CN104614384A - Quality detecting method of printing product character - Google Patents
Quality detecting method of printing product character Download PDFInfo
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- CN104614384A CN104614384A CN201510065317.8A CN201510065317A CN104614384A CN 104614384 A CN104614384 A CN 104614384A CN 201510065317 A CN201510065317 A CN 201510065317A CN 104614384 A CN104614384 A CN 104614384A
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Abstract
The invention relates to a printing quality detecting method of a printing product character, and belongs to the technical field of printing. The printing detecting method comprises the following steps: performing printing output by using a vector character and a dual-dot icon loaded above the character as a digital origination to obtain a detection pattern; performing resolving power calibration and optical reflectivity calibration by adopting a digital imaging system; converting the detection pattern of a printing product character into an RGB digital image with high resolution by using the digital imaging system; obtaining an optical reflectivity gray scale image by virtue of a calibration relation; performing orientation correction; converting the resolution of the corrected character gray level image into a resolution of the digital origination, and extracting a character region in a sample image according to an extracting manner of the digital origination; and comparing with pixels in the same positions of the image of the character region of the digital origination and performing processing analysis to obtain a character quality index value. A printing product character quality index established by the printing quality detecting method is capable of characterizing characteristics of darkness, deformation and skip printing of character strokes, and can be used for quality characterization and control of layout and printing product characters in conventional and digital printing.
Description
Technical field
The present invention relates to a kind of quality determining method of printing word, belong to printing technology.
Background technology
Printed matter is indispensable in daily life, as books, package etc.For any printing, word is all important content, particularly for books, newpapers and periodicals, and the printing such as description of commodity, the printing quality of word is particularly important.But during current print quality detects, only pass judgment on by the printing quality of visually-perceptible to different font size word, the index still do not quantized.
In referential correlation technique, international standard ISO/IEC 13660 and ISO/IEC TS 24790, for the achromaticity forming monochrome image quality that the office equipment hard copies such as printing and duplicating export in white substrate, to lines, large area look on the spot, and the image quality of the printing such as ground unrest has carried out index definition, can be used for objective measurement and the evaluation of this field hard copy image quality.Wherein, for character literal, except associated line quality attribute, also define the index " filling " containing defect of biting in its stroke of reflection, the area namely bitten accounts for the area ratio of overall stroke.But this definition, for " expansion " or edge " incompleteness " that the darkness of stroke, stroke trace usually occur etc., does not provide assessment indicator.In addition, Chinese character style form is abundant, stroke is complicated and simple various, and identical printing condition, print quality also has very big-difference.Such as, the word of identical font size, easily there is the phenomenon that stroke broadens in the relatively the widest black matrix of stroke, and the Song typeface of relative narrower, then easily there is the phenomenon of stroke incompleteness.The darkness of different in width stroke word is also obviously different.These phenomenons use in the printing of small type size word at such as blocking product, medical product instructions etc. and more easily occur.
Therefore, it is possible to for the morphological feature of Chinese character, directly provide the quantitatively evaluating compared with comprehensive information such as word darkness and stroke defect characteristic, the quality characterization of printing product word is very necessary.
Summary of the invention
The object of the invention is a kind of print quality inspection method setting up printing word, comprise forme and final printed matter.By obtaining the digitized video of word in printing and utilizing image analysis technology, this word and its Digital Manuscript being compared obtains the printing quality of word.
A quality determining method for printing word, comprises the following steps:
(1) using vectorial characters and two round dot icons of loading above word as Digital Manuscript, Digital Manuscript is converted to * .GIF or * .bmp image, prints output and obtain detecting pattern;
(2) adopt the digital imaging system of high resolution, resolving power demarcation and light reflectivity calibration are carried out to this imaging system;
(3) by digital imaging system, printing text detection pattern is converted to high-resolution RGB digitized video;
(4) to the RGB digitized video that step (3) obtains, by the calibration relation of step (2), light reflectivity grayscale image is obtained;
(5) to the grayscale image that step (4) obtains, directional correction is carried out;
(6) after correction step (5) obtained, the resolution conversion of word grayscale image is the resolution of its Digital Manuscript, and presses the extracting mode of Digital Manuscript, extracts the character area in this sample image;
(7) to the word sample image that step (6) obtains, by comparing with the co-located pixel in its Digital Manuscript image character region and analyze, text quality desired value is obtained.
In step (1), make vectorial characters pattern in software for composing, and above word, load two round dot icon, Digital Manuscript is * .ai form, and the design of word icon comprises dark-coloured and light tone word; Afterwards, word vector pattern is converted to suitable high resolving power * .GIF or * .bmp image, prints output and obtain detecting pattern; Finally, in high resolving power word image, take out the region only comprising word according to two round dot logo location, be detection character area image.
The Digital Manuscript of printing word used is the representational word for paying close attention to font size and font.The font size paid close attention to be need in specific printing mode application or to the representational font size of printing quality, as 4 pounds; Representational font need select the everyday character body characteristics that can represent Chinese character, as the Song typeface or black matrix; Representational word need stroke containing the different directions such as horizontal, vertical, oblique.
Two dot charts above word be designated as that horizontal direction separates two are with large dot, and in the same horizontal line, distance of separation is a bit larger tham the character area width that will test in the two round dot centers of circle.
In step (2), the resolving power of digitized video imaging system must meet the requirement of analysis precision, namely must ensure that the most wide available several imaging pixel of thin stroke for analyzing represents.
For the CCD digital imaging system be made up of optical amplifier and CCD image device, CCD image device adjusts to white balance to imaging white light source used, select certain enlargement ratio, under the micro-imaging condition selected, resolving power demarcation and light reflectivity calibration are carried out to this imaging system.
To the method that CCD imaging system resolving power is demarcated, comprise the steps:
1) take two round dot scale icon by CCD image device, form scale map target digitized video; Two round dot scale icon comprises the identical round dot of two diameters, and the diameter of round dot and two round dot distance of center circle can carry out designing and adjusting as required.
2) resolving power of digitized video under this image-forming condition is calculated by the pixel count that two round dot distance of center circle in two round dot scale icon digitized video are corresponding.
Wherein, the actual resolving power selected should be determined according to the font size for detecting.As the text detection for 4 pounds of sizes, system become the dimension on the corresponding imaging object plane of each pixel of digitized video to be not more than 2 μm.
To the method that the light reflectivity of CCD digital imaging system is calibrated, comprise the steps:
1) colour table of several color lump compositions that changes from shallow to deep is printed; Described colour table includes the color lump being no less than 15 different dot area percentages, and the shape of each color lump is square, and the length of side is not less than 10mm.Such as dot area percentage value is from even value between 0% ~ 100%, and the color lump choosing more than 15 different dot area percentages, as Digital Manuscript, is printed output and obtained colour table under the printing condition identical with manuscript.
2) measure and calculate the light reflectivity ρ of each color lump of colour table;
To forme situation, by the spectral reflectivity of each color lump of spectrophotometer measurement colour table, again according to the color characteristic of forme imaging, a suitable wavelength coverage is chosen in its complementary color optical band, as for blue-green, the light reflectivity difference of different ink amount color lump mainly occurs in its complementary color light-red spectral band, then selectable wavelength coverage is between 600nm ~ 700nm.Afterwards, ask for respectively each color lump spectral reflectivity in selected wavelength coverage and with standard white version spectral reflectivity and ratio, be the light reflectivity ρ of each color lump.
Printing product situation, then by (optics) density D of each color lump of spectrophotometer measurement colour table, calculate light reflectivity ρ by definition (1) formula of (optics) density further.As follows:
D＝-log
10ρ (1)
ρ＝10
-D(2)
3) by CCD imaging system to the assorted block imaging of colour table, the middle part of digital picture is asked for the mean value of RGB response, chooses in rgb value and change maximum color value with different color blocks, and normalization, be designated as d;
4) according to ρ and the d value of all color lumps of colour table, mathematical relation is between the two set up, the calibration relation namely under this image formation state between CCD image response and printing light reflectivity.
In step (3), printing text detection pattern is taken into high-resolution RGB digitized video; Image-forming condition used is same as step (2).The RGB digitized video of captured printing word, need save as * .GIF or * .bmp form.During shooting, the two round dots above word will be on same level line substantially, and two circle center line connectings and horizontal line deviation angle are not more than 2 degree.
In step (5), described directional correction is the two round dot regions adopting adaptive method automatically to take out top, and solves the central coordinate of circle of two round dot, according to this two central coordinate of circle rotary sample image to two round dot center of circle in the same horizontal line.
In step (6), the resolution conversion of described image is the alphanumeric master copy image will set up in the resolution match of sample image to step (1), namely reaches the pixel-physical size corresponding relation identical with alphanumeric original copy.The method adopted determines a zoom factor k, zooms in or out the sample image after the directional correction that step (5) obtains with this zoom factor.Zoom factor k is the ratio of sample image two round dot distance of center circle after the distance of center circle of two round dots in alphanumeric master copy image and directional correction.
With the center of circle, the upper left corner for round dot, when extracting with alphanumeric original copy, identical position and size extract the character area in sample image, formed and Digital Manuscript character area image targeted by can the sample image that compares of co-located pixel.
In step (7), the quality index of printing word comprises empty number and cyst areas ratio in word light reflectivity, the broken string number of character stroke, broken string and incomplete total area ratio, expansion area ratio, stroke.
Each index is defined as follows:
1) word light reflectivity or density
For the average light reflectivity in character stroke or (optics) density, represent the darkness of word.
2) the broken string number of character stroke
For printing stroke is compared with the standard stroke of alphanumeric original copy, the stroke open position number of appearance, reflects a kind of incomplete defect.
3) broken string and incomplete total area ratio
For compared with the standard stroke of alphanumeric original copy, the stroke area that broken string and stroke edge place lack accounts for the number percent of standard stroke area, the deficiency of reflection text printout inking amount.
4) expansion area ratio
The area extended away for stroke accounts for the number percent of standard stroke area, the impact that reflection printing ink quantity is sprawled on base material.
5) empty number in stroke
For stroke internal cause bite formed the empty number of independence.
6) cyst areas ratio in stroke
For cyst areas in stroke accounts for the number percent of standard stroke area, the bite degree of reflection printing inking on base material.
For base material inking, the word formed by non-inking (being called " leaking white "), above-mentioned definition is applicable equally, and only inking implication is contrary.
The method for solving of each quality index is as follows:
(1) set a gray threshold, extract the stroke area of word; For each closed stroke area, remove the noise region not having common ground with corresponding alphanumeric master copy image character area, retain the trace region belonging to character stroke.
(2) for the region belonging to character stroke in sample image, ask for light reflectivity (gray-scale value) mean value, be the light reflectivity of word; For final printing word situation, further according to the relation of light reflectivity ρ with (optics) density D, i.e. the inverse operation relation D=-log of (1) formula
10ρ obtains (optics) density D of word.
(3) the sample grayscale image only retaining character area is converted to two-value image, character area part value is 1, and remainder value is 0 (identical with alphanumeric master copy image).
(4) ask for the closed region number belonging to word segment in sample image, this number deducts word used due closed region number, is place's number of word broken string.
(5) ask for the difference of alphanumeric original copy and sample word two-value image, difference be 1 part be the part of sample character stroke incompleteness, all 1 values and divided by all 1 values of original copy for type composition stroke and, namely obtain breaking and incomplete total area ratio.
(6) ask for the difference of sample word two-value image and alphanumeric original copy, difference be 1 part be the part of sample character stroke expansion, all 1 values and divided by all 1 values of original copy for type composition stroke and, be the total area ratio of expansion; And the part that difference is-1 is the hollow sectors in word trace stroke, its closed region number is empty number, all-1 values and absolute value divided by all 1 values of alphanumeric original copy stroke and, namely obtain cyst areas ratio in stroke.
The present invention designs the word of paid close attention to font size and font and two round dot identification image, forms printing file and detection image file respectively.Micro-amplification and CCD imaging are carried out to the printing word pattern exported, imaging system is carried out by the calibration of image value to printing ink marks light reflectivity, and changes printing word image into light reflectivity grayscale image with this.Utilizing the two round dot centers of circle positioning function in image, is consistent with original copy for type composition by printing word grayscale image directional correction; Further, convert its resolution for identical with original copy for type composition, and extract identical character area.Compared by the respective pixel in printing image and master copy image same text region, the quality index realizing printing word solves.The printing text quality index set up can characterize character stroke darkness, be out of shape and the feature such as to bite, can be used for quality characterization and the control of tradition and the digital printed middle space of a whole page and printing word.
The present invention is reflected and quality morphology with the light of the digital imagery response of word trace and the deformation behaviour reflection word trace of character stroke respectively.Quality index comprises the darkness feature of word, and the number of drawbacks feature of character stroke, can characterize the visual quality of printing word comparatively all sidedly.
Accompanying drawing explanation
Fig. 1 is the process flow diagram of detection method.
Fig. 2 (a) to Fig. 2 (f) is embodiment of the present invention word pattern used master copy image; Wherein, Fig. 2 (a) and Fig. 2 (b) is dark word pattern original copy; Fig. 2 (c) and Fig. 2 (d) is bright word pattern original copy; Fig. 2 (e) and Fig. 2 (f) is detection character area image.
Fig. 3 is two round dot icons of the embodiment of the present invention different distance of center circle used.
Fig. 4 (a) and Fig. 4 (b) is embodiment of the present invention imaging system calibration used colour table image; Wherein, Fig. 4 (a) is to forme imaging calibration colour table; Fig. 4 (b) is the black trace imaging calibration colour table to paper printing products.
Fig. 5 (a) and Fig. 5 (b) is respectively the forme dark-coloured word pattern image of embodiment of the present invention printout, and Fig. 5 (c) and Fig. 5 (d) is respectively the forme light colour word pattern image of embodiment of the present invention printout.
Fig. 6 (a) and Fig. 6 (b) is respectively embodiment of the present invention paper printing products black letters dark-coloured word pattern image, and Fig. 6 (c) and Fig. 6 (d) is respectively embodiment of the present invention paper printing products black letters light colour word pattern image.
Fig. 7 is the embodiment of the present invention used pair of round dot icon area extraction method schematic diagram.
Fig. 8 (a) and Fig. 8 (b) is the embodiment of the present invention two round dot centers of circle determination result signal image.
Fig. 9 (a) and Fig. 9 (b) are detected the character area signal image that pattern extracts for the embodiment of the present invention; Wherein, Fig. 9 (a) is character area light reflectivity grayscale image; The two-value image that Fig. 9 (b) is character area.
Figure 10 is that qualitative character after the tested printing word of the embodiment of the present invention is aimed at original copy word illustrates image.
Figure 11 (a) to Figure 11 (c) is for the embodiment of the present invention is to forme and two kinds of paper printing products text quality testing result figure; Wherein, Figure 11 (a) is character stroke average light reflectivity results; Figure 11 (b) is the incomplete area ratio result of character stroke; Figure 11 (c) is character stroke expansion area ratio result.
Embodiment
Further illustrate the present invention below in conjunction with drawings and Examples, but can not be used for limiting the scope of the invention.
As shown in Figure 1, for the flow process of detection method, comprise that word pattern original copy makes and prints, the micro-amplification of pattern and CCD imaging, yardstick demarcation and calibration are carried out to CCD imaging, image reflectivity conversion, image direction correct, character stroke extracts and quality index solves.
Following examples are forme prepared by a kind of inkjet printing, and are printed onto the black letters printing on two kinds of paper.And this embodiment pays close attention to the word of 4 pounds of sizes, the trace namely for 4 pounds of words detects.The following detailed description of testing process.
Detection system used comprises hardware and software two parts.Hardware comprises micro-magnifying optics, CCD color imaging device and computing machine; The computational tool that software is developed image acquisition and each quality index.
Wherein, microscope used is Chongqing special SZ66-TR difficult to understand, has enlargement ratio and the continuous regulatory function of focal length, and the enlargement ratio of object lens is continuously adjustabe from 0.68 times to 4.5 times, and the enlargement ratio of eyepiece is 10, and total enlargement ratio is 6.8 times to 45 times.Microscope imaging termination CCD image device, brand and model is COOLSNAP3.3M, has 2048 × 1536 CCD unit, and the digitized video namely formed has 2048 × 1536 pixels.CCD image device is connected with computing machine, makes picture by computer controlled.Microscope object space end is fixed with D65 annular white light source, irradiate lower can the object disposing platform of x, y direction movement.Detected sample pattern is placed on articles holding table, is gathered form RGB digitized video after micro-imaging by CCD, and computer software carries out process to image and realizes detecting.
Testing process is as follows:
1, made respectively in Illustrate software and comprised 4 pounds of Song typefaces and 4 pounds of black matrix words " sub-v " and two dot chart target two-value vectorial characters pattern.Wherein, above word, the size of two horizontal positioned round dots is identical, and diameter is 0.5mm, is spaced apart 2.4mm, as shown in Fig. 2 (a), Fig. 2 (b).This original copy saves as * .ai form, keeps the vectorial property of image.
Word vector pattern is converted to suitable high resolving power * .GIF or * .bmp image, prints and obtain dark-coloured and light tone word pattern.Fig. 2 (a) and Fig. 2 (b) is respectively the dark-coloured word of 4 pounds of Song typefaces and black matrix, and dark-coloured word segment will be made up of printing-ink or marking ink; By anti-phase for these two images, result, as shown in Fig. 2 (c) He Fig. 2 (d), is respectively the light tone word of 4 pounds of Song typefaces and black matrix, and dark-coloured background parts will be made up of ink or marking ink, and word segment will be made up of substrate surface look, as paper surface.
This word icon is designed with dark-coloured and light tone word, is to consider except books and periodicals class printing mainly uses dark-coloured word, often presents word, with aobvious noble quality by exposing paper substrate look on dark background in packaging printing.These two kinds of words are all Detection of content, can reflect the adaptability of printing two kinds of different application.
The Song typeface and black matrix is selected to be because black matrix is that in Chinese character, stroke is the widest, and the same width of horizontal, vertical stroke, and the horizontal, vertical stroke of the Song typeface is all narrower, and horizontal, vertical stroke width difference is maximum, the Song typeface and black matrix are also two kinds of conventional fonts in Chinese character, and thus most is representative.
Selecting " son " and " v " two characters, is consider that horizontal, vertical in word, oblique stroke has, and stroke is simple, can embody disappearance and the expansion characteristics of stroke.
In this embodiment, first make forme in the mode of inkjet printing, print resolution is 1200dpi.Afterwards, this forme is re-used at printed on paper.For this reason, above-mentioned word icon file need be converted to the pdf document of 1200dpi for printing plate-making.Meanwhile, for text quality detects use, also this word icon file is converted to the bi-level digital image of 15000dpi, saves as * .GIF form.Now, the diameter of round dot is 295 pixels, and two distance of center circle are 1417 pixels.
Afterwards, with Fig. 2 (a), the round dot center of circle, Fig. 2 (b) upper left corner for initial point, one determines that position intercepts the region that 1151 pixel × 715 pixels comprising word are about 1.95mm × 1.21mm size to the right, form the image part only containing word, and be anti-phasely converted to stroke shown in Fig. 2 (e), Fig. 2 (f) and background area is for subsequent use by the two-value image of 1 and 0 value expression respectively, be called detection character area image.
The resolution of detection character area image is definitely unfixing.Being designed to 15000dpi in this embodiment, is the similar resolution for the sample digitized video formed with this detection imaging system CCD under suitable enlargement ratio.
2, digital imaging system have selected a suitable enlargement ratio, visual field is just held and comprises two dot chart target word printing patterns.
Two round dot scale icons of different distance of center circle as shown in Figure 3.Calibration process is: the center of circle pixel coordinate asking for two round dots in two round dot scale image, carries out the directional correction of two circle center line connectings, namely becomes horizontal line, and determine pixel distance of center circle now according to two central coordinate of circle; The resolving power of image is characterized by the distance of center circle designed and this pixel distance of center circle ratio.In this embodiment, two round dot imagings of C scale are almost full of whole visual field, are convenient to utilize larger pixel distance of center circle value to improve resolving power computational accuracy.Therefore, the calibration result of C scale to imaging object plane yardstick resolving power is selected to be 1.531 μm/px (micron/pixel).
For detect 4 pounds of Song typefaces and black matrix character stroke in, the horizontal stroke width of the thinnest Song typeface is about 34 μm, and therefore, the pixel resolving power of image 1.531 μm can ensure the sign precision of 4 pounds of character stroke width practicality.The forme word pattern image formed is as shown in Fig. 5 (a) to Fig. 5 (d).
As follows to the calibration process of CCD digital imaging system:
(1) to print or even value between printing one 0% ~ 100%, the square color lump images original copy that formed of totally 15 different dot area percentages, the length of side of each color lump is 12mm.The situation of forme is as shown in Fig. 4 (a), and the situation of printed on paper black letters is as shown in Fig. 4 (b).Wherein, low haze is base materials employed or paper look, and the darkest color is mass colour on the spot.
(2) this forme is printed as picture and employs glaucous ink, and on calibration colour table, the light reflectivity Main Differences of different ink amount color lump occurs in red spectral band.Through selecting, in 640nm ~ 700nm, between color lump, the difference of reflectivity is relatively large, like this, can be embodied and characterize the difference of different color blocks ink amount by maximum difference.
By light reflectivity or (optics) density of each color lump of spectrophotometer measurement colour table, be designated as ρ or D.Wherein, the light reflectivity ρ of forme situation be the spectral reflectivity of color lump in 640nm ~ 700nm wavelength coverage and with standard white version spectral reflectivity and ratio, and the situation measured value of black printing is vision (optics) density D on paper, then be converted to ρ by (2) formula.Forme situation selects the wavelength coverage of 640nm ~ 700nm, be because in this wavelength coverage the assorted interblock reflectivity of forme and difference maximum.
(3) by CCD imaging system to the assorted block imaging of colour table, and the middle part of digital picture is asked for the mean value of RGB response, chooses R value, be normalized to d; Colour imaging used is 8 codings, then d=R/255.
(4) according to ρ and the d value of all color lumps, the mathematical relation between ρ and d is set up by one dimension approximating method; In this embodiment, the situation of forme and black printing all have employed 3 rank polynomial relations, is respectively:
ρ＝0.098d
3+0.064d
2+0.959d+0.000 (3)
ρ＝0.459d
3-0.115d
2+1.094d-0.005 (4)
(3), (4) formula relation is the calibration relation of CCD imaging response respectively and between forme and printing black ink marks light reflectivity under this image formation state.
3, the word pattern of shooting printing, saves as * .GIF form.During shooting, ensure that the two round dots above word are on same level line substantially, two circle center line connectings and horizontal line deviation angle are less than 2 degree.Fig. 5 (a) to Fig. 5 (d) is depicted as by the word image on 1200dpi inkjet printing forme, and Fig. 6 (a) to Fig. 6 (d) is then for being printed onto the image of black letters trace on a kind of paper with this forme.
4, to forme and paper printing products, the R value in image is extracted, respectively by (2) formula and (3) formula relation, R value is converted to light reflectivity, form reflectivity grayscale image.
5, for bright word light reflectivity grayscale image, deduct this image with 1 value image of equidimension, dark word image then remains unchanged, like this, the word of two kinds of situations is all converted to character stroke and circular segment gray-scale value is less, and the situation that background parts gray-scale value is larger.
After this, all row of word image are averaging, and carry out certain level and smooth, obtain average gray value with row-coordinate change curve as shown in Figure 7.In Fig. 7, the corresponding word image of the row-coordinate of curve is rotated counterclockwise the position of 90 degree, and be equivalent to the row-coordinate of former image, ordinate is the light reflectivity of column average.
In Fig. 7 curve change procedure from left to right, being first the high reflectivity regions on round dot top, is the low reflectivity regions that two round dot is on average formed afterwards, then to two high reflectivity regions between round dot and word.Therefore, in change procedure from left to right, first light reflectivity peak position then correspond to two clear area between round dot and below word.So solve the curve level coordinate position A that this peak position point is corresponding, be the row-coordinate position extracting two round dot regions, 1 row is pair round dot region to A image in the ranks.
Edge extracting is carried out to two round dot region and the center of circle solves.The method adopted is: carry out edge extracting and binary conversion treatment for each single round dot region respectively, then ask the center of circle to round dot region, result is as shown in Fig. 8 (a) He Fig. 8 (b).
Wherein the threshold value of edge extracting is that background gray levels adds 0.1.The ranks coordinate in two centers of circle is respectively (219,191) and (211,1786).If two centers of circle are adjusted on same level line, then can obtain and need turn clockwise 0.2874 °.
Afterwards, rotate whole word image by this anglec of rotation, obtain the word image of two round dot at same level line, and now this pair of round dot central coordinate of circle and distance of center circle can be obtained.
6, due to the sample word image that gathers during test and the resolution of alphanumeric original copy inconsistent, compare as may correspond to position pixel, then need resolution consistent.In the alphanumeric master copy image of design, the distance of center circle of two round dot is known, and be 1431 pixel distances, the situation solving sample word image is 1595, then need by sample word image by 1417/1595 multiple convergent-divergent sample word image.Like this, then consistent with the same resolution of alphanumeric master copy image, the orientation sample word image that may correspond to pixel and compare is obtained.
To sample word image now, with the round dot center of circle, the upper left corner for starting point, take original copy for type composition image from containing row and column identical to the right two dot chart target digitized video, and identical row, column scope take out word segment, as shown in Fig. 9 (a).
7, for the image 9 (a) that step 6 obtains, deduct a threshold value by the average background reflectivity gray-scale value of surrounding mean pixel, pattern word image two-value is turned to stroke area is 1, background area is 0, result is as shown in Fig. 9 (b).In this embodiment, forme condition threshold is 0.1, and printing black letters condition threshold is 0.15.
Afterwards, Fig. 2 (e) alphanumeric master copy image Fig. 9 (b) image and step 1 prepared, carries out regional compare and difference and calculating etc. with pixel, obtains aforementioned every text quality index.For one of them forme word pattern, the character stroke light reflectivity formed, incompleteness and expansion area comparison ratio are as shown in Figure 10.Wherein, light gray areas is original copy for type composition stroke part, and black and white pixel is compared to the expansion of original copy for type composition stroke and incomplete part respectively.In addition, this printing character inside does not have cavity.
Apply above-mentioned test process, to this forme and the black printing word on two kinds of paper, test obtains each text quality desired value as shown in Figure 11 (a) ~ Figure 11 (c).
From Figure 11 (a), the optical reflection values of dark-coloured word trace stroke and size compare and find out, with regard to forme, the light reflectivity of Song typeface trace stroke is higher than black matrix situation, show that Song typeface stroke color is shallow, institute's inking amount not as good as black matrix situation, its result cause printing stroke on same paper also always the ink amount of the Song typeface not as good as black matrix situation.Indicate the depth difference between different stroke width printing word.See, for the light colour word situation formed by " showing money or valuables one carries unintentionally ", numerical value change situation is contrary, but this result exactly give also the advantage of the wide stroke of black matrix word simultaneously.In addition, more also finding out between two kinds of paper, paper is very large to word trace quality influence, and paper 1 wherein has better word expressive ability.
From Figure 11 (b), the incomplete area ratio value of word trace stroke and size compare and find out, no matter are dark word or bright word, and the thinner Song typeface stroke incompleteness amount of stroke is always more unfavorable compared with the performance of black matrix situation to overall word.And printing on paper, the incomplete degree of dark word reduces all greatly, and the incomplete degree of bright word then significantly improves.Should be caused by printing process, the irregularity of ink on paper is sprawled.These intensity of variations of dark word, bright word are still closely related with paper.
From Figure 11 (c), the expansion area ratio value of word trace stroke and size compare and find out, similarly, no matter are dark word or bright word, and the thinner Song typeface stroke swell increment of stroke is always more unfavorable compared with the performance of black matrix situation to overall word.Print to after on paper, the degrees of expansion of dark word is significantly increased, and the degrees of expansion of bright word then reduces greatly.Reflect that ink in printing process sprawls degree on paper.These intensity of variations are also closely related with paper.
On the whole, no matter be on forme, or on paper printing products, incompleteness and the expansion of stroke are all simultaneous, and reason is that the irregularity of stroke edge is coarse and fuzzy.But this defect of forme is transferred to after on paper printing products, the incomplete degree of the situation of dark word always reduces, and degrees of expansion always increases; Bright word situation is then contrary.
Above-mentioned Testing index, can be different literals need for exhibition, different forme and different paper situation, provides the quality characterization means of quantification, by accumulation and the analysis of achievement data, instructs process optimization and developing material process, also can be used for the quality of production and controls.
Claims (10)
1. a quality determining method for printing word, comprises the following steps:
(1) using vectorial characters and two round dot icons of loading above word as Digital Manuscript, print output and obtain detecting pattern;
(2) resolving power demarcation and light reflectivity calibration are carried out to digital imaging system;
(3) by digital imaging system, printing text detection pattern is converted to high-resolution RGB digitized video;
(4) to RGB digitized video, by calibration relation, light reflectivity grayscale image is obtained;
(5) to the grayscale image obtained, directional correction is carried out;
(6) be the resolution of its Digital Manuscript by the resolution conversion of word grayscale image after the correction obtained, and by the extracting mode of Digital Manuscript, extract the character area in this sample image;
(7) to the word sample image obtained, by comparing and Treatment Analysis with the co-located pixel of its Digital Manuscript word image, text quality desired value is obtained.
2. the quality determining method of printing word according to claim 1, is characterized in that: the two dot charts above word be designated as that horizontal direction separates two are with large dot, and in the same horizontal line, distance of separation is greater than character area width in the two round dot centers of circle.
3. the quality determining method of printing word according to claim 1, it is characterized in that: the CCD digital imaging system that optical amplifier and CCD image device are formed, CCD image device adjusts to white balance to imaging white light source used, under micro-imaging condition, resolving power demarcation and light reflectivity calibration are carried out to imaging system.
4. the quality determining method of printing word according to claim 1, is characterized in that: the method that CCD imaging system resolving power is demarcated, and comprises the steps:
1) take two round dot scale icon by CCD image device, form scale map target digitized video;
2) resolving power of digitized video under this image-forming condition is calculated by the pixel count that two round dot distance of center circle in two round dot scale icon digitized video are corresponding.
5. the quality determining method of printing word according to claim 1, is characterized in that: the method for the light reflectivity calibration of CCD digital imaging system, comprises the steps:
1) colour table of several color lump compositions that changes from shallow to deep is printed;
2) the light reflectivity ρ of each color lump of colour table is calculated by spectrophotometer measurement; Wherein, for final printing situation, by (optics) density D of each color lump of spectrophotometer measurement colour table, calculate light reflectivity ρ by definition (1) formula of (optics) density.As follows:
D＝-log
10ρ (1)
ρ＝10
-D(2)
3) by CCD imaging system to the assorted block imaging of colour table, and the middle part of digital picture is asked for the mean value of RGB response, chooses in rgb value and change maximum color value with different color blocks, and normalization, be designated as d;
4) according to ρ and the d value of all color lumps of colour table, mathematical relation is between the two set up, the calibration relation namely under this image formation state between CCD image response and printing light reflectivity.
6. the quality determining method of printing word according to claim 1, is characterized in that: RGB digitized video is * .GIF or * .bmp form, and two circle center line connectings and the horizontal line deviation angle of the two round dots above word are not more than 2 degree.
7. the quality determining method of printing word according to claim 1, it is characterized in that: described directional correction is the two round dot regions adopting adaptive method automatically to take out top, and solve the central coordinate of circle of two round dot, according to this two central coordinate of circle rotary sample image to two round dot center of circle in the same horizontal line.
8. the quality determining method of printing word according to claim 1, is characterized in that: the resolution conversion of described image is to the alphanumeric master copy image set up by the resolution match of sample image.
9. the quality determining method of printing word according to claim 1, is characterized in that: described text quality index comprises empty number and cyst areas ratio in word light reflectivity, the broken string number of character stroke, broken string and incomplete total area ratio, expansion area ratio, stroke.
10. the quality determining method of printing word according to claim 9, is characterized in that: the preparation method of described text quality index comprises the steps:
(1) set gray threshold, extract the stroke area of word; For each closed stroke area, remove the noise region not having common ground with character area in corresponding alphanumeric master copy image, retain the trace region belonging to character stroke;
(2) for the region belonging to character stroke in sample image, ask for light reflectivity mean value, be the light reflectivity of word; For the situation of final printing, according to the inverse operation relation D=-log of (1) formula
10ρ obtains (optics) density D of word.
(3) the sample grayscale image only retaining character area is converted to two-value image, character area part value is 1, and remainder value is 0;
(4) ask for the closed region number belonging to word segment in sample image, this number deducts word used due closed region number, is place's number of word broken string;
(5) ask for the difference of alphanumeric original copy and sample word two-value image, difference be 1 part be the part of sample character stroke incompleteness, all 1 values and divided by all 1 values of original copy for type composition stroke and, namely obtain breaking and incomplete total area ratio;
(6) ask for the difference of sample word two-value image and alphanumeric original copy, difference be 1 part be the part of sample character stroke expansion, all 1 values and divided by all 1 values of original copy for type composition stroke and, be the total area ratio of expansion; And the part that difference is-1 is the hollow sectors in word trace stroke, its closed region number is empty number, all-1 values and absolute value divided by all 1 values of alphanumeric original copy stroke and, namely obtain cyst areas ratio in stroke.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106056636A (en) * | 2016-05-31 | 2016-10-26 | 公安部禁毒情报技术中心 | Methamphetamine tablet identifier feature information extraction method |
| CN106530289A (en) * | 2016-11-03 | 2017-03-22 | 刘国勇 | Code spraying definition machine vision detecting method based on lattices |
| CN108681114A (en) * | 2018-05-17 | 2018-10-19 | 福建师范大学 | A kind of detection device and method of small size LCD character display defects |
| CN108982525A (en) * | 2018-08-23 | 2018-12-11 | 云南省印刷技术研究所 | A kind of analysis and detection method for books and periodicals green fine printing quality |
| CN110021048A (en) * | 2019-03-22 | 2019-07-16 | 杭州电子科技大学上虞科学与工程研究院有限公司 | A kind of mass colour evaluation method of newspaper printing |
| CN110501335A (en) * | 2019-08-23 | 2019-11-26 | 北京印刷学院 | A kind of detection of asterisk print quality and characterizing method |
| CN110514675A (en) * | 2019-08-29 | 2019-11-29 | 珠海格力电器股份有限公司 | A kind of intelligent detecting method and system of label |
| CN111199527A (en) * | 2020-01-04 | 2020-05-26 | 圣点世纪科技股份有限公司 | Finger vein image noise detection method based on multi-direction self-adaptive threshold |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002099899A (en) * | 2000-09-21 | 2002-04-05 | Fuji Heavy Ind Ltd | Pattern quality inspection method and device |
| US6731787B1 (en) * | 1996-09-20 | 2004-05-04 | Kla-Tencor Corporation | System and method for determining reticle defect printability |
| CN1842417A (en) * | 2003-08-28 | 2006-10-04 | 曼·罗兰·德鲁克马辛伦公司 | Method and device for controlling processes during printing |
| CN202149886U (en) * | 2011-06-23 | 2012-02-22 | 云南省印刷技术研究所 | Printing quality detection device |
| CN102680497A (en) * | 2011-03-11 | 2012-09-19 | 三星电机株式会社 | Device for detecting pattern defects |
-
2015
- 2015-02-06 CN CN201510065317.8A patent/CN104614384B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6731787B1 (en) * | 1996-09-20 | 2004-05-04 | Kla-Tencor Corporation | System and method for determining reticle defect printability |
| JP2002099899A (en) * | 2000-09-21 | 2002-04-05 | Fuji Heavy Ind Ltd | Pattern quality inspection method and device |
| CN1842417A (en) * | 2003-08-28 | 2006-10-04 | 曼·罗兰·德鲁克马辛伦公司 | Method and device for controlling processes during printing |
| CN102680497A (en) * | 2011-03-11 | 2012-09-19 | 三星电机株式会社 | Device for detecting pattern defects |
| CN202149886U (en) * | 2011-06-23 | 2012-02-22 | 云南省印刷技术研究所 | Printing quality detection device |
Non-Patent Citations (1)
| Title |
|---|
| 王晓红等: "基于机器视觉的文字印刷质量检测与评价", 《包装工程》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106056636A (en) * | 2016-05-31 | 2016-10-26 | 公安部禁毒情报技术中心 | Methamphetamine tablet identifier feature information extraction method |
| CN106056636B (en) * | 2016-05-31 | 2019-04-02 | 公安部禁毒情报技术中心 | A kind of identification characteristics information extracting method of methamphetamine tablet |
| CN106530289A (en) * | 2016-11-03 | 2017-03-22 | 刘国勇 | Code spraying definition machine vision detecting method based on lattices |
| CN106530289B (en) * | 2016-11-03 | 2019-04-30 | 刘国勇 | A kind of coding clarity machine vision detection method based on dot matrix |
| CN108681114A (en) * | 2018-05-17 | 2018-10-19 | 福建师范大学 | A kind of detection device and method of small size LCD character display defects |
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| CN110501335A (en) * | 2019-08-23 | 2019-11-26 | 北京印刷学院 | A kind of detection of asterisk print quality and characterizing method |
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| CN110514675A (en) * | 2019-08-29 | 2019-11-29 | 珠海格力电器股份有限公司 | A kind of intelligent detecting method and system of label |
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