CN209820398U - Target and system for calibrating fisheye camera - Google Patents
Target and system for calibrating fisheye camera Download PDFInfo
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- CN209820398U CN209820398U CN201920664110.6U CN201920664110U CN209820398U CN 209820398 U CN209820398 U CN 209820398U CN 201920664110 U CN201920664110 U CN 201920664110U CN 209820398 U CN209820398 U CN 209820398U
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Abstract
The application provides a mark target and system for fisheye camera is markd, the mark target includes casing and a plurality of mark point, the casing include to the inside sunken hemisphere internal surface of casing, a plurality of mark points for form in a plurality of holes of hemisphere internal surface or install the inboard spherical mark point in the hole. Therefore, the fisheye camera can shoot the target to obtain a target image, and the target image is analyzed and processed through electronic equipment, so that the fisheye camera can be calibrated quickly and accurately by acquiring only one target image.
Description
Technical Field
The utility model relates to a technical field is markd to the camera, and more specifically relates to a mark target and system that fisheye camera was markd.
Background
The camera calibration is one of key technologies in the work of machine vision, photogrammetry, 3D imaging, image geometric correction and the like, and the main function of the camera calibration is to estimate internal and external parameters of the camera. The accuracy of the calibration result and the stability of the calibration algorithm directly affect the accuracy of subsequent work. In a general calibration method, a plurality of images need to be acquired, so that a calibration plate or a camera needs to be manually moved, and in practical application, time and labor are wasted, and the production cost is increased.
SUMMERY OF THE UTILITY MODEL
The application provides a mark target for fisheye camera calibration, can only gather a mark target image through this mark target and realize the calibration to the quick high accuracy of fisheye camera.
The embodiment of the application is realized as follows:
the application provides a mark target for fisheye camera is markd, it includes casing and a plurality of mark point, the casing include to the inside sunken hemisphere internal surface of casing, a plurality of mark point for form in a plurality of holes of hemisphere internal surface, the distance of the centre of hole to the centre of sphere of hemisphere internal surface equals the radius of hemisphere internal surface.
Optionally, in this embodiment of the application, the target further includes at least one light source, the at least one light source is disposed inside the housing, light emitted by the at least one light source irradiates the plurality of holes, and the mark point is formed on the hemispherical inner surface.
Optionally, the holes are covered with a light-transmitting diffuse reflection film.
Optionally, the hemispherical inner surface is black.
Optionally, the number of the marking points is not less than 23, and one of the marking points is arranged at the center of the inner surface of the hemisphere.
The embodiment of the application provides a mark target for fisheye camera is markd, a serial communication port, the mark target includes casing and a plurality of mark point, the casing include to the inside sunken hemisphere internal surface of casing, a plurality of holes have been seted up on the hemisphere internal surface, install a plurality of spherical mark points in a plurality of holes of hemisphere internal surface, the diameter of a plurality of spherical mark points is the same, just the centre of sphere of spherical mark point is on the line of the center of hole and the centre of sphere of hemisphere internal surface.
Optionally, the surface of the spherical mark point is a diffuse reflection surface, the target further includes at least one light source, the at least one light source is disposed on the hemispherical inner surface, light emitted by the at least one light source is irradiated onto the plurality of spherical mark points, and the plurality of mark points are formed on the hemispherical inner surface.
Optionally, the spherical mark points are self-luminous mark points.
Optionally, the number of the plurality of marking points is not less than 23, and one marking point is arranged at the center of the inner surface of the hemisphere.
The application provides a camera calibration system, which comprises a fisheye camera, electronic equipment and the target, wherein the fisheye camera is arranged at the center of a sphere of the hemispherical inner surface of the target, and the electronic equipment is electrically connected with the fisheye camera; the electronic equipment is used for calibrating the fisheye camera according to a target image, and the target image is obtained by shooting the target at the spherical center position of the target by the fisheye camera.
The application provides a mark target and system for fisheye camera is markd, the mark target includes casing and a plurality of mark point, the casing include to the inside sunken hemisphere internal surface of casing, a plurality of mark points for form in a plurality of holes of hemisphere internal surface or install the inboard spherical mark point in the hole. Therefore, the fisheye camera can shoot the target to obtain a target image, and the target image is analyzed and processed through electronic equipment, so that the fisheye camera can be calibrated quickly and accurately by acquiring only one target image.
Additional features and advantages of the present application will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 shows a schematic diagram of a fisheye camera calibration system provided in an embodiment of the present application.
Fig. 2 shows a schematic structural diagram of a target for fisheye camera calibration according to an embodiment of the present disclosure.
Fig. 3 shows a distribution diagram of the mark points in the target for fisheye camera calibration according to an embodiment of the application.
Fig. 4 shows a schematic structural diagram of a target for fisheye camera calibration according to another embodiment of the present disclosure.
Fig. 5 shows a schematic structural diagram of a target for fisheye camera calibration according to still another embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
The camera calibration is one of key technologies in the work of machine vision, photogrammetry, 3D imaging, image geometric correction and the like, and the main function of the camera calibration is to estimate internal and external parameters of the camera. The accuracy of the calibration result and the stability of the calibration algorithm directly affect the accuracy of subsequent work. A general visual angle camera can be represented by a pinhole model, and can be calibrated by using perspective projection mapping and affine transformation. In recent years, the fisheye camera is widely applied to the fields of panoramic vision, video monitoring, automobile navigation, virtual reality and the like due to the ultra-large field range. However, the large field of view also brings about serious image distortion, which affects the visual perception of human eyes and the utilization of image information. In order to correct for image distortion, the fisheye camera needs to be calibrated.
The calibration method related to the fisheye camera can be to use a plane target, and tool software based on the plane target is available, for example: matlab toolbox and Opencv tool software. In these methods, a planar calibration plate is placed in front of a camera at different positions to acquire multiple target images, so as to obtain calibration raw data with a large distribution range. The method needs to place the calibration plate at different positions and acquire target images for many times, or rotate the camera at different directions and acquire the target images for many times. These methods are not suitable for some applications where it is necessary to quickly install the fisheye camera and perform calibration, such as mass production or production line for assembling fisheye cameras.
Therefore, the inventor proposes the utility model discloses a mark target for fisheye camera is markd, mark target includes the casing and a plurality of mark point, the casing include to the casing is inside sunken hemisphere internal surface, a plurality of mark point are formed at hemisphere internal surface. Through the target, a plurality of target images do not need to be acquired by moving the target or a camera, and the fisheye camera can be calibrated quickly and with high precision by acquiring one target image.
The fisheye camera calibration target and the fisheye camera calibration system provided by the embodiments of the present application will be described in detail by the following specific embodiments.
Referring to fig. 1, the present embodiment provides a fisheye camera calibration system, which may specifically include a target 100, a fisheye camera 200 and an electronic device 300. The fisheye camera 200 is electrically connected to the electronic device 300. The shell of the target comprises a hemispherical inner surface which is concave inwards, the fisheye camera 200 is arranged at the position of the center of the sphere corresponding to the hemispherical inner surface of the target 100 and used for shooting the target 100 to obtain a target image, and the electronic device 300 analyzes and processes the target image shot by the fisheye camera and determines the imaging model parameters of the fisheye camera 200, so that the fisheye camera 200 is calibrated. By shooting the target 100 provided by the embodiment of the application, the fisheye camera 200 can be calibrated quickly and accurately by acquiring only one target image.
Referring to fig. 2, a target 100 for fisheye camera calibration provided by the present application is shown, wherein the target 100 includes a housing 110 and a plurality of mark points 120, and the mark points 120 are disposed on the housing 110.
The housing 110 includes an outer surface and a hemispherical inner surface 111 recessed into the housing 110, the outer surface of the housing may be hemispherical as shown in fig. 2, or may be rectangular or have other shapes, and the overall shape of the housing and the shape of the outer surface of the housing are not limited herein.
In one embodiment, the plurality of markers 120 may be a plurality of holes on the hemispherical inner surface 111, the plurality of holes are all the same size, and the light emitted from the light source through the holes forms the markers 120 on the hemispherical inner surface 111. In another embodiment, the plurality of marker points 120 may be a plurality of spherical marker points installed in the holes of the hemispherical inner surface 111, wherein the diameters of the plurality of spherical marker points are the same. Specifically, the marks 120 are distributed on the hemispherical inner surface such that one mark 120 is disposed at the center of the hemispherical inner surface 111, and the rest marks 120 can be uniformly distributed on the hemispherical inner surface 111 according to actual requirements.
Referring to fig. 3, a plan view of the distribution of marker points 120 on the hemispherical inner surface 111 of target 100 is shown according to an embodiment of the present application. Wherein the hemispherical inner surface 111 has marking points 120 distributed therein. The number of the mark points 120 is not less than 23, so that the precision of the fisheye camera calibration by the target is higher. The mark points 120 are arranged in fixed latitude and longitude in the hemispherical inner surface 111, in fig. 3, the latitude line 112 is a circular ring, and the longitude line 113 is a line segment passing through the center of the hemispherical inner surface 111. Specifically, the longitude and latitude of each marker 120 may be set according to needs, in this embodiment, the number of the set markers 120 is 49, for example, as shown in fig. 3, the longitude may be 12 in total, and the latitude may be five in total, where 0,30,60,90,120,150,180,210,240,270,300,330, and the marker 120 is set at the intersection of the latitude line 112 and the longitude line 113.
Referring to fig. 4, a target 100 for fisheye camera calibration is shown according to some embodiments of the present disclosure. The target 100 includes a casing 110, a mark point 120 and at least one light source 130, the casing 110 includes a hemispherical inner surface 111 recessed toward the inside of the casing, and the mark point 120 is formed on the hemispherical inner surface 111 with a plurality of circular holes, wherein the holes have the same diameter. The light emitted by the at least one light source 130 through the hole forms the marker 120 on the hemispherical inner surface 111. Since the holes have the same size, the light emitted from the light source 130 through the holes has the same size, that is, the size of the mark point 120 formed by the light emitted from the light source through the holes is the same.
Specifically, the at least one light source 130 is disposed inside the housing 110. As shown in fig. 4, the housing of the housing 110 has a rectangular shape, and the light source 130 is disposed on the rectangular shape. It is understood that the shape of the shell of the housing 110 can be set according to the requirement, and is not limited herein.
It can be understood that, the light emitted by the light source 130 is emitted from the hole to form the mark point 120, and the other part of the housing 110 needs to be shielded from light so that the light emitted by the light source is emitted from the hole only. The holes can be further pasted with light-transmitting diffuse reflection films 121 covering the holes, so that light emitted from the holes is more uniform and clearer. In addition, the hemispherical inner surface 111 can be set to be black so as to form contrast with light emitted from the hole, so that the mark point of the fisheye camera is imaged more clearly when the fisheye camera shoots the target image, and the calibration of the fisheye camera is more accurate.
The target 100 for fisheye camera calibration provided by the embodiment of the application comprises a shell 110 and a plurality of mark points 120, wherein the shell 110 comprises a hemispherical inner surface 111 recessed towards the inside of the shell 110, and the plurality of mark points 120 are a plurality of holes formed on the hemispherical inner surface 111. The target 100 may further include at least one light source 130, and the mark point 120 is formed by emitting light emitted from the at least one light source 130 through a hole. The fisheye camera is arranged at the center of the sphere of the hemispherical inner surface 111, so that the fisheye camera can shoot the hemispherical inner surface 111 to obtain a target image, and the target image is analyzed and processed through electronic equipment, so that the fisheye camera can be calibrated quickly and accurately.
Referring to fig. 5, a target 100 for fisheye camera calibration according to another embodiment of the present application is shown, wherein the target 100 includes a housing 110, a mark point 120, and a light source 130, and the housing 110 includes a hemispherical inner surface 111 recessed toward the inside of the housing; the mark points 120 are spherical mark points and are installed in the plurality of holes on the hemispherical inner surface, wherein the diameters of the installed plurality of spherical mark points are the same, and the centers of the spherical mark points are located on the connecting line of the centers of the holes and the center of the hemispherical inner surface. Specifically, the spherical mark points may be embedded in the hemispherical inner surface 111, that is, a part of the spherical mark points protrudes from the hemispherical inner surface 111, or the whole spherical mark points protrude from the hemispherical inner surface 111. As shown in fig. 5, the diameter of the spherical mark point is larger than that of the hole, and the spherical mark point protrudes from the hemispherical inner surface as a whole, it is understood that the diameter of the spherical mark point may be equal to that of the hole, and is not limited herein.
In one embodiment, the spherical mark points are small balls having a diffuse reflection surface, the target 100 may further include at least one light source 130, the at least one light source 130 is disposed on the inner surface side of the hemisphere in the housing 110, and the light emitted from the at least one light source 130 may be irradiated to the plurality of spherical mark points to form the mark points 120 on the inner surface 111 of the hemisphere.
In another embodiment, the spherical mark point may be a self-luminous mark point, the light emitted from itself may illuminate the spherical mark point, the surface of the spherical mark point may be a diffuse reflection surface, and the mark point 120 is formed on the hemispherical inner surface 111 by the light emitted from itself.
The number of the spherical mark points installed in the holes is not less than 23, so that the accuracy of calibrating the fisheye camera by adopting the target is higher.
It is understood that the mark points 120 formed by irradiating the plurality of spherical mark points with light emitted from the light source 130 or the mark points 120 formed by emitting light from the spherical mark points themselves need to be light-absorbed by other parts of the housing 110, so that the light emitted from the light source only illuminates the spherical mark points. In addition, the hemispherical inner surface 111 may be set to black to compare with light diffusely reflected by the spherical mark points, so that the mark points are imaged more clearly when the fisheye camera shoots the target image, and the fisheye camera is calibrated more accurately.
In the embodiment of the present application, the color of the hemispherical inner surface 111 and the mark point 120 is a color capable of forming a strong contrast, for example, the color of the hemispherical inner surface 111 is black, and the color of the mark point 120 is white, so as to highlight the mark point 120, so that the image of the mark point is clearer when the fisheye camera takes the target image, and the calibration of the fisheye camera is more accurate. The color of the hemispherical inner surface 111 and the color of the mark point 120 may also be set according to actual requirements, and are not limited herein.
The utility model provides a mark target 100 for fisheye camera is markd, mark target 100 includes casing 110, mark point 120, casing 110 include to casing 110 inside sunken hemisphere internal surface 111, a plurality of holes have been seted up on the hemisphere internal surface, install the same spherical mark point of diameter in a plurality of holes of hemisphere internal surface, the sphere of spherical mark point is on the line of the center of hole and the centre of sphere of hemisphere internal surface. The plurality of markers 120 are spherical markers formed in a plurality of holes of the hemispherical inner surface 111. The inner hemispherical surface 111 has a sphere center, and the fisheye camera is arranged at the sphere center position, so that the fisheye camera can shoot the inner hemispherical surface 111 to obtain a target image, and the target image is analyzed and processed by electronic equipment, so that the fisheye camera can be calibrated quickly and accurately.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The target for calibrating the fisheye camera is characterized by comprising a shell and a plurality of marking points, wherein the shell comprises a hemispherical inner surface sunken towards the inside of the shell, the marking points are a plurality of holes formed in the hemispherical inner surface, and the distance from the center of each hole to the center of the sphere of the hemispherical inner surface is equal to the radius of the hemispherical inner surface.
2. A target according to claim 1, further comprising at least one light source disposed within the housing, wherein the at least one light source shines light at the plurality of cavities to form the marker points on the hemispherical inner surface.
3. A target according to claim 2, wherein the plurality of holes are coated with a light-transmissive diffusely reflective film covering the holes.
4. A target according to claim 1, wherein the hemispherical inner surface is black.
5. A target according to claim 1, wherein the number of the plurality of marker points is not less than 23, and one marker point is disposed at a central position of the hemispherical inner surface.
6. The target for calibrating the fisheye camera is characterized by comprising a shell and a plurality of mark points, wherein the shell comprises a hemispherical inner surface sunken into the shell, a plurality of holes are formed in the hemispherical inner surface, a plurality of spherical mark points are installed in the holes of the hemispherical inner surface, the diameters of the spherical mark points are the same, and the sphere center of each spherical mark point is located on a connecting line of the center of each hole and the sphere center of the hemispherical inner surface.
7. A target according to claim 6, wherein the spherical marker surfaces are diffusely reflective surfaces, the target further comprising at least one light source disposed on the hemispherical inner surface, the at least one light source emitting light that impinges on the plurality of spherical markers forming the plurality of markers on the hemispherical inner surface.
8. A target according to claim 6, wherein the spherical marker points are self-luminous marker points.
9. A target according to claim 6, wherein the number of the plurality of marking points is not less than 23, and one marking point is arranged at the center of the hemispherical inner surface.
10. A camera calibration system, comprising a fisheye camera, an electronic device and a target according to any one of claims 1 to 9, wherein the fisheye camera is disposed at a center of a hemisphere of an inner surface of the target, and the electronic device is electrically connected to the fisheye camera; the electronic equipment is used for calibrating the fisheye camera according to a target image, and the target image is obtained by shooting the target at the spherical center position of the target by the fisheye camera.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920664110.6U CN209820398U (en) | 2019-05-08 | 2019-05-08 | Target and system for calibrating fisheye camera |
| PCT/CN2019/113440 WO2020224199A1 (en) | 2019-05-08 | 2019-10-25 | Fisheye camera calibration system, method and apparatus, electronic device, and storage medium |
| EP19928032.2A EP3967969B1 (en) | 2019-05-08 | 2019-10-25 | Fisheye camera calibration system, method and apparatus, electronic device, and storage medium |
| US17/469,840 US11514608B2 (en) | 2019-05-08 | 2021-09-08 | Fisheye camera calibration system, method and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920664110.6U CN209820398U (en) | 2019-05-08 | 2019-05-08 | Target and system for calibrating fisheye camera |
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| Publication Number | Publication Date |
|---|---|
| CN209820398U true CN209820398U (en) | 2019-12-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201920664110.6U Active CN209820398U (en) | 2019-05-08 | 2019-05-08 | Target and system for calibrating fisheye camera |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113432536A (en) * | 2021-08-25 | 2021-09-24 | 深圳市勘察研究院有限公司 | Target and target device |
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2019
- 2019-05-08 CN CN201920664110.6U patent/CN209820398U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113432536A (en) * | 2021-08-25 | 2021-09-24 | 深圳市勘察研究院有限公司 | Target and target device |
| CN113432536B (en) * | 2021-08-25 | 2021-12-17 | 深圳市勘察研究院有限公司 | Target and target device |
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