glasses want to identify that the site of printed matter is that some are difficult.There is a method in which, i.e. more than 40 times of site set cooperation
Magnifying glass contrast printing sample, improvements are the fine rule profiles that site is made, very directly perceived for identification more than 50% big site,
But be at deficiency because phototypesetting output accuracy problem lead to fine rule can slightly thick so that the precision of less than 10% little site is not high.
The technical problem that prior art exists specifically includes that and understands from the concept of dot area coverage, wants to obtain site
Coverage rate it is necessary to find the real area of unit site, then divided by unit area.The halftone dot image generally obtaining, or be mould
Paste, or being that unit area is excessive or too small, all directly influence the accuracy of measured value.In a word, even if obtaining less
Accurate but result of preferably drawing a design is also required to average more than 3 times debugging check and correction, time-consuming and not accurate.
Content of the invention
It is an object of the invention to provide a kind of be suitable to print whole high power dot of image coverage rate digital measuring method,
Whole general in printing complete procedure, and standard unification, obtain accurately reliable dot area coverage, no longer rely primarily on people
The estimation of work knowledge and experience, judgement, are adapted for engagement with the artificial bottleneck acquisition of high accuracy fast automatic printing technology breakthrough and develop rapidly.
The purpose of the present invention will be realized by following technical measures: measuring method flow process includes: in plate-making, reprint, goes out
In the printing overall process such as film, choose test print image, carry out grabgraf using high magnified glass and obtain tinctorial pattern, using figure work
Tool software measurement tinctorial pattern pixel number, netting twine judges that measurement pixel away from d and draws netting twine l value, wherein, and l=25.4/d, utilize
General formula carries out percentage judgement, then draws dot area coverage through contrast correction；Wherein:
General formula is:=2
=2
=2
Wherein, n is the netting twine measuring and calculating.
Especially, using 200-500 times of high magnified glass, adjusting focal length, to test print image clearly, is taken pictures and is stored
Halftone dot image file is to hard disk；Site part in image and non-site are partially separated, are directly calculated by histogram tools
Go out the ratio of the two, that is, the pixel of site part and the ratio of actual measurement area pixel, select four colors to be measured respectively
Passage or Spot Channel, constituency pixel number represents to be numerical value shown by histogram, the whole pixel of measured area
Value does not need to measure, and the pixel quantity shown by whole image size is exactly the total pixel of area of measurement；The printing net-point of four colors,
If the image obtaining is rgb triple channel image, need for rgb image to be converted to cmyk tetra- chrominance channel acquisition four chrominance channels
Site；In the case of intercepting specific dimensions painting canvas, choose certain passage, choose non-pixel portion in image, more counter select, choose figure
Pixel portion in picture, i.e. printing net-point part, intact selection passage site；When obtaining image, " grey " color is set
It is set to white point or white field is realized selection precision and is immune；In the magnifying glass visual field, netting twine number is arranged for 5-10, high magnified glass times
Rate is 200-500 times；One conventional measurement area of setting, arranges unified canvas size, and this constant total pixel value is constant,
The divisor calculating dot area coverage is constant, and setting divisor is this numerical value, directly calculates the site pixel number of 1%-99%；Will
Unified canvas size is set to whole ten thousand numerical value, without calculating coverage rate again it is only necessary to select the pixel of site part；Meet
To in the measurement visual field, the situation that site is not full of, can be by reducing canvas size, in painting canvas, dot area is full of and is
Only；Preferably use 300 times of 0.001 millimeter of precision high magnified glasses, first measurement point is away from determination screen density, then measures the straight of site
Footpath, the contrast corresponding diameter of screen density obtains dot percentage numerical value with dot percentage numerical value.
Especially, amplitude modulation side, round dot, judge 175 lines data use 0.145mm point away from；Public according to rip principle and area
Formula, obtains 175 line round dot 1-78.5% diameter formula as follows:
=2r s=r2 ≈3.14 1 inch =25.4 mm=175 lpi
=2
=2
=2
=2
=2
Wherein:: diameter s: area r: radius of circle n: unit area net number m: dot percentage numerical value.
Especially, non-175 lines, using formula: away from d, calculate is screen density l to netting twine l=25.4 ÷ point, then calculates correspondence
Site diameters.
Especially, site set obtains the data of 175 line 1-78% circular shaped lattice point diameter, more than 79% site according to formula
Area distributions rule and area relationship, are highlighted by more than 79% site, make the 1:1 site set of 79-99%, according to area ratio
Rate and 175 gauzes point and characteristics of diameters in professional software filter by highlight numerical value make highlight round dot, covered with the effect highlighting
Cover net point blank parts measure site.
Especially, more than 79% site highlights shape and has been sufficiently close to square, is highlighted by square site.79%
Above site highlights shape square site Analysis of Nested Design error and is less than 2%；Square site length of side formula is as follows:
a=
=
=
Calculate square site 1-21% by this formula, that is, 79%-99% site highlights the length of side:
| Dot percentage | Dot percentage | Site diameter (millimeter) |
| 1% | 99% highlights | 0.014 |
| 2% | 98% highlights | 0.020 |
| 3% | 97% highlights | 0.025 |
| 4% | 96% highlights | 0.029 |
| 5% | 95% highlights | 0.032 |
| 6% | 94% highlights | 0.035 |
| 7% | 93% highlights | 0.038 |
| 8% | 92% highlights | 0.041 |
| 9% | 91% highlights | 0.043 |
| 10% | 90% highlights | 0.046 |
| 11% | 89% highlights | 0.048 |
| 12% | 88% highlights | 0.050 |
| 13% | 87% highlights | 0.052 |
| 14% | 86% highlights | 0.054 |
| 15% | 85% highlights | 0.056 |
| 16% | 84% highlights | 0.058 |
| 17% | 83% highlights | 0.059 |
| 18% | 82% highlights | 0.061 |
| 19% | 81% highlights | 0.063 |
| 20% | 80% highlights | 0.065 |
| 21% | 79% highlights | 0.066 |
| 22% | 78% highlights | 0.068 |
| 23% | 77% highlights | 0.0695 |
| 24% | 76% highlights | 0.071 |
| 25% | 75% highlights | 0.072 |
| 26% | 74% highlights | 0.074 |
| 27% | 73% highlights | 0.075 |
| 28% | 72% highlights | 0.077 |
| 29% | 71% highlights | 0.078 |
| 30% | 70% highlights | 0.079 |
| 31% | 69% highlights | 0.081 |
| 32% | 68% highlights | 0.082 |
| 33% | 67% highlights | 0.083 |
| 34% | 66% highlights | 0.085 |
| 35% | 65% highlights | 0.086 |
| 36% | 64% highlights | 0.087 |
| 37% | 63% highlights | 0.088 |
| 38% | 62% highlights | 0.089 |
| 39% | 61% highlights | 0.0905 |
| 40% | 60% highlights | 0.092 |
| 41% | 59% highlights | 0.093 |
| 42% | 58% highlights | 0.094 |
| 43% | 57% highlights | 0.095 |
| 44% | 56% highlights | 0.096 |
| 45% | 55% highlights | 0.097 |
| 46% | 54% highlights | 0.098 |
| 47% | 53% highlights | 0.099 |
| 48% | 52% highlights | 0.100 |
| 49% | 51% highlights | 0.101 |
| 50% | 50% highlights | 0.1025 |
In the 45%-65% easily side's of showing examples of dot shaped, it is suitable for being calculated with square site formula and compares；Simultaneously because, deep layer
Cylinder point highlight shape closer to square, so 85-99% part passes through the method acquisition of the measurement side point length of side.
Especially, diameter data is converted into dot area coverage, further according to the normal loss amount of the reality output film, comes to survey
Numerical quantity corrects, and foundation is the numerical value after printing down；Above numerical value will be regime values.Due to already allowing for reality output numerical value
Lose the factors such as difference with the difference of standard figures, printing down, that is, under the stable case of phototypesetting or ctp, even if there being the error of 1-2%,
Nor affect on the digitization of the present invention.Numerical value is as follows:
| Standard figures | 2% | 5% | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
| After standard film printing down | 1.1 | 3.5 | 7.6 | 16.5 | 26 | 36.5 | 47 | 57 | 67 | 78.3 | 89 |
| Standard film printing down loss amount | 0.9 | 1.5 | 2.4 | 3.5 | 4 | 3.5 | 3 | 3 | 3 | 2.7 | 1 |
| The reality output film | 2.2 | 5.3 | 10.3 | 20.7 | 31 | 40.8 | 51.3 | 61.3 | 72.5 | 81.5 | 90.5 |
| After reality output film printing down | 0.6 | 2.7 | 7.1 | 16 | 25.2 | 35.1 | 44.6 | 55.6 | 66.2 | 78 | 88.6 |
| Reality output film printing down loss amount | 1.6 | 2.6 | 3.2 | 4.7 | 5.9 | 5.7 | 6.7 | 5.7 | 6.3 | 3.5 | 1.9 |
| Numerical value after measured value contrast |
Especially, the situation of dot gain has two kinds of situations:
A kind of be different netting twines dot gain, by radius increase by 0.01 millimeter be defined, the site and 175 of 150 lines 50%
Line, the site of 200 lines 50% compare according to the calculating of formula above, obtain:
| 50% round dot | 150 lines | 175 lines | 200 lines |
| Diameter (millimeter) | 0.135 | 0.116 | 0.100 |
| Girth | 0.424 | 0.364 | 0.314 |
| Area (square millimeter) | 0.0143 | 0.0106 | 0.0079 |
| Area after expanding 0.01 millimeter | 0.0189 | 0.0145 | 0.0113 |
| Dot gain value (%) | 32% | 37% | 43% |
Another kind is the site of same netting twine different weight percentage, increases by 0.01 millimeter by diameter and is defined, respectively to 25%, 50%
It is compared as follows with 75%:
| 175 line round dots | 25% site | 50% site | 75% site |
| Diameter (millimeter) | 0.082 | 0.116 | 0.142 |
| Diameter (millimeter) after expansion | 0.092 | 0.126 | 0.152 |
| Area occupation ratio after expansion | 32% | 32% | 32% |
| Dot gain value (%) | 55% | 37% | 30% |
Especially, a kind of intuitive judgment method also including non-data is used for treating the judgement of survey grid point, that is, with standard literary composition
Part using 175,200 line slices, prints the reference standard of sample respectively as measurement；In addition, making on normal 4 colors and spot color site
Mark, comprising: do the hidden pattern of a numerical value slight variation in plain net, or, go out not in the diverse location of identical file
With netting twine or angle, or, go out different angles in same position, or more at least two kinds combination of the above, as false proof
Measure once completes with normal printing.
Advantages of the present invention and effect: according to new theory and measure formula, accurately and quickly measure dot area
Rate and in addition rationally correction, to replace coverage rate, are not required to other Special Equipments, manufacture necessary accessories low cost, convenient to carry out,
Economy, effect is significant.Automatically round-off error, certainty of measurement is high.Site diameter data dot area coverage is clearly clear, secondary color
Identification accurately, in the case that resolution ratio and magnifying power are very high, are done contrast site with making site and is drawn dot percentage value.
Check the film or ps version, precision is not less than Density Measuring Instrument although specific density instrument reading is slow, but can read what Density Measuring Instrument cannot read
Secondary color site and yellow net, and be more convenient for carrying out digitization and automation linking.Printing to printing modulating net, to printing net-point
In, the clear shapeliness in site of the film or ps version is it is easy to determine border, shape, point away from distinguishing precision and identification error is permissible
It is accurately controlled in the range of 1%.
Brief description
Fig. 1 is the measuring method schematic flow sheet in the present invention.
Fig. 2 is for 175 line 0.145mm points in the embodiment of the present invention 1 away from site schematic diagram.
Fig. 3 is that in the embodiment of the present invention 1, site more than 79% highlights schematic diagram.
Fig. 4 is square site schematic diagram in the embodiment of the present invention 1.
Specific embodiment
The principle of the invention is, according to the definition of printing net-point coverage rate, inking site and the ratio of area coverage, only needs
The ratio tried to achieve therebetween can obtain dot area coverage, if the directly area of measurement inking site and measurement place face
Long-pending, can be because of the different weight percentage of site, different netting twine quantity are different, and stock surface roughness is different, and by measured
The shape of area is different it may appear that different degrees of measurement is difficult, by the halftone dot image obtaining, by the site part in image
It is partially separated with non-site, the image that screening high magnified glass obtains, the high power electronic image that will obtain, isolate site part
With non-site part, it is also to isolate ink portions and non-ink parts, it may appear that 4 kinds or more after corresponding secondary color imaging
The overlapping situation in site, the excessively site of complexity, need manual separation or measurement；In the range of camera view, occur full
, with direct measurement dot cover area, in the range of camera view, can the feelings of local plain net in the situation of version plain net
Condition, can first intercept the image of full version plain net in the visual field, then measure dot cover area.In the accuracy condition proving simulation
Under, calculate conversion and the calculating of dot area percentage using simulation, such as realize using photoshop software simulating.According to rip
The site diameter data understanding the simultaneously 1-99% that bonded area formula calculates of principle, the data reference area of diameter by comparison
Measurement is got up more directly perceived.
As shown in Figure 1, in the present invention, measuring method flow process includes: in plate-making, reprint, goes out the printing overall process such as film
In, choose test print image, carry out grabgraf using high magnified glass and obtain tinctorial pattern, measure tinctorial pattern picture using graphical tool software
Prime number value, netting twine judges that measurement pixel away from d and draws netting twine l value, wherein, and l=25.4/d, carry out percentage using general formula
Ratio judgement, then draw dot area coverage through contrast correction；Wherein:
General formula is:=2
=2
=2
Wherein, n is the netting twine measuring and calculating.
The invention will be further described with reference to the accompanying drawings and examples.
Embodiment 1: preferably use 300 times of 0.001 millimeter of precision high magnified glasses, first measurement point away from determine screen density, then
The diameter of measurement site, the contrast corresponding diameter of screen density obtains dot percentage numerical value with dot percentage numerical value.
In aforementioned, as shown in Figure 2, taking 175 lines as a example, amplitude modulation side, round dot, judge that the data of 175 lines uses 0.145mm
Point away from；According to rip principle and area formula, obtain 175 line round dot 1-78.5% diameter formula as follows:
=2r s=r2 ≈3.14 1 inch =25.4 mm=175 lpi
=2
=2
=2
=2
=2
Wherein:: diameter s: area r: radius of circle n: unit area net number m: dot percentage numerical value.
In aforementioned, non-175 lines, using formula: away from d, calculate is screen density l to netting twine l=25.4 ÷ point, then calculates correspondence
Site diameters.
In aforementioned, such as using photoshop professional software, image is simulated calculating.Because of stock surface color
Difference, when high magnified glass obtains the image in certain visual field, the whiteness of stock is possibly shown as " grey " color, is choosing image net
During point, choosing precision can be affected, and solution is, when obtaining image, to be set to " grey " color white in photoshop
Point or white field are realized selection precision and are immune.The image of different magnifying glass multiplying powers, because multiplying power is different, the size that site shows is not
With number is also different, and under low range, the visual field is larger, so site " less than normal ", number is more, and under high magnification, the visual field is relatively
Little, so site " bigger than normal ", number is less, and because of the difference of multiplying power, site netting twine of different sizes number is different, for the survey of site
For amount, site is much or too small, netting twine number excessive or very few be all unfavorable for site measure, in general, netting twine number with
5-10 clears clear site and is advisable, although very few excessive site measurement is accurately, represent is the site of more low coverage, has limitation
Property, excessive number of outlet on the contrary, also can be big because of field range, the little Relative Fuzzy in site, thus affect certainty of measurement it is proposed that again
Rate selects 200-500 times to be advisable；The different numerical value of measurement, the site of zones of different, are required for measuring site covering pixel respectively every time
With total pixel of place area, always pixel is also different to measure area difference, so always has two variables, affects measuring speed,
Amount because of site pixel is always intended to change, and measures area and can immobilize, thus two variables are reduced to one, if
Put a conventional measurement area, that is, in the canvas size that photoshop setting is unified, be conducive to improving measuring speed, this
Constant total pixel value is constant, that is, the divisor calculating dot area coverage is constant, and in excel, setting divisor is this numerical value, can
Directly to calculate the site pixel number of 1%-99%；Unified canvas size is set to whole ten thousand numerical value, without calculating covering again
It is only necessary to select the pixel of site part, this is technique emphasis to be protected to rate.If fixed pixel is 1000000,
Constituency pixel is 605710, then dot area coverage is exactly 60.57%；Run in the measurement visual field, the situation that site is not full of,
Following left figure, can be by reducing canvas size, till dot area is full of in the painting canvas.
In aforementioned, the solution of measurement spot color, if measurement color is partial to blue, red, yellow, black respectively, can use upper
State the method measurement of measurement, if not this 4 kinds of colors, the form and aspect such as purple, clear water, brown in this way, can be selected using photoshop
Instrument, after choosing for different color regions, then measures dot area coverage.
In aforementioned, as shown in Figure 3, site set obtains the number of 175 line 1-78% circular shaped lattice point diameter according to formula
According to, more than 79% dot area Distribution dynamics and area relationship, highlighted by more than 79% site, make the 1:1 net of 79-99%
Point set, highlights round dot by highlighting numerical value and make according to area ratio and 175 gauzes point and characteristics of diameters in professional software filter,
Cover site blank parts measurement site with the effect highlighting.While obtaining these sites, make figure and be also easy to obtain
Effect after must highlighting, in actual applications, this effect more preferably, refers to cover site blank parts with the effect highlighting
Measurement site.According to the data calculating, the picture file making 1:1 in vector software in proportion can do normative document
Use, amplification effect can be used for teaching and uses, and every film setter and rip lead to the solution to gray scale because of a variety of causes after all
Release difference, the vector normative document made be on the spot can exclude above-mentioned difference.Take out 90%, 95%, 100% 3 group of data
Checking, error is below 5/1000000ths.
In aforementioned, as shown in Figure 4, more than 79% site highlights shape and has been sufficiently close to square, can pass through square
Site highlights.More than 79% site highlights shape square site Analysis of Nested Design error and is less than 2%；Square site length of side formula is as follows:
a=
=
=
Calculate square site 1-21% by this formula, that is, 79%-99% site highlights the length of side:
| Dot percentage | Dot percentage | Site diameter (millimeter) |
| 1% | 99% highlights | 0.014 |
| 2% | 98% highlights | 0.020 |
| 3% | 97% highlights | 0.025 |
| 4% | 96% highlights | 0.029 |
| 5% | 95% highlights | 0.032 |
| 6% | 94% highlights | 0.035 |
| 7% | 93% highlights | 0.038 |
| 8% | 92% highlights | 0.041 |
| 9% | 91% highlights | 0.043 |
| 10% | 90% highlights | 0.046 |
| 11% | 89% highlights | 0.048 |
| 12% | 88% highlights | 0.050 |
| 13% | 87% highlights | 0.052 |
| 14% | 86% highlights | 0.054 |
| 15% | 85% highlights | 0.056 |
| 16% | 84% highlights | 0.058 |
| 17% | 83% highlights | 0.059 |
| 18% | 82% highlights | 0.061 |
| 19% | 81% highlights | 0.063 |
| 20% | 80% highlights | 0.065 |
| 21% | 79% highlights | 0.066 |
| 22% | 78% highlights | 0.068 |
| 23% | 77% highlights | 0.0695 |
| 24% | 76% highlights | 0.071 |
| 25% | 75% highlights | 0.072 |
| 26% | 74% highlights | 0.074 |
| 27% | 73% highlights | 0.075 |
| 28% | 72% highlights | 0.077 |
| 29% | 71% highlights | 0.078 |
| 30% | 70% highlights | 0.079 |
| 31% | 69% highlights | 0.081 |
| 32% | 68% highlights | 0.082 |
| 33% | 67% highlights | 0.083 |
| 34% | 66% highlights | 0.085 |
| 35% | 65% highlights | 0.086 |
| 36% | 64% highlights | 0.087 |
| 37% | 63% highlights | 0.088 |
| 38% | 62% highlights | 0.089 |
| 39% | 61% highlights | 0.0905 |
| 40% | 60% highlights | 0.092 |
| 41% | 59% highlights | 0.093 |
| 42% | 58% highlights | 0.094 |
| 43% | 57% highlights | 0.095 |
| 44% | 56% highlights | 0.096 |
| 45% | 55% highlights | 0.097 |
| 46% | 54% highlights | 0.098 |
| 47% | 53% highlights | 0.099 |
| 48% | 52% highlights | 0.100 |
| 49% | 51% highlights | 0.101 |
| 50% | 50% highlights | 0.1025 |
Generally in the 45%-65% easily side's of showing examples of dot shaped, it is suitable for being calculated with square site formula and compares；Simultaneously because,
Deep layer cylinder point highlight shape closer to square, so 85-99% part passes through the method acquisition of the measurement side point length of side.
In aforementioned, diameter data is converted into dot area coverage, further according to the normal loss amount of the reality output film, comes to survey
Numerical quantity corrects, and foundation is the numerical value after printing down；Above numerical value will be regime values.Due to already allowing for reality output numerical value
Lose the factors such as difference with the difference of standard figures, printing down, that is, under the stable case of phototypesetting or ctp, even if there being the error of 1-2%,
Nor affect on the digitization of the present invention.Numerical value is as follows:
| Standard figures | 2% | 5% | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
| After standard film printing down | 1.1 | 3.5 | 7.6 | 16.5 | 26 | 36.5 | 47 | 57 | 67 | 78.3 | 89 |
| Standard film printing down loss amount | 0.9 | 1.5 | 2.4 | 3.5 | 4 | 3.5 | 3 | 3 | 3 | 2.7 | 1 |
| The reality output film | 2.2 | 5.3 | 10.3 | 20.7 | 31 | 40.8 | 51.3 | 61.3 | 72.5 | 81.5 | 90.5 |
| After reality output film printing down | 0.6 | 2.7 | 7.1 | 16 | 25.2 | 35.1 | 44.6 | 55.6 | 66.2 | 78 | 88.6 |
| Reality output film printing down loss amount | 1.6 | 2.6 | 3.2 | 4.7 | 5.9 | 5.7 | 6.7 | 5.7 | 6.3 | 3.5 | 1.9 |
| Numerical value after measured value contrast |
In aforementioned, with site diameter data, coordinate 200 times with 0.002 millimeter of minimum scale high magnified glass measurement of upper band
The diameter data of site, and clearly differentiate green grass or young crops, product, Huang and black site.However, the visual field very little of high magnified glass, such as 300
The high magnified glass visual field again only has 0.48 millimeter, and 0.2 millimeter of measurement range, so its measurement area very little, can only be done a little
Measurement, must finish scope before measuring.
In aforementioned, 300 times carry pure white light source reading microscope to have following characteristics: adjustable focus, and carry pure white light source employing
More than 10 years long-lives highlighted crystal light-emitting diodes are illumination field of view, are not limited by ambient light during use；With a scale, can
Accurately read the actual size of small article；Be aligned observes thing when focusing clear, and the little lattice in 1 on rule are equal to actual size
0.0025mm, 0-1 are equal to actual size 1mm, and visual field is 0.6mm；Multiplication factor is 300x, and observation is clear, accurate, pure white light source
Not colour cast；Low energy consumption adopts pure white crystal light-emitting diodes operating current 0.015a than 18 times general of torch bulb power consumptive province,
Bulb power consumption 0.25a；True field 0.6mm, object space operating distance 2.5mm, system length 143mm, numerical aperture 0.45, system
Focal length -0.833, certainty of measurement≤± 1%, -20～50 DEG C of environment temperature, measurement range length 0-0.6mm, volume size 50
× 23 × 138mm, measures scale unit 0.0025mm 2.5um.
In the present embodiment, using 200-500 times of high magnified glass, adjusting focal length, to test print image clearly, is taken pictures simultaneously
Storage halftone dot image file, to hard disk, is opened using photoshop；Site part in image and non-site are partially separated,
Directly calculate the ratio of the two by histogram tools in software photoshop, i.e. the pixel of site part and actual measurement
The ratio calculation of area pixel obtains, and selects four chrominance channels to be measured or Spot Channel, constituency pixel number respectively
Expression is the numerical value shown by histogram, and the whole pixel value of measured area does not need to measure, and whole image size is shown
The pixel quantity showing is exactly the total pixel of area of measurement；The printing net-point of general four colors, the image of acquisition is rgb triple channel figure
Picture, will obtain the site of four chrominance channels, need for rgb image to be converted to cmyk tetra- chrominance channel, can be direct in photoshop
Conversion；In the case of intercepting specific dimensions painting canvas, choose certain passage, press ctrl key and click on this passage icon to choose in image
Non- pixel portion, more counter select, choose image in pixel portion, i.e. printing net-point part, intact selection passage site；
When obtaining image, in photoshop, " grey " color is set to white point or white field is realized selection precision and is immune；Magnifying glass
In the visual field, netting twine number is arranged for 5-10, arranges a conventional measurement area, that is, in the painting canvas chi that photoshop setting is unified
Very little, this constant total pixel value is constant, that is, the divisor calculating dot area coverage is constant, and in excel, setting divisor is this number
Value, can directly calculate the site pixel number of 1%-99%；Unified canvas size is set to whole ten thousand numerical value, without calculating again
Coverage rate is it is only necessary to select the pixel of site part；Run in the measurement visual field, the situation that site is not full of, Ke Yitong
Cross and reduce canvas size, till dot area is full of in the painting canvas.
Embodiment 2: in the case of dot gain, preceding method is still adopted for the site measurement that little version reprint is drawn a design.
Can there is the situation of dot gain when big version exports, dot gain situation is complicated, there is no the correction " contracting of coupling
Little " before data, prior art generally uses the method for printing down added-time to ensure big version net-point printing with sample, ctp will plus bent accordingly
Line solves.
In aforementioned, the situation of dot gain has two kinds of situations:
A kind of be different netting twines dot gain, by radius increase by 0.01 millimeter be defined, the site and 175 of 150 lines 50%
Line, the site of 200 lines 50% compare according to the calculating of formula above, obtain:
| 50% round dot | 150 lines | 175 lines | 200 lines |
| Diameter (millimeter) | 0.135 | 0.116 | 0.100 |
| Girth | 0.424 | 0.364 | 0.314 |
| Area (square millimeter) | 0.0143 | 0.0106 | 0.0079 |
| Area after expanding 0.01 millimeter | 0.0189 | 0.0145 | 0.0113 |
| Dot gain value (%) | 32% | 37% | 43% |
Another kind is the site of same netting twine different weight percentage, increases by 0.01 millimeter by diameter and is defined, respectively to 25%, 50%
It is compared as follows with 75%:
| 175 line round dots | 25% site | 50% site | 75% site |
| Diameter (millimeter) | 0.082 | 0.116 | 0.142 |
| Diameter (millimeter) after expansion | 0.092 | 0.126 | 0.152 |
| Area occupation ratio after expansion | 32% | ||
| Dot gain value (%) | 55% | 37% | 30% |
In the present invention, a kind of intuitive judgment method also including non-data is used for treating the judgement of survey grid point, that is, with standard
File respectively using 175,200 line slices, reference standard as measurement printing sample although, accuracy may decline, but more
Quickly, convenient and directly effective.
In the present invention, with there being measurement film function 300_icplate forme measuring instrument to measure the colour code of 175 lines, accurately take out
Survey diameter data, the result is consistent.
The present invention, under conditions of phototypesetting precision reaches requirement, produces vector file by numerical value corrected, goes out the film
Direct measurement is verified.It is 6-7% in the error going out 100%, 200% error only 1/3 can reach 4%, 300% error only has 2/3 can
To reach 2% it is believed that can be with error 1% in the case of 1000%.Other side's round dot can be with 50% as boundary, shallow site and depth
Site highlight compare whether correct；Make 1-99% gray color and mark the film and measure this numerical value whether data is consistent.
The present invention is inapplicable to entirely obscuring site, half-and-half fuzzy halftone dot image, needs first half-and-half fuzzy halftone dot image to process
Afterwards, then measure dot cover area.
In the present invention, solve the problems, such as site measurement and beasurement base, the thick judgement from original site rises to site essence
Really measure, make a common making person become senior making person, the print front site error in judgement solving long-standing problem is necessary
Repeatedly draw a design the problem repeatedly proofreaded, provide foundation for Digital Control before print, it is to avoid in the past by manually seeing what site led to
5-10% error, error is significantly reduced to 1-3%.
The present invention in use, additionally aiding promotion four colors and the research and development of spot color site anti-counterfeiting technology, such as, in normal 4 colors and
Spot color makes a mark on site, such as: do the hidden pattern of a numerical value slight variation in plain net, or, in identical file
Diverse location goes out different netting twines or angle, or, go out different angles in same position, or do multiple combination effect, due to this
Invention certainty of measurement is done basis and can conveniently be realized, and, such class anti-counterfeit measures once can complete with normal printing, closely
Cost-effective, by being difficult to imitate.
Advantage of the present invention and effect also include: filled up the blank of print front site high-acruracy survey, improve reprint and draw a design
One-time success rate, it closely couples together tinctorial pattern-e-file first, and tinctorial pattern-site measurement-e-file-
Film measurement-printing down loss-ps version numerical value links together as a digitized mine, is applied to reprint and draws a design and usual
Site monitors, relatively traditional low power magnifying glass, sees site by rule of thumb, this technology has direct-recording high power picture, it is to avoid
" by rule of thumb " the probabilistic subjectivity impact bringing, the theory of existing amplitude measurement, it is biased in measurement amplitude modulation net
The diameter of point, reconvert becomes corresponding dot area coverage numerical value, and technical scheme provides measurement dot area coverage
Method is its area ratio of direct measurement, can also measure frequency-modulation halftone dot, has surmounted the measuring method of amplitude comprehensively.This Shen
Technical scheme directly Dot Area please be contrasted with the unit area being located, compare and be converted into net by measuring site diameter
Dot coverage, faster more accurate；Relatively transmission-type Density Measuring Instrument, this technology also has different colours inside recognition reflection original text printing net-point
Function, and contrast reflection type density instrument for, except higher have more advantage in addition to, although reflection type density instrument have different
Coloured light passage, but also it is difficult to differentiate between the close red indigo plant net of site ratio, rouge et noir net in secondary color site etc..Relatively
Reflection type density instrument, this technology equally has the advantage of recognition modulating net, and can distinguish the color component of secondary color site, such as
Two kinds of sites of c100m50 and c100k40, using reflection type density instrument in red channel or black channel, the red net read more and
Black site numerical value is all unfixed, and this technology is because using manual color separation measurement, no doubt advantage is more.Continuous solution is above to ask
Topic is it is not necessary to multiple solve problem is it is only necessary to arrange unified action it would be desirable to the problem solving is continuous in photoshop
Record, for needing step measurement to be recorded as single action, such as measure blue site, " a blueness can be recorded
The action of site ", others can be " red site " " yellow site " " black site " etc..Once fulfil ahead of schedule normal
Reprint is drawn a design, and every economization is once drawn a design and at least saved 1000 yuan, supports fast proofing, and solving of essence restricts this area for a long time
The bottleneck problem of development.
Claims (10)
1. it is suitable to print whole high power dot of image coverage rate digital measuring method it is characterised in that measuring method flow process
Including: in plate-making, reprint, go out in film printing overall process, choose test print image, carry out grabgraf using high magnified glass and obtain
To tinctorial pattern, measure tinctorial pattern pixel number using graphical tool software, netting twine judges that measurement pixel away from d and draws netting twine l value, its
In, l=25.4/d, carry out percentage judgement using general formula, then draw dot area coverage through contrast correction；Wherein:
General formula is:=2
=2
=2
Wherein, n is the netting twine measuring and calculating.
2. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, using 200-500 times of high magnified glass, halftone dot image literary composition is taken pictures and stored to adjusting focal length, to test print image clearly,
Part, to hard disk, the site part in image and non-site is partially separated, and directly calculates the ratio of the two by histogram tools
Rate, that is, the pixel of site part and the ratio of actual measurement area pixel, select four chrominance channels to be measured or spot color respectively
Passage, constituency pixel number represents to be numerical value shown by histogram, and the whole pixel value of measured area does not need to survey
Amount, the pixel quantity shown by whole image size is exactly the total pixel of area of measurement；The printing net-point of four colors, the image of acquisition
It is rgb triple channel image, need for rgb image to be converted to the site that cmyk tetra- chrominance channel obtains four chrominance channels；Specific intercepting
In the case of size painting canvas, choose certain passage, choose non-pixel portion in image, more counter select, choose the pixel portion in image,
I.e. printing net-point part, intact selection passage site；When obtaining image, " grey " color is set to white point or white field is real
Now choose precision to be immune；In the magnifying glass visual field, netting twine number is arranged for 5-10, and high magnified glass multiplying power is 200-500 times；If
Put a conventional measurement area, unified canvas size is set, this constant total pixel value is constant, that is, calculate dot area coverage
Divisor constant, setting divisor be this numerical value, directly calculate the site pixel number of 1%-99%；Unified canvas size is set
It is set to whole ten thousand numerical value, without calculating coverage rate again it is only necessary to select the pixel of site part；Run in the measurement visual field, net
Point situation about not being full of, can be by reducing canvas size, till dot area is full of in the painting canvas.
3. it is suitable to as claimed in claim 2 print whole high power dot of image coverage rate digital measuring method, its feature
It is, using 300 times of 0.001 millimeter of precision high magnified glasses, first measurement point is away from determining screen density, then measures the diameter of site,
The contrast corresponding diameter of screen density obtains dot percentage numerical value with dot percentage numerical value.
4. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
Be, amplitude modulation side, round dot, judge 175 lines data use 0.145mm point away from；According to rip principle and area formula, obtain
175 line round dot 1-78.5% diameter formula are as follows:
=2r s=r2 ≈3.14 1 inch =25.4 mm=175 lpi
=2
=2
=2
=2
=2
Wherein:: diameter s: area r: radius of circle n: unit area net number m: dot percentage numerical value.
5. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, non-175 lines, using formula: netting twine l=25.4 ÷ point, away from d, calculates screen density l, then calculates corresponding site diameters.
6. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, site set obtains the data of 175 line 1-78% circular shaped lattice point diameter, more than 79% dot area distribution rule according to formula
Rule and area relationship, are highlighted by more than 79% site, make the 1:1 site set of 79-99%, according to area ratio and 175 lines
Site and characteristics of diameters highlight round dot by highlighting numerical value and make in professional software filter, cover site with the effect highlighting blank
Part measurement site.
7. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, more than 79% site highlights shape and has been sufficiently close to square, highlighted by square site；More than 79% site is anti-
White shape square site Analysis of Nested Design error is less than 2%；Square site length of side formula is as follows:
a=
=
=
Calculate square site 1-21% by this formula, that is, 79%-99% site highlights the length of side:
In the 45%-65% easily side's of appearance examples of dot shaped, it is suitable for being calculated with square site formula and compares；Simultaneously because, deep layer cylinder point
Highlight shape closer to square, so 85-99% part passes through the method acquisition of the measurement side point length of side.
8. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, diameter data is converted into dot area coverage, further according to the normal loss amount of the reality output film, come to measured value school
Just, foundation is the numerical value after printing down；Above numerical value will be regime values；Due to already allowing for reality output numerical value and criterion numeral
The difference of value, printing down loss difference factor, that is, under the stable case of phototypesetting or ctp, even if there being the error of 1-2%, nor affect on this
The digitization of invention；Numerical value is as follows:
.
9. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, the situation of dot gain has two kinds of situations:
A kind of be different netting twines dot gain, increase by 0.01 millimeter by radius and be defined, the site of 150 lines 50% and 175 lines, 200
The site of line 50% is compared according to the calculating of formula above, obtains:
Another kind is the site of same netting twine different weight percentage, increases by 0.01 millimeter by diameter and is defined, respectively to 25%, 50% and
75% is compared as follows:
.
10. it is suitable to as claimed in claim 1 print whole high power dot of image coverage rate digital measuring method, its feature
It is, a kind of intuitive judgment method also including non-data is used for treating the judgement of survey grid point, is used respectively with normative document
175th, 200 line slice, as the reference standard of measurement printing sample；In addition, making a mark on normal 4 colors and spot color site, comprising:
Do the hidden pattern of a numerical value slight variation in plain net, or, the diverse location of identical file go out different netting twines or
Angle, or, go out different angles in same position, or more at least two kinds combination of the above, as anti-counterfeit measures with normal
Printing once completes.
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| CN107944131A (en) * | 2017-11-22 | 2018-04-20 | 山东农业大学 | A kind of printing net-point coverage rate analog measurement method |
| CN108088396B (en) * | 2017-12-15 | 2019-11-05 | 杭州电子科技大学 | A method of the dot area of prediction ink-jetting forme-producing |
| CN109228611B (en) * | 2018-09-13 | 2023-05-09 | 南京林业大学 | Design method of adjustable gravure plate pillow net-shaped structure |
| CN109727232B (en) * | 2018-12-18 | 2023-03-31 | 上海出版印刷高等专科学校 | Method and apparatus for detecting dot area ratio of printing plate |
| CN112848727B (en) * | 2021-01-07 | 2022-06-28 | 北京印刷学院 | Screening method, printing method, system and device for image halftone color generation |
| CN117218452B (en) * | 2023-11-02 | 2024-02-06 | 临沂市兰山区自然资源开发服务中心 | Automatic classification management system for land images |
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