阅读说明：本技术 一种变焦相机光轴晃动量的测量方法 (Method for measuring optical axis shaking amount of zoom camera ) 是由 王海 赵胜强 马仁旺 于 2019-10-12 设计创作，主要内容包括：本发明属于变焦相机的参数测量方法,为了解决现有技术中变焦相机光轴晃动量测量方法涉及测量设备多导致成本高,以及测量过程复杂和耗时长的技术问题,提供一种变焦相机光轴晃动量的测量方法,具体为：选定靶标,固定变焦相机,调节变焦相机至预设焦距；调整变焦相机,使变焦相机的光轴中心位置对准靶标中心,记录所述靶标中心到变焦相机中心处的第一横向脱靶量x<Sub>0</Sub>和第一纵向脱靶量y<Sub>0</Sub>；按预设角度间隔旋转变焦相机,分别记录靶标中心到变焦相机中心处的横向脱靶量x<Sub>n</Sub>和纵向脱靶量y<Sub>n</Sub>；对所得横向脱靶量和纵向脱靶量分别进行傅里叶变换,得到的二阶分量x<Sub>a</Sub>和y<Sub>a</Sub>,计算得到的<Image he="85" wi="240" file="DDA0002230956270000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>即为该变焦相机在所述预设焦距下的光轴晃动量。(The invention belongs to a parameter measuring method of a zoom camera, and provides a method for measuring the optical axis shaking amount of the zoom camera, aiming at solving the technical problems that the measuring method of the optical axis shaking amount of the zoom camera in the prior art is high in cost caused by more measuring devices, and complex in measuring process and long in time consumption, and the method specifically comprises the following steps: selecting a target, fixing the zooming camera, and adjusting the zooming camera to a preset focal length; adjusting the zoom camera to enable the optical axis center position of the zoom camera to be aligned with the center of the target, and recording a first transverse miss distance x from the center of the target to the center of the zoom camera 0 And a first longitudinal miss distance y 0 (ii) a Rotating the zooming camera according to a preset angle interval, and respectively recording the transverse miss distance x from the center of the target to the center of the zooming camera n And longitudinal miss distance y n (ii) a Fourier transform is respectively carried out on the obtained transverse miss distance and the longitudinal miss distance, and the obtained second-order component x a And y a Calculated to obtain Namely the optical axis shaking amount of the zoom camera under the preset focal length.)

1. A method for measuring the optical axis shaking amount of a zoom camera is characterized by comprising the following steps:

step 1, selecting a target, fixing a zoom camera, and adjusting the zoom camera to a preset focal length;

step 2, adjusting the zoom camera to enable the optical axis center position of the zoom camera to be aligned to the center of the target, and recording a first transverse miss distance x from the center of the target to the center of the zoom camera₀And a first longitudinal miss distance y₀；

Step 3, rotating the zooming camera for i times according to the preset angle interval, and respectively recording the transverse miss distance x from the center of the target to the center of the zooming camera each time_nAnd longitudinal miss distance y_nWherein i is a positive integer, n is more than or equal to 1 and less than or equal to i, and n is an integer;

step 4, aiming at the first transverse miss distance x in the step 2₁And i sets of transverse miss distance x in step 3_nFourier transform is carried out to obtain second-order component x of transverse miss distance_aFor the first longitudinal miss distance y in step 2₀And i sets of longitudinal miss distance y in step 3_nFourier transform is carried out to obtain a second-order component y of the longitudinal miss distance_a；

Step 5, calculating a formula

2. The method of claim 1, wherein the step of measuring the amount of shake of the optical axis of the zoom camera comprises: in the step 1, the target is selected, and the zoom camera is fixed, specifically, a corner or a tower top is selected as a target (5), and the zoom camera (4) is fixed on the camera mounting seat (1); the camera mounting seat (1) is mounted on the vertical type indexing table (2), the vertical type indexing table (2) is connected to the two-dimensional adjusting frame (3), and a rotating shaft of the vertical type indexing table (2) is parallel to an optical axis of the zoom camera (4).

3. The method of claim 2, wherein the step of measuring the amount of shake of the optical axis of the zoom camera comprises: the precision of the vertical type indexing table (2) is more than or equal to 30', and the measuring range is 0-360 degrees.

4. A method of measuring an amount of shake of an optical axis of a zoom camera according to claim 3, comprising: the included angle between the table surface of the vertical type dividing table (2) and the ground horizontal plane is 89-91 degrees.

5. The method of claim 4, wherein the step of measuring the amount of shake of the optical axis of the zoom camera comprises: the parallelism of the rotating shaft of the vertical type indexing table (2) and the optical axis of the zooming camera (4) is one third of the field angle under the preset focal length.

6. The method of claim 1 or 5, wherein the step of measuring the amount of shake of the optical axis of the zoom camera comprises: in step 3, the preset angle is 30 °.

Technical Field

The invention belongs to a parameter measuring method of a zoom camera, and particularly relates to a method for measuring the optical axis shaking amount of the zoom camera.

Background

The zooming optical system generally comprises a fixed group, a zooming group and a compensation group, wherein the zooming group and the compensation group move along a guide rail or a cam according to a specific rule to realize the continuous change of focal length and the stability of an image plane, and when the zooming group and the compensation group move along the guide rail or the cam, a certain gap exists between the zooming group and the compensation group and the guide rail and the cam due to the processing and assembling errors of the guide rail and the cam, the gap is inevitable and is generally smaller than 0.01mm-0.02 mm. When the installation direction of the zoom camera and the gravity direction change, even if the focal length is not moved, the optical axis still changes, and in the photoelectric stabilization platform, the zoom camera changes along with the position change of the installation platform.

As described above, for the zoom camera, the optical axis shaking amount is caused by the gap between the variable magnification group and the compensation group and the guide rail and the cam. After the lens is assembled, the clearance is basically determined, so that the shaking amount of the optical axis is basically a fixed value and does not change depending on the change of the focal length. However, the field of view of the zoom camera changes with the change of the focal length, and when the zoom camera is in a large field of view, i.e., when the focal length is small, the ratio of the optical axis shaking amount to the field of view is small, so the optical axis shaking amount can be almost ignored and cannot be seen from the image. When the zoom camera is in a small field of view, i.e. the focal length is long, the ratio of the optical axis shaking amount to the field of view is large, and the magnification is determined by the optical variable magnification of the zoom camera. For example, in the case of a 30-fold optical zoom system, the value of the ratio of the optical axis shake amount to the field of view is increased by 30 times at a small field of view than at a large field of view, and therefore the shake amount is easily seen from the image at a small field of view, i.e., at a long focal length.

For the photoelectric stabilization platform, different optical loads need to be installed inside the photoelectric stabilization platform, the optical axes among the loads can be debugged to be in a parallel state, and when the photoelectric stabilization platform works, the pitching can be changed, namely, the included angle between the installation direction and the gravity direction can be changed. When the shaking amount of the optical axis of the zoom camera is too large, the optical axis of the zoom camera is not parallel, and when the target is aimed at in a long distance, the aimed target has larger deviation. Therefore, it is necessary to sort out a camera having a small amount of optical axis fluctuation before mounting, or measure the amount of optical axis fluctuation before mounting, and compensate after mounting. However, in any of the above-described methods, the amount of fluctuation of the optical axis of the zoom camera needs to be measured.

At present, for measuring the optical axis shaking amount of a zoom camera at a specified focal length, generally, the optical axis of the zoom camera at the specified focal length is calibrated by a laser, the zoom camera is calibrated into a parallel state, the zoom camera is placed in front of a collimator as a whole, different installation angles are changed, and the maximum miss distance of a laser spot on the zoom camera is measured, namely the optical axis shaking amount of the camera at the specified focal length. However, the calibration and measurement process of this method is complicated, and the method involves more measurement devices in the measurement process, resulting in longer measurement time and higher cost.

Disclosure of Invention

The invention mainly aims to solve the technical problems that in the prior art, the measurement method of the optical axis shaking amount of the zoom camera involves more measurement equipment, so that the cost is high, the measurement process is complex and the time consumption is long, and provides the measurement method of the optical axis shaking amount of the zoom camera.

In order to achieve the purpose, the invention provides the following technical scheme:

a method for measuring the optical axis shaking amount of a zoom camera is characterized by comprising the following steps: step 1, selecting a target, fixing a zoom camera, and adjusting the zoom camera to a preset focal length;

step 2, adjusting the zoom camera to enable the optical axis center position of the zoom camera to be aligned to the center of the target, and recording a first transverse miss distance x from the center of the target to the center of the zoom camera₁And a first longitudinal miss distance y₁；

Step 3, rotating the zooming camera for i times according to the preset angle interval, and respectively recording the transverse miss distance x from the center of the target to the center of the zooming camera each time_nAnd longitudinal miss distance y_nWherein i is a positive integer, n is more than or equal to 1 and less than or equal to i, and n is an integer;

step 4, aiming at the first transverse miss distance x in the step 2₁And i sets of transverse miss distance in step 3x_nFourier transform is carried out to obtain second-order component x of transverse miss distance_aFor the first longitudinal miss distance y in step 2₀And i sets of longitudinal miss distance y in step 3_nFourier transform is carried out to obtain a second-order component y of the longitudinal miss distance_a；

Step 5, calculating a formula

And obtaining a numerical value which is the optical axis shaking amount of the zoom camera under the preset focal length.

X calculated in the above step 4_aAnd y_aI.e., the components of the optical axis shaking amount in the lateral and longitudinal directions. Therefore, in order to calculate the amount of optical axis fluctuation, it is necessary to synthesize the amount of optical axis fluctuation by a vector addition method, and the result of the synthesis is the amount of optical axis jump.

Further, in the step 1, the step of selecting the target and fixing the zoom camera specifically includes selecting a corner or a tower top as the target and fixing the zoom camera on the camera mounting seat; the camera mounting base is arranged on a vertical type indexing table, the vertical type indexing table is connected to the two-dimensional adjusting frame, and a rotating shaft of the vertical type indexing table is parallel to an optical axis of the zooming camera. The method rotates the optical axis of the zoom camera through the rotation of the table top of the vertical type indexing table; the two-dimensional adjusting frame is more convenient for adjusting the verticality of the vertical dividing table and the horizontal plane of the ground.

Furthermore, the precision of the vertical type indexing table is more than or equal to 30', and the measuring range is 0-360 degrees.

Furthermore, the included angle between the table surface of the vertical type dividing table and the ground horizontal plane is 89-91 degrees.

Further, the parallelism between the rotating shaft of the vertical type indexing table and the optical axis of the zoom camera is one third of the field angle under the preset focal length.

Further, in step 3, the preset angle is 30 °.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the method for measuring the optical axis shaking amount of the zoom camera, the transverse shaking amount and the longitudinal shaking amount of different positions of the zoom camera in a circle are recorded, the optical axis shaking amount of the zoom camera is obtained through direct, simple and convenient Fourier transform measurement, the optical axis stability under any specified focal length can be measured, and the measuring process is simple and efficient.

2. The camera mounting base arranged on the vertical type indexing table is used for conveniently and accurately completing the rotation of the zoom camera; the vertical indexing table is arranged on the two-dimensional adjusting frame, so that the verticality between the table surface of the vertical indexing table and the ground horizontal plane can be conveniently adjusted, and the operation is more convenient. The measuring device suitable for the measuring method is simple in structure and does not need to be calibrated.

3. The zooming camera rotates at intervals of 30 degrees during measurement, so that the measurement precision can be ensured, and the measurement efficiency is not influenced by too many values.

Drawings

Fig. 1 is a schematic view of an installation structure of a zoom camera according to an embodiment of the present invention.

Wherein, 1-camera mounting seat; 2-vertical indexing table; 3-two-dimensional adjusting frame; 4-a zoom camera; 5-target.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings, and it is obvious that the described embodiments do not limit the present invention.

The zoom camera generally comprises a fixed group, a zoom group and a compensation group, wherein the zoom group and the compensation group move along a guide rail and a cam according to a specific rule to realize continuous change of focal length and stabilization of an image plane. When the zoom lens group and the compensation lens group move along the guide rail and the cam, certain gaps exist among the zoom lens group and the compensation lens group, the guide rail and the cam due to processing and assembling errors of the guide rail and the cam, and the gaps are inevitable. When the installation direction of the lens and the gravity angle change, the zoom lens group and the compensation lens group generate displacement due to the existence of a gap, and the optical axis still changes even if the focal length is not changed, so that the optical axis shakes. Therefore, a simple and efficient method for measuring the corresponding optical axis shaking amount is needed.