Servo total station and polygon prism identification method

Abstract

The invention discloses a servo total station and a polygon prism identification method. The total station comprises a target identification unit, a servo driving unit, a measuring unit, a main control unit, a communication unit and a storage unit. According to the invention, coordinate and angle information of all prisms in the field of view can be identified and output simultaneously; only one time of ATR is needed, and then automatic rotation can be carried out for measurement according to angle information identified for the first time; the laser intensity and the receiving gain can be dynamically adjusted according to the prism distance, the signal intensity and other conditions, the stability and accuracy of signals under different distances and light conditions are ensured, then clear and stable light spot characteristics are obtained, and the method is particularly suitable for stable measurement under the condition of large atmospheric jitter. In a word, compared with a traditional single-target servo total station, the total station has remarkable advantages in the aspects of measurement efficiency, operation convenience, environmental adaptability, intelligent data processing and the like, and particularly, the total station shows obvious efficiency improvement and environmental adaptability in a scene with multiple prisms.

Description

Technical Field

[0001] The invention belongs to the technical field of automated surveying, and in particular relates to a servo total station and a multi-prism identification method. Background Art

[0002] The servo total station is an intelligent electronic total station that can automatically search, track, identify and accurately aim at the target and obtain information such as angle, distance, three-dimensional coordinates and images. Among them, the automatic target recognition function is the core and decisive factor in the measurement accuracy of the total station. The automatic target recognition function requires the instrument to automatically aim at the prism, which involves two steps: identifying the prism and aligning the prism.

[0003] The main method for identifying prisms is to use a 2D sensor. The laser diode in the instrument emits a laser beam, which is coaxially projected onto the telescope axis through optical components and emitted from the objective lens port. After the laser reaches the prism, the prism reflects the laser into the telescope. The beam splitter in the telescope separates the reflected receiving beam and guides the receiving beam to the 2D sensor to form a light spot. The 2D sensor converts the received light signal into corresponding image data, and the calculation module inside the instrument processes the image data to obtain the coordinates of the center point of the light spot. After the coordinates are converted, the angular offset value of the center of the prism reflected light spot relative to the center of the instrument is obtained. Since the total station needs to aim at the target before it can measure the angle and distance of the target, after obtaining the angular offset value of the center of the prism reflected light spot relative to the center of the instrument, it is also necessary to move the center of the instrument's telescope to the center of the prism. This process is implemented by the servo system.

[0004] Traditional manual total stations manually aim at each measuring point. Although the existing servo total stations have changed manual aiming into automatic aiming, the measurement efficiency has been improved to some extent, but they basically measure single points. For application scenarios of multi-target measurement, its measurement efficiency still needs to be improved. Summary of the invention

[0005] The invention provides a servo total station and a multi-prism identification method to solve the multi-prism identification problem during total station measurement, thereby improving measurement efficiency.

[0006] The technical solution provided by the present invention is as follows:

[0007] A servo total station, comprising a target recognition unit, a servo drive unit, a measuring unit, a main control unit, a communication unit and a storage unit; the target recognition unit is used to recognize and locate multiple prism targets, and the target recognition unit comprises a laser emission module, a laser receiving module and a processing control module; the laser emission module is used to emit a laser beam covering the entire field of view, the laser receiving module is used to receive reflected light and form an image, and the processing control module is used to process the image to obtain position information of each prism target; the servo drive unit is used to drive the rotation of the total station's sighting part in the horizontal direction and the total station's telescope in the vertical direction according to the position information of the prism target provided by the target recognition unit , so as to realize aiming at the target prism; the measuring unit includes a distance measuring unit and an angle measuring unit, the distance measuring unit is used to measure the distance of the target prism after aligning the prism, and the angle measuring unit is used to measure the angles of the horizontal axis and the vertical axis of the total station; the main control unit is used to receive the user's operation instructions or external communication instructions, and decompose the operation instructions or communication instructions into the execution tasks of each unit module, so as to realize automatic alignment and measurement of the prism target; the communication unit is used to provide communication support between the total station and external devices, output the internal measurement data and equipment status to the external monitoring system, or receive external communication instructions; the storage unit is used to provide data storage function, and support temporary storage and long-term storage of measurement data.

[0008] Furthermore, the laser receiving module in the target recognition unit includes a receiving lens and a photoelectric sensor. The receiving lens converges the reflected light onto the image sensor, and the image sensor converts the received reflected light into an electrical signal to form an image.

[0009] Furthermore, the processing control module in the target recognition unit is also used to automatically adjust the intensity of laser emission, the receiving gain and exposure time of the image sensor.

[0010] Furthermore, the total station also includes a graphic interaction unit, which includes an input device and an output device, and is used to provide an interactive interface between the user and the instrument. The user inputs operating instructions through this unit and views the measurement results and system status in real time.

[0011] Furthermore, the total station also includes a tilt compensation unit, which is used to collect the tilt angle of the vertical axis of the total station, and automatically compensate the angle when the total station tilts.

[0012] Furthermore, the total station simultaneously contains data of multiple prism targets during input and output, and the data includes prism type, constant, distance, angle and coordinates of the prism in the total station coordinate system.

[0013] A multi-prism identification method based on the above-mentioned total station is characterized by comprising a prism learning stage and a prism monitoring stage;

[0014] Prism learning stage: first manually aim at the prism in the middle of the field of view, which is recorded as the preferred position; then the laser emission module projects the laser into the field of view of the telescope so that the laser covers all prism positions; the laser receiving module captures the light beam reflected by each prism and converts the light signal into an image through the image sensor; the processing and control module of the target recognition unit first pre-processes the image to ensure the contrast and clarity of the prism spot, and then distinguishes the spot of each prism from the image background through threshold segmentation to form an independent spot; finally, the prism information including the coordinates of the center of each spot is obtained and saved;

[0015] Monitoring prism stage: first, align the preferred position through the servo drive unit, then obtain the position information of all prisms in the field of view through the target recognition unit and compare it with the prism information saved in the learning prism stage. If all prisms in the learning prism stage exist, then align each prism in turn through the servo drive unit and measure the distance of the prism through the ranging unit, otherwise the prism loss information is output.

[0016] Furthermore, the processing control module of the target recognition unit automatically adjusts the laser intensity and the receiving gain of the image sensor according to actual conditions: when multiple prism reflected light spots are received, the first image is obtained according to the default gain, and then the light spots are divided into two groups according to the difference between the light spots and the ideal values. The features of the group with appropriate gain are first extracted to calculate the center position of each prism light spot; for the group with inappropriate gain, a light spot is first selected to set a suitable gain value for it and feature extraction is performed to obtain the center position of the light spot, and then the other light spots in the group under the gain value are regrouped; the above process is repeated until all light spots are traversed.

[0017] Furthermore, the image preprocessing performed by the processing control module includes spatial domain filtering and frequency domain filtering, and the threshold segmentation adopts Otsu method or maximum entropy method.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] (1) Efficient simultaneous recognition and output of multiple targets

[0020] Traditional servo total stations can only aim and measure single targets one by one, and can only output data of one prism at a time. When processing multiple targets, it is necessary to repeat aiming, measuring and data transmission multiple times. The present invention can cover the entire field of view and simultaneously identify and output the coordinates and angle information of all prisms in the field of view. This function is suitable for multi-prism monitoring scenarios, avoiding the tedious operations of learning and aiming one by one, and significantly improving measurement efficiency, especially in projects with a large number of prisms in the field of view.

[0021] (2) Automatic rotation and multi-target fast mode

[0022] The total station of the present invention has the ability to automatically turn to each prism, eliminating the step of manual aiming. Its workflow has been optimized, and it can obtain the angle information of multiple prisms during one automatic target recognition (ATR) process, and automatically rotate to each prism based on this information to complete the distance measurement, thereby realizing fast data acquisition. In traditional total stations, monitoring multiple targets requires N ATR searches one by one, while the total station of the present invention only requires one ATR, and then automatically rotates to measure according to the angle information of the initial recognition, thereby reducing N-1 ATR search processes.

[0023] (3) Enhanced environmental adaptability

[0024] The present invention has stronger adaptability in complex field environments. Under conditions of large weather changes and strong signal interference, a single-target servo total station may cause data measurement deviations or even interruptions due to unstable signals. For example, in extreme weather such as rain and fog, if the reflection signal of the current prism of a single-target instrument is weak or missing, the data of other nearby prisms may be mistakenly identified as target data, affecting the measurement accuracy. The present invention intelligently detects changes in signal strength of each prism in the field of view to avoid mismeasurement. At the same time, it intelligently identifies prisms with missing signals by comparing historical data and reports abnormalities, making monitoring more reliable.

[0025] (4) Intelligent image processing and gain control

[0026] The present invention supports multi-spot recognition processing of images and has advanced image preprocessing, spot separation and feature extraction functions. Through spatial domain and frequency domain filtering, high-quality image recognition effects can be maintained in various noise environments. In addition, the present invention dynamically adjusts the laser intensity and receiving gain according to the prism distance, signal strength, etc., to ensure the stability and accuracy of the signal under different distances and light conditions, thereby obtaining clear and stable spot features, which is particularly suitable for stable measurement under conditions of large atmospheric jitter.

[0027] (5) Convenient multi-target data interface

[0028] The multi-target servo total station supports the simultaneous output of measurement data of multiple targets on the data interface, including the distance, angle and coordinates of each prism. This parallel output method improves the data transmission efficiency and is suitable for real-time monitoring and analysis in conjunction with an external monitoring system, greatly reducing the measurement and data processing time, thereby reducing the measurement cost.

[0029] In general, the present invention has significant advantages over traditional single-target servo total stations in terms of measurement efficiency, operational convenience, environmental adaptability, and intelligent data processing, especially in scenarios with multiple prisms, showing significant efficiency improvements and environmental adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0031] Figure 1 It is a schematic diagram of the composition of a servo total station module provided by an embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of the basic working process of a servo total station provided by an embodiment of the present invention;

[0033] Figure 3 It is a schematic diagram of a prism learning process of a servo total station provided by an embodiment of the present invention;

[0034] Figure 4 It is a schematic diagram of an image in a certain field of view of a servo total station provided by an embodiment of the present invention;

[0035] Figure 5 It is a schematic diagram of a target recognition process of a servo total station provided by an embodiment of the present invention;

[0036] Figure 6 It is a flow chart of the servo total station monitoring prism stage provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of protection of the present invention.

[0038] like Figure 1 As shown, the servo total station provided in this embodiment mainly includes a target recognition unit, a servo drive unit, a measurement unit, a main control unit, a communication unit and other auxiliary units.

[0039] The target recognition unit is mainly used to identify and locate multiple prism targets. Its core functions include laser intensity adjustment, spot exposure control, and multi-prism image processing. Specifically, the unit includes the following modules:

[0040] 1. Laser emission module: The core task is to emit a laser beam to cover the entire field of view of the telescope. The emission light source is a laser diode, which is coupled to the emission reflector through an optical fiber and a coupling lens, and the emission reflector then emits the laser. By setting a specific emission angle, the laser beam evenly covers the reflection positions of multiple prisms, ensuring that each prism can receive the laser.

[0041] 2. Laser receiving module: including receiving lens and image sensor. After the laser returns from the reflecting prism, the receiving lens (objective lens) converges the received light onto the image sensor, which is responsible for converting the received reflected light spot light signal into an electrical signal to form a two-dimensional image.

[0042] 3. Processing and control module: processes the received image signals and completes tasks such as image preprocessing, spot segmentation, feature extraction, etc. This module also has the function of automatically adjusting the laser intensity, sensor receiving gain, and exposure time to adapt to different distances and ambient light.

[0043] The servo drive unit is mainly used to drive the rotation of the total station sighting part in the horizontal direction and the telescope in the vertical direction to achieve automatic aiming of the target prism. The servo system adjusts the total station telescope to the center of the prism according to the angle data provided by the target recognition unit to achieve efficient automatic aiming. Specifically, the unit includes a horizontal drive module and a vertical drive module. The horizontal drive module is used to control the horizontal rotation of the instrument so that the telescope can be aimed at prisms in different directions. The vertical drive module is used to control the vertical rotation of the telescope so that the instrument can be aimed at prisms at different heights. The combination of horizontal and vertical rotation enables the instrument to automatically align and lock the position of each target prism.

[0044] As the core control module of the whole system, the main control unit is mainly used to coordinate the various modules of the instrument, especially to control the recognition data of the target recognition unit to be transmitted to the servo drive unit to realize automatic alignment and measurement. The main control unit receives operation instructions from the user or external communication instructions, and decomposes the operation into execution tasks of each module through data processing and signal transmission. The communication unit provides communication support between the instrument and external devices, outputs internal measurement data and equipment status to the external monitoring system, or receives external instructions for operation. The communication unit supports a variety of wired and wireless communication methods, including serial port, USB, Ethernet, optical fiber, WIFI, Bluetooth, etc. It enables the total station to be used as a sensor of the external system to realize remote monitoring and data sharing.

[0045] The measuring unit includes a distance measuring unit and an angle measuring unit. The distance measuring unit is responsible for measuring the distance of the target prism after aligning the prism. It uses laser distance measurement technology, usually based on pulse or phase measurement. The laser signal is emitted from the transmitting end and reflected back to the instrument through the prism. The distance measuring unit calculates the target distance based on the time or phase difference between the emission and return of the laser, and the measurement accuracy reaches the millimeter level. The angle measuring unit usually includes a precision angle encoder, which is used to measure the rotation angle of the total station in the horizontal and vertical directions (the angle between the horizontal axis and the vertical axis of the total station). The high-precision angle measurement of the angle measuring unit is crucial for target aiming, allowing the total station to accurately locate the angle to the target.

[0046] The storage unit is used to provide data storage functions, supporting temporary and long-term storage of measurement data. It includes the storage of all information from user input data, measurement process data to final measurement results, and provides support for data export and historical records.

[0047] In some embodiments, the servo total station also includes a graphic interaction unit. The graphic interaction unit includes an input device (such as a keyboard, a touch screen, etc.) and an output device (such as an LCD screen, an indicator light, a speaker, etc.), which is used to provide an interactive interface between the user and the instrument. The user inputs operating instructions through this unit and views the measurement results and system status on the display screen in real time. It allows users to operate the instrument more conveniently through intuitive graphic display.

[0048] In some embodiments, the servo total station also includes a tilt compensation unit: used to collect the tilt angle of the vertical axis of the total station. When the instrument tilts, the angle will be automatically compensated so that the measurement data can still maintain accuracy.

[0049] like Figure 2 As shown in the figure, the basic working process of the servo total station is as follows: the user inputs the measurement command through the graphic interaction unit, or receives the control signal of the external device through the external communication unit. After receiving the command, the main control unit starts the target recognition unit to identify and measure the angle of the prism and determine the position of the prism in the instrument coordinate system. The servo drive unit rotates the instrument according to the measured angle data so that the center of the telescope is aligned with the target prism. The distance measurement unit measures the precise distance of the prism, the angle measurement unit records the angle information of the instrument, and the tilt compensation unit corrects the error caused by the tilt of the instrument. The data is transmitted to the external system or stored in the storage unit through the external communication unit to complete the data acquisition process.

[0050] The workflow of the servo total station is divided into two main stages: the learning prism stage and the monitoring prism stage. Figure 3 As shown, in the prism learning stage, if in a certain area, such as Figure 4, you can see 5 prisms at the same time from the instrument, namely P1, P2, P3, P4 and P5. Because P3 is in the middle, if you set P3 as the target prism, you can see 5 prisms at the same time, which is the most efficient. The user first manually aims at P3, clicks on the measurement, and the instrument follows Figure 5 The program is run in this process until the characteristic information of all prisms (center coordinates, etc.) is calculated. Figure 6 The process diagram of the prism monitoring stage is similar to the learning stage, except that the input information is the information of the preferred prism and other prisms in the preferred prism area. During the monitoring process, the system monitors the signal strength of each prism in real time. All measurement data are output to the external system in real time through the communication unit and stored in the storage unit to ensure the subsequent analysis of the data.

[0051] In addition, during the monitoring process, the multi-target servo total station has stronger environmental adaptability. In monitoring applications, especially in field applications, the received signal strength of the automatic target is often affected by the weather. Under extreme weather conditions such as rain and fog, the return light signal of the prism may even be completely absent. If there is only one prism in the field of view, the performance of the single-target servo total station and the multi-target servo total station is the same, and both will display that no prism is found. If there are multiple prisms in the field of view, due to the influence of the weather, the signal of the current prism is very weak, and the return light signal is not received at all, and there is another or several prism signals in the field of view with a return light signal. At this time, according to the search strategy of the single-target servo total station, the instrument will search for the prism closest to the telescope crosshairs, which will cause the instrument to export the measurement data of another prism as the measurement data of the current prism to be measured, which will cause a relatively large error. For the same scenario, the total station of this embodiment will adopt a more intelligent strategy. Specifically, the total station of this embodiment will compare the prism data in the field of view with the previous data, find the disappeared prism, and display that no prism is found in the field of view.

[0052] The most basic function of the processing control module of the target recognition unit is the ability to process multiple light spots in the image. The processing steps are: S1, preprocessing the image; S2, segmenting the prism light spots in the image; S3, extracting features from each prism light spot.

[0053] The image preprocessing in step S1 generally includes geometric operations, grayscale transformation, and filtering transformation of the image, etc. The main purpose is to eliminate image recognition interference as much as possible, which is conducive to image feature extraction and recognition analysis. Image filtering mainly uses spatial domain filtering or frequency domain filtering to make the image quality better. The spatial domain refers to the image plane space visible to the naked eye, and the spatial domain filtering performs convolution operations on the image. In specific implementation, a sliding window of a fixed size is generally used to scan the image, sliding from left to right and from top to bottom, calculating and updating the pixel value of the center of the window until all pixel values ​​of the entire image are scanned and replaced, that is, the spatial domain filtering of the image is completed. Since the spatial domain filtering directly acts on the image itself, different filtering methods have more stringent requirements on the type of noise, and the best filtering method needs to be determined according to the characteristics of different noises. Noise is generally a high-frequency component, which is difficult to distinguish through spatial domain operations, but in the frequency domain, low-frequency components and high-frequency components can be easily separated through Fourier transform. It is only necessary to use a low-pass filter to retain the low-frequency components of the image and suppress the high-frequency components to remove the noise, and then restore the image from the frequency domain to the spatial domain by inverse transformation, that is, the frequency domain filtering is completed.

[0054] Step S2 is mainly to perform image segmentation. The main purpose of image segmentation is to distinguish the prism target from the background. Since the prism is illuminated by active light emission, the prism spot is relatively bright compared to the background. This is generally done by threshold segmentation. The basic principle of the threshold segmentation method is: by setting different feature thresholds, the image pixels are divided into several categories of target areas and background areas with different gray levels. In determining the optimal threshold, possible methods include Otsu method, maximum entropy method, etc.

[0055] Step S3 is mainly the feature extraction of the prism target. When there is only one prism in the image, it is only necessary to extract the features of one prism target. Because the purpose of automatic target recognition is to align with the center of the prism, it is necessary to extract the coordinates of the center of the light spot at this time. When there are multiple prism targets on the image. First, it is necessary to separate each prism target, obtain the areas of several prism targets, and perform feature extraction on each area. In the case of interference targets, it is also necessary to distinguish the targets and distinguish the prism targets from the interference targets. After obtaining all the prism target areas in the image, the next step is to extract features for each prism target, especially the feature of the prism center must be extracted.

[0056] In the application of total station, the distance range of prism is about 1.5m to 3000m. According to the calculation formula of spherical crown area, the total area of ​​laser at distance R can be obtained as S1 = 2π*R 2*(1-sin(90-θ / 2)), where θ is the divergence angle of the light beam. Back to the laser energy, let the energy emitted by the laser be P, assuming that there is no attenuation during the laser transmission process, and the area of ​​the prism is A, then the energy received on the prism at a distance of R is P1=P*A / S1. Similarly, assuming that the prism is totally reflected, the total area of ​​the light beam returning from the prism to the instrument end is S2=2π*(2R) 2 *(1-sin(90-θ2 / 2)), where R is still the distance between the prism and the instrument, and θ2 is the angle of the prism relative to the laser light point. Assuming that the total area of ​​the receiving end of the instrument is B, the energy received by the instrument is P2=P1*B / S2=P*A / S1*B / S2. From this, it can be seen that the reflection ability of the prism is inversely proportional to the fourth power of the distance. In this way, for the same system, the strength of the energy will vary many times due to different distances. In addition, the laser energy is attenuated by the atmosphere, and this attenuation may vary with the weather. Therefore, for the automatic target recognition system, the received energy changes greatly due to changes in distance and environment. Therefore, in order to achieve the clearest edge of the prism light spot, it is necessary to automatically adjust the receiving gain of the laser and the receiver according to different situations.

[0057] When the system receives a single prism spot, the adjustment is relatively simple, that is, the edge clarity of the prism spot under different system gains. At the same time, due to the jitter of the atmosphere, the gain needs to be adjusted to make the spot more stable. Or filter a single image, or filter multiple consecutive images to remove unstable images. Ensure that the data is relatively stable or close to the actual result when the feature is extracted later.

[0058] When the system receives multiple prism light spots, the adjustment is relatively complicated. One strategy is to adjust the system gain of each prism according to the light spot in the image. Another strategy is to group the prisms. After obtaining the first image at the default gain, the light spots with a small difference from the ideal value (assuming the empirical value is 10%) are grouped into one group, and the light spots with a large difference from the ideal value are grouped into another group. First, extract the features of the targets with appropriate gain and calculate the center position of all targets. Then process the target group with unreasonable gain. First select a target, select a suitable gain value for the target, and select the relevant group at the same time. Repeat the above process until all targets are traversed.

[0059] In terms of the interface, the input and output are data containing several prism targets. Each target may contain the type of prism, the constant, distance, angle or coordinate of the prism in the coordinate system of the total station. On the traditional servo total station, the input and output interfaces are all single-target data. In the monitoring stage, if a traditional single-target servo total station is used, the user needs to learn each point, and obtain the distance, angle or coordinate information of the target after measurement. At the same time, the user specifies or the system automatically assigns the ID of this point. When the servo total station of this embodiment has only a single prism in the field of view, the working process is consistent with that of an ordinary single-target servo total station. When there are multiple prisms in the field of view, in addition to providing the working mode of a single-target servo total station, another multi-target fast method is also provided. Specifically, when multiple prisms appear in the field of view, the multi-target servo total station will output the coordinates of all prisms in the field of view or the angles of multiple prisms within the range set by the user. The advantage of this is that it can save time. The multi-target servo total station reduces the ATR (automatic target recognition) search process from N times to 1 time, and changes N-1 times of manual aiming at the prism to N-1 times of automatic rotation to the prism target. The time saved is of great advantage in projects with many prisms. The previous discussion was about saving time in the prism learning process. Similarly, during the monitoring process, an ATR can be performed to obtain the angle information of all prisms in the field of view. It can also save N-1 times of ATR search time.

[0060] In summary, the multi-target recognition process of the servo total station is divided into the steps of laser coverage, light signal reception, image preprocessing, spot segmentation, multi-target feature extraction and data output. After multiple gain adjustments, angle recognition and signal monitoring, efficient measurement and monitoring of multiple prisms can be achieved. Through the above steps, the servo total station not only realizes multi-target recognition and high-precision measurement, but also can adapt to a variety of environments to ensure the stability and reliability of data. These functions make it highly efficient, adaptable and accurate in multi-target measurement scenarios, especially suitable for large-scale, multi-prism monitoring projects.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A servo total station, characterized in that: It includes a target recognition unit, a servo drive unit, a measurement unit, a main control unit, a communication unit and a storage unit; The target recognition unit is used to identify and locate multiple prism targets, and the target recognition unit includes a laser emitting module, a laser receiving module and a processing control module; the laser emitting module is used to emit a laser beam covering the entire field of view, the laser receiving module is used to receive reflected light and form an image, and the processing control module is used to process the image to obtain the position information of each prism target; The servo drive unit is used to drive the rotation of the total station sighting part in the horizontal direction and the total station telescope in the vertical direction according to the position information of the prism target provided by the target recognition unit, so as to realize aiming at the target prism; The measuring unit comprises a distance measuring unit and an angle measuring unit, the distance measuring unit is used to measure the distance of the target prism after aligning the prism, and the angle measuring unit is used to measure the angles of the horizontal axis and the vertical axis of the total station; The main control unit is used to receive user operation instructions or external communication instructions, and decompose the operation instructions or communication instructions into execution tasks of each unit module to achieve automatic alignment and measurement of the prism target; The communication unit is used to provide communication support between the total station and external devices, output internal measurement data and device status to an external monitoring system, or receive external communication instructions; The storage unit is used to provide a data storage function and support temporary preservation and long-term storage of measurement data.

2. A servo total station as claimed in claim 1, characterized in that: The laser receiving module in the target recognition unit includes a receiving lens and a photoelectric sensor. The receiving lens converges the reflected light onto the image sensor, and the image sensor converts the received reflected light into an electrical signal to form an image.

3. A servo total station as claimed in claim 2, characterized in that: The processing control module in the target recognition unit is also used to automatically adjust the intensity of laser emission, the receiving gain and exposure time of the image sensor.

4. A servo total station as claimed in claim 1, characterized in that: The total station also includes a graphic interaction unit, which includes an input device and an output device and is used to provide an interactive interface between the user and the instrument. The user inputs operating instructions through this unit and views the measurement results and system status in real time.

5. A servo total station as claimed in claim 1, characterized in that: The total station also includes a tilt compensation unit, which is used to collect the tilt angle of the vertical axis of the total station and automatically compensate the angle when the total station tilts.

6. A servo total station as claimed in claim 1, characterized in that: The total station simultaneously contains data of multiple prism targets during input and output, and the data includes prism type, constant, distance, angle and coordinates of the prism in the total station coordinate system.

7. A prism identification method based on the total station according to any one of claims 1 to 6, characterized in that: It includes the learning prism stage and the monitoring prism stage; Prism learning stage: first manually aim at the prism in the middle of the field of view, which is recorded as the preferred position; then the laser emission module projects the laser into the field of view of the telescope so that the laser covers all prism positions; the laser receiving module captures the light beam reflected by each prism and converts the light signal into an image through the image sensor; the processing and control module of the target recognition unit first pre-processes the image to ensure the contrast and clarity of the prism spot, and then distinguishes the spot of each prism from the image background through threshold segmentation to form an independent spot; finally, the prism information including the coordinates of the center of each spot is obtained and saved; Monitoring prism stage: first, align the preferred position through the servo drive unit, then obtain the position information of all prisms in the field of view through the target recognition unit and compare it with the prism information saved in the learning prism stage. If all prisms in the learning prism stage exist, then align each prism in turn through the servo drive unit and measure the distance of the prism through the ranging unit, otherwise the prism loss information is output.

8. The prism recognition method according to claim 7, characterized in that: The processing control module of the target recognition unit automatically adjusts the laser intensity and the receiving gain of the image sensor according to the actual situation: when multiple prism reflected light spots are received, the first image is obtained according to the default gain, and then the light spots are divided into two groups according to the difference between the light spots and the ideal value. The features of the group with appropriate gain are first extracted to calculate the center position of each prism light spot; for the group with inappropriate gain, a light spot is first selected to set a suitable gain value for it and feature extraction is performed to obtain the center position of the light spot, and then the other light spots in the group under the gain value are regrouped; the above process is repeated until all the light spots are traversed.

9. The prism recognition method according to claim 7, characterized in that: The image preprocessing performed by the processing control module includes spatial domain filtering and frequency domain filtering, and the threshold segmentation adopts Otsu method or maximum entropy method.

Images