CN116310289B - System and method for on-line measurement of ink-jet printing and real-time adjustment of printing position angle - Google Patents
System and method for on-line measurement of ink-jet printing and real-time adjustment of printing position angle Download PDFInfo
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- CN116310289B CN116310289B CN202310532218.0A CN202310532218A CN116310289B CN 116310289 B CN116310289 B CN 116310289B CN 202310532218 A CN202310532218 A CN 202310532218A CN 116310289 B CN116310289 B CN 116310289B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J29/00—Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for
- B41J29/38—Drives, motors, controls or automatic cut-off devices for the entire printing mechanism
- B41J29/393—Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/24—Aligning, centring, orientation detection or correction of the image
- G06V10/242—Aligning, centring, orientation detection or correction of the image by image rotation, e.g. by 90 degrees
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/24—Aligning, centring, orientation detection or correction of the image
- G06V10/247—Aligning, centring, orientation detection or correction of the image by affine transforms, e.g. correction due to perspective effects; Quadrilaterals, e.g. trapezoids
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- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/70—Arrangements for image or video recognition or understanding using pattern recognition or machine learning
- G06V10/74—Image or video pattern matching; Proximity measures in feature spaces
- G06V10/75—Organisation of the matching processes, e.g. simultaneous or sequential comparisons of image or video features; Coarse-fine approaches, e.g. multi-scale approaches; using context analysis; Selection of dictionaries
- G06V10/751—Comparing pixel values or logical combinations thereof, or feature values having positional relevance, e.g. template matching
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Abstract
The invention discloses a system and a method for on-line measurement of inkjet printing and real-time adjustment of printing position angle, belonging to the technical field of inkjet printing, wherein the method comprises the following steps: collecting image information of a product; correcting the acquired image, and correcting the acquired image by aligning a straight line through a pixel lattice etched in the liquid crystal panel; identifying an ink zone and an operable zone of the product to be detected, respectively; calculating the distance between an ink area and an operable area of a product to be detected; ink edge and operable zone distance calculations for the ink zone and measurement results display: ink zone to operable zone distance = ink zone coordinates-operable zone coordinates; and correcting the printing parameters according to the preset demand parameters. According to the system and the method for online measurement of the inkjet printing and real-time adjustment of the printing position angle, disclosed by the invention, the position state of a product can be accurately known through the acquired product image, and the parameter data of the product to be corrected can be known, so that the position of an actual product on equipment can be adjusted.
Description
Technical Field
The invention relates to the technical field of ink-jet printing, in particular to an on-line measurement and real-time adjustment system and method for printing position and angle of ink-jet printing.
Background
Currently, for borderless and narrow-frame lcd or display panels, in order to meet the market demands of minimizing the outer frame and overall display of the display screen, unlike the CF (front, or Color Filter) light-emitting of the conventional lcd or display panel, a TF (TF, thin Film) surface is required to be used for making a light surface. Under the condition that the traditional CF surface is made into a smooth surface, the audience/observer faces the CF surface, the frame part of the display panel is a BM (black shading frame) surface between the TF plate and the CF plate, and the display panel is pure black in appearance and attractive in overall image quality. When the TF surface is made into a smooth surface, the traditional liquid crystal panel manufacturing process flow does not have a separate BM process, so that the metal circuit of the frame part reflects light, and the attractive appearance and the pure appearance of the whole picture edge are affected. Therefore, an external BM process needs to be added to the TF-side frame area to meet the product requirements.
The prior art requires measuring the distance of the ink edge to the display area off-line using a microscope. The prior art has long measurement time, and each measurement takes 10 minutes. The prior art can not realize online measurement, real-time feedback and real-time adjustment of the printing starting position and angle. Since the ink edge covers the panel circuit features, no suitable feature area can be found in the picture to determine the location of the AA area (operable area). Because the gray level difference between the ink edge and the BM area is small, the existing image processing algorithm cannot well distinguish the ink edge from the BM area, and the ink edge position measurement is wrong.
Disclosure of Invention
The invention overcomes the defects of the prior art, and provides the system and the method for on-line measurement and real-time adjustment of the printing position angle of the ink-jet printing, which can accurately know the position state of a product and the parameter data of the product to be corrected through the collected product image, thereby adjusting the position of the actual product on equipment.
In order to achieve the above purpose, the invention adopts the following technical scheme: an inkjet printing online measurement and printing position angle real-time adjustment method comprises the following steps:
step S1, collecting an image of a product to be detected;
step S2, correcting the acquired image, namely aligning straight lines through a pixel lattice etched in the liquid crystal panel, wherein the pixel lattice comprises a plurality of relatively parallel straight lines, and further reducing angle errors of the aligned straight lines in a mode of aligning the plurality of straight lines to obtain corrected information, and turning the acquired image;
step S3, respectively identifying an ink area and an operable area of a product to be detected;
step S4, calculating the distance between the ink area and the operable area of the product to be detected, and judging whether the product meets the product requirement; calculating the ink edge and operable area distance of the ink area and displaying the measurement result: ink zone to operable zone distance = ink zone coordinates-operable zone coordinates;
and S5, correcting the printing parameters according to the preset demand parameters.
In a preferred embodiment of the present invention, in step S1, the product to be detected is a liquid crystal panel, and two sets of diagonal images of the liquid crystal panel are obtained by a camera, so as to obtain images of four corner regions of the liquid crystal panel.
Specifically, since the measurement of the ink edge position of the ink area and the position of the operable area is required to be performed on the premise that the liquid crystal panel is placed in a completely horizontal and vertical state, the liquid crystal panel cannot be placed in the completely horizontal and vertical state in the field of view of the camera, a pretreatment operation for accurately correcting the image must be added, and the operation must have high stability to correct the liquid crystal panel.
In a preferred embodiment of the present invention, the step S2 includes the following steps:
step S2.1, gray scale corrosion is carried out on the width direction of the acquired image, and the difference of red, green and blue lattices in the pixel lattices is eliminated;
gray scale etching operation:the method comprises the steps of carrying out a first treatment on the surface of the Wherein b is the size of the core used for corrosion or expansion, s and t are the length and width of b; x and y are coordinates of each point in the image; replacing the gray scale of each point x, y in the image with the minimum gray scale in the sliding window with the size b;
s2.2, carrying out gray scale expansion on the width direction of the acquired image, and closing the concave-convex of the lattice in the transverse direction; gray scale expansion operation:the method comprises the steps of carrying out a first treatment on the surface of the Replacing the gray scale of each point x, y in the image with the maximum gray scale in the sliding window with the size of b;
step S2.3, obtaining a plurality of lines to be selected through a calliper edge inspection algorithm on the image operated in the step S2.2; taking the median of the angles of a plurality of lines to be selected to obtain the angle to be rotated by the final image;
in step S2.4, the image is rotated by scaling the rotation matrix formula with the image center as the rotation center, center. X=image width/2, center. Y=image height/2, scaling factor scale=1.
In a preferred embodiment of the invention, in step S2.4,； the method comprises the steps of carrying out a first treatment on the surface of the In the formula, center.x, center.y, angle and scale are known quantities, alpha and beta are calculated by the known quantities, the whole scaling rotation matrix is solved, and affine transformation is carried out on an original image by using the scaling rotation matrix to obtain an image after correction.
In a preferred embodiment of the invention, the identification of the ink zone of the product to be detected comprises the following steps:
step S3.1.1, removing image interference through binarization and morphological opening and closing operation according to the significant difference of the brightness of the ink area and the operable area, and dividing the image area into the ink area and the operable area;
step S3.1.2, calculating the gray average meanlink and standard deviation DeviationInk, sigmaInk of the ink area as multiples of the set allowable deviation standard deviation DeviationInk, and calculating the filling threshold value limit ink=meanlink+sigmaink; uniformly filling pixels of which the ink areas are lower than the limit ink gray level with the limit ink gray level;
step S3.1.3, calculating the gray average MeanAA and standard deviation DeviationAA, sigmaAA of the operable area as multiples of the set allowable deviation standard deviation DeviationAA, and calculating the operable area filling threshold limit aa=meanaa+sigmaaa; uniformly filling pixels with the operable area higher than the limit AA gray level with the limit AA gray level;
s3.1.4, stretching the image obtained in the step S3.1.3 to a gray scale range of 0-255, and highlighting the transition boundary of the ink area and the panel black frame area;
step S3.1.5, performing image secondary enhancement using the formula res=round (origin-mean) +origin; orig=original image, mean=gray average value of original image, factor=artificially set enhancement coefficient, round=rounding;
step S3.1.6, using gray level stacking and vertical stacking formulas;
the gray level stacking formula is:；
the vertical stacking formula is:；
projecting the two-dimensional image to one dimension in the horizontal direction and the vertical direction; wherein n in the formula 1 For the number of sigma sum elements, (r, c) is the x, y coordinates of the upper left corner of the selected area, and (r ', c') is the x, y coordinates of the current pixel in the coordinate system of the selected area, and the gray average value of the two-dimensional image after projection in the horizontal direction and the vertical direction is obtained;
and S3.1.7, finding a cut-off line on the one-dimensional projection chart through threshold judgment, and finally determining the position of the edge of the ink area.
In a preferred embodiment of the invention, the identification of the operative area of the product to be detected comprises the steps of:
step S3.2.1: extracting an ink region of the image;
step S3.2.2: image enhancement is carried out on the ink area by using a formula res=round (origin-mean) +origin, and circuit features in the ink area are highlighted; orig=original image, mean=gray average value of original image, factor=artificially set enhancement coefficient, round=rounding;
step S3.2.3: an improved NCC template matching algorithm adopts at least two feature frames to respectively grasp the features of the ink area in the horizontal direction and the vertical direction.
In a preferred embodiment of the present invention, the measurement result in step S4 is fed back to the anomaly management statistical system, and the printing parameters are corrected according to the preset demand parameters in the anomaly management statistical system;
matching formula of NCC template matching algorithm:
；
；/>；；
；
wherein: u, v is the x, y coordinates of each point in the template Roi area; r is a set of coordinates u, v of each point in the plurality of Roi areas; n is n 2 The number of all points in the Roi area of the template;the gray average value of all points in the Roi area of the template is obtained; />Gray mean square error of all points in the template Roi area; r, c is the x, y coordinates of the upper left corner of the template matching sliding window; />Matching the gray average value of all points of the sliding window for the template; />The gray mean square error of all points in the sliding window is matched for the template;the gray scale of the current point in the Roi area of the template is obtained; />The gray scale of the current point of the sliding window is matched for the template.
In particular, the method comprises the steps of,wherein t is a superscript, and is an english abbreviation for template. i.eIs gray scale, and the value range is real number which is more than or equal to 0. (r+u, c+v) is the coordinates of the current point; i (r+u, c+v) the gray scale of the current point.
In a preferred embodiment of the present invention, the measurement data is counted by an anomaly management counting system:
and selecting a plurality of references in the abnormal management system, carrying out abnormal management on the distances from the ink areas to the operable areas at a plurality of measuring positions, and triggering calculation and feedback of the printing position and angle compensation amount when the abnormality occurs. In a preferred embodiment of the present invention, the print position and angle compensation amount calculation feedback:
calculating a printing position and an angle compensation amount;
horizontal direction angle=average (arctan ((upper left long side distance-upper right long side distance)/operable area length)), arctan ((lower left long side distance-lower right long side distance)/operable area length);
vertical direction angle=average (arctan ((upper left short side distance-lower left short side distance)/operable area width)), arctan ((upper right short side distance-lower right short side distance)/operable area width);
average print angle=average (horizontal direction angle, vertical direction angle);
when correcting the printing angle, the liquid crystal panel needs to rotate around the rotation center of the platform and can drive the four corners x coordinate and y coordinate of the liquid crystal panel to move, so that after the printing angle is rotated, new coordinates of the four corners x coordinate and y coordinate of the liquid crystal panel need to be calculated, and the formula is as follows:
；
x and y are coordinates of the point in a rotating center coordinate system, θ is the average printing angle, and x1 and y1 are new x and y coordinates after rotation;
a print start position compensation amount Δt= - θ;
print start position compensation amount Δx=x1-standard distance;
print start position compensation amount Δy=y1-standard distance;
and sending the delta X, delta Y and delta T to a printing control mechanism, and printing by using the new position and angle when the next material is printed.
In a preferred embodiment of the invention, an inkjet printing on-line measurement and printing position angle real-time adjustment system of an inkjet printing on-line measurement and printing position angle real-time adjustment method comprises a carrier adjustment mechanism, wherein a jig carrier for loading a product to be detected is arranged on the carrier adjustment mechanism in a driving manner; the upper part of the jig carrier is also provided with a plurality of groups of image acquisition mechanisms, and the image acquisition mechanisms are arranged above the jig carrier through driving of the displacement mechanisms.
The invention solves the defects existing in the technical background, and has the beneficial technical effects that:
according to the system and the method for online measurement of the inkjet printing and real-time adjustment of the printing position angle, the position state of the product can be accurately known through the acquired product image, and the parameter data of the product to be corrected can be known, so that the position of the actual product on equipment can be adjusted.
The pixel lattice in the product is used for finding a straight line, so that the accurate acquisition of the position state of the product on the equipment is improved. And carrying out image processing on the corrected image to distinguish areas in the acquired product image, and finding out boundary lines. Calculating the distance between the ink area and the operable area, and judging whether the ink area and the operable area meet the product requirements; and correcting the printing parameters according to the preset demand parameters.
Drawings
The invention will be further described with reference to the drawings and examples.
FIG. 1 is a schematic flow diagram of a system in accordance with an embodiment of the present invention;
FIG. 2 is a schematic diagram of a system architecture in an embodiment of the present invention;
FIG. 3 is a partial view of a product to be inspected (an image of the product to be inspected, i.e., a partial photograph, is taken);
FIG. 4 is a graph (algorithmically processed photograph) of an image collected using a pixel lattice alignment etched inside a liquid crystal panel according to an embodiment of the present invention;
FIG. 5 is a photograph (processed by an algorithm) of an image obtained by performing gray scale erosion in the width direction and gray scale expansion in the width direction on a pixel lattice alignment line in an embodiment of the present invention;
FIG. 6 is a drawing showing an image obtained in FIG. 5 through a caliper rule edge algorithm to obtain images (photographs processed by the algorithm) of a plurality of lines to be selected in an embodiment of the present invention;
FIG. 7 is a photograph (processed by an algorithm) of an image before the image is transferred, in an embodiment of the present invention;
FIG. 8 is a photograph (processed by an algorithm) of an image obtained by correcting the obtained image in an embodiment of the present invention;
FIG. 9 is an image (algorithmically processed photograph) of an image area divided into ink areas and operational areas in an embodiment of the invention;
FIG. 10 is an image (algorithmically processed photograph) from which image information that is not useful for distinguishing between the ink border of an ink zone and the border of a black mask is removed in an embodiment of the invention by compressing the range of image gray levels in FIG. 9 to a range greater than the average gray level of the ink zone and less than the average gray level of the operable zone;
FIG. 11 is a photograph showing the transition boundary (algorithmically processed) between the ink area and the black mask frame in an embodiment of the present invention by re-stretching the gray scale range of the image of FIG. 10 to between 0-255;
FIG. 12 is a photograph of an area (algorithmically processed) in the ink area of an extracted image in an embodiment of the invention;
FIG. 13 is a photograph of the extracted image of FIG. 12 with areas in the ink area for the extracted image enhanced, highlighting circuit features (algorithmically processed) within the ink area, in accordance with an embodiment of the present invention;
FIG. 14 is a schematic diagram (algorithmically processed photograph) of the calculation result displayed on the software interface by way of drawing lines and text in an embodiment of the present invention;
FIG. 15 is a schematic diagram (algorithmically processed photograph) of the calculation result displayed on the software interface by way of drawing lines and text in an embodiment of the present invention;
FIG. 16 is a schematic of one of the anomaly references;
FIG. 17 is a schematic illustration of one of the anomaly references;
FIG. 18 is a schematic illustration of one of the anomaly references;
wherein: 1-stage adjustment mechanism, 2-image acquisition mechanism, 3-displacement mechanism, 4-industrial camera, 5-telecentric lens, 6-image acquisition frame, 7-tool carrier.
Detailed Description
The invention will now be described in further detail with reference to the drawings and examples, which are simplified schematic illustrations of the basic structure of the invention, which are presented only by way of illustration, and thus show only the structures that are relevant to the invention.
It should be noted that, if a directional indication (such as up, down, bottom, top, etc.) is involved in the embodiment of the present invention, the directional indication is merely used to explain the relative positional relationship between the components, the movement situation, etc. in a certain specific posture, and if the specific posture is changed, the directional indication is correspondingly changed. The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. Unless specifically stated or limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1
As shown in fig. 1, an inkjet printing online measurement and printing position angle real-time adjustment method includes the following steps:
step S1, collecting an image of a product. The product to be detected is a liquid crystal panel, and two sets of diagonal images of the liquid crystal panel shown in fig. 3 are obtained through a camera, so that images of four corner areas of the liquid crystal panel are obtained.
And step S2, correcting the acquired image.
Specifically, since the measurement of the ink edge position of the ink area and the position of the operable area needs to be performed on the premise that the liquid crystal panel is placed in a completely horizontal and vertical state, and the liquid crystal panel cannot be placed in the completely horizontal and vertical state in the field of view of the camera, a pretreatment operation for accurately correcting the image must be added, and the operation must have higher stability, so that the liquid crystal panel is corrected.
There are two ways to use in the prior art: first, as shown in fig. 3, the outer edge line of the liquid crystal panel is found to perform image correction. The stability of the alignment is very poor due to the influence of factors such as burrs and errors on the straight line of the outer edge of the cut liquid crystal panel and the uncoated ink. Secondly, the second step is that; as shown in fig. 3, the inner edge line of the BM portion of the liquid crystal panel is found, and the inner edge line of the BM portion is very close to the ink, and when the ink is applied more, the deviation of the line direction occurs, and the stability is extremely poor. In order to reduce the error, this embodiment adopts: as shown in fig. 4 to 6, the alignment lines are aligned by the pixel lattices etched in the liquid crystal panel, the pixel lattices include a plurality of relatively parallel lines, and then the angle error of the alignment lines is further reduced by the way of aligning the plurality of lines to obtain the corrected information, as shown in fig. 7 and 8, and the acquired images are corrected. The alignment of the straight line by the pixel lattice is based on the fact that the FAB etching precision of the product is very high, so that the straight line precision of the pixel lattice is very high, the straight line repeatedly appears, and the angle error of alignment can be further reduced by the way of finding the median of a plurality of straight lines.
Step S3, respectively identifying an ink area and an operable area of a product to be detected; as shown in fig. 9 to 11, the characteristics of the ink area and the operable area in the image are highlighted by gray scale erosion and gray scale expansion of the image, and the areas to be distinguished are distinguished by different gray scale blocks by filling the two areas with different gray scales. And (3) judging through a threshold value on the one-dimensional projection graph, finding a cut-off line, and finally determining the position of the edge of the ink area, thereby realizing the identification of the ink area and the operable area.
Step S4, calculating the distance between the ink area and the operable area of the product to be detected, and judging whether the product meets the product requirement;
and S5, correcting the printing parameters according to the preset demand parameters.
Example two
As shown in fig. 1 to 14, an inkjet printing online measurement and printing position angle real-time adjustment method includes the following steps:
step S1, collecting image information of a product; as shown in fig. 3, the product to be detected is a liquid crystal panel, and two sets of diagonal images of the liquid crystal panel are obtained by a camera, so that images of four corner areas of the liquid crystal panel are obtained.
And step S2, correcting the acquired image.
Specifically, as shown in fig. 4 to 8, since the measurement of the ink edge position of the ink area and the position of the operable area needs to be performed on the premise that the liquid crystal panel is placed in a completely horizontal and vertical state, the liquid crystal panel cannot be placed in the completely horizontal and vertical state in the field of view of the camera, a pretreatment operation for accurately correcting the image must be added, and the operation must have high stability to correct the liquid crystal panel.
There are two ways to use in the prior art: one of them; as shown in fig. 3, the outer edge line of the liquid crystal panel is found, and image alignment is performed. Secondly, the second step is that; as shown in fig. 3, the inner edge line of the BM portion of the liquid crystal panel is found, and the inner edge line of the BM portion is very close to the ink, and when the ink is applied more, the deviation of the line direction occurs, and the stability is extremely poor.
In order to reduce the error, this embodiment adopts: as shown in fig. 4 to 8, the alignment lines are aligned by the pixel lattices etched in the liquid crystal panel, the pixel lattices include a plurality of relatively parallel lines, and then the angle error of the alignment lines is further reduced by the way of aligning the plurality of lines to obtain corrected information, and the acquired image is converted. The alignment of the straight lines by the pixel lattices is based on high FAB etching precision, so that the straight lines of the pixel lattices have high precision, the straight lines repeatedly appear, and the angle error of the alignment can be further reduced by the way of finding the median of a plurality of straight lines.
More specifically, the step S2 includes the steps of:
s2.1, gray scale corrosion is carried out on the width direction, and the difference of red, green and blue crystal lattices is eliminated; gray scale etching operation:the method comprises the steps of carrying out a first treatment on the surface of the Wherein b is the kernel size used for corrosion or expansion, s and t are the length and width of b; x and y are coordinates of each point in the image; the gray scale of each point x, y in the image is replaced by the minimum gray scale in the sliding window with the size of b.
S2.2, carrying out gray scale expansion on the width direction, and closing the concave-convex of the lattice in the transverse direction; gray scale expansion operation:the method comprises the steps of carrying out a first treatment on the surface of the Replacing the gray scale of each point x, y in the image with the maximum gray scale in the sliding window with the size of b; as shown in fig. 5.
S2.3, obtaining a plurality of lines to be selected through a caliper edge inspection algorithm; taking the median of the plurality of straight line angles to obtain an angle to be rotated by the final image; as shown in fig. 6.
In step S2.4, the image is rotated by scaling the rotation matrix formula with the image center as the rotation center and the scaling factor scale=1, as shown in fig. 8.
Specifically, in step S2.4, definition is given； The method comprises the steps of carrying out a first treatment on the surface of the In the formula, center.x, center.y, angle and scale are known quantities, alpha and beta are calculated by the known quantities, the whole scaling rotation matrix is solved, affine transformation is carried out on an original image by using the scaling rotation matrix, and an image after correction is obtained, as shown in fig. 8.
Step S3, respectively identifying an ink area and an operable area of a product to be detected; the characteristics of the ink area and the operable area in the image are highlighted by carrying out gray scale corrosion and gray scale expansion on the image, and the areas needing to be distinguished are distinguished by different gray scale blocks when filling the two areas with different gray scales. And finding a cut-off line on the one-dimensional projection graph through threshold judgment, and finally determining the position of the edge of the ink area to realize the identification of the ink area and the operable area. As shown in fig. 9, the area illustrated by the grid in the drawing is an AA area (operable area), and the peripheral gradation area is a BM area (black light-shielding frame area).
More specifically, step S3 further includes the steps of:
step S3.1, identifying an ink area of the product to be detected, comprising the steps of:
step S3.1.1, removing image interference through binarization and morphological opening and closing operation according to the significant difference of the brightness of the ink area and the operable area, and dividing the image area into the ink area and the operable area; as shown in fig. 9.
Step S3.1.2, calculating the gray average value meanlink and standard deviation DeviationInk of the ink area, artificially setting SigmaInk, and calculating the filling threshold value limit ink=meanlink+sigmaink; uniformly filling pixels of which the ink areas are lower than the limit ink gray level with the limit ink gray level; as shown in fig. 10. More specifically, sigmaInk is a multiple of the allowable deviation standard deviation DeviationInk set for the process experience according to production.
Step S3.1.3, calculating the gray average MeanAA and standard deviation DeviationAA of the operable area, manually setting SigmaAA, and calculating the filling threshold limit aa=meanaa+sigmaaa; pixels with operable areas higher than the limittaa gray scale are uniformly filled with the limittaa gray scale. More specifically, sigmaAA is a multiple of the allowable deviation standard deviation DeviationAA set according to the process experience of production.
S3.1.4, stretching the gray scale range of the image obtained in the step S3.3 to 0-255, and highlighting the transition boundary of the ink area and the panel black frame area; as shown in fig. 11, in the area at the rectangular box in the figure are INK and BM transition boundaries.
Step S3.1.5, performing image secondary enhancement using the formula res=round (origin-mean) +origin; orig=original image, mean=gray average value of original image, factor=artificially set enhancement coefficient, round=rounding; as shown in fig. 12.
Step S3.1.6, using gray level stacking and vertical stacking formulas;
the gray level stacking formula is:；
the vertical stacking formula is:；
projecting the two-dimensional image to one dimension in the horizontal direction and the vertical direction; wherein n in the formula 1 For the number of sigma sum elements, (r, c) is the x, y coordinates of the upper left corner of the selected area, and (r ', c') is the x, y coordinates of the current pixel in the coordinate system of the selected area, and the gray average value of the two-dimensional image after being projected in the horizontal and vertical directions is obtained; as shown in fig. 13.
And S3.1.7, finding a cut-off line on the one-dimensional projection graph through threshold judgment, and finally determining the position of the edge of the ink area.
Specifically, after steps S3.2 and S3.3, the image gray scale range is compressed to a range larger than the average gray scale of the INK region and smaller than the average gray scale of the operable region, and the image information useless for distinguishing the INK region INK side and the BM side of the panel black frame region is removed.
Step S3.2 of identifying an operable zone of the product to be detected, comprising the steps of:
step S3.2.1: extracting an ink region of the image;
step S3.2.2: image enhancement is carried out on the ink area by using a formula res=round (origin-mean) +origin, and circuit features in the ink area are highlighted; orig=original image, mean=gray average value of original image, factor=artificially set enhancement coefficient, round=rounding;
step S3.2.3: an improved NCC template matching algorithm adopts two feature frames to respectively grasp the features of the ink area in the horizontal direction and the vertical direction. Although the circuit features are repeated in a horizontal direction or a vertical direction, when the features in the horizontal direction and the vertical direction are found at the same time, the relative position relationship between the features becomes a newly added position clamping feature, so that the position of the only non-repeated correct template is found finally.
And S4, calculating the distance between the ink area and the operable area of the product to be detected, and judging whether the product meets the product requirement.
ncc template matching formula:；
；/>；/>；
；
wherein: u, v is the x, y coordinates of each point in the template Roi area; r is a set of coordinates u, v of each point in the plurality of Roi areas; n is n 2 The number of all points in the Roi area of the template;the gray average value of all points in the Roi area of the template is obtained; />Gray mean square error of all points in the template Roi area; r, c is the x, y coordinates of the upper left corner of the template matching sliding window; />Matching the gray average value of all points of the sliding window for the template; />The gray mean square error of all points in the sliding window is matched for the template;the gray scale of the current point in the Roi area of the template is obtained; />The gray scale of the current point of the sliding window is matched for the template, as shown in fig. 14 and 15. Specifically, the->Wherein t is a superscript, and is an english abbreviation for template. i is gray scale, and the value range is real number more than or equal to 0. (r+u, c+v) is the coordinates of the current point; i (r+u, c+v) the gray scale of the current point.
In a preferred embodiment of the invention, the ink edge and operable zone distance calculations for the ink zone and the measurement results show: ink zone to operable zone distance = ink zone coordinates-operable zone coordinates.
And S5, correcting the printing parameters according to the preset demand parameters. And feeding back the measurement data to the anomaly management statistical system, and correcting the printing parameters according to the preset demand parameters in the anomaly management statistical system.
And (3) counting by a measurement data anomaly management system: and selecting a plurality of most main abnormal management references in an abnormal management system to perform abnormal management on distances from the ink areas at a plurality of measurement positions to the operable areas, triggering calculation and feedback of the printing position and angle compensation amount when abnormality occurs, and automatically improving the engineering capacity state of the equipment.
In one of the examples, 3 abnormality management criteria are as follows:
as shown in fig. 16, anomaly reference one: 1 point exceeds the upper and lower distance limits. As shown in fig. 17, anomaly reference two: the 9 consecutive points fall on the same side of the center line. As shown in fig. 18, anomaly reference three: the continuous 6 points increment or decrement.
Print position and angle offset calculation feedback: calculating a printing position and an angle compensation amount; horizontal direction angle=average (arctan ((upper left long side distance-upper right long side distance)/operable area length)), arctan ((lower left long side distance-lower right long side distance)/operable area length); vertical direction angle=average (arctan ((upper left short side distance-lower left short side distance)/operable area width)), arctan ((upper right short side distance-lower right short side distance)/operable area width); average print angle=average (horizontal direction angle, vertical direction angle); when the printing angle is corrected, the liquid crystal panel needs to rotate around the rotation center of the platform and can drive the four-corner X and Y coordinates of the liquid crystal panel to move, so that new coordinates of the four-corner X and Y of the liquid crystal panel need to be calculated after the printing angle rotates.
The formula is as follows:；
x and y are coordinates of the point in a rotating center coordinate system, θ is the average printing angle, and x1 and y1 are new x and y coordinates after rotation; a print start position compensation amount Δt= - θ; print start position compensation amount Δx=x1-standard distance; print start position compensation amount Δy=y1-standard distance; and sending the delta X, delta Y and delta T to a printing control mechanism, and printing by using the new position and angle when the next material is printed.
Example III
In a preferred embodiment of the present invention, as shown in fig. 2, an on-line measurement and real-time adjustment system for the printing position angle of the inkjet printing using an on-line measurement and real-time adjustment method for the printing position angle of the inkjet printing includes a stage adjustment mechanism 1, wherein a jig stage 7 for loading a product to be detected is driven on the stage adjustment mechanism 1; a plurality of groups of image acquisition mechanisms 2 are further arranged above the jig carrier 7, and the image acquisition mechanisms 2 are arranged above the jig carrier 7 in a driving mode through the displacement mechanisms 3.
In this embodiment, the image acquisition mechanism 2 includes an industrial camera 4 and a telecentric lens 5 assembled and connected with the industrial camera 4, the lower part of the telecentric lens 5 is further provided with an image acquisition frame 6, and a coaxial light source is arranged in the image acquisition frame 6. Further, in order to enhance the working effect, a double-station arrangement is adopted, and thus, a pair of image pickup mechanisms 2 are adopted which are driven to be arranged on the drive of the displacement mechanism 3. The driving track of the carrier driven by the carrier adjusting mechanism 1 and the driving track of the image acquisition mechanism 2 driven by the displacement mechanism 3 are intersected. Furthermore, the driving track of the jig carrier 7 of the carrier adjusting mechanism 1 and the driving track of the image acquisition mechanism 2 driven by the displacement mechanism 3 are intersected with each other and are distributed at an included angle of 90 degrees.
Working principle:
an ultrathin black shading (antireflection) layer is manufactured in the frame area of the TF panel by adopting an ink-jet printing technology, and the frame shading function is realized on the premise of not influencing the polaroid attaching process of the subsequent manufacturing flow. Compared with the existing film manufacturing process, the existing process such as screen printing, pad printing and the like has extremely low efficiency when corresponding to a large-size panel, is difficult to manage consumables, is a substrate contact type process characteristic, and is difficult to ensure the yield rate of scratch and the like on the surface of a product. The ink jet printing technology well solves the difficulties as a non-contact film manufacturing process.
The above specific embodiments are specific support for the solution idea provided by the present invention, and are not limited to the scope of the present invention, and any equivalent changes or equivalent modifications made on the basis of the technical solution according to the technical idea provided by the present invention still belong to the scope of the technical solution protection of the present invention.
Claims (10)
1. An inkjet printing online measurement and printing position angle real-time adjustment method is characterized by comprising the following steps:
step S1, collecting an image of a product to be detected;
step S2, correcting the acquired image, namely aligning straight lines through a pixel lattice etched in the liquid crystal panel, wherein the pixel lattice comprises a plurality of relatively parallel straight lines, and further reducing angle errors of the aligned straight lines in a mode of aligning the plurality of straight lines to obtain corrected information, and turning the acquired image;
step S3, respectively identifying an ink area and an operable area of a product to be detected;
step S4, calculating the distance between the ink area and the operable area of the product to be detected, and judging whether the product meets the product requirement; calculating the ink edge and operable area distance of the ink area and displaying the measurement result: ink zone to operable zone distance = ink zone coordinates-operable zone coordinates;
and S5, correcting the printing parameters according to the preset demand parameters.
2. The method for on-line measurement and real-time adjustment of printing position angle for inkjet printing according to claim 1, wherein the method comprises the steps of: in step S1, the product to be detected is a liquid crystal panel, and two sets of diagonal images of the liquid crystal panel are obtained through a camera, so as to obtain images of four corner areas of the liquid crystal panel.
3. The method for on-line measurement and real-time adjustment of printing position angle for inkjet printing according to claim 1, wherein the step S2 includes the following steps:
step S2.1, gray scale corrosion is carried out on the width direction of the acquired image, and the difference of red, green and blue lattices in the pixel lattices is eliminated;
gray scale etching operation:the method comprises the steps of carrying out a first treatment on the surface of the Wherein b is the size of the core used for corrosion or expansion, s and t are the length and width of b; x and y are coordinates of each point in the image; replacing the gray scale of each point x, y in the image with the minimum gray scale in the sliding window with the size b;
s2.2, carrying out gray scale expansion on the width direction of the acquired image, and closing the concave-convex of the lattice in the transverse direction; gray scale expansion operation:the method comprises the steps of carrying out a first treatment on the surface of the Replacing the gray scale of each point x, y in the image with the maximum gray scale in the sliding window with the size of b;
step S2.3, obtaining a plurality of lines to be selected through a calliper edge inspection algorithm on the image operated in the step S2.2; taking the median of the angles of a plurality of lines to be selected to obtain the angle to be rotated by the final image;
in step S2.4, the image is rotated by scaling the rotation matrix formula with the image center as the rotation center, center. X=image width/2, center. Y=image height/2, scaling factor scale=1.
4. A method for on-line measurement and real-time adjustment of printing position angle for inkjet printing according to claim 3, wherein: in the step S2.4 of the method,；/> the method comprises the steps of carrying out a first treatment on the surface of the In the formula, center.x, center.y, angle and scale are known quantities, alpha and beta are calculated by the known quantities, the whole scaling rotation matrix is solved, and affine transformation is carried out on an original image by using the scaling rotation matrix to obtain an image after correction.
5. The method for on-line measurement and real-time adjustment of printing position angle for inkjet printing according to claim 1, wherein the step of identifying the ink area of the product to be detected comprises the steps of:
step S3.1.1, removing image interference through binarization and morphological opening and closing operation according to the significant difference of the brightness of the ink area and the operable area, and dividing the image area into the ink area and the operable area;
step S3.1.2, calculating the gray average meanlink and standard deviation DeviationInk, sigmaInk of the ink area as multiples of the set allowable deviation standard deviation DeviationInk, and calculating the filling threshold value limit ink=meanlink+sigmaink; uniformly filling pixels of which the ink areas are lower than the limit ink gray level with the limit ink gray level;
step S3.1.3, calculating the gray average MeanAA and standard deviation DeviationAA, sigmaAA of the operable area as multiples of the set allowable deviation standard deviation DeviationAA, and calculating the operable area filling threshold limit aa=meanaa+sigmaaa; uniformly filling pixels with the operable area higher than the limit AA gray level with the limit AA gray level;
s3.1.4, stretching the image obtained in the step S3.1.3 to a gray scale range of 0-255, and highlighting the transition boundary of the ink area and the panel black frame area;
step S3.1.5, performing image secondary enhancement using the formula res=round (origin-mean) +origin; orig=original image, mean=gray average value of original image, factor=artificially set enhancement coefficient, round=rounding;
step S3.1.6, using gray level stacking and vertical stacking formulas;
the gray level stacking formula is:；
the vertical stacking formula is:；
projecting the two-dimensional image to one dimension in the horizontal direction and the vertical direction; wherein n in the formula 1 For the number of sigma sum elements, (r, c) is the x, y coordinates of the upper left corner of the selected area, and (r ', c') is the x, y coordinates of the current pixel in the coordinate system of the selected area, and the gray average value of the two-dimensional image after projection in the horizontal direction and the vertical direction is obtained;
and S3.1.7, finding a cut-off line on the one-dimensional projection chart through threshold judgment, and finally determining the position of the edge of the ink area.
6. The method for on-line measurement and real-time adjustment of printing position angle for inkjet printing according to claim 1, wherein the identification of the operable area of the product to be detected comprises the steps of:
step S3.2.1: extracting an ink region of the image;
step S3.2.2: image enhancement is carried out on the ink area by using a formula res=round (origin-mean) +origin, and circuit features in the ink area are highlighted; orig=original image, mean=gray average value of original image, factor=artificially set enhancement coefficient, round=rounding;
step S3.2.3: an improved NCC template matching algorithm adopts at least two feature frames to respectively grasp the features of the ink area in the horizontal direction and the vertical direction.
7. The method for on-line measurement and real-time adjustment of printing position angle for inkjet printing according to claim 1, wherein the method comprises the steps of: feeding back the measurement result in the step S4 to an anomaly management statistical system, and correcting printing parameters according to preset demand parameters in the anomaly management statistical system;
matching formula of NCC template matching algorithm:
；
；/>；；
；
wherein: u, v is the x, y coordinates of each point in the template Roi area; r is a set of coordinates u, v of each point in the plurality of Roi areas; n is n 2 The number of all points in the Roi area of the template;the gray average value of all points in the Roi area of the template is obtained; />All of the region for template RoiGray mean square error of the point; r, c is the x, y coordinates of the upper left corner of the template matching sliding window; />Matching the gray average value of all points of the sliding window for the template; />The gray mean square error of all points in the sliding window is matched for the template;the gray scale of the current point in the Roi area of the template is obtained; />The gray scale of the current point of the sliding window is matched for the template.
8. The method for online measurement and real-time adjustment of printing position angle for inkjet printing according to claim 5 wherein the measurement data is counted by an anomaly management statistics system:
and selecting a plurality of references in the abnormal management system, carrying out abnormal management on the distances from the ink areas to the operable areas at a plurality of measuring positions, and triggering calculation and feedback of the printing position and angle compensation amount when the abnormality occurs.
9. The method for on-line measurement and real-time adjustment of printing position and angle for inkjet printing according to claim 8 wherein the feedback is calculated from the printing position and angle compensation amounts:
calculating a printing position and an angle compensation amount;
horizontal direction angle=average (arctan ((upper left long side distance-upper right long side distance)/operable area length)), arctan ((lower left long side distance-lower right long side distance)/operable area length);
vertical direction angle=average (arctan ((upper left short side distance-lower left short side distance)/operable area width)), arctan ((upper right short side distance-lower right short side distance)/operable area width);
average print angle=average (horizontal direction angle, vertical direction angle);
when correcting the printing angle, the liquid crystal panel needs to rotate around the rotation center of the platform and can drive the four corners x coordinate and y coordinate of the liquid crystal panel to move, so that after the printing angle is rotated, new coordinates of the four corners x coordinate and y coordinate of the liquid crystal panel need to be calculated, and the formula is as follows:
；
x and y are coordinates of the point in a rotating center coordinate system, θ is the average printing angle, and x1 and y1 are new x and y coordinates after rotation;
a print start position compensation amount Δt= - θ;
print start position compensation amount Δx=x1-standard distance;
print start position compensation amount Δy=y1-standard distance;
and sending the delta X, delta Y and delta T to a printing control mechanism, and printing by using the new position and angle when the next material is printed.
10. An inkjet printing on-line measurement and printing position angle real-time adjustment system adopting the inkjet printing on-line measurement and printing position angle real-time adjustment method according to any one of claims 1-9 is characterized by comprising a carrier adjustment mechanism, wherein a jig carrier for loading a product to be detected is arranged on the carrier adjustment mechanism in a driving manner; the upper part of the jig carrier is also provided with a plurality of groups of image acquisition mechanisms, and the image acquisition mechanisms are arranged above the jig carrier through driving of the displacement mechanisms.
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| CN111275697A (en) * | 2020-02-10 | 2020-06-12 | 西安交通大学 | Battery silk-screen quality detection method based on ORB feature matching and LK optical flow method |
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