A focal plane compensation method for imaging of targets at limited distances

Abstract

The invention discloses a focal plane compensation method for imaging a target at a limited distance, and the method comprises the following steps: first, in the Zemax software, the object distance of the optical system to be optically calibrated is set as the target distance, the environmental parameters and other optical parameters are set, the back intercept is obtained through image quality optimization, and the variables on the back intercept are cancelled to make it fixed; then, the parameters of the collimator are input into the Zemax optical system, the previous object distance is replaced, and the distance between the collimator light source and the main surface of the collimator is set as the only variable for image quality optimization; finally, the light source distance obtained after optimization is compared with the focal length of the collimator, and the focal plane of the imaging of the target at a limited distance is compensated by adjusting the position of the collimator light source. The invention has the advantages that the optical system is optically calibrated in the laboratory space, and the focal plane compensation of the imaging of the target at a limited distance can be realized, that is, the clear imaging of the target at the limited distance can be realized.

Description

Technical Field

[0001] The invention relates to the field of optics, and in particular to a focal plane compensation method for imaging a target at a limited distance. Background Art

[0002] When calibrating the lens, the collimator is a key instrument. It can emit approximately parallel light. As the reference light source during optical calibration, it can achieve the purpose of the detector to clearly image the infinitely far target. During optical calibration, first make the mechanical axis of the lens parallel to the optical axis of the collimator, then power on the detector to be installed, image the parallel light emitted by the collimator, and adjust the azimuth and pitch position of the detector so that the image of the collimator is clearly located in the center of the detector. At this time, the focal plane of the camera corresponds to infinity.

[0003] If the camera is designed to focus at a distance that is not infinite but a very close distance within the scale of the laboratory space, such as within ten meters, targets such as stripes can be placed at the corresponding distance, and the detector can be used to simultaneously observe the light spots of the parallel light tube and the stripes at very close distances, so as to achieve the purpose of detector centering and clear imaging at very close distances.

[0004] If the camera is designed to focus at a limited distance beyond the laboratory space scale, such as several hundred meters or several thousand meters, the above two solutions cannot achieve the purpose of clear imaging of targets at this distance. Therefore, a focal plane compensation method for imaging targets at a limited distance in the laboratory is proposed. Summary of the invention

[0005] The object of the present invention is to provide a focal plane compensation method for finite distance target imaging, so as to solve the difficulty of focal plane compensation for finite distance target imaging in laboratory operation.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The focal plane compensation method for imaging a target at a limited distance in a laboratory specifically includes the following steps:

[0008] 1) Get the back intercept at the target object distance.

[0009] 1-1) In Zemax software, set the object distance of the optical system to be calibrated to the target distance;

[0010] 1-2) Only set the back intercept as a variable to optimize image quality;

[0011] 1-3) After the optimization is completed, the posterior intercept is obtained and the variable is cancelled to make it fixed.

[0012] 2) Determine the moving direction and distance of the collimator light source.

[0013] 2-1) Input the parameters of the collimator into the Zemax optical system, replacing the previous object distance;

[0014] 2-2) The distance between the collimator light source and the main surface of the collimator is set as the only variable to optimize the image quality;

[0015] 2-3) By comparing the optimized light source distance with the focal length of the collimator, we can know how to move the collimator light source.

[0016] 3) Move the collimator light source according to the analysis results and perform optical calibration under this condition.

[0017] The advantages of the present invention are:

[0018] In the laboratory, through the collimator, the optical system can be focused on the target at a limited distance after optical calibration. That is, in the laboratory, the focal plane of the imaging of the target at a limited distance can be compensated through simple operations, so as to achieve clear imaging of the target at a limited distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention.

[0020] Figure 2 It is a schematic diagram of the principle of the collimator in normal working mode, that is, the light source is at the focus.

[0021] Figure 3 Schematic diagram of the principle of the collimator simulating the limited distance target working mode, that is, the light source is not at the focus.

[0022] Figure 4 Equivalent schematic diagram for simulating the limited-distance target working mode for the collimator. DETAILED DESCRIPTION

[0023] like Figure 1 As shown, a focal plane compensation method for imaging a target at a limited distance comprises the following steps:

[0024] (1) Obtain the back intercept at the target object distance. First, set the object distance of the optical system to be calibrated to the target distance in the Zemax software; second, only set the back intercept as a variable for image quality optimization; finally, after the optimization is completed, the back intercept is obtained and the variable is canceled to make it fixed.

[0025] (2) Determine the moving direction and distance of the collimator light source. First, input the collimator parameters into the Zemax optical system to replace the previous object distance; second, set the distance between the collimator light source and the main surface of the collimator as the only variable for image quality optimization; finally, compare the optimized light source distance with the focal length of the collimator to know how to move the collimator light source.

[0026] 3) Move the collimator light source according to the analysis results and perform optical calibration under this condition. Figure 2 As shown in the figure, the light source of the collimator is originally located at the focus of the collimator, and the collimator emits parallel light; according to the simulation results of Zemax software, the light source is moved, as shown in Figure 3 As shown in , the light emitted by the collimator is non-parallel light. Figure 4 shown.

[0027] The above content is a further detailed description of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to this description. The authority of the present invention is limited by the claims, and the technologies related to the present invention obtained by the technical personnel in this field based on the methods that can be changed, reorganized, etc. according to the present invention are all within the protection scope of the present invention.

Claims

1. A focal plane compensation method for imaging a close-range target in a limited space, characterized in that: The method comprises the following steps: 1) Get the back intercept at the target object distance, The specific steps are as follows: 1-1) in the Zemax software, the object distance of the optical system to be calibrated is set as the target distance; 1-2) only the back intercept is set as a variable for image quality optimization; 1-3) after the optimization is completed, the back intercept is obtained, and the variable is cancelled to make it fixed; 2) Determine the moving direction and distance of the collimator light source, The specific steps are as follows: 2-1) input the parameters of the collimator into the Zemax optical system to replace the previous object distance; 2-2) set the distance between the collimator light source and the main surface of the collimator as the only variable to optimize the image quality; 2-3) compare and analyze the optimized light source distance and the focal length of the collimator; 3) Move the collimator light source according to the analysis results and perform optical calibration.

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