CN214376603U - Three-dimensional calibration plate for correcting imaging distortion of complex curved surface glass window - Google Patents
Three-dimensional calibration plate for correcting imaging distortion of complex curved surface glass window Download PDFInfo
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- CN214376603U CN214376603U CN202022617269.8U CN202022617269U CN214376603U CN 214376603 U CN214376603 U CN 214376603U CN 202022617269 U CN202022617269 U CN 202022617269U CN 214376603 U CN214376603 U CN 214376603U
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- 238000003702 image correction Methods 0.000 abstract 1
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Abstract
The utility model relates to a three-dimensional calibration plate for complicated curved surface glass window imaging distortion is revised belongs to distortion image correction technical field. The glass substrate comprises a plurality of layers of stacked glass substrates, wherein the upper surface of each glass substrate is provided with a black-white staggered checkerboard pattern, and white symbol patterns are arranged in black checkerboards; the checkerboard pattern areas on each layer of glass substrate are arranged in a staggered mode. Not only the coordinates of the corner points of the checkerboard but also the coordinates of the characteristic points (end points, intersection points) of the symbols can be obtained through feature matching and identification, so that more equations can be provided for optimizing the correction function. The three-dimensional correction of imaging distortion of the complex curved surface glass window is realized, the calibration precision is high, the structure is simple, and the processing is easy.
Description
Technical Field
The utility model relates to a distortion image revises technical field, and specifically speaking relates to a three-dimensional calibration plate that is used for complicated curved surface glass window imaging distortion to revise.
Background
In engineering application, various experimental information can be obtained by recording images, and the method has the advantages of objectivity, non-contact, high precision and the like. In the measurement of velocity field, pressure field, temperature field, particle field, etc., an optical window is generally provided in order to maintain the field parameters and ensure the normal operation of the image recording device.
With the development of science and technology, the requirement on measurement is higher and higher, the plane observation window cannot meet the current application requirement, and the complex curved surface glass window is applied. For example, in order to observe and analyze the atomization and ignition combustion processes of fuel in a combustion chamber of an internal combustion engine, optical observation windows in the proposed optical combustion chamber are mostly complex curved glass windows; in order to measure and analyze the flow field parameters in the gas turbine/aeroengine, an arc-shaped optical window needs to be designed; due to the structural characteristics of the inward rotation type air inlet, the inner flow channel is shielded, in order to observe the information of the inner flow field by applying an optical measurement technology, an optical window is required to be formed on the wall surface of the flow channel, the molded surface of the inward rotation type air inlet is a special-shaped curved surface, the conventional plane observation window can cause the change of the structure of the flow field, and the real flow field information cannot be obtained. The special-shaped surface glass observation window is required to be designed, wherein the inner surface of the special-shaped curved surface glass observation window is consistent with the wall surface of the inner runner of the special-shaped curved surface of the inward turning type air inlet, and the outer surface of the special-shaped curved surface glass observation window is a correction curved surface. The test shows that the flow field image in the complex curved surface glass window is distorted due to the limitation of the processing precision, and the analysis of the test result is influenced.
In order to correct imaging distortion caused by a complex curved glass window, a calibration plate is required to be used for researching and analyzing distortion characteristics, so that a correction algorithm is proposed. The optical calibration plate is widely applied to the fields of machine vision, image measurement, photogrammetry, three-dimensional reconstruction and the like. The existing optical calibration board comprises a checkerboard calibration board, a dot array calibration board, a bar calibration board, a two-dimensional code calibration board and the like, and is mainly used for correcting lens distortion and determining a conversion relation between a physical size and pixels.
The prior art is used for the imaging distortion correction of the complex curved surface glass window and has the defects that: the symbol characteristic information of the calibration plate is the same, and the matching is difficult; when the distortion is large, the dots of the dot calibration plate become ellipses, and the center positioning precision is obviously reduced; when distortion is complex, more feature points are needed to solve to obtain an optimized correction function, and the existing calibration plate is lack of feature points.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a three-dimensional calibration plate for complicated curved surface glass window imaging distortion is revised, it is markd the precision height, and has simple structure, workable advantage.
In order to achieve the above object, the utility model discloses a three-dimensional calibration plate for complicated curved surface glass window imaging distortion correction, including the multilayer glass substrate that stacks, glass substrate upper surface is equipped with the crisscross checkerboard pattern of black and white, wherein, is equipped with white symbol pattern in the black checkerboard; the checkerboard pattern areas on each layer of glass substrate are arranged in a staggered mode.
Optionally, in an embodiment, the symbol pattern includes: plus, - (minus), × (multiplication), ÷ (division), > (greater than), < (smaller than), > (equal to),/(slash), and | (vertical bar).
When designing a white symbol pattern in a black checkerboard, adjacent symbols are different in order to increase the difference and improve the matching efficiency.
Optionally, in one embodiment, each 9 black and white checkerboard grids constitute a module, including 3 rows and 3 columns, each module having uniqueness. The center of the module is provided with a black checkerboard or a white checkerboard with symbols, and the uniqueness of each module is ensured during design. Each module comprises 16 angular points and symbol characteristic points, and the one-to-one correspondence between the angular points and the characteristic points is enough for solving and optimizing the correction function. Because complicated curved surface glass window imaging distortion is complicated, distortion characteristic is different everywhere, and this just requires to divide complicated curved surface glass window into one by one subregion, marks every subregion respectively, and every subregion corresponds the utility model discloses a module of calibration board.
Optionally, in one embodiment, the checkerboard pattern on the first glass substrate layer from top to bottom is located in the center of the substrate and is composed of 16 modules in 4 rows and 4 columns; the checkerboard pattern on the second layer of glass substrate is formed by arranging a circle of single modules around the checkerboard pattern on the first layer of glass substrate; the pattern on the third layer of glass substrate is that a single module is arranged for a circle around the checkerboard pattern on the second layer of glass substrate; and so on.
In order to apply the three-dimensional calibration plate for correcting the imaging distortion of the complex curved glass window to correct the image distortion of a three-dimensional space, preferably, the thickness of the glass substrate is 0.5-1 mm.
In order to improve the recognition degree of the symbol pattern and keep the characteristics of the black checkerboard, the line width of the symbol pattern is one tenth of the width of the checkerboard, and the distance between the end part of the symbol pattern and the edge frame of the checkerboard is also one tenth of the width of the checkerboard. If the lines are too thin, the symbol characteristics can be submerged by strong background noise, and the identification degree of the symbols is reduced; too thick lines of the symbol can weaken the characteristics of the black checkerboard, cause the difficulty in identifying the angular points and reduce the calibration precision.
Optionally, in an embodiment, the checkerboard pattern on the glass substrate has 48 rows and 48 columns, 256 modules, and the width of the blank frame is 7 times of the checkerboard width, which is composed of 13 glass substrates. The blank frame may be used for the mounting of the calibration plate.
Not only the coordinates of the corner points of the checkerboard but also the coordinates of the characteristic points (end points, intersection points) of the symbols can be obtained through feature matching and identification, so that more equations can be provided for optimizing the correction function.
Compared with the prior art, the utility model discloses an useful part lies in:
through the utility model discloses a mark the body and have depth direction's information, can realize the three-dimensional correction of complicated curved surface glass window imaging distortion, it is markd the precision height, simple structure, and easily processing.
Drawings
FIG. 1 is a schematic view of a three-dimensional calibration plate for correcting imaging distortion of a complex curved glass window according to an embodiment of the present invention;
FIG. 2 is an enlarged view of a module of a three-dimensional calibration plate for correcting imaging distortion of a complex curved glass window according to the present invention;
FIG. 3 is a schematic view of a checkered pattern on a first layer of high-transmittance quartz glass substrate;
fig. 4 is a schematic view of a checkered pattern on the second layer of high-transmittance quartz glass substrate.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be further described below with reference to the following embodiments and accompanying drawings. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the described embodiments without any inventive step, are within the scope of the present invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which the invention belongs. The use of the terms "comprising" or "including" and similar referents in the context of describing the invention as being "comprising" and the like, is to be construed to cover the listed referents or items, including but not limited to the listed referents or items, and equivalents thereof. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
Examples
Referring to fig. 1, the three-dimensional calibration plate for correcting imaging distortion of a complex curved glass window of the present embodiment includes: the multilayer high-light-transmission quartz glass substrate 1 is provided with black checkerboards 2 and white checkerboards 3 on the high-light-transmission quartz glass substrate 1, and the side lengths of the black checkerboards 2 and the white checkerboards 3 are 1 mm.
In order to distinguish the checkerboards, a white symbol pattern 5 is provided in the black checkerboard 2, the symbol pattern 5 including: plus, - (minus), × (multiplication), ÷ (division), > (greater than), < (smaller than), - (equal to),/(slash), | (vertical bar), ": (colons), · (dots), etc.
When designing a white symbol pattern in a black checkerboard, adjacent symbols are different in order to increase the difference and improve the matching efficiency.
As shown in fig. 2, every 9 black and white checkerboards form a module 6, which comprises 3 rows and 3 columns, and the center of the module is a black checkerboard or a white checkerboard provided with symbols, which is designed to ensure that each module has uniqueness. Each module comprises 16 angular points and symbol characteristic points, and the one-to-one correspondence between the angular points and the characteristic points is enough for solving and optimizing the correction function.
In order to improve the recognition degree of the symbol pattern and simultaneously keep the characteristics of the black checkerboard, the width of the lines of the symbol pattern is 0.1mm, and the distance between the end part of the symbol and the checkerboard frame is also 0.1 mm. If the lines are too thin, the symbol characteristics can be submerged by strong background noise, and the identification degree of the symbols is reduced; too thick lines of the symbol can weaken the characteristics of the black checkerboard, cause the difficulty in identifying the angular points and reduce the calibration precision.
The checkerboard pattern on the substrate has 48 rows and 48 columns, 256 modules, and a blank frame with the width of 7mm can be used for installing the calibration body.
The three-dimensional calibration plate of the embodiment is composed of 13 layers of substrates, and the pattern on the first layer of high-transparency quartz glass substrate from top to bottom is positioned in the center of the calibration plate and is composed of 16 modules in 4 rows and 4 columns, as shown in fig. 3. The pattern on the second layer of high-transparency quartz glass substrate is formed by arranging a single module around the pattern on the first layer of high-transparency quartz glass substrate, as shown in fig. 4. The pattern on the third layer of high-light-transmittance quartz glass substrate is formed by arranging a circle of single modules around the pattern on the second layer of high-light-transmittance quartz glass substrate. And so on.
Because complicated curved surface glass window imaging distortion is complicated, distortion characteristic is different everywhere, and this just requires to divide complicated curved surface glass window into one by one subregion, marks every subregion respectively, and every subregion corresponds the utility model discloses a module of calibration board.
And matching the image of the calibration plate when the glass window with the complex curved surface is matched by using the uniqueness of the symbol characteristic and the module characteristic of the calibration body. The effect of the glass window on the imaging can be generally generalized to a geometric transformation of the image, such as translation, scaling, and rotation.
In order to correct the distorted image, the mapping parameters of the normal image and the distorted image need to be solved, and the mapping relationship of translation, scaling and rotation of the image can be summarized as the following polynomial:
x＝a0+a1u+a2v+a3uv+a4u2+a5v2+…
y＝b0+b1u+b2v+b3uv+b4u2+b5v2+…
generally, when the degree of the polynomial is 2, the distortion of translation, scaling, rotation, bending and the like of the image can be basically corrected. In order to obtain the coefficient of polynomial, the mapping parameter of image promptly, utilize the utility model discloses a mark the body and mark complicated curved surface glass window.
Not only coordinates of the checkerboard corner points but also coordinates of the symbol feature points (end points and intersection points) can be obtained through feature matching and identification, more equations can be provided for optimizing the correction function, and the correction precision is improved.
Claims (8)
1. A three-dimensional calibration plate for correcting imaging distortion of a complex curved glass window is characterized by comprising a plurality of layers of stacked glass substrates, wherein the upper surface of each glass substrate is provided with black and white staggered checkerboard patterns, and white symbol patterns are arranged in the black checkerboard patterns; the checkerboard pattern areas on each layer of glass substrate are arranged in a staggered mode.
2. The three-dimensional calibration plate for distortion correction in imaging of complex curved glass windows as claimed in claim 1, wherein said symbol pattern comprises: +, -, ×, div, <, ═ v, |.
3. The three-dimensional calibration plate for image distortion correction of complex curved glass windows according to claim 1, wherein every 9 chequer grids are combined into a module, and each module has uniqueness.
4. The three-dimensional calibration plate for the imaging distortion correction of the complex curved glass window as claimed in claim 3, wherein the checkerboard pattern on the first glass substrate layer from top to bottom is positioned at the center of the substrate and is composed of 16 modules with 4 rows and 4 columns; the checkerboard pattern on the second layer of glass substrate is formed by arranging a circle of single modules around the checkerboard pattern on the first layer of glass substrate; the pattern on the third glass substrate is such that the individual modules are arranged in a circle around the checkerboard pattern on the second glass substrate.
5. The three-dimensional calibration plate for the imaging distortion correction of the complex curved glass window as claimed in claim 1, wherein the thickness of the glass substrate is 0.5-1 mm.
6. The three-dimensional calibration plate for distortion correction in imaging of complex curved glass windows as claimed in claim 1, wherein the width of the lines of the symbol pattern is one tenth of the width of the checkerboard, and the distance between the end of the symbol pattern and the border of the checkerboard is also one tenth of the width of the checkerboard.
7. The three-dimensional calibration plate for distortion correction in imaging of complex curved glass windows as claimed in claim 1, wherein the checkerboard pattern on the glass substrate has 48 rows and 48 columns, 256 modules, and the width of the blank frame is 7 times of the checkerboard width, and the checkerboard pattern is composed of 13 glass substrates.
8. The three-dimensional calibration plate for the imaging distortion correction of the complex curved glass window as claimed in claim 1, wherein the coordinates of the checkerboard corner points and the symbol feature points are obtained by feature matching and recognition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022617269.8U CN214376603U (en) | 2020-11-12 | 2020-11-12 | Three-dimensional calibration plate for correcting imaging distortion of complex curved surface glass window |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022617269.8U CN214376603U (en) | 2020-11-12 | 2020-11-12 | Three-dimensional calibration plate for correcting imaging distortion of complex curved surface glass window |
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| Publication Number | Publication Date |
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| CN214376603U true CN214376603U (en) | 2021-10-08 |
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| CN202022617269.8U Active CN214376603U (en) | 2020-11-12 | 2020-11-12 | Three-dimensional calibration plate for correcting imaging distortion of complex curved surface glass window |
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| CN (1) | CN214376603U (en) |
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