Photoelectric theodolite shooting time calibration system and method

Abstract

The present invention belongs to the field of photoelectric measurement technology, and in particular, relates to a system and method for calibrating the shooting time of a photoelectric theodolite. The system includes: a control panel, a servo control unit, a timing control unit and a light source. The user operates the control panel to set the control parameters of the shooting time calibration system; the timing control unit sends a trigger signal to the servo control unit and the encoder of the photoelectric theodolite according to the control parameters of the shooting time calibration system; the motor drives the baffle to rotate according to the control parameters, controls the photoelectric theodolite to align with the collimator, places the bright spot at the center of the field of view of the photoelectric theodolite, and records the calibration value output by the encoder; the calibration instrument detection software realizes the calibration of the shooting time of the photoelectric theodolite according to the calibration value, the point target image sequence and the control parameters. The present invention can calibrate the shooting time of the photoelectric theodolite.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric measurement, and in particular relates to a shooting time calibration system and method for a photoelectric theodolite. Background Art

[0002] As an important optoelectronic tracking and measurement equipment, the photoelectric theodolite is widely used in weapon testing at the shooting range, flight equipment trajectory tracking, attitude measurement and other tasks. It can track the target in real time and dynamically, measure and evaluate the key flight characteristics and parameters of the target, and has the advantages of high measurement accuracy and strong anti-interference ability, providing reliable measurement data for weapon trajectory detection and aerospace flight equipment evaluation.

[0003] The task of the photoelectric theodolite is to obtain the image information of the characteristic event, and it is necessary to accurately know the image information, standard time information and encoder information of the characteristic event. During the production and manufacturing of the existing photoelectric theodolites, high-frequency disturbance shooting of point targets is generally used to perform the same-frame calibration of the image information and the encoder information. However, there is a lack of a simple and effective means for the calibration of the image information and the standard time information. Moreover, for a 100Hz infrared camera, 1000Hz encoder information and standard time information, different exposure time settings will also affect the correspondence between the final image information and the standard time information. Therefore, a method is needed to calibrate the accuracy of the images taken by the photoelectric theodolite and the additional information of the images, so that the accuracy of the same-frame synthesis function of the visible light, short-wave infrared and medium-wave infrared camera images of the photoelectric theodolite can be determined at different exposure times.

[0004] At present, there is no instrument specifically for calibrating the images captured by photoelectric theodolites and the standard time information and encoder information attached to the images. During production and manufacturing, the accuracy of the encoder information and image information is generally calibrated by making high-frequency disturbances on electrical targets, but the accuracy of the standard time information and image information cannot be calibrated. A calibrator is urgently needed to solve this problem. Summary of the invention

[0005] In view of this, the invention aims to provide a photoelectric theodolite shooting time calibration system and method to solve the problem that the prior art cannot calibrate the accuracy of standard time information and image information. On the basis of solving the problem that the prior art cannot calibrate the accuracy of standard time information and image information, the present invention can also calibrate the correction amount of the camera to the standard time information and encoder information at different exposure times by accurately controlling the lighting time of the point target at 1000Hz.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0007] A shooting time calibration system for a photoelectric theodolite comprises: a control panel, a servo control unit, a time control unit and a light source, wherein:

[0008] The servo control unit includes a motor, a baffle, tin foil and a collimator. The motor is connected to the baffle, a slit is provided on the baffle, and a small hole is provided at the center of the tin foil. The light emitted by the light source is incident on the photoelectric theodolite through the slit of the baffle, the small hole of the tin foil and the collimator in sequence, and forms a bright spot on the imaging target surface of the photoelectric theodolite.

[0009] The user operates the control panel to set the control parameters of the shooting time calibration system; the time control unit outputs AC code and DC code to the photoelectric theodolite for time synchronization according to the control parameters of the shooting time calibration system, so that the time of the photoelectric theodolite is synchronized with the time of the shooting time calibration system, and the time control unit also sends a trigger signal to the servo control unit and the encoder of the photoelectric theodolite; the motor drives the baffle to rotate according to the control parameters, controls the photoelectric theodolite to align with the collimator, and places the bright spot at the center of the field of view of the photoelectric theodolite, records the calibration value output by the encoder, and inputs the calibration value output by the encoder into the calibration instrument detection software of the photoelectric theodolite; the user controls the photoelectric theodolite to perform periodic high-frequency sinusoidal disturbance with the current position of the bright spot as the center, and uses the set of point target images obtained in each motion cycle as a point target image sequence; the calibration instrument detection software of the photoelectric theodolite realizes the calibration of the shooting time of the photoelectric theodolite according to the calibration value output by the encoder, the point target image sequence and the control parameters.

[0010] Furthermore, the imaging band of the light source includes a shortwave band, a mediumwave band, a visible band and a longwave band.

[0011] Furthermore, the control parameters of the shooting time calibration system include bright spot delay time and bright light duration. The bright spot delay time is the time interval between the bright spot moment when the bright spot appears in the point target image sequence and the second signal of the timing control unit, and the bright light duration is the duration of the bright spot in the point target image sequence.

[0012] A method for calibrating the shooting time of a photoelectric theodolite is implemented by using a calibration system for the shooting time of the photoelectric theodolite, and specifically comprises the following steps:

[0013] S1: The user sets the bright spot delay time to 0, and makes the bright light duration shorter than the exposure time of the photoelectric theodolite. The motor drives the baffle to rotate according to the control parameters, and controls the photoelectric theodolite to align with the collimator, so that the light emitted by the light source forms a bright spot on the imaging target surface of the photoelectric theodolite.

[0014] S2: Place the bright spot at the center of the field of view of the photoelectric theodolite, read the calibration value output by the encoder, and input the calibration value into the calibration instrument detection software, control the photoelectric theodolite to perform periodic high-frequency sinusoidal disturbances with the current position of the bright spot as the center, and record and store the obtained point target image sequence;

[0015] The point target image includes a header file, which stores the storage time when the bright spot in the point target image appears and the encoder output value.

[0016] S3: The calibration instrument detection software reads the point target image sequence, and reads the stored time when the current bright spot appears in the header file of the point target image with the bright spot, compares the stored time when the current bright spot appears with the real time when the current bright spot appears, and calibrates the time deviation of the photoelectric theodolite;

[0017] S4: Set the bright light duration to be equal to the exposure time of the photoelectric theodolite. The calibration instrument detection software reads the encoder output value stored in the header file of the point target image with the bright spot located at the center of the field of view of the photoelectric theodolite. If the encoder output value is the same as the calibration value, the calibration is completed. Otherwise, reset the bright spot delay time and repeat step S4 until the calibration is completed.

[0018] Furthermore, the actual moment when the current bright spot appears is determined according to the bright spot delay time and the bright light duration time.

[0019] Furthermore, if the calibration instrument detection software reads the point target image sequence and finds that the storage time of the header file in the point target image with a bright spot is different from the actual time when the current bright spot appears, it is determined that the exposure time of the digital camera of the photoelectric theodolite is too long. The user performs early exposure timing correction processing on the external trigger of the digital camera to obtain the point target image with the bright spot.

[0020] Furthermore, in step S3, the time interval between the delay times of two adjacent bright spots is the same, which is the reciprocal of the frequency of the external trigger signal of the timing system of the photoelectric theodolite.

[0021] Compared with the prior art, the invention can achieve the following beneficial effects:

[0022] (1) The present invention creates a photoelectric theodolite shooting time calibration system and method, which solves the problem that the prior art generally uses a high-frequency disturbance method on the electric target to calibrate the accuracy of the encoder information and image information, but cannot calibrate the accuracy of the standard time information and image information. The present invention calibrates the correction amount of the digital camera to the standard time information and encoder information at different exposure times by accurately controlling the lighting time of the point target at 1000 Hz.

[0023] (2) The present invention creates a photoelectric theodolite shooting time calibration system and method. According to different set parameters, the correction amount of the encoder and the correction amount of the image information under the frequency and different exposure time application scenarios can be calibrated to complete the information calibration of the image shooting time. This has a strong practical value for the use of photoelectric theodolites. In addition, the instrument can be used to calibrate the working parameters of different photoelectric theodolites under the same conditions, which has a great reference significance for the deviation correction of multiple sets of photoelectric theodolites shooting targets in a shooting range. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0025] Figure 1 A schematic diagram of the structure of the photoelectric theodolite shooting time calibration system according to an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a flow chart of a method for calibrating the shooting time of a photoelectric theodolite according to an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of the output timing of the digital camera according to an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of the calibration principle described in an embodiment of the present invention.

[0029] Description of reference numerals:

[0030] 1. Control panel; 2. Servo control unit; 3. Timing control unit; 4. Photoelectric theodolite; 5. Light source; 6. Baffle; 7. Tin foil; 8. Collimator. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0032] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0034] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0035] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0036] like Figure 1 As shown, the present invention provides a shooting time calibration system for a photoelectric theodolite 4, comprising: a control panel 1, a servo control unit 2, a time control unit 3 and a light source 5, wherein:

[0037] The servo control unit 2 includes a motor, a baffle 6, tin foil 7 and a collimator 8. The motor is connected to the baffle 6. The baffle 6 is provided with a slit. A small hole is provided at the center of the tin foil 7. The light emitted by the light source 5 is incident on the photoelectric theodolite 4 through the slit of the baffle 6, the small hole of the tin foil 7 and the collimator 8 in sequence, and forms a bright spot on the imaging target surface of the photoelectric theodolite 4.

[0038] The user operates the control panel 1 to set the control parameters of the shooting time calibration system; the time control unit 3 outputs AC code and DC code to the photoelectric theodolite 4 for timing according to the control parameters of the shooting time calibration system, so that the time of the photoelectric theodolite 4 is synchronized with the time of the shooting time calibration system, and the time control unit 3 also sends a trigger signal to the servo control unit 2 and the encoder of the photoelectric theodolite 4; after receiving the trigger signal, the servo control unit 2 drives the motor to rotate the baffle 6 according to the control parameters, controls the photoelectric theodolite 4 to align the collimator 8, and places the bright spot at the center of the field of view of the photoelectric theodolite 4, records the calibration value output by the encoder, and inputs the calibration value output by the encoder into the calibration instrument detection software of the photoelectric theodolite 4; the user controls the photoelectric theodolite 4 to perform periodic high-frequency sinusoidal disturbance with the current position of the bright spot as the center, and uses the set of point target images obtained in each motion cycle as a point target image sequence; the calibration instrument detection software of the photoelectric theodolite 4 realizes the calibration of the shooting time of the photoelectric theodolite 4 according to the calibration value output by the encoder, the point target image sequence and the control parameters. That is, the header file of each stored target image is read through the calibration instrument detection software (the header file stores the storage time and encoder output value when the bright spot appears in the target image).

[0039] The imaging band of the light source 5 includes a short wave band, a medium wave band, a visible wave band and a long wave band.

[0040] The control parameters of the shooting time calibration system include the bright spot delay time and the bright spot duration time. The bright spot delay time is the time interval between the bright spot moment when the bright spot appears in the point target image sequence and the second signal of the timing control unit 3. The bright spot duration time is the duration of the bright spot in the point target image sequence.

[0041] The servo control unit 2 drives the light source 5 (including an incandescent lamp) and the baffle 6 between the collimator 8 to work according to the test state input by the control panel 1. During the rotation of the baffle 6, when the slit on the baffle 6 and the small hole on the tin foil 7 are located on the same straight line, the light emitted by the light source 5 will pass through the slit and the small hole and enter the photoelectric theodolite 4. The encoder outputs a position signal of the slit. The photoelectric theodolite 4 takes a picture of the collimator 8. When the slit on the baffle 6 and the small hole on the tin foil 7 are located on the same straight line, an image with a bright spot in the center is taken. When the slit on the baffle 6 and the small hole on the tin foil 7 are not located on the same straight line, a uniform background is taken.

[0042] The working principle of the shooting time calibration system of the photoelectric theodolite 4 is as follows: (1) First, the control panel 1 reads the control parameters currently set by the user; (2) The timing control unit 3 acts as a clock source to output AC code and DC code to the photoelectric theodolite 4, so that the time of the photoelectric theodolite 4 is synchronized with the time of the shooting time calibration system, and generates trigger signals of different frequencies for use by the servo control unit 2 and the encoder; (3) The servo control unit 2 reads the control parameters set by the user and controls the movement of the motor. The movement of the motor will drive the baffle 6 to rotate. There is a slit on the baffle 6, and the encoder will feedback the position signal of the slit; (4) The light emitted by the incandescent lamp passes through the baffle 6 controlled by the motor, and shines on the small hole of the tin foil 7 through the slit of the baffle 6 at the set time, and then is illuminated by the parallel light The light from the tube 8 is irradiated onto the photoelectric theodolite 4. At this time, the point target image captured by the digital camera of the photoelectric theodolite 4 is a point target image with light and dark changes; (5) The photoelectric theodolite 4 is controlled to place the point target at the center of the field of view, and the encoder output value at this time (including the azimuth encoder value and the pitch encoder value) is recorded and input into the calibration instrument detection software as basic data. Then, the photoelectric theodolite 4 is operated to perform high-frequency sinusoidal disturbance with this position as the center point, and then the image of 15-20 motion cycles is recorded; (6) The calibration instrument detection software reads the recorded point target image, and combines the calibration value of the bright spot at the center point and the motion parameters of the bright spot to give the point target image, time calibration and encoder calibration results, thereby completing the calibration work of the photoelectric theodolite 4 at the shooting time.

[0043] like Figure 2 As shown, the method for calibrating the shooting time of the photoelectric theodolite provided by the present invention is implemented by using the shooting time calibration system of the photoelectric theodolite 4, and specifically includes the following steps:

[0044] S1: The user sets the bright spot delay time to 0, and makes the bright light duration shorter than the exposure time of the photoelectric theodolite 4. The motor drives the baffle 6 to rotate according to the control parameters, and controls the photoelectric theodolite 4 to align with the collimator 8, so that the light emitted by the light source 5 forms a bright spot on the imaging target surface of the photoelectric theodolite 4.

[0045] S2: Place the bright spot at the center of the field of view of the photoelectric theodolite 4, read the calibration value output by the encoder, and input the calibration value into the calibration instrument detection software, control the photoelectric theodolite 4 to perform periodic high-frequency sinusoidal disturbances with the current position of the bright spot as the center, and record and store the obtained point target image sequence.

[0046] The point target image includes a header file, which stores the storage time when the bright spot in the point target image appears and the encoder output value.

[0047] S3: The calibration instrument detection software reads the point target image sequence, and reads the stored time when the current bright spot appears in the header file of the point target image with the bright spot, compares the stored time when the current bright spot appears with the real time when the current bright spot appears, and calibrates the time deviation of the photoelectric theodolite 4.

[0048] The actual moment when the current bright spot appears is determined according to the bright spot delay time and the bright light duration.

[0049] The time interval between the delay times of two adjacent bright spots is the same, which is the reciprocal of the frequency of the external trigger signal of the timing system of the photoelectric theodolite 4 .

[0050] S4: Set the bright light duration to be equal to the exposure time of the photoelectric theodolite 4. The calibration instrument detection software reads the encoder output value stored in the header file of the point target image where the bright spot is located at the center of the field of view of the photoelectric theodolite 4. If the encoder output value is the same as the calibration value, the calibration is completed. Otherwise, reset the bright spot delay time and repeat step S4 until the calibration is completed.

[0051] If, when the calibration instrument detection software reads the point target image sequence, the storage time of the header file in the point target image with a bright spot is different from the actual time when the current bright spot appears, it is determined that the exposure time of the digital camera of the photoelectric theodolite 4 is too long. The user performs early exposure timing correction processing on the external trigger of the digital camera to obtain the point target image with the bright spot.

[0052] like Figure 3 As shown, the readout methods of digital cameras include integration and simultaneous output (IWR) and integration before output (ITR). The timing interval between the output image of an IWR camera and the camera's external trigger is a fixed delay (Td). For an ITR camera, the timing interval between the output image and the camera's external trigger varies (Tp+Td) due to the current exposure time (Tp).

[0053] like Figure 4 As shown, the calibration principle of the image of the photoelectric theodolite 4, the output value of the encoder and the standard time information is as follows: taking the timing calibration of the IWR camera (integrated simultaneous output digital camera) of the 100Hz photoelectric theodolite 4 as an example, the photoelectric theodolite 4 receives the AC code / DC code of the time control unit 3 to complete the timing, synchronizes with the second signal of the time control unit 3, and the photoelectric theodolite 4 generates a 100Hz trigger signal for each camera / subsystem synchronized with the DC code; the moment Sd (the bright spot delay time after the second signal is triggered, which can be set to 0-20ms, with a step length of 1ms) and Sw (the bright spot duration, which can be set to 0-20ms, with a step length of 1ms) of the point target are set, and the sequence of point target images taken by the photoelectric theodolite 4 is I0, I1... to I99, and the image taken by the digital camera is read. Through image processing, it is possible to find the specific image in which the point target image with the bright spot is taken.

[0054] First step, set Sd = 0, Sw = 1 ms and Sw < Tp. The calibrator detection software reads the point target images of the digital camera. If there are no bright point targets in all the point target images output by the digital camera, it is determined that the exposure delay Td of the current photoelectric theodolite 4 is too long, and it is necessary to perform timing correction for early exposure outside the digital camera to solve this problem.

[0055] Second step, set Sd = 0. The calibrator detection software reads the point target images of the digital camera. If the output image of the digital camera is a point target image with bright points, extract the storage time of the current bright point from the additional information of the header file. If the storage time of the current bright point is the T0th second (such as the I0 image shown in Figure 4 is a bright target image), then the output time of the current photoelectric theodolite 4 is the accurate time; if the I99 image shown in Figure 4 is a bright target image at the (T0 - 10) ms moment of the current photoelectric theodolite 4, then the output time of the current photoelectric theodolite 4 for shooting is 1 frame ahead; if the I1 image shown in Figure 4 is a bright target image at the (T0 + 10) ms moment of the current photoelectric theodolite 4, then the output time of the current photoelectric theodolite 4 for shooting lags behind by 1 frame, and so on. It is necessary to correct the photoelectric theodolite 4 in the image storage / character superposition time sequence to solve this problem. The bright target image described above is a point target image with bright points. For the sake of brief description, it is described as a bright target image here.

[0056] Third step, set Sd = 0, Sw = Tp. The calibrator detection software reads the point target images of the digital camera, reads the encoder output value in the additional information of the header file of the bright target image, and compares it with the calibration value. If the difference between the encoder values is small, it is considered that the superposition of the encoder and the captured image is accurate. If the deviation is large, set Sd = 1 ms, 2 ms, 3 ms... respectively and repeat the determination until the encoder output value in the additional information of the header file of the bright target image is consistent with the calibration value. At this time, the Sd value is the deviation amount between the encoder value of the point target image at the shooting moment and the encoder true value.

[0057] According to the different set parameters, the correction amount of the encoder and the correction amount of the image information under different exposure time application occasions at this frequency can be calibrated, and the information calibration at the image shooting moment can be completed. This has great practical value for the use of the photoelectric theodolite 4. In addition, through this instrument, the working parameters of different photoelectric theodolites 4 under the same conditions can be calibrated, which has great reference significance for the deviation correction of multiple sets of photoelectric theodolites 4 shooting targets in the shooting range.

[0058] Working principle of the calibration instrument detection software: (1) The calibration instrument detection software generally needs to be installed on the storage computer of the photoelectric theodolite 4 (due to the confidentiality requirements of the photoelectric theodolite 4, the image cannot be read and copied at will). The calibration instrument detection software provides an operation interface, and the user enters the control parameters of the current calibration system, the central position of the bright spot and the encoder value of the pitch on the interface; (2) The calibration instrument detection software can read the header file information of each point target image according to the storage format of the target range image information, and can extract the additional information of the header file of each point target image in real time (encoder output value, etc.); (3) The calibration instrument detection software completes the automatic judgment function of the point target image, extracts the central off-target value of the bright spot in the point target image, and finds the encoder value of the frame image with a central off-target value less than 3 pixels, and compares it with the initial value of the encoder output when the bright spot is in the center of the field of view to give a judgment; and gives a time judgment of the current shooting moment based on the time information of the point target image and the input parameter information.

[0059] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0060] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A photoelectric theodolite shooting time calibration system, characterized in that: include: Control panel, servo control unit, timing control unit and light source, wherein: The servo control unit includes a motor, a baffle, tin foil and a collimator, wherein the motor is connected to the baffle, the baffle is provided with a slit, and the center of the tin foil is provided with a small hole, and the light emitted by the light source is incident on the photoelectric theodolite through the slit of the baffle, the small hole of the tin foil and the collimator in sequence, and forms a bright spot on the imaging target surface of the photoelectric theodolite; The user operates the control panel to set the control parameters of the shooting time calibration system; the timing control unit outputs AC code and DC code to the photoelectric theodolite for timing according to the control parameters of the shooting time calibration system, so that the time of the photoelectric theodolite is synchronized with the time of the shooting time calibration system, and the timing control unit also sends a trigger signal to the servo control unit and the encoder of the photoelectric theodolite; the motor drives the baffle to rotate according to the control parameters, controls the photoelectric theodolite to align with the collimator, and places the bright spot at the center of the field of view of the photoelectric theodolite, records the calibration value output by the encoder, and inputs the calibration value output by the encoder into the calibration instrument detection software of the photoelectric theodolite; the user controls the photoelectric theodolite to perform periodic high-frequency sinusoidal disturbance with the current position of the bright spot as the center, and uses the set of point target images obtained in each motion cycle as a point target image sequence; the calibration instrument detection software of the photoelectric theodolite realizes the calibration of the shooting time of the photoelectric theodolite according to the calibration value output by the encoder, the point target image sequence and the control parameters.

2. The photoelectric theodolite shooting time calibration system according to claim 1, characterized in that: The imaging band of the light source includes a short wave band, a medium wave band, a visible wave band and a long wave band.

3. The photoelectric theodolite shooting time calibration system according to claim 1, characterized in that: The control parameters of the shooting time calibration system include the bright spot delay time and the bright spot duration time. The bright spot delay time is the time interval between the bright spot moment when the bright spot appears in the point target image sequence and the second signal of the timing control unit. The bright spot duration time is the duration of the bright spot in the point target image sequence.

4. A method for calibrating the shooting time of a photoelectric theodolite, implemented by using the photoelectric theodolite shooting time calibration system according to any one of claims 1 to 3, characterized in that: The specific steps include: S1: The user sets the bright spot delay time to 0, and makes the bright light duration shorter than the exposure time of the photoelectric theodolite. The motor drives the baffle to rotate according to the control parameters, and controls the photoelectric theodolite to align with the collimator, so that the light emitted by the light source forms a bright spot on the imaging target surface of the photoelectric theodolite. S2: Place the bright spot at the center of the field of view of the photoelectric theodolite, read the calibration value output by the encoder, and input the calibration value into the calibration instrument detection software, control the photoelectric theodolite to perform periodic high-frequency sinusoidal disturbances with the current position of the bright spot as the center, and record and store the obtained point target image sequence; The point target image includes a header file, and the header file stores the storage time when the bright spot in the point target image appears and the encoder output value; S3: The calibration instrument detection software reads the point target image sequence, and reads the stored time when the current bright spot appears in the header file of the point target image with the bright spot, compares the stored time when the current bright spot appears with the real time when the current bright spot appears, and calibrates the time deviation of the photoelectric theodolite; S4: Set the bright light duration to be equal to the exposure time of the photoelectric theodolite. The calibration instrument detection software reads the encoder output value stored in the header file of the point target image with the bright spot located at the center of the field of view of the photoelectric theodolite. If the encoder output value is the same as the calibration value, the calibration is completed. Otherwise, reset the bright spot delay time and repeat step S4 until the calibration is completed.

5. The method for calibrating the shooting time of a photoelectric theodolite according to claim 4, characterized in that: The actual moment when the current bright spot appears is determined according to the bright spot delay time and the bright light duration.

6. The method for calibrating the shooting time of a photoelectric theodolite according to claim 4, characterized in that: If the storage time of the header file in the point target image with a bright spot is different from the actual time when the current bright spot appears when the calibration instrument detection software reads the point target image sequence, it is determined that the exposure time of the digital camera of the photoelectric theodolite is too long. The user performs early exposure timing correction processing on the external trigger of the digital camera to obtain the point target image with the bright spot.

7. The method for calibrating the shooting time of a photoelectric theodolite according to claim 4, characterized in that: In step S3, the time interval between the delay times of two adjacent bright spots is the same, which is the reciprocal of the frequency of the external trigger signal of the photoelectric theodolite.

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