CN111009015B - Calibration device and calibration method - Google Patents
Calibration device and calibration method Download PDFInfo
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- CN111009015B CN111009015B CN201911355718.1A CN201911355718A CN111009015B CN 111009015 B CN111009015 B CN 111009015B CN 201911355718 A CN201911355718 A CN 201911355718A CN 111009015 B CN111009015 B CN 111009015B
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/80—Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/30—Subject of image; Context of image processing
- G06T2207/30204—Marker
Abstract
The invention discloses a calibration device and a calibration method. The device comprises: the device comprises a calibration plate, a module to be calibrated and a control module; the control module is connected with the calibration plate and used for controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern, wherein the reference calibration pattern comprises a first background and a first reference pattern, the complementary reference calibration pattern comprises a second background and a second reference pattern, the first background and the second reference pattern are the same in color, and the second background and the first reference pattern are the same in color; the module to be calibrated is used for acquiring images of the reference calibration patterns to obtain a first image, and acquiring images of the complementary reference calibration patterns to obtain a second image; the control module is connected with the module to be calibrated and is used for calculating an average edge contour according to the first image and the second image, and calculating the calibration parameters of the module to be calibrated and the posture parameters of the calibration plate according to the average edge contour. The device can realize high-precision extraction of the marking position of the calibration plate, and improve the precision of the calibration result.
Description
Technical Field
The embodiment of the invention relates to the technical field of machine vision, in particular to a calibration device and a calibration method.
Background
The machine vision technology is an important direction of industrial automation technology, and plays an important role in various aspects of social production and life, such as intelligent assembly, logistics sorting, three-dimensional reconstruction, medical image processing, railway monitoring, security and protection and the like. In the field of machine vision, main equipment for completing a measurement task is an imaging system, and parameter calibration of the imaging system is a precondition for realizing a high-precision measurement task.
Conventional calibration plates are typically made by several methods: paper printing, glass coating, ceramic materials, and the like. The paper printing is limited by the precision of the printer, the flatness problem of printing paper pasting and the like, so that the consistency of the calibration reference object is poor, and the calibration of the high-precision imaging system is difficult to realize. The glass coating calibration plate can reach micron-scale precision in a small size range, but the glass surface has specular reflection, so that the quality of a calibration image is easily affected by ambient stray light, and a mark point cannot be extracted. The ceramic material can manufacture the high-precision calibration plate, and the surface diffuse reflection structure has better adaptability, but the large-size calibration plate is not easy to manufacture and is fragile. The calibration plates are all required to adjust the ambient light to ensure that enough contrast between the mark points and the background is obtained, the contrast is easy to be interfered by the ambient light, and even the mark points can not be extracted when the ambient light condition is too bad. In addition, the edge of the mark graph of the calibration plate is blurred due to factors such as defocusing of the calibration shooting system, so that the accuracy of extracting the mark points is reduced, and the accuracy of a calibration result of the calibration plate is reduced.
Disclosure of Invention
In order to solve the problems, the invention provides the calibration device and the calibration method, which can realize high-precision extraction of the marked position of the calibration plate and improve the precision of the calibration result.
In a first aspect, an embodiment of the present invention provides a calibration device, where the device includes a calibration board, a module to be calibrated, and a control module;
the control module is connected with the calibration plate and used for controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern, the reference calibration pattern comprises a first background and a first reference pattern, the complementary reference calibration pattern comprises a second background and a second reference pattern, the first background color is the same as the second reference pattern, and the second background color is the same as the first reference pattern;
the module to be calibrated is used for acquiring the image of the reference calibration pattern to obtain a first image, and acquiring the image of the complementary reference calibration pattern to obtain a second image;
the control module is connected with the module to be calibrated and is used for calculating an average edge contour according to the first image and the second image, and calculating calibration parameters of the module to be calibrated and attitude parameters of the calibration plate according to the average edge contour.
In a second aspect, an embodiment of the present invention further provides a calibration method, where the method is applied to the calibration device provided in the first aspect, and the method includes:
controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern;
acquiring a first image acquired by the module to be calibrated based on the reference calibration pattern and a second image acquired by the module to be calibrated based on the complementary reference calibration pattern;
calculating an average edge contour from the first image and the second image;
and calculating the calibration parameters of the module to be calibrated and the attitude parameters of the calibration plate according to the average edge profile.
According to the calibration device, the calibration plate, the module to be calibrated and the control module are arranged, the control module is connected with the calibration plate, the control calibration plate generates the reference calibration pattern and the complementary reference calibration pattern, the module to be calibrated is used for collecting the image of the reference calibration pattern to obtain a first image, the image of the complementary reference calibration pattern is collected to obtain a second image, the control module is connected with the module to be calibrated, the average edge profile is calculated according to the first image and the second image, and the calibration parameters of the module to be calibrated and the gesture parameters of the calibration plate are calculated according to the average edge profile.
Drawings
FIG. 1 is a schematic structural diagram of a calibration device according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a reference calibration pattern according to an embodiment of the present invention;
FIG. 3 is a schematic illustration of a complementary reference calibration pattern to the reference calibration pattern shown in FIG. 2;
FIG. 4 is a schematic view of an image light intensity curve according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a calibration plate according to an embodiment of the present invention;
FIG. 6 is a schematic structural diagram of another calibration plate according to an embodiment of the present invention;
FIG. 7 is a schematic structural diagram of another calibration plate according to an embodiment of the present invention;
FIG. 8 is a schematic structural diagram of another calibration plate according to an embodiment of the present invention;
FIG. 9 is a schematic flow chart of a calibration method according to an embodiment of the present invention;
FIG. 10 is a flow chart of a calibration method according to an embodiment of the present invention;
FIG. 11 is a flowchart of a method for obtaining a marked edge according to an embodiment of the present invention;
FIG. 12 is a flowchart of a method for calculating an average edge profile according to an embodiment of the present invention;
FIG. 13 is a flowchart illustrating another method for calculating an average edge profile according to an embodiment of the present invention;
fig. 14 is a flow chart of another calibration method according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
FIG. 1 is a schematic structural diagram of a calibration device according to an embodiment of the present invention. As shown in fig. 1, the calibration device includes a calibration plate 110, a module to be calibrated 120, and a control module 130;
the control module 130 is connected to the calibration board 110, and is configured to control the calibration board 110 to generate a reference calibration pattern and a complementary reference calibration pattern, where the reference calibration pattern includes a first background and a first reference pattern, and the complementary reference calibration pattern includes a second background and a second reference pattern, and the first background color is the same as the second reference pattern, and the second background color is the same as the first reference pattern;
the to-be-calibrated module 120 is configured to acquire an image of a reference calibration pattern to obtain a first image, and acquire an image of a complementary reference calibration pattern to obtain a second image;
the control module 130 is connected to the module to be calibrated 120, and is configured to calculate an average edge profile according to the first image and the second image, and calculate a calibration parameter of the module to be calibrated 120 and a posture parameter of the calibration board 110 according to the average edge profile.
Specifically, according to a preset pattern to be calibrated, the control module 130 generates a corresponding reference calibration pattern control signal, the calibration board 110 receives the reference calibration pattern control signal to generate a reference calibration pattern (as shown in fig. 2), the module to be calibrated 120 acquires an image of the reference calibration pattern to obtain a first image, the control module 130 generates a corresponding complementary reference calibration pattern control signal according to a complementary pattern having the same shape and opposite brightness as the preset pattern to be calibrated, the calibration board 110 receives the complementary reference calibration pattern control signal to generate a complementary reference calibration pattern (as shown in fig. 3), the module to be calibrated 120 acquires an image of the complementary reference calibration pattern to obtain a second image, extracts a first mark edge of the first image according to the first image, extracts a second mark edge of the first image according to the second image, obtains a first mark edge profile of the first image according to the first mark edge, obtains a second mark edge profile of the second image according to the second mark edge profile, calculates an average edge profile as a calibration profile according to the first mark edge profile and the second mark edge profile, and combines the average edge profile with the calibration parameters of the calibration board 120 through a conventional calibration algorithm.
Fig. 2 is a schematic diagram of a reference calibration pattern provided in an embodiment of the present invention, and fig. 3 is a schematic diagram of a complementary reference calibration pattern of the reference calibration pattern shown in fig. 2. Referring to fig. 2 and 3, the background of the reference calibration pattern is bright, the mark pattern is dark, the background of the complementary reference calibration pattern is dark, the mark pattern is bright, the shapes of the reference calibration pattern and the calibration pattern of the complementary reference calibration pattern are the same, and only the colors are complementary, namely the background color of the reference calibration pattern is the mark pattern color of the complementary reference calibration pattern, and the background color of the complementary reference calibration pattern is the mark pattern color of the reference calibration pattern.
Specifically, the module to be calibrated 120 acquires the image of the reference calibration pattern shown in fig. 2 to obtain a first image C1, and selects a mark point M on the first image C1 to obtain the light intensity from the center of the mark point M to the background area, as shown by a 1a curve in fig. 4; under the same image acquisition condition, the module to be calibrated 120 acquires the image of the complementary reference calibration pattern shown in fig. 3 to obtain a second image D1, and selects a marking point N corresponding to the marking point M on the second image D1 to obtain the light intensity from the center of the marking point N to the background area, as shown by a 2a curve in fig. 4; in the process of obtaining the first image C1, the image quality of the first image C1 is affected by the illumination condition and the defocus of the module to be calibrated, when the illumination condition is poor or the defocus of the module to be calibrated 120 is unfavorable, a blurred first image C2 may be obtained, at this time, a mark point M on the first image C2 is selected to obtain the light intensity from the center of the mark point M to the background area, as shown by a 1b curve in fig. 4, while in the same image acquisition condition, the module to be calibrated 120 acquires an image of a complementary reference calibration pattern to obtain a second image D2, and a mark point N corresponding to the mark point M on the second image D2 is selected, and the light intensity from the center of the mark point N to the edge area, as shown by a 2b curve in fig. 4.
Fig. 4 is a schematic diagram of a light intensity curve of an image according to an embodiment of the present invention, where the vertical axis is the light intensity of the edge of a mark point and the horizontal axis is the position of the mark point. In order to extract the detected edge position, the gray gradient of the image is calculated first, and then the edge position is selected according to the gray gradient. As shown in fig. 4, as the mark point goes from the center to the edge, the light intensity of the curve 1a and the light intensity of the curve 1b are all from large to small, when the image is not clear enough, the gray scale of the image edge becomes more gentle as can be seen by the curve 1b, and at this time, the wrong edge position may be obtained or the edge meeting the condition may not be found by adopting the same edge detection parameters as the curve 1a, thereby causing the decrease of the calibration accuracy or the calibration failure. The different image acquisition conditions obtain images with different definition, so that the gray distribution of the images is different, as shown in fig. 4, the distribution of the light intensity curves 1a and 1b of the mark points of the reference calibration pattern is different, and the distribution of the light intensity curves 2a and 2b of the mark points of the complementary reference calibration pattern corresponding to the mark points of the reference calibration pattern is also different, but under the same image acquisition condition, the light intensity curves of the mark points of the reference calibration pattern and the light intensity curves of the mark points corresponding to the complementary reference calibration pattern are bilaterally symmetrical relative to the real edge, so that the intersection point positions of the two light intensity curves are the real edge positions, namely the intersection point of the curves 1a and 2a and the intersection point of the curves 1b and 2b are both the real edge positions, and the two mark edge contours respectively obtained by the two light intensity curves are also bilaterally symmetrical relative to the real edge positions, so that the average value of the two mark edge contour positions can be used as the mark edge contour. Therefore, the influence of the image definition on the extraction precision of the calibration contour can be avoided by calculating the calibration parameters of the calibration module 120 and the posture parameters of the calibration plate 110 according to the average edge contour.
According to the calibration device, the calibration plate, the module to be calibrated and the control module are arranged, the control module is connected with the calibration plate, the control calibration plate generates the reference calibration pattern and the complementary reference calibration pattern, the module to be calibrated is used for collecting the image of the reference calibration pattern to obtain a first image, the image of the complementary reference calibration pattern is collected to obtain a second image, the control module is connected with the module to be calibrated, the average edge profile is calculated according to the first image and the second image, and the calibration parameters of the module to be calibrated and the gesture parameters of the calibration plate are calculated according to the average edge profile.
In the calibration device provided by the embodiment of the invention, the calibration plate can comprise any one of a micro-electromechanical system, a digital micro-mirror device, a liquid crystal display panel and an ink display screen, and can also be a device capable of generating a complementary reference calibration pattern without specific limitation.
Fig. 5 is a schematic structural diagram of a calibration plate according to an embodiment of the present invention. As shown in fig. 5, the calibration plate includes a microelectromechanical system 140;
the mems 140 unit includes a frame 141, a plurality of color units 142, a plurality of rotating shafts 143, and a plurality of first electrodes 144, the color units 142 are in one-to-one correspondence with the rotating shafts 143, and the color units 142 are connected to the frame 141 through the rotating shafts 143; the first electrodes 144 are disposed on one side of the color units 142, and each color unit 142 corresponds to at least two first electrodes 144;
the color unit 142 includes a first face 141a and a second face 141b disposed opposite to each other, and the colors of the first face 141a and the second face 141b are different;
the first electrode 144 is electrically connected to the control module, and is configured to drive the color unit 142 to rotate around the rotation axis 143 according to a control signal provided by the control module, so as to display the first surface 141a or the second surface 141b.
Specifically, for example, the first surface 141a of the color unit 142 is black, the second surface 141b is white, the first electrode 144 drives the color unit 142 to rotate around the rotation axis 143 under the control of the first control signal, the color unit 142 of the first area exposes the first surface 141a to display black, the color unit 142 of the second area exposes the second surface 141b to display white, and thus, the reference calibration pattern is generated on the calibration board; the first electrode 144 drives the color unit 142 to rotate around the rotation axis 143 under the control of the second control signal, the color unit 142 of the first area exposes the first face 141b to display white, the color unit 142 of the second area exposes the second face 141a to display black, and thus, the complementary reference calibration pattern is generated on the calibration plate.
In this embodiment, the first surface 141a of the color unit 142 may be white, and the second surface 141b may be black.
FIG. 6 is a schematic structural diagram of another calibration plate according to an embodiment of the present invention. As shown in fig. 6, the calibration plate includes a digital micromirror device 150;
the digital micromirror device 150 includes a plurality of micromirrors 151 and a plurality of second electrodes 152, the second electrodes 152 being disposed on one side of the micromirrors 151;
the second electrode 152 is electrically connected to the control module, and is used for controlling the rotation angle of the micro mirror 151 according to the control signal provided by the control module.
Specifically, the second electrode 152 rotates the angle of the micro-mirror 151 under the control of the first control signal, the light beam incident on the mirror 151 in the first area can be incident on the module to be calibrated after being reflected, the bright color is displayed, the light beam incident on the mirror 151 in the second area cannot be incident on the module to be calibrated after being reflected, and the dark color is displayed, so that the reference calibration pattern is generated on the calibration plate; under the control of the second control signal of the second electrode 152, the angle of the micro-mirror 151 is rotated, the light beam incident on the mirror 151 in the first area cannot be incident on the module to be calibrated after being reflected, the dark color is displayed, the light beam incident on the mirror 151 in the second area can be incident on the module to be calibrated after being reflected, and the bright color is displayed, so that the complementary reference calibration pattern is generated on the calibration plate.
FIG. 7 is a schematic structural diagram of another calibration plate according to an embodiment of the present invention. As shown in fig. 7, the calibration plate includes a liquid crystal display panel 160;
the liquid crystal display panel 160 includes a backlight unit 161, an array substrate 162, a liquid crystal layer 163, and a color film substrate 164, which are sequentially stacked;
the third electrode 165 is arranged on the array substrate 162, and the fourth electrode 166 is arranged on the array substrate 162 or the color film substrate 164;
the third electrode 165 and the fourth electrode 166 are electrically connected to the control module for controlling the deflection of the liquid crystal 1631 in the liquid crystal layer 163 according to the control signal provided by the control module.
Specifically, the third electrode 165 and the fourth electrode 166 drive the liquid crystal 1631 to deflect under the control of the first control signal, the long axis of the liquid crystal 1631 in the first area in the liquid crystal layer 163 is perpendicular to the light beam incident on the liquid crystal 1631, the light beam cannot pass through the liquid crystal layer 163 to display dark color, the long axis of the liquid crystal 1631 in the second area in the liquid crystal layer 163 is parallel to the light beam incident on the liquid crystal 1631, the light beam can pass through the liquid crystal layer 163 to emit light, and the light beam displays bright color, so that a reference calibration pattern is generated on the calibration plate; the third electrode 165 and the fourth electrode 166 drive the liquid crystal 1631 to deflect under the control of the second control signal, the long axis of the liquid crystal 1631 in the first region in the liquid crystal layer 163 is parallel to the light beam incident on the liquid crystal 1631, the light beam can be emitted after passing through the liquid crystal layer 163 to display bright color, the long axis of the liquid crystal 1631 in the second region in the liquid crystal layer 163 is perpendicular to the light beam incident on the liquid crystal 1631, the light beam cannot pass through the liquid crystal layer 163 to display dark color, and therefore, a complementary reference calibration pattern is generated on the calibration plate.
FIG. 8 is a schematic structural diagram of another calibration plate according to an embodiment of the present invention. As shown in fig. 8, the calibration plate includes an ink display 170;
the ink display screen 170 includes a receiving cavity 171, a first color charged bead 172, a second color charged bead 173, a fifth electrode 174, and a transparent protective layer 175 disposed in the receiving cavity 171, the fifth electrode 174 and the transparent protective layer 175 being disposed on two sides of the first color charged bead 172 and the second color charged bead 173, respectively; wherein the first color charged globules 172 are of opposite charge polarity to the second color charged globules 173;
the fifth electrode 174 is electrically connected to the control module, and is configured to control the first color charged pellets 172 to move toward the fifth electrode 174 according to the control signal provided by the control module, and the second color charged pellets 173 to move toward the transparent protective layer 175; alternatively, the second color charged beads 173 are controlled to move toward the fifth electrode 174, and the first color charged beads 172 move toward the transparent protective layer 175
Specifically, the exemplary first color charged beads 172 are black, the second color charged beads 173 are white, the fifth electrode 174 controls the first color charged beads 172 of the first region to move toward the fifth electrode 174 according to the first control signal, the second color charged beads 173 to move toward the transparent protective layer 175, displaying a bright color, the first color charged beads 172 of the second region to move toward the transparent protective layer 175, and the second color charged beads 173 to move toward the fifth electrode 174, displaying a dark color, thus generating a reference calibration pattern on the calibration plate; the fifth electrode 174 controls the first color charged beads 172 of the first region to move toward the transparent protective layer 175, the second color charged beads 173 to move toward the fifth electrode 174 to display dark colors, the first color charged beads 172 of the second region to move toward the fifth electrode 174, and the second color charged beads 173 to move toward the transparent protective layer 175 to display bright colors according to the second control signal, and thus complementary reference calibration patterns are generated on the calibration plate.
Based on the same inventive concept, the embodiment of the invention also provides a calibration method which is applied to the calibration device provided by any embodiment of the invention, and has the corresponding functions and beneficial effects of the device.
Fig. 9 is a schematic flow chart of a calibration method according to an embodiment of the present invention. As shown in fig. 9, the calibration method specifically includes:
910, controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern;
920, acquiring a first image acquired by the module to be calibrated based on the reference calibration pattern and a second image acquired by the module to be calibrated based on the complementary reference calibration pattern;
930, calculating an average edge profile from the first image and the second image;
940, calculating the calibration parameters of the module to be calibrated and the attitude parameters of the calibration plate according to the average edge profile.
According to the embodiment of the application, the calibration board generates the reference calibration pattern and the complementary reference calibration pattern, the to-be-calibrated module is used for acquiring the image of the reference calibration pattern to obtain a first image, the image of the complementary reference calibration pattern is acquired to obtain a second image, the control module is connected with the to-be-calibrated module, the average edge profile is calculated according to the first image and the second image, and the calibration parameters of the to-be-calibrated module and the gesture parameters of the calibration board are calculated according to the average edge profile.
Fig. 10 is a flow chart of another calibration method according to an embodiment of the present invention. As shown in fig. 10, the calibration method specifically includes:
910, controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern;
920, acquiring a first image acquired by the module to be calibrated based on the reference calibration pattern and a second image acquired by the module to be calibrated based on the complementary reference calibration pattern;
931, extracting a first marked edge of the first image by adopting an edge detection method according to the first image, and extracting a second marked edge of the second image by adopting an edge detection method according to the second image;
specifically, corresponding marking points are selected on the first image and the second image, a light intensity change curve from a central area of the marking points to a background area is obtained, and marking edges of the first image and the second image are extracted from the light intensity change curve by adopting an edge detection method, as shown in the figure, fig. 11 is a flow diagram of a method for obtaining marking edges according to an embodiment of the invention. As shown in fig. 11, specifically, the method includes:
951, selecting a first mark point in the first image, and acquiring a first light intensity curve from a central area of the first mark point to a background area;
952, extracting the first mark edge by using the edge detection method according to the first light intensity curve;
953, selecting a second mark point in the second image, and obtaining a second light intensity curve from the central area of the second mark point to the background area; wherein the second mark point corresponds to the first mark point;
and 954, extracting the second marked edge by adopting the edge detection method according to the second light intensity curve.
The same mark point can obtain a plurality of light intensity curves, each light intensity curve corresponds to one edge point, and a plurality of edge points corresponding to the plurality of light intensity curves provide enough sampling points for obtaining a mark edge contour through subsequent fitting, so that the more the obtained light intensity curves, the more accurate the mark edge contour is fitted.
932, obtaining a first marked edge contour of the first image according to the first marked edge using an edge fitting algorithm, and obtaining a second marked edge contour of the second image according to the second marked edge using an edge fitting algorithm;
940, calculating an average edge profile from the first marked edge profile and the second marked edge profile.
Specifically, there are two ways to calculate the average edge profile from the first marked edge profile and the second marked edge profile, as shown in fig. 12 and 13. Fig. 12 is a flowchart of a method for calculating an average edge profile according to an embodiment of the present invention, where specific steps shown in fig. 12 include:
961, dispersing the first marked edge profile to obtain a first discrete point group, dispersing the second marked edge profile to obtain a second discrete point group, wherein the first discrete point group and the second discrete point group comprise equal numbers of discrete points;
962, performing ellipse fitting by using the first discrete point group and the second discrete point group as fitting data fitting, so as to obtain the average edge profile.
Fig. 13 is a flowchart of another method for calculating an average edge profile according to an embodiment of the present invention, where, as shown in fig. 13, specific steps include:
963, acquiring a first center, a first eccentricity, a first long axis length and a first included angle between the first long axis and a preset direction of the first mark edge outline; acquiring a second center, a second eccentricity, a second long axis length and a second included angle between a second long axis and the preset direction of the second mark edge outline;
964 calculating an average center from the first center and the second center; calculating an average eccentricity from the first eccentricity and the second eccentricity; calculating an average long axis length according to the first long axis length and the second long axis length; calculating an average included angle according to the first included angle and the second included angle;
965 determining the average edge profile based on the average center, the average eccentricity, the average major axis length, and the average included angle.
Fig. 14 is a flow chart of another calibration method according to an embodiment of the present invention. As shown in fig. 14, the calibration method specifically includes:
911 controlling the calibration plate to generate a first reference calibration pattern and a first complementary reference calibration pattern based on a first attitude of the calibration plate;
912, adjusting the gesture of the calibration plate for multiple times to generate a plurality of second reference calibration patterns and a plurality of second complementary reference calibration patterns;
921 respectively obtaining a first image acquired by the module to be calibrated based on the first reference calibration pattern and the second reference calibration pattern and a second image acquired by the module to be calibrated based on the first complementary reference calibration pattern and the second complementary reference calibration pattern;
930, calculating an average edge profile from the first image and the second image;
940, calculating the calibration parameters of the module to be calibrated and the attitude parameters of the calibration plate according to the average edge profile.
According to the method and the device for calibrating the module, multiple groups of complementary reference calibration patterns with multiple postures are generated, multiple groups of first images and multiple groups of second images are collected, average edge contours are calculated for each group of first images and each group of second images, so that multiple average edge contours are calculated, the number of samples is increased, the calibration parameters of the module to be calibrated and the posture parameters of the calibration plate are calculated according to the multiple average edge contours, and the accuracy of the calibration result can be improved.
The calibration method provided by the embodiment of the present invention also has the beneficial effects of the calibration device in the above embodiment, and will not be described herein.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (11)
1. The calibration device is characterized by comprising a calibration plate, a module to be calibrated and a control module;
the control module is connected with the calibration plate and used for controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern, the reference calibration pattern comprises a first background and a first reference pattern, the complementary reference calibration pattern comprises a second background and a second reference pattern, the first background color is the same as the second reference pattern, and the second background color is the same as the first reference pattern;
the module to be calibrated is used for acquiring the image of the reference calibration pattern to obtain a first image, and acquiring the image of the complementary reference calibration pattern to obtain a second image;
the control module is connected with the module to be calibrated and is used for calculating an average edge contour according to the first image and the second image, and calculating calibration parameters of the module to be calibrated and attitude parameters of the calibration plate according to the average edge contour.
2. The calibration device of claim 1, wherein the calibration plate comprises a microelectromechanical system;
the micro-electromechanical system unit comprises a frame, a plurality of color units, a plurality of rotating shafts and a plurality of first electrodes, wherein the color units are in one-to-one correspondence with the rotating shafts, and the color units are connected to the frame through the rotating shafts; the first electrodes are arranged on one side of the color units, and each color unit corresponds to at least two first electrodes;
the color unit comprises a first surface and a second surface which are oppositely arranged, and the colors of the first surface and the second surface are different;
the first electrode is electrically connected with the control module and is used for driving the color unit to rotate around the rotating shaft according to a control signal provided by the control module so as to display the first surface or the second surface.
3. The calibration device of claim 1, wherein the calibration plate comprises a digital micromirror device;
the digital micro-mirror device comprises a plurality of micro-mirrors and a plurality of second electrodes, wherein the second electrodes are arranged on one sides of the micro-mirrors;
the second electrode is electrically connected with the control module and is used for controlling the rotation angle of the micro-reflector according to the control signal provided by the control module.
4. The calibration device of claim 1, wherein the calibration plate comprises a liquid crystal display panel;
the liquid crystal display panel comprises a backlight unit, an array substrate, a liquid crystal layer and a color film substrate which are sequentially stacked;
the array substrate is provided with a third electrode, and the array substrate or the color film substrate is provided with a fourth electrode;
the third electrode and the fourth electrode are electrically connected with the control module and are used for controlling the deflection of the liquid crystal in the liquid crystal layer according to the control signals provided by the control module.
5. The apparatus of claim 1, wherein the calibration plate comprises an ink display screen;
the ink display screen comprises a containing cavity, a first color charged small ball, a second color charged small ball, a fifth electrode and a transparent protective layer, wherein the first color charged small ball, the second color charged small ball, the fifth electrode and the transparent protective layer are arranged in the containing cavity, and the fifth electrode and the transparent protective layer are respectively arranged on two sides of the first color charged small ball and two sides of the second color charged small ball; wherein the first color charged globules are of opposite charge polarity to the second color charged globules;
the fifth electrode is electrically connected with the control module and is used for controlling the first color charged pellets to move towards the fifth electrode according to the control signal provided by the control module, and the second color charged pellets to move towards the transparent protective layer; alternatively, the second color charged pellets are controlled to move toward the fifth electrode, and the first color charged pellets are controlled to move toward the transparent protective layer.
6. A calibration method applied to the calibration device according to any one of claims 1 to 5, comprising:
controlling the calibration plate to generate a reference calibration pattern and a complementary reference calibration pattern;
acquiring a first image acquired by the module to be calibrated based on the reference calibration pattern and a second image acquired by the module to be calibrated based on the complementary reference calibration pattern;
calculating an average edge contour from the first image and the second image;
and calculating the calibration parameters of the module to be calibrated and the attitude parameters of the calibration plate according to the average edge profile.
7. The method of calibrating according to claim 6, wherein said calculating an average edge profile from said first image and said second image comprises:
extracting a first marked edge of the first image by adopting an edge detection method according to the first image, and extracting a second marked edge of the second image by adopting an edge detection method according to the second image;
obtaining a first marked edge contour of the first image by adopting an edge fitting algorithm according to the first marked edge, and obtaining a second marked edge contour of the second image by adopting an edge fitting algorithm according to the second marked edge;
an average edge profile is calculated from the first marked edge profile and the second marked edge profile.
8. The method according to claim 7, wherein the extracting the first marked edge of the first image according to the first image using an edge detection method and the extracting the second marked edge of the second image according to the second image using an edge detection method includes:
selecting a first mark point in the first image, and acquiring a first light intensity curve from the central area of the first mark point to the background area;
extracting the first mark edge by adopting the edge detection method according to the first light intensity curve;
selecting a second mark point in the second image, and acquiring a second light intensity curve from the central area of the second mark point to the background area; wherein the second mark point corresponds to the first mark point;
and extracting the second mark edge by adopting the edge detection method according to the second light intensity curve.
9. The method of calibrating according to claim 7, wherein said calculating an average edge profile from said first marked edge profile and said second marked edge profile comprises:
dispersing the first marked edge contour to obtain a first discrete point group, dispersing the second marked edge contour to obtain a second discrete point group, wherein the first discrete point group and the second discrete point group comprise equal numbers of discrete points;
and taking the first discrete point group and the second discrete point group as fitting data to fit an ellipse, so as to obtain the average edge profile.
10. The method of calibrating according to claim 7, wherein said calculating an average edge profile from said first marked edge profile and said second marked edge profile comprises:
acquiring a first center, a first eccentricity, a first long axis length and a first included angle between a first long axis and a preset direction of the first mark edge outline; acquiring a second center, a second eccentricity, a second long axis length and a second included angle between a second long axis and the preset direction of the second mark edge outline;
calculating an average center from the first center and the second center; calculating an average eccentricity from the first eccentricity and the second eccentricity; calculating an average long axis length according to the first long axis length and the second long axis length; calculating an average included angle according to the first included angle and the second included angle;
and determining the average edge profile according to the average center, the average eccentricity, the average long axis length and the average included angle.
11. The calibration method of claim 6, wherein controlling the calibration plate to generate the reference calibration pattern and the complementary reference calibration pattern comprises:
controlling the calibration plate to generate a first reference calibration pattern and a first complementary reference calibration pattern based on a first posture of the calibration plate;
adjusting the gesture of the calibration plate for multiple times to generate a plurality of second reference calibration patterns and a plurality of second complementary reference calibration patterns;
the obtaining of the first image acquired by the module to be calibrated based on the reference calibration pattern and the second image acquired based on the complementary reference calibration pattern comprises the following steps:
and respectively acquiring a first image acquired by the module to be calibrated based on the first reference calibration pattern and the second reference calibration pattern and a second image acquired by the module to be calibrated based on the first complementary reference calibration pattern and the second complementary reference calibration pattern.
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