Photoelectric telescope control method and control system capable of continuously tracking target

Abstract

The invention relates to the technical field of astronomical observation, in particular to a photoelectric telescope control method and control system capable of continuously tracking a target, a timing system terminal provides an image acquisition trigger signal and an exposure center moment for a camera and an image processing system of a photoelectric telescope, and an encoder value of the photoelectric telescope corresponding to the exposure center moment is obtained; when the camera collects a target image, the target miss distance is calculated according to the target image, and then the photoelectric telescope is guided to track the target through the target miss distance; when the camera does not collect the target image, the target miss distance estimated value is calculated according to the actual target direction, and then the photoelectric telescope is guided to track the target through the target miss distance estimated value. When the frame loss condition occurs in the camera, the guide data in the frame loss state is obtained by calculating the target miss distance estimated value to guide the photoelectric telescope, and continuous target closed-loop tracking of the photoelectric telescope is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of astronomical observation, and specifically provides a control method and a control system for an optoelectronic telescope for continuously tracking a target. Background Art

[0002] In recent years, optoelectronic telescope observation technology has shown a rapid development trend, playing an important role in scientific and technological fields such as astronomical observation, aerospace and situational awareness. Different optoelectronic telescopes have certain differences in mechanical structure, optical path design, and camera selection, which means they have different observation target types and usage scenarios.

[0003] Target closed-loop tracking is one of the important functions of the optoelectronic telescope. The target closed-loop tracking method commonly used in optoelectronic telescopes can be summarized as follows: the image processing system receives the image collected by the camera in the optoelectronic telescope, calculates the target miss amount through the image processing algorithm and the optical system parameters, and sends the target miss amount to the servo control system of the optoelectronic telescope. The optoelectronic telescope servo control system smoothly guides the optoelectronic telescope to the pointing offset represented by the target miss amount during the next exposure cycle of the camera, thereby completing the target closed-loop tracking of one exposure cycle. The above process is executed once in each exposure cycle to complete the target closed-loop tracking of the entire observation process.

[0004] As an important component of the photoelectric telescope, the imaging quality and stability of scientific cameras directly affect whether related scientific experiments can be carried out smoothly. The development of scientific cameras has evolved from the traditional visible light band to the short-wave infrared, medium-wave infrared and long-wave infrared in previous years, and then to the commonly used J-band and K-band in recent years. The detectors of scientific cameras have also gradually developed from small targets with low resolution to large targets with high resolution. The rapid development of scientific cameras has played an important role in promoting the development of photoelectric telescopes.

[0005] The existing technology relies on the camera to continuously collect images. Whether the camera can continuously and stably output images determines whether the photoelectric telescope can continuously perform closed-loop tracking of the target. In actual work, due to certain reasons, such as setting camera parameters, the camera may drop frames. At this time, the image processing system cannot calculate the effective target miss amount, which may cause the target closed-loop tracking to fail. However, in the process of closed-loop tracking of the target, it is very necessary to set the camera parameters. For example, during the observation process, the intensity of the target signal varies. At this time, it is necessary to adjust the exposure time or gain according to a certain method to ensure that the target details can be observed throughout the process. For example, the speed and acceleration of the target will continue to change during the observation process. At this time, it is necessary to adjust the camera frame rate according to the actual situation to ensure that the telescope can perform stable closed-loop tracking of the target. When the camera drops frames, it cannot send the accurate target miss amount to the telescope servo control system in time, which easily causes the target to be lost.

[0006] The Chinese patent publication number is CN115480480A, the publication date is December 16, 2022, and the patent name is "Off-target and trajectory prediction collaborative control closed-loop tracking system and method" invention patent. This method improves the telescope's ability and accuracy in tracking highly maneuverable targets, but it relies on the camera's continuous image acquisition and cannot effectively solve the problem of the telescope's continuous target closed-loop tracking when the camera loses frames. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a control method and control system for an optoelectronic telescope for continuously tracking a target. When frame loss occurs due to a camera of the optoelectronic telescope, the optoelectronic telescope is guided to track the target by calculating an estimated miss amount, thereby ensuring that the optoelectronic telescope continuously tracks the target.

[0008] The present invention provides a method for controlling an optoelectronic telescope for continuously tracking a target, comprising: S1: Provide a trigger signal for collecting images to the camera of the optoelectronic telescope at a predetermined frequency, and provide the exposure center time to the image processing system of the optoelectronic telescope; S2: According to the exposure center time, the encoder value of the photoelectric telescope corresponding to the exposure center time is obtained; S3: Determine whether the camera has captured the target image through the image processing system: If the camera captures the target image, the target miss distance is calculated based on the target image; If the camera does not capture the target image, The target miss amount estimate is calculated based on the actual target pointing and exposure center moment. The actual target pointing is the sum of the corresponding target miss amount and the encoder value when the camera captures the target image. S4: Based on the calculated target miss amount or the estimated target miss amount, guide the photoelectric telescope to track the target; record the actual target pointing and the corresponding exposure center time.

[0009] Preferably, the predetermined frequency is the same as the exposure frequency of the camera.

[0010] Preferably, the number of actual targets The value is .

[0011] Preferably, the target miss amount estimate is calculated as follows: in accordance with The target trajectory equation is fitted based on the actual target pointing and exposure center time, and the parameters of the target trajectory equation are solved by the least squares method; Obtain the predicted target orientation on the target trajectory equation based on the exposure center moment; The difference between the predicted target pointing and the encoder value corresponding to the exposure center moment is calculated to obtain the target miss distance estimate.

[0012] A control system for an optoelectronic telescope for continuously tracking a target, based on an optoelectronic telescope control method for continuously tracking a target, controls the optoelectronic telescope, including: a time synchronization terminal, an image processing system and an optoelectronic telescope, wherein the optoelectronic telescope includes a camera and a servo control system; The timing terminal provides the camera with a trigger signal for collecting images at a predetermined frequency, and provides the exposure center time to the image processing system; If the camera captures the target image, the image processing system receives the target image, calculates the target miss amount and sends the target miss amount to the servo control system; If the camera does not capture the target image, the image processing system calculates the target miss amount estimate value and sends the target miss amount estimate value to the servo control system; The servo control system receives the target miss amount or the estimated target miss amount, controls the optoelectronic telescope to track the target, and feeds back the encoder value of the optoelectronic telescope to the image processing system.

[0013] Compared with the prior art, the present invention can achieve the following beneficial effects: When the optoelectronic telescope performs closed-loop target tracking, frame loss may occur due to camera setting parameters or other situations, resulting in interrupted guidance data. In the frame loss state, the present invention calculates the estimated value of the target miss amount and then obtains the guidance data to complete the guidance of the optoelectronic telescope, thereby solving the problem of discontinuous guidance caused by frame loss in the process of closed-loop target tracking of the optoelectronic telescope. In the frame loss state, the image processing system can still send the correct miss amount to the telescope servo control system to complete continuous closed-loop target tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of a method for controlling an optoelectronic telescope for continuously tracking a target according to an embodiment of the present invention; Figure 2 is a flow chart of calculating an estimated value of a target miss amount according to an embodiment of the present invention; Figure 3 It is a structural diagram of an optoelectronic telescope control system for continuously tracking a target provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and advantages of the invention clearer, 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 herein are only used to explain the invention and do not constitute a limitation to the invention. Similar components in different embodiments use associated similar component numbers. In the following embodiments, many detailed descriptions are to enable the invention to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other components, materials, and methods. In some cases, some operations related to the invention are not shown or described in the specification, in order to avoid the core part of the invention being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0016] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0017] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the 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 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. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0018] 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.

[0019] So far, experiments have found that among the various models of cameras used in optoelectronic telescopes at home and abroad, frame loss of tens of milliseconds will occur when setting camera parameters (approximately 1 to 4 frames are lost depending on the frame rate). Some cameras lose frames because the camera circuit system is not mature enough. Some cameras lose frames because the camera detector does not support continuous image acquisition when the camera parameters are modified. At this time, the image processing system cannot calculate the effective target miss distance, which may cause the failure of continuous target closed-loop tracking.

[0020] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0021] When the photoelectric telescope is performing closed-loop tracking of the target, the servo control system guides the photoelectric telescope according to the guidance data so that it points to the target to complete the closed-loop tracking. The pointing direction is the direction of observation of the photoelectric telescope, which is expressed as the coordinates of the azimuth and elevation angles. The guidance data is a series of data required by the photoelectric telescope to accurately track the target during the observation process. These data can guide the telescope to accurately point to the target and maintain stable tracking during the observation process. When observing a target through an photoelectric telescope, the pointing direction of the photoelectric telescope is the coordinate of the target position. The coordinate of the target position is the pointing direction under ideal conditions, but there is often a deviation in the actual target pointing direction. This deviation is called the target miss amount. The sum of the target miss amount and the encoder value is the actual target pointing direction.

[0022] The camera inside the photoelectric telescope will collect images of the target at a certain frequency, which is the camera exposure frequency. When the camera loses frames due to some reasons, the image collection will be interrupted, and the guidance data of the photoelectric telescope will also be interrupted, such as Figure 1 As shown, the present invention provides a control method for an optoelectronic telescope for continuously tracking a target, which is specifically as follows: In the method of the present invention, the method for acquiring each frame of guidance data is the same, therefore, only the method for acquiring a single frame of guidance data is described, and the overall process is a combination of multiple single frame processes.

[0023] S1: When the camera loses frames, it no longer performs normal target image acquisition, so the frame rate will be interrupted, which will lead to time rhythm disorder. The embodiment of the present invention is provided with a timing terminal, and according to a predetermined frequency, a trigger signal is provided to the camera of the photoelectric telescope through the timing terminal, and the trigger signal triggers the camera to acquire the target image. At the same time, the timing terminal provides the exposure center time to the image processing system of the photoelectric telescope. , the exposure center moment It is sustainable and uninterrupted. Therefore, during the closed-loop target tracking process, when the camera parameters are set manually or automatically according to the actual situation, resulting in a brief frame loss, the time information will not be interrupted. This ensures that the overall system will not have time rhythm confusion or interruptions during closed-loop target tracking, providing a time basis for continuous closed-loop target tracking.

[0024] The predetermined frequency is the same as the camera exposure frequency, and the specific frequency can be set according to the target closed-loop tracking requirements.

[0025] S2: When the photoelectric telescope performs closed-loop tracking of the target, each frame of guidance data tracking is performed, and the photoelectric telescope corresponds to an encoder value according to the exposure center time provided by the time system terminal. , get the exposure center time The encoder value of the corresponding photoelectric telescope reflects the direction of the photoelectric telescope at the exposure center. Include azimuth and pitch angle ,Right now .

[0026] When the optoelectronic telescope performs closed-loop tracking of a target, its pointing direction changes and the corresponding encoder value changes. Therefore, even if the camera of the optoelectronic telescope does not capture an image, that is, when a frame is lost, the encoder value can still be obtained.

[0027] S3: Determine whether the photoelectric telescope camera has captured the target image, that is, determine whether a frame is lost. If the camera has captured the target image, no frame loss has occurred. If the camera has not captured the target image, a frame loss has occurred.

[0028] When no frame is lost, the following calculation is performed: Calculate the target off-target amount Sent to the optoelectronic telescope to guide the optoelectronic telescope to perform closed-loop tracking of the target.

[0029] Target miss amount Including azimuth miss and pitch miss ,Right now Calculating the target miss amount based on the image collected by the photoelectric telescope camera is a mature existing technology. Due to different camera detection bands, different types of observed targets, different usage scenarios, etc., the method of calculating the target miss amount based on the image is also different, which will not be repeated here.

[0030] When the frame is dropped, the camera does not capture the target image. At this time, the target miss distance is estimated to obtain the target miss distance estimate value, as follows: like Figure 2 As shown in the figure, when the camera acquires the target image, several frames of image frame loss will occur continuously, that is, it will transition from no frame loss to frame loss. After several consecutive frame losses, it will transition to no frame loss. Therefore, when calculating the target miss amount estimation under the frame loss state, the most recent The actual target points to the fitting target trajectory equation, the nearest The actual target pointing is the actual target pointing in the adjacent non-frame-losing state before the current frame-losing state. The actual target pointing is the sum of the corresponding target miss distance and the encoder value when the camera captures the target image. In this embodiment of the present invention, the number of actual target pointing is taken as The actual target pointing includes azimuth and elevation, so the equation obtained by fitting is expressed as azimuth and pitch : ; ; in, Indicates time, and Respectively represent the coefficients of the corresponding equations. By solving the above coefficients by the least square method, the final fitting equation can be obtained. Fitting equations according to coordinates and solving equation coefficients by the least square method is a prior art.

[0031] Exposure center time provided by the time system terminal , combined with the fitted equation, the target prediction direction can be solved , and then calculate the target miss amount estimate , that is, the difference between the predicted target point and the encoder value corresponding to the exposure center moment, that is , .

[0032] S4: When there is no frame loss, the calculated target miss amount is the guidance data for the final guidance of the optoelectronic telescope. When there is frame loss, the estimated target miss amount is the guidance data for the final guidance of the optoelectronic telescope. The guidance data is used to guide the optoelectronic telescope to track the target, thereby achieving closed-loop tracking of the target without being affected by frame loss.

[0033] At the same time, the actual target orientation and the corresponding exposure center moment are recorded to fit the target trajectory equation when the target miss distance estimate is calculated when a frame loss occurs later. The actual target orientation recorded here is calculated in the same way as the actual target orientation in S3 above, except that it corresponds to the actual target orientation at different exposure center moments.

[0034] In order to implement the above-mentioned photoelectric telescope control method, the embodiment of the present invention also provides a photoelectric telescope control system, such as Figure 3 As shown, it includes a time-keeping terminal, a computer terminal and an optoelectronic telescope, the computer terminal is an image processing system, and the optoelectronic telescope includes a camera and a servo control system. The time-keeping terminal is connected to the image processing system and the camera respectively, and the image processing system is connected to the camera and the servo control system respectively.

[0035] The timing terminal provides a trigger signal for collecting images to the camera at a predetermined frequency, triggering the camera to collect the target image. The camera sends the collected target image to the image processing system. At the same time, the timing terminal provides the exposure center time to the image processing system.

[0036] When the camera captures an image, the image processing system receives the target image sent by the camera, extracts the target based on the received target image and calculates the target miss distance, and then sends the target miss distance to the servo control system. At the same time, the image processing system records the actual target pointing and the corresponding exposure center time, which is used to fit the target trajectory equation when the target miss distance estimate is calculated when frame loss occurs later.

[0037] If the camera does not capture an image, the image processing system fits the target trajectory equation based on the actual target pointing, and then calculates the target miss distance estimate, and sends the target miss distance estimate to the servo control system.

[0038] The servo control system receives the target miss amount or the estimated target miss amount sent by the image processing system, obtains the guidance data, controls the optoelectronic telescope to track the target, and feeds back the encoder value of the optoelectronic telescope to the image processing system.

[0039] When the photoelectric telescope is controlled by the above method, the following closed-loop target tracking is performed: after completing the previous tracking step, the timing terminal of the photoelectric telescope provides the next trigger signal to the camera and provides the exposure center time to the image processing system. The trigger signal triggers the camera to collect the target image at a predetermined frequency, and the camera sends the collected target image to the image processing system. The image processing system calculates the target miss amount based on the target image, and sends the target miss amount to the servo control system of the photoelectric telescope to guide the photoelectric telescope. Record the actual target pointing and the corresponding exposure center time of the currently completed tracking. Proceed to the next step of tracking.

[0040] If after the previous tracking step is completed, when the timing terminal of the photoelectric telescope provides the next trigger signal to the camera, the camera loses the frame and fails to collect the target image, then the target motion equation is fitted based on the multiple actual target pointing and corresponding exposure center time recorded in the adjacent tracking step without frame loss, and the target miss amount estimation is calculated. The photoelectric telescope is guided to complete the tracking based on the target miss amount estimation. Then the next tracking step is carried out.

[0041] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0042] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for controlling an optoelectronic telescope for continuously tracking a target, characterized in that: include: S1: Provide a trigger signal for collecting images to the camera of the optoelectronic telescope at a predetermined frequency, and provide the exposure center time to the image processing system of the optoelectronic telescope; S2: according to the exposure center moment, obtaining the encoder value of the photoelectric telescope corresponding to the exposure center moment; S3: Determine whether the camera has captured the target image through the image processing system: If the camera captures a target image, the target miss distance is calculated based on the target image; If the camera does not capture the target image, The target miss amount estimation value is calculated based on the actual target pointing and the exposure center moment, wherein the actual target pointing is the sum of the corresponding target miss amount and the encoder value when the camera captures the target image; S4: Based on the calculated target miss amount or the estimated target miss amount, guide the photoelectric telescope to track the target; record the actual target pointing and the corresponding exposure center time.

2. The method for controlling an optoelectronic telescope for continuously tracking a target as claimed in claim 1, characterized in that: The predetermined frequency is the same as the exposure frequency of the camera.

3. The method for controlling an optoelectronic telescope for continuously tracking a target as claimed in claim 1, characterized in that: The number of actual targets The value is .

4. The method for controlling an optoelectronic telescope for continuously tracking a target as claimed in claim 1, characterized in that: The target miss distance estimate is calculated as follows: According to the The target trajectory equation is fitted based on the actual target pointing and exposure center moment, and the parameters of the target trajectory equation are solved by the least square method; Obtaining a predicted target orientation on the target trajectory equation according to the exposure center moment; The difference between the predicted target pointing and the encoder value corresponding to the exposure center moment is calculated to obtain the target miss distance estimate.

5. An optoelectronic telescope control system for continuously tracking a target, characterized in that: Based on the control method of an optoelectronic telescope for continuously tracking a target as claimed in any one of claims 1 to 4, an optoelectronic telescope is controlled, comprising: a time system terminal, an image processing system and an optoelectronic telescope, wherein the optoelectronic telescope comprises a camera and a servo control system; The timing terminal provides a trigger signal for collecting images to the camera at a predetermined frequency, and provides an exposure center time to the image processing system; If the camera captures the target image, the image processing system receives the target image, calculates the target miss amount and sends the target miss amount to the servo control system; If the camera does not capture the target image, the image processing system calculates the target miss amount estimate value and sends the target miss amount estimate value to the servo control system; The servo control system receives the target miss amount or the target miss amount estimation, controls the photoelectric telescope to track the target, and feeds back the photoelectric telescope encoder value to the image processing system.

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