CN105758428B - Method for calibrating dynamic deformation angle measurement error of dynamic target by utilizing calibration device - Google Patents

Abstract

The invention relates to a method for using a calibration device to calibrate the dynamic deformation angle measurement error of a dynamic target, aiming at solving the problem of low calibration accuracy of the traditional calibration device and method. The calibration device includes a dynamic target and an imaging device; the dynamic target is composed of a shaft angle encoder, a light source, a collimating objective lens and a reflector; the imaging device includes a first objective lens, a diffuser plate, a second objective lens and a CCD rigidly connected in sequence through the lens barrel , and the diffuser is located on the image focal plane of the first objective lens, and the CCD is located on the image plane of the second objective lens. The light emitted from the light source is collimated by the collimating objective lens and then incident on the reflector, the reflected light beam of the reflector is incident on the imaging device, and the star point image coordinates of the dynamic target are collected by the imaging device. The calibration method includes the following steps: 1) calibrate the dynamic target in advance when it is static; 2) calibrate the dynamic target in real time when it moves at a specific angular velocity; 3) calculate the angle error. The invention has the advantage of high calibration accuracy.

Description

Method of Calibrating Dynamic Deformation Angle Measurement Error of Dynamic Target Using Calibration Device

technical field

The invention belongs to the field of optics, and relates to a calibration device and a calibration method for the dynamic deformation angle measurement error of a dynamic target in a shooting range.

Background technique

Photoelectric theodolites usually consist of more than two units, arranged in the first area, navigation area or final area shooting range, and undertake ballistic measurement tasks in missile measurement and control, satellite observation, and conventional weapon testing. The tracking speed, tracking accuracy and capture ability of photoelectric theodolites When leaving the factory, simulation tests are usually carried out indoors with dynamic targets. During the test, the dynamic target rotates at a specific speed, and the dynamic target often produces a small amount of mechanical deformation during the rotation, which directly affects the calibration accuracy of the photoelectric theodolite.

The traditional calibration method is carried out in the static state of the dynamic target. By calibrating the spatial angle of the target output when the dynamic target is in different spatial positions, the geometric parameters of the dynamic target are determined, and at the same time combined with the shaft angle encoder reading on the rotation axis of the dynamic target , to realize the calibration of the dynamic target. This calibration method is less accurate.

Contents of the invention

The technical problem to be solved by the present invention is to provide a calibration device and a calibration method for the dynamic deformation angle measurement error of a dynamic target with high calibration accuracy.

Technical scheme of the present invention is:

The calibration device for the dynamic deformation angle measurement error of a dynamic target includes a dynamic target; the dynamic target includes an axis angle encoder, a light source and a reflector; a collimating objective lens is arranged on the optical path between the light source and the reflector; the axis angle The rotation axis of the encoder coincides with the rotation axis of the dynamic target; its special feature is that it also includes an imaging device; the imaging device includes a first objective lens, a diffuser plate, a second objective lens and a CCD rigidly connected in sequence through the lens barrel; The diffuser plate is positioned on the focal plane of the image side of the first objective lens; the CCD is positioned on the image plane of the second objective lens; The light beam is incident on the imaging device, and the star point image coordinates of the dynamic target are collected by the imaging device.

The above-mentioned calibration device also includes control analysis software, which is used to compare and calculate the angle error introduced by the mechanical deformation generated when the dynamic target moves at a specific angular velocity.

The calibration method of the calibration device based on the dynamic deformation angle measurement error of the above-mentioned dynamic target is special in that it includes the following steps:

(1) The dynamic target is calibrated in advance when it is static

A. Adjust the position of the imaging device so that the optical axis of the first objective lens is coaxial with the rotation axis of the shaft angle encoder;

B. Stop the dynamic target at a specific position and read the reading θ of the shaft angle encoder at this time; turn on the light source and adjust the position of the imaging device so that the first objective lens can fully receive the parallel light output when the dynamic target is at this position ;

C, the imaging device collects the star point image of the dynamic target at the specific position: the parallel light in step (1) B is imaged on the diffuser plate through the first objective lens, and the light passing through the diffuser plate is captured on the CCD through the second objective lens For imaging, the CCD converts the image signal into star point image coordinates (x _θ , y _θ ), where θ is the indication of the shaft angle encoder;

(2) Real-time calibration of the dynamic target when it moves at a specific angular velocity

A, keeping the state of the imaging device in step (1);

B. Make the dynamic target rotate at a specific angular velocity;

C. The imaging device collects the star point image of the dynamic target in real time: the parallel light output after being collimated by the collimating objective lens is imaged on the diffuser plate through the first objective lens, and the light passing through the diffuser plate is imaged on the CCD through the second objective lens , the CCD converts the image signal of the dynamic target at each position into the corresponding star point image coordinates (x _θ ', y _θ '), where θ is the indication of the shaft angle encoder;

(3) Calculate the angle error introduced by the mechanical deformation of the dynamic target

A. The control analysis software extracts the angle of dynamic target rotation in real time, that is, the real-time indication θ of the shaft angle encoder;

B. The control analysis software extracts the star point image coordinates (x _θ , y _θ ) in the above step (1) C and the star point image coordinates (x _θ ', y _θ ') in the step (2) C in real time;

C. The control analysis software combines the data of steps (3) A and B to calculate the angular error introduced by the mechanical deformation of the dynamic target when the dynamic target rotates at a specific angular velocity and the indication of the shaft angle encoder is θ.

The specific positions selected in the above-mentioned steps (1) are four positions of 0°0′0″, 90°0′0″, 180°0′0″, and 270°0′0″; adjust the position of the imaging device, Make the four star-like coordinates of the dynamic target fall on the same circle at these four positions.

The advantages of the present invention are:

The space angle of the moving dynamic target can be precisely calibrated, so that the space angle error introduced by the mechanical deformation generated when the dynamic target moves can be quantitatively and accurately calibrated.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Among them: 1-light source; 2-collimating objective lens; 3-axis angle encoder; 4-mirror; 5-first objective lens; 6-diffusion plate; 7-second objective lens; 8-CCD; 9-lens barrel .

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in FIG. 1 , the calibration device for dynamic deformation angle measurement error of a dynamic target provided by the present invention includes a dynamic target, an imaging device and control analysis software.

The dynamic target includes a shaft-angle encoder 3, a light source 1 and a reflector 4; a collimating objective lens 2 is arranged on the optical path of the incident light of the reflector 4, and the rotation axis of the shaft-angle encoder 3 coincides with the rotation axis of the dynamic target; The collimating objective lens 2 is located between the light source 1 and the mirror 4 .

The imaging device comprises a first objective lens 5, a diffuser plate 6, a second objective lens 7 and a CCD8 which are rigidly connected in sequence through the lens barrel 9, and the diffuser plate 6 is located on the image side focal plane of the first objective lens 5, and the CCD8 is located on the second objective lens 7 on the image surface. The present invention is by arranging diffuse plate 6 and second objective lens 7 between first objective lens 5 and CCD8, by twice imaging the reflected light of reflection mirror 4 is imaged on CCD8, can effectively avoid because the focal length of first objective lens 5 is excessive The long light beam cannot be completely received by the CCD8, thus ensuring the calibration accuracy.

The control analysis software is used to extract the real-time reading of the shaft angle encoder 3 (that is, the angle of rotation of the dynamic target) and the star point image coordinates collected by the CCD8 (star point image coordinates when the dynamic target is static, star point image coordinates when the dynamic target rotates at a specific angular velocity) Point image coordinates), and compare and calculate the angular error introduced by the mechanical deformation generated when the dynamic target moves at a specific angular velocity.

The present invention also provides a calibration method of a calibration device based on the above-mentioned dynamic deformation of the dynamic target and the angle measurement error, comprising the following steps:

(1) The dynamic target is calibrated in advance when it is static

A. Adjust the position of the imaging device so that the optical axis of the first objective lens 5 is coaxial with the rotation axis of the shaft angle encoder 3;

B. Stop the dynamic target at a specific position (0°0'0", 90°0'0", 180°0'0", 270°0'0"), and read the corresponding axis The indication θ of the angle encoder 3; open the light source 1 and adjust the position of the lens barrel 9, so that the first objective lens 5 can fully receive the parallel light output by the reflector 4 when the reflector 4 is in this specific position;

C, the parallel light in step (1) B is imaged on the diffuser plate 6 through the first objective lens 5, and the light passing through the diffuser plate 6 is imaged on the CCD8 through the second objective lens 7, and the image signal is converted into a star by the CCD8. Point image coordinates (x _θ , y _θ ), θ is the indication of the shaft angle encoder 3;

The specific principles and processes are:

When the shaft angle encoder 3 reads 0°0′0″, the coordinates of the star image captured by the CCD8 are (x ₁ , y ₁ ); when the shaft angle encoder 3 reads 90°0′0″, the CCD8 The coordinates of the captured star image are (x ₂ , y ₂ ); when the shaft angle encoder 3 reads 180°0′0″, the coordinates of the star image captured by the CCD8 are (x ₃ , y ₃ ); When the angle encoder 3 reads 270°0′0″, the coordinates of the star image captured by CCD8 are (x ₄ , y ₄ ); if the coordinates of the four star images fall on the same circle, the system is adjusted in place. The circle equation can be expressed as:

In the formula, (x _θ , y _θ ) is the coordinate position of the star point image on the CCD8 when the encoder indication is θ.

(2) Real-time calibration of the dynamic target when it moves at a specific angular velocity

A, keeping the state of the imaging device in step (1);

B. Make the dynamic target rotate at a specific angular velocity;

C. The imaging device collects the star point image of the dynamic target in real time: the parallel light output after being collimated by the collimating objective lens 2 is imaged on the diffuser plate 6 through the first objective lens 5, and the light passing through the diffuser plate 6 passes through the second objective lens 7 Imaging on the CCD8, the CCD8 converts the image signal of the dynamic target at each position (that is, the dynamic target at each space angle) into the corresponding star point image coordinates (x _θ ', y _θ '), θ is the axis angle The indication of the encoder;

(3) Calculate the angle error introduced by the mechanical deformation of the dynamic target

A. The control analysis software extracts the angle of dynamic target rotation in real time, that is, the real-time reading θ of the shaft angle encoder 3;

B. The control analysis software extracts the star point image coordinates (x _θ , y _θ ) in the above step (1) C and the star point image coordinates (x _θ ', y _θ ') in the step (2) C in real time;

C. The control analysis software combines the data of steps (3) A and B to calculate the angular error introduced by the mechanical deformation of the dynamic target when the dynamic target rotates at a specific angular velocity and the indication of the shaft angle encoder is θ.

According to the above step (3), when the dynamic target rotates dynamically at a specific angular velocity, when the encoder indication is θ, the star point image coordinates collected by CCD8 are (x _θ ', y _θ '), then the mechanical deformation of the dynamic target is introduced into The angular error Δr _θ is:

In the formula, β is the angle value of the moving target represented by the unit pixel of CCD8.

Claims (2)

1. using the method for caliberating device calibration dynamic target dynamic deformation angle error, the caliberating device includes Dynamic Targets Mark, imaging device and control analysis software；The dynamic target includes shaft-position encoder, light source and speculum；In light source and instead Collimator objective is provided in the light path penetrated between mirror；The rotary shaft of the shaft-position encoder and the rotation overlapping of axles of dynamic target； The imaging device is included through lens barrel successively rigidly connected first object lens, diffusing panel, the second object lens and CCD；Its feature exists In including the following steps：

(1) it is demarcated in advance when dynamic target is in static

A, the position of imaging device is adjusted, makes the optical axis of the first object lens and the concentric rotation axis of shaft-position encoder；

B, dynamic target is rested on into specific location, and reads the registration θ of shaft-position encoder；It opens light source and adjusts imaging dress The position put enables the first object lens to receive dynamic target completely and is in the directional light exported during the specific position；

C, imaging device acquisition dynamic target is in the asterism picture of the specific position：Directional light in step (1) B is through the first object lens It is imaged on diffusing panel, is imaged on CCD through the second object lens through the light of diffusing panel, picture signal is converted into asterism by CCD As coordinate (x_θ,y_θ), θ is the registration of shaft-position encoder；

(2) real-time calibration is carried out to it when dynamic target is moved with specific angular speed

A, keep state in step (1) constant imaging device；

B, dynamic target is made to be rotated with specific angular speed；

C, imaging device acquires the asterism picture of dynamic target in real time：The directional light exported after collimated object lens collimation is through the first object lens It is imaged, is imaged on CCD through the second object lens through the light of diffusing panel, by CCD by dynamic target in position on diffusing panel Picture signal be converted to corresponding asterism as coordinate (x_θ',y_θ'), θ is the registration of shaft-position encoder；

(3) the introduced angular error of the mechanical deformation of dynamic target is calculated

A, the real-time registration θ of the angle, i.e. shaft-position encoder of the rotation of control analysis software extract real-time dynamic target；

B, the asterism in analysis software extract real-time above-mentioned steps (1) C is controlled as coordinate (x_θ,y_θ) and step (2) C in asterism As coordinate (x_θ',y_θ')；

C, the data of control analysis software combination step (3) A, B are calculated dynamic target and are rotated with specific angular speed, shaft encode When the registration of device is θ, the introduced angular error of the mechanical deformation of dynamic target.

2. the method according to claim 1 using caliberating device calibration dynamic target dynamic deformation angle error, special Sign is：Specific position described in step (1) is 0 ° 0 ' 0 ", 90 ° 0 ' 0 ", 180 ° 0 ' 0 ", 270 ° 0 ' 0 " this four positions；Adjustment The position of imaging device makes four asterisms of the dynamic target at this four positions as coordinate is fallen on same circle.