CN108765301B - An optical system and its distortion correction method and system - Google Patents

Abstract

The invention discloses an optical system and its distortion correction method and system. The distortion correction method includes: acquiring the focal length of the first collimator lens when the collimator produces parallel light; determining the visible light image and the near-infrared image according to the focal length of the first collimator lens; taking the optical axis of the incident light as Z axis, the plane perpendicular to the optical axis is the XOY plane, and the image coordinate system is established; the side length of the unit square in the grid plate is obtained; the grid plate includes a plurality of unit squares; the unit square is determined according to the side length. corresponding pixel points; determine a coordinate transformation matrix according to the pixel points and the image coordinate system; determine a visible light undistorted image according to the visible light image and the transformation matrix; determine a near-infrared image according to the near-infrared image and the transformation matrix Infrared distortion-free images. Using the optical system and the distortion correction method and system provided by the present invention can reduce the measurement error of the optical system.

Description

An optical system and its distortion correction method and system

technical field

The invention relates to the technical field of optical distortion correction, in particular to an optical system and a distortion correction method and system thereof.

Background technique

The laser semi-active terminal-guided weapon system consists of an illuminator and a guided munition. The illuminator emits laser light to illuminate the attacked target, and the guided munition recognizes and strikes the target according to the irradiation spot; the laser irradiation performance is an important indicator for evaluating the weapon system, and the spatial characteristics of the laser irradiation performance The monitoring system captures the moving diffuse reflection target and measures it with a single visible light camera. However, when a single visible light camera is downgraded for measurement, since the imaging spectral response range of the visible light camera only has a high quantum efficiency in the visible light range, although it has a response to the near-infrared light of 1064 nm, the quantum efficiency is low, so a single visible light camera has a low quantum efficiency. When the target plate (visible light) and the spot (near-infrared) are imaged at the same time, a single visible light camera must have a large integration time to image, so a large background noise will be introduced, and the signal-to-noise ratio of the spot image will be low, resulting in a large measurement error of the optical system. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an optical system and its distortion correction method and system, so as to solve the problem of large measurement error of the optical system in the prior art.

For achieving the above object, the present invention provides the following scheme:

An optical system, comprising: a light source, a collimator light pipe and a telephoto optical system are sequentially arranged on one side of the light source, and the telephoto optical system is connected with a computer;

The parallel light pipe is provided with a grid plate;

The light source, the collimator light pipe and the bottom of the telephoto optical system are respectively provided with an adjustment table; the adjustment table is used to adjust the positions of the light source, the collimator light pipe and the telephoto optical system;

The telephoto optical system includes a Cassegrain reflection structure, a lens, a beam splitter prism, a visible light camera, a filter, a reflection mirror and a near-infrared camera; the lens includes a first lens, a second lens and a third lens; the The telephoto optical system receives the light emitted by the light source, and is transmitted to the beam splitting prism by the Cassegrain reflection structure through the first lens; the beam splitting prism divides the light into two paths, the first The path light is collected by the visible light camera through the second lens, and the positions of the grid plate and the telephoto optical system are adjusted to obtain a visible light image; the second path light passes through the filter, and then passes through the reflector. The second path of light is collected by the near-infrared camera through the third lens, and the positions of the grid plate and the telephoto optical system are adjusted again to obtain a near-infrared image; The coordinate system conversion of the near-infrared image is performed to obtain an undistorted visible light image and a near-infrared undistorted image.

A distortion correction method for an optical system, the distortion correction method being applied to an optical system of claim 1, the distortion correction method comprising:

Obtain the focal length of the first collimator lens when the collimator produces parallel light;

Determine the visible light image and the near-infrared image according to the focal length of the first collimator lens;

Taking the optical axis of the incident light as the Z axis and the plane perpendicular to the optical axis as the XOY plane, establish the image coordinate system;

Obtain the side length of the unit square in the grid plate; the grid plate includes a plurality of unit squares;

Determine the pixel point corresponding to the unit square according to the side length;

A coordinate transformation matrix is determined according to the pixel points and the image coordinate system; the coordinate transformation matrix is used to transform the distorted image into an undistorted image; the distorted image is a visible light image and a near-infrared image; the undistorted image includes Visible light distortion-free images and near-infrared distortion-free images;

determining an undistorted visible light image according to the visible light image and the transformation matrix;

A near-infrared undistorted image is determined according to the near-infrared image and the transformation matrix.

Optionally, the determining of the visible light image and the near-infrared image according to the focal length of the first collimator lens specifically includes:

Determine the visible light adjustment distance of the collimator according to the focal length of the first collimator lens;

A visible light image is determined according to the visible light adjustment distance.

Optionally, the determining of the visible light image and the near-infrared image according to the focal length of the first collimator lens specifically includes:

determining the focal length of the second collimator lens according to the focal length of the first collimator lens;

determining the near-infrared adjustment distance of the collimator according to the focal length of the second collimator lens;

A near-infrared image is determined according to the near-infrared adjustment distance.

Optionally, the determining the pixel point corresponding to the unit square according to the side length specifically includes:

According to the side length, a pinhole imaging model is used to determine the pixel point corresponding to the unit square.

Optionally, the determining a coordinate transformation matrix according to the pixel points and the image coordinate system specifically includes:

Get the world coordinate system;

determining a world-image transformation matrix according to the world coordinate system and the image coordinate system;

A coordinate transformation matrix is determined according to the pixel points and the world-image transformation matrix.

An optical system distortion correction system, comprising:

The first collimator lens focal length acquiring module is used to acquire the focal length of the first collimator lens when the collimator generates parallel light;

an image determination module, configured to determine a visible light image and a near-infrared image according to the focal length of the first collimator lens;

The image coordinate system establishment module is used to establish the image coordinate system with the optical axis of the incident light as the Z axis and the plane perpendicular to the optical axis as the XOY plane;

a side length acquiring module, used for acquiring the side length of a unit square in the grid board; the grid board includes a plurality of unit squares;

a pixel point determination module, configured to determine the pixel point corresponding to the unit square according to the side length;

a coordinate transformation matrix determination module, configured to determine a coordinate transformation matrix according to the pixel points and the image coordinate system; the coordinate transformation matrix is used to transform a distorted image into an undistorted image; the distorted image is a visible light image and a near-infrared image an image; the undistorted image includes a visible light undistorted image and a near-infrared undistorted image;

a visible light undistorted image determination module, configured to determine a visible light undistorted image according to the visible light image and the transformation matrix;

A near-infrared undistorted image determination module, configured to determine a near-infrared undistorted image according to the near-infrared image and the transformation matrix.

Optionally, the image determination module specifically includes:

a visible light adjustment distance determining unit, configured to determine the visible light adjustment distance of the collimator according to the focal length of the first collimator lens;

A visible light image determination unit, configured to determine a visible light image according to the visible light adjustment distance.

Optionally, the image determination module specifically includes:

a second collimator lens focal length determining unit, configured to determine the second collimator lens focal length according to the first collimator lens focal length;

a near-infrared adjustment distance determining unit, configured to determine the near-infrared adjustment distance of the collimator according to the focal length of the second collimator lens;

A near-infrared image determination unit, configured to determine a near-infrared image according to the near-infrared adjustment distance.

Optionally, the pixel point determination module specifically includes:

The pixel point determination unit is configured to use the pinhole imaging model to determine the pixel point corresponding to the unit square according to the side length.

According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the present invention provides an optical system and a distortion correction method and system thereof. The optical system is provided with a visible light camera and a near-infrared camera. By correcting the images obtained by the two cameras, a corrected image without distortion can be obtained. Compared with the imaging technology using a single visible light camera in the prior art, it can The imaging time is greatly shortened, and the measurement error of the optical system is reduced.

The distortion correction method and system of the optical system provided by the present invention determine the coordinate transformation matrix according to the unit square in the grid plate, thereby transforming the visible light image obtained by the visible light camera into a visible light undistorted image, and converting the image obtained by the near-infrared camera. The near-infrared image is transformed into a near-infrared undistorted image, thereby reducing the measurement error of the optical system.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative labor.

1 is a structural diagram of an optical system provided by the present invention;

Fig. 2 is the first calibration image provided by the present invention;

3 is a structural diagram of a telephoto optical system provided by the present invention;

4 is a flowchart of an optical distortion correction method provided by the present invention;

Fig. 5 is the coordinate system transformation relation diagram provided by the present invention;

6 is a schematic diagram of a first captured image provided by the present invention;

FIG. 7 is a schematic diagram of an image after distortion correction of the first captured image in FIG. 6 provided by the present invention;

Fig. 8 is the coordinate point marking diagram to be collected to mark the first collected image in Fig. 6 provided by the present invention;

9 is a schematic diagram of a near-infrared image provided by the present invention;

10 is a schematic diagram of the near-infrared image in FIG. 9 after distortion correction provided by the present invention;

Fig. 11 is a marker diagram of coordinate points to be collected to mark the near-infrared image in Fig. 9 provided by the present invention

FIG. 12 is a structural diagram of an optical system distortion correction system provided by the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The purpose of the present invention is to provide an optical system and its distortion correction method and system to reduce the measurement error of the optical system.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a structural diagram of an optical system provided by the present invention. As shown in FIG. 1, an optical system includes: a light source 1, and a collimator light pipe 2 and a telephoto optical system 3 are arranged on one side of the light source 1 in sequence. , the telephoto optical system 3 is connected with the computer 4; the parallel light pipe 2 is provided with a grid plate 5; the bottom of the light source 1, the collimated light pipe 2 and the telephoto optical system 3 are respectively There is an adjustment table; the adjustment table is used to adjust the positions of the light source 1, the collimator light pipe 2 and the telephoto optical system 3; the adjustment table includes a first adjustment table 6 and a second adjustment table 7 , the third adjustment stage 8, wherein, as shown in FIG. 1, the first adjustment stage 6, the second adjustment stage 7 and the third adjustment stage 8 are connected with the light source 1, the collimator light pipe 2 and the telephoto optical system 3 one by one correspond. Before acquiring an image, first adjust the positions of each device in the optical system so that the center point of the grid plate 5 is imaged in the center of the visible light image, as shown in FIG. 2 .

FIG. 3 is a structural diagram of a telephoto optical system provided by the present invention. As shown in FIG. 3 , the telephoto optical system includes a Cassegrain reflection structure 3-1, a lens, a beam splitter prism 3-2, and a visible light camera 3-3 , a filter 3-4, a mirror 3-5 and a near-infrared camera 3-6; the lens includes a first lens, a second lens and a third lens; the telephoto optical system receives the light emitted by the light source 1 The light is transmitted by the Cassegrain reflection structure 3-1 to the beam splitting prism 3-2 via the first lens 3-7; the beam splitting prism 3-2 divides the light into two paths, The first line of light is collected by the visible light camera 3-3 through the second lens 3-8, and the positions of the grid plate 5 and the telephoto optical system are adjusted to obtain a visible light image; the second line of light passes through the The filter 3-4 and the reflector 3-5, through the reflector 3-5, the second path of light is collected by the near-infrared camera 3-6 through the third lens 3-9 , adjust the position of the grid plate 5 and the telephoto optical system again to obtain a near-infrared image; perform coordinate system conversion on the visible light image and the near-infrared image to obtain an undistorted visible light image and a near-infrared undistorted image image.

The optical system provided by the invention can shorten the imaging time, reduce the background noise, and improve the signal-to-noise ratio of the spot image, thereby reducing the measurement error of the optical system and improving the measurement accuracy of the optical system.

According to the optical system provided by the present invention, the light source at the equivalent distance L of the collimator is adopted, and the adjustment position of the grid plate 5 corresponding to the equivalent L light source of the two cameras is calculated as follows:

Among them, the collimator used is an adjustable collimator, the focal length is f' when the parallel light is generated, and the scale of the fine-tuning scale of the collimator is r.

FIG. 4 is a flowchart of an optical distortion correction method provided by the present invention. As shown in FIG. 4 , a method for correcting optical system distortion includes:

Step 401: Obtain the focal length of the first collimator lens when the collimator produces parallel light.

其中k为比例常系数，n为空气中折射率，n'为可见光相机透镜折射率。It is known that the relationship between the focal length of the first collimator lens and the refractive index is as follows

Where k is the proportional constant coefficient, n is the refractive index in air, and n' is the refractive index of the visible light camera lens.

Step 402: Determine a visible light image and a near-infrared image according to the focal length of the first collimator lens.

由此计算第二平行光管透镜焦距，此时，空气中折射率n，近红外光谱范围透镜折射率n'_IR，k已知，可得

其中f'_IR为产生近红外平行光等效目标源时，平行光管调整后的第二平行光管透镜焦距。From the known parameters in step 401, f', n, n' can be obtained:

From this, the focal length of the second collimator lens is calculated. At this time, the refractive index n in the air and the refractive index n' _IR of the lens in the near-infrared spectral range are known, and k can be obtained.

Wherein f' _IR is the focal length of the second collimator lens adjusted by the collimator when the near-infrared parallel light equivalent target source is generated.

等效v＝L网格板距离平行光管的距离为

其中，f是焦距，v为像距(就是等效距离L)，u是物距，就是网格板距离平行光管透镜的距离。Imaging formula:

The distance between the equivalent v=L grid plate and the collimator light pipe is

Among them, f is the focal length, v is the image distance (that is, the equivalent distance L), and u is the object distance, which is the distance between the grid plate and the collimator lens.

近红外光时，网格板距离平行光管透镜的距离

When the visible light is calculated by the imaging formula, the distance between the grid plate and the collimator lens

For near-infrared light, the distance between the grid plate and the collimator lens

Therefore, the relative position adjustment relative to the focal length of the collimator is:

When visible light: Δu _Vis = u _Vis -f';

For near-infrared light: Δu _IR =u _IR -f'.

The corresponding collimator fine-tuning scale scale is:

In visible light: r _Vis =r+Δu _Vis ;

For near-infrared light: r _IR =r+Δu _IR .

Adjust the position of the grid plate to r _Vis to make the visible light camera image clear and collect the visible light image; adjust the position of the grid plate to r _IR again to make the near-infrared camera image clear and collect the near-infrared image.

When rotating the telephoto optical system, the central axis of the image remains unchanged during each rotation, and the adjustment is based on the fact that the center of the grid plate is imaged in the center of the field of view of the two cameras, and the angle between the grid line and the horizontal line gradually increases.

The position of the grid plate is adjusted cyclically, and the telephoto optical system is adjusted, so that the visible light camera and the near-infrared camera can obtain images from different shooting angles, and re-collect multiple pairs of visible light images and near-infrared images of different angles, and the number of cycles N is greater than or equal to 14 times (The number of times is determined by the final required number of unknowns, the number of equations that can be listed per image, and the reprojection error).

Step 403: Taking the optical axis of the incident light as the Z axis, and the plane perpendicular to the optical axis as the XOY plane, establish an image coordinate system.

As shown in Figure 5, take the optical axis of the incident light as the Z axis, and the plane perpendicular to the optical axis as the XOY plane, establish the incident light coordinate system O-XCYCZC; take the optical axis of the visible light camera as the Z axis, perpendicular to the visible light incident light The axis is the XOY plane, and the visible camera coordinate system OC1-XC1YC1ZC1 is established; the optical axis of the near-infrared camera is the Z axis, and the XOY plane is perpendicular to the near-infrared incident optical axis, and the near-infrared camera coordinate system OC2-XC2YC2ZC2 is established; the image pixel coordinate system: Taking the upper left corner of the two-dimensional image as the coordinate origin, the horizontal axis is the u axis, and the vertical axis is the v axis, the image pixel coordinate system is established; the image physical coordinate system: the image center point is the origin, the horizontal axis is the x axis, and the vertical axis is y. axis. The world coordinate system OX _W Y _W Z _W and the incident light coordinate system OX _C Y _C Z _C are the relationship between rotation and translation, which requires 6 parameters; point P is any point in the world coordinate system OX _W Y _W Z _W , through the incident light The coordinate system OX _C Y _C Z _C connects the visible light camera coordinate system O _C1 -X _C1 Y _C1 Z _C1 with the near-infrared camera coordinate system O _C2 -X _C2 Y _C2 Z _C2 , and requires 12 parameters, among which, the three-dimensional coordinate system It is transformed into a rotation and translation relationship, and the rotation and translation have 3 parameters respectively, a total of 6 parameters; therefore, between the incident light coordinate system OX _C Y _C Z _C and the visible light camera coordinate system O _C1 -X _C1 Y _C1 Z _C1 is the rotation and The translation relationship has a total of 6 parameters; similarly, 6 parameters are also required between the incident light coordinate system OX _C Y _C Z _C and the near-infrared camera coordinate system O _C2 -X _C2 Y _C2 Z _C2 ; as shown in Figure 5, a total of 6 parameters are required. The axis part is the incident light axis, which is the Z _C axis of the incident light coordinate system OX _C Y _C Z _C. The light reaching the two cameras is the same light before the beam splitting prism, and the two cameras are connected by this coaxial part.

The relationship between the visible light camera coordinate system OC1-XC1YC1ZC1 and the visible light image pixel coordinate system u1ov1 is that the internal parameters of the camera are 4 parameters. Similarly, the near-infrared camera also has 4 internal parameters, and then the visible light image pixel coordinate system u1ov1 and the near-infrared image. The pixel coordinate system u2ov2 relationship is determined. A total of 6+12+4+4=26 parameters need to be solved. Here, it is explained that a camera needs to solve 16 parameters. If the two cameras are not related, 32 parameters need to be solved. Here, the two cameras have coaxial parts, so one less rigid body transformation can be done.

It can be seen that the traditional single-camera optical correction needs to solve 16 parameters, and the two cameras need 32 parameters. While our optical correction method requires a total of 26 parameters for the two cameras, the distortion correction method provided by the present invention can reduce the calculation amount of the parameter solution.

It can provide 8 variances for plane images, that is, mapping a square to a quadrilateral can be described by 4 (x, y), and for four fields of view, there are 8*4=32=4*6+4+4, that is, the solution For all parameters, at least four fields of view are required, that is, the visible light camera and the near-infrared camera require a total of four fields of view, so a total of four images (two for visible light and two for near-infrared) are required. In order to improve the accuracy and reduce the random error, the number of images N is greater than or equal to 14, and the reprojection error is less than 0.5 pixels. Table 1 is the reprojection error statistics table, as shown in Table 1.

Table 1

number of images 10 14 16 18 Reprojection error (pixels) 0.550324 0.451422 0.440131 0.380354

It can be seen from Table 1 that the larger the number of acquired images, the lower the reprojection error.

Step 404: Obtain the side lengths of the unit squares in the grid board; the grid board includes a plurality of unit squares.

Step 405: Determine the pixel point corresponding to the unit square according to the side length.

Step 406: Determine a coordinate transformation matrix according to the pixel points and the image coordinate system; the coordinate transformation matrix is used to transform the distorted image into an undistorted image; the distorted image is a visible light image and a near-infrared image; Distorted images include visible light undistorted images and near-infrared undistorted images.

Step 407: Determine an undistorted visible light image according to the visible light image and the transformation matrix.

Step 408: Determine a near-infrared undistorted image according to the near-infrared image and the transformation matrix.

Distortion coordinate extraction, the collected images are shown in Figure 6 and Figure 9, and the grid corner points with the size of the 9*9 matrix in the image center are selected, that is, the image formed by the 9*9 grid points in the dotted frame in Figure 2, Extract grid corner coordinates. The extraction coordinates are as shown in Figure 8, the grid point coordinates marked in Figure 11, wherein, Figure 8 is the grid point marked by the visible light image, and Figure 11 is the grid point marked by the near-infrared image; wherein, the marked grid point coordinates It's a bright dot.

Calculate the dual camera calibration model, as shown in Figure 5, the visible light image physical coordinate system x1oy1, the near-infrared image physical coordinate system x2oy2, the visible light image pixel coordinate system u1ov1, the near-infrared image pixel coordinate system u2ov2, and the world coordinate system OX _W Y _W Z _W , the incident light takes the optical axis as the Z axis and the XOY plane perpendicular to the optical axis to establish a coordinate system (incident light coordinate system) OX _C Y _C Z _C , the visible light camera coordinate system O _C1 -X _C1 Y _C1 Z _C1 , near infrared Camera coordinate system O _C2 -X _C2 Y _C2 Z _C2 . From the world coordinate system to the image pixel coordinate system is represented by the matrix T _m . As shown in the grid plate in Figure 2, each small grid is a square with side length d. Through the small hole imaging model, the pixel size dpix corresponding to the side length d on the ideal image can be calculated, and the ideal undistorted image can be determined according to dpix. The grid point coordinate relationship, combined with the matrix T _m to obtain the ideal undistorted image coordinate C _d , therefore, the previously extracted distortion coordinate is marked as C, and the relationship between C _d and C is: C _d =C · T, where T is the distortion The coordinate transformation matrix of the image to the undistorted image.

Assume that the image after optical correction is I', and the image with optical distortion is I. According to the matrix T, the relationship between the three is obtained as: I'=I·T

Collect the images, and through matrix transformation, the visible light and near-infrared undistorted images are obtained. The visible light images are shown in Figure 6 and the near-infrared images are shown in Figure 9. The matrix T transformation is performed to obtain the visible light undistorted images as shown in Figure 7 and the near-infrared undistorted images. The image shown in Figure 10.

Applying the distortion correction method provided by the present invention to practice, the present invention adopts the equivalent 1Km light source of the collimator, and the calculation of the adjustment position of the grid plate corresponding to the equivalent 1Km light source of the two cameras is as follows:

因此，n＝1，n'＝1.516960102，k＝0.0012000907；

即产生等效1Km近红外光的平行光管焦距为f'_IR＝1611.87mm；平行光管微调标尺刻度为r＝105mm。When the invention generates parallel light, f'=1604.07mm, and the scale of the fine-tuning scale of the parallel light pipe is r=97.2mm, then f'=1604.07mm, n=1, n'=1.5194725831 can be obtained,

Therefore, n=1, n'=1.516960102, k=0.0012000907;

That is, the focal length of the collimator that generates the near-infrared light equivalent to 1Km is f' _IR =1611.87mm; the scale of the fine-tuning scale of the collimator is r=105mm.

等效v＝1000000mm网格板放置位置为

计算可得，u_Vis＝1606.64717mm，u_IR＝1614.47232mm，那么相对于平行光管焦距调整相对位置为Δu_Vis＝u_Vis-f'＝1606.64717-1604.07＝2.57717mm以及Δu_IR＝u_IR-f'＝1614.47232-1604.07＝10.40232mm；对应平行光管微调标尺刻度为r_Vis＝r+Δu_Vis＝99.77717mm以及r_IR＝r+Δu_IR＝107.60232mm；By the imaging formula:

The equivalent v=1000000mm grid plate placement position is

It can be calculated that u _Vis =1606.64717mm, u _IR =1614.47232mm, then the relative position adjustment relative to the focal length of the collimator is Δu _Vis =u _Vis -f'=1606.64717-1604.07=2.57717mm and Δu _IR =u _IR -f '=1614.47232-1604.07=10.40232mm; the corresponding collimator fine-tuning scale scale is r _Vis =r+Δu _Vis =99.77717mm and r _IR =r+Δu _IR =107.60232mm;

Adjust the position of the grid plate to r _Vis to make the visible light camera image clear and collect the visible light image; adjust the position of the grid plate to r _IR again to make the near-infrared camera image clear and collect the near-infrared image; The center axis of the image remains unchanged during the rotation process, and the adjustment is based on the fact that the center of the grid plate is imaged in the center of the field of view of the two cameras, and the angle between the grid line and the horizontal line gradually increases.

The above adjustment steps are repeated, and the number of cycles N is greater than or equal to 14 times (the number of times is determined by the number of unknowns finally required and the number of equations that can be listed in each image, and the reprojection error is calculated).

As shown in FIG. 5, the coordinate transformation matrix T is determined.

For restoration and correction, during the test, images are collected, and after A/D conversion, the system-level matrix T processes the images to obtain visible light and near-infrared distortion-free images, as shown in Figure 6-11.

FIG. 12 is a structural diagram of an optical system distortion correction system provided by the present invention. As shown in FIG. 12 , an optical system distortion correction system includes:

The first collimator lens focal length acquiring module 1201 is configured to acquire the focal length of the first collimator lens when the collimator generates parallel light.

The image determination module 1202 is configured to determine a visible light image and a near-infrared image according to the focal length of the first collimator lens.

The image determination module 1202 specifically includes: a visible light adjustment distance determination unit, used for determining the visible light adjustment distance of the collimator according to the focal length of the first collimator lens; a visible light image determination unit, used for adjusting according to the visible light Distance determines the visible light image.

The image determination module 1202 specifically includes: a second collimator lens focal length determination unit, used to determine the second collimator lens focal length according to the first collimator lens focal length; The focal length of the second collimator lens determines the near-infrared adjustment distance of the collimator; the near-infrared image determination unit is configured to determine the near-infrared image according to the near-infrared adjustment distance.

The image coordinate system establishing module 1203 is used for establishing the image coordinate system with the optical axis of the incident light as the Z axis and the plane perpendicular to the optical axis as the XOY plane.

The side length acquiring module 1204 is configured to acquire the side length of a unit square in the grid board; the grid board includes a plurality of unit squares.

The pixel point determination module 1205 is configured to determine the pixel point corresponding to the unit square according to the side length.

The pixel point determination module 1205 specifically includes: a pixel point determination unit, configured to use a pinhole imaging model to determine the pixel point corresponding to the unit square according to the side length.

The coordinate transformation matrix determination module 1206 is used to determine a coordinate transformation matrix according to the pixel points and the image coordinate system; the coordinate transformation matrix is used to transform the distorted image into an undistorted image; the distorted image is a visible light image and a near- Infrared images; the undistorted images include visible light undistorted images and near-infrared undistorted images.

The visible light undistorted image determination module 1207 is configured to determine the visible light undistorted image according to the visible light image and the transformation matrix.

The near-infrared undistorted image determination module 1208 is configured to determine the near-infrared undistorted image according to the near-infrared image and the transformation matrix.

Using the optical system distortion correction method and system provided by the present invention can improve the measurement accuracy of the optical system and reduce the measurement error.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The principles and implementations of the present invention are described herein using specific examples. The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; meanwhile, for those skilled in the art, according to the present invention There will be changes in the specific implementation and application scope. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. An optical system, characterized in that, comprising: a light source, a parallel light pipe and a telephoto optical system are sequentially arranged on one side of the light source, and the telephoto optical system is connected with a computer; The parallel light pipe is provided with a grid plate; The light source, the collimator light pipe and the bottom of the telephoto optical system are respectively provided with an adjustment table; the adjustment table is used to adjust the positions of the light source, the collimator light pipe and the telephoto optical system; The adjustment stage includes a first adjustment stage, a second adjustment stage, and a third adjustment stage, wherein the first adjustment stage, the second adjustment stage and the third adjustment stage are connected to the light source, the collimator light pipe and the telephoto optical system. One correspondence; before acquiring the image, first adjust the position of each device in the optical system, so that the center point of the grid plate is imaged in the center of the visible light image; The telephoto optical system includes a Cassegrain reflection structure, a lens, a beam splitter prism, a visible light camera, a filter, a reflection mirror and a near-infrared camera; the lens includes a first lens, a second lens and a third lens; the The telephoto optical system receives the light emitted by the light source, and is transmitted to the beam splitting prism by the Cassegrain reflection structure through the first lens; the beam splitting prism divides the light into two paths, the first The path light is collected by the visible light camera through the second lens, and the positions of the grid plate and the telephoto optical system are adjusted to obtain a visible light image; the second path light passes through the filter, and is then reflected by the The second path of light is collected by the near-infrared camera through the third lens, and the positions of the grid plate and the telephoto optical system are adjusted again to obtain a near-infrared image; for the visible light image And the coordinate system conversion of the near-infrared image is performed to obtain an undistorted visible light image and a near-infrared undistorted image. 2. An optical system distortion correction method, wherein the distortion correction method is applied to an optical system of claim 1, and the distortion correction method comprises: Obtain the focal length of the first collimator lens when the collimator produces parallel light; Determine the visible light image and the near-infrared image according to the focal length of the first collimator lens; Taking the optical axis of the incident light as the Z axis and the plane perpendicular to the optical axis as the XOY plane, establish the image coordinate system; Obtain the side length of the unit square in the grid plate; the grid plate includes a plurality of unit squares; Determine the pixel point corresponding to the unit square according to the side length; A coordinate transformation matrix is determined according to the pixel points and the image coordinate system; the coordinate transformation matrix is used to transform the distorted image into an undistorted image; the distorted image is a visible light image and a near-infrared image; the undistorted image includes Visible light distortion-free images and near-infrared distortion-free images; determining an undistorted visible light image according to the visible light image and the transformation matrix; A near-infrared undistorted image is determined according to the near-infrared image and the transformation matrix. 3. The distortion correction method according to claim 2, wherein the determining of the visible light image and the near-infrared image according to the focal length of the first collimator lens specifically comprises: Determine the visible light adjustment distance of the collimator according to the focal length of the first collimator lens; A visible light image is determined according to the visible light adjustment distance. 4 . The distortion correction method according to claim 3 , wherein the determining of the visible light image and the near-infrared image according to the focal length of the first collimator lens specifically comprises: 5 . determining the focal length of the second collimator lens according to the focal length of the first collimator lens; determining the near-infrared adjustment distance of the collimator according to the focal length of the second collimator lens; A near-infrared image is determined according to the near-infrared adjustment distance. 5. The distortion correction method according to claim 2, wherein the determining the pixel corresponding to the unit square according to the side length specifically comprises: According to the side length, a pinhole imaging model is used to determine the pixel point corresponding to the unit square. 6. The distortion correction method according to claim 2, wherein the determining a coordinate transformation matrix according to the pixel points and the image coordinate system specifically comprises: Get the world coordinate system; determining a world-image transformation matrix according to the world coordinate system and the image coordinate system; A coordinate transformation matrix is determined according to the pixel points and the world-image transformation matrix. 7. An optical system distortion correction system, wherein the optical system distortion correction system is applied to an optical system of claim 1, comprising: The first collimator lens focal length acquiring module is used to acquire the focal length of the first collimator lens when the collimator generates parallel light; an image determination module, configured to determine a visible light image and a near-infrared image according to the focal length of the first collimator lens; The image coordinate system establishment module is used to establish the image coordinate system with the optical axis of the incident light as the Z axis and the plane perpendicular to the optical axis as the XOY plane; a side length acquiring module, used for acquiring the side length of a unit square in the grid board; the grid board includes a plurality of unit squares; a pixel point determination module, configured to determine the pixel point corresponding to the unit square according to the side length; a coordinate transformation matrix determination module, configured to determine a coordinate transformation matrix according to the pixel points and the image coordinate system; the coordinate transformation matrix is used to transform a distorted image into an undistorted image; the distorted image is a visible light image and a near-infrared image an image; the undistorted image includes a visible light undistorted image and a near-infrared undistorted image; a visible light undistorted image determination module, configured to determine a visible light undistorted image according to the visible light image and the transformation matrix; A near-infrared undistorted image determination module, configured to determine a near-infrared undistorted image according to the near-infrared image and the transformation matrix. 8. The distortion correction system according to claim 7, wherein the image determination module specifically comprises: a visible light adjustment distance determining unit, configured to determine the visible light adjustment distance of the collimator according to the focal length of the first collimator lens; A visible light image determination unit, configured to determine a visible light image according to the visible light adjustment distance. 9. The distortion correction system according to claim 8, wherein the image determination module specifically comprises: a second collimator lens focal length determining unit, configured to determine the second collimator lens focal length according to the first collimator lens focal length; a near-infrared adjustment distance determining unit, configured to determine the near-infrared adjustment distance of the collimator according to the focal length of the second collimator lens; A near-infrared image determination unit, configured to determine a near-infrared image according to the near-infrared adjustment distance. 10. The distortion correction system according to claim 7, wherein the pixel point determination module specifically comprises: The pixel point determination unit is configured to use the pinhole imaging model to determine the pixel point corresponding to the unit square according to the side length.

Images