Laser ranging based geodetic measurement system

Abstract

A laser ranging based geodetic measurement system, relating to the technical field of geographic information measurement. The system comprises a laser emission module, a ranging processing module, and a measurement point reselection module. The laser emission module is configured to control n laser emitters to emit laser pulses to a target object from a measurement point within the same time interval, so as to provide a reference basis for subsequent determination of the measurement point. The ranging processing module is configured to determine whether normal and accurate laser ranging can be performed at the measurement point; when it is determined that the laser ranging is normal at the measurement point, there is no need to select another measurement point for laser ranging; and when it is determined that the laser ranging is abnormal at the measurement point, another measurement point is selected in time for laser ranging. The measurement point reselection module is configured to quickly select a measurement point on the basis of an abnormal measurement point, and ensure to select an appropriate measurement point each time for remeasurement. In this way, the reselection frequency of the measurement point is reduced, thereby improving the efficiency and accuracy of the laser ranging.

Description

A geodetic surveying system based on laser ranging Technical Field

[0001] The present invention relates to the technical field of geographic information measurement, and more particularly to a geodetic measurement system based on laser ranging. Background Art

[0002] Laser ranging uses a laser as a light source to measure distance. Laser ranging is categorized into continuous lasers and pulsed lasers based on how the laser operates. Laser ranging is a commonly used method in geodetic surveying. While this method offers high accuracy, it also suffers from low efficiency. It requires multiple measurements at selected points, and the data from these points must be compared to determine accuracy. Technical issues

[0003] In view of the shortcomings of the prior art, the present invention aims to provide a geodetic surveying system based on laser ranging. Technical Solutions

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A geodetic measurement system based on laser ranging includes a laser emission module, a ranging processing module, and a measuring point reselection module;

[0006] The laser emission module controls n laser emitters to send laser pulses at equal intervals from a measurement point toward the target object. The measurement point is manually selected, typically in a location with a wide field of view. The geodetic surveying system includes a total of 10 laser emitters, each of which emits laser pulses toward the target every five minutes.

[0007] The ranging processing module is used to determine whether normal laser ranging can be performed on the measuring point. Specifically:

[0008] Step 1: Get the return time difference Js;

[0009] Step 2: Set a return time difference value Gi for each general return time difference, compare the general return time difference with the return time difference value, and when the general return time difference is less than the return time difference value, mark the general return time difference as the return time difference low value. Calculate the difference between the return time difference value and the return time difference low value to obtain the low value standard deviation; sum all the low value standard deviations to obtain the low value total standard deviation and mark it as Rw; obtain the total number of low return time difference values ​​and mark it as Ky;

[0010] Step 3: When the normal return time difference is greater than the return time difference value, mark the normal return time difference as a return time difference excess value. Calculate the difference between the return time difference excess value and the return time difference value to obtain the excess standard deviation. Sum all excess standard deviations to obtain the total excess standard deviation and mark it as Ej. Obtain the total number of return time difference excess values ​​and mark it as Sc.

[0011] Using the formula Obtain the laser low precision value Hm; where b1 and b2 are both preset proportional coefficients;

[0012] Using the formula Obtain the laser super-measurement accuracy value Bk; where c1 and c2 are both preset proportional coefficients;

[0013] Using the formula Obtain the laser warning quasi-value Pe of the measurement point, where d1 and d2 are preset proportional coefficients. Set the laser warning quasi-value threshold to Cz. When the laser warning quasi-value Pe ≥ the laser warning quasi-value threshold Cz, mark the measurement point as an abnormal measurement point. When the laser warning quasi-value Pe < the laser warning quasi-value threshold Cz, mark the measurement point as a normal measurement point. When the measurement point is judged to be normal, there is no need to select other measurement points for laser ranging. When the measurement point is judged to be abnormal, select other measurement points for laser ranging in a timely manner.

[0014] The measuring point reselection module is used to reselect measuring points based on abnormal measuring points, specifically:

[0015] Step 1: Get the position of the abnormal measurement point, and use the current position as the center and draw a circle with a preset radius to get the fixed point range. Mark the unmeasured points within the fixed point range as pre-selected measurement points.

[0016] Step 2: The measurement point determination module controls the drone to arrive at the preselected measurement point and shoot a video of the target object to obtain the preferred value Ak of ​​the video corresponding to the same preselected measurement point;

[0017] Step 3: Mark the pre-selected measurement point with the smallest preferred value Ak as the final measurement point, and quickly select measurement points based on the abnormal measurement points to ensure that the appropriate measurement point is selected for re-measurement each time.

[0018] Furthermore, the return time difference is obtained by the following steps: the ranging processing module controls the photographing component to take a photo of the target object, pre-processes the photo, obtains the pre-processed photo, uses the pre-processed photo as the input data of the image analysis model to obtain the output data of the image analysis model, and marks the output data as the target label; the target label is the image label corresponding to each grid; the value range of the image label is set to [0-3], where the larger the value of the image label, the larger the area occupied by the target object in the grid; all image labels are summed up to obtain the total value of the image label and marked as Tb, using the formula The return time difference is obtained, where m1 is the preset proportional coefficient.

[0019] Furthermore, the photo preprocessing includes image denoising, grayscale conversion and sharpening processing.

[0020] Furthermore, the image analysis model goes through the following steps: obtaining N image materials, marking the image materials as training images, dividing the training images into multiple identical grids by multiple equally spaced horizontal lines and multiple equally spaced vertical lines, and assigning an image label to each grid; dividing the training images into a training set and a validation set according to a set ratio; constructing a neural network model; iteratively training the neural network model through the training set and the validation set, and when the number of iterative training is greater than the iteration number threshold, it is determined that the neural network model has completed training, and the trained neural network model is marked as an image analysis model.

[0021] Furthermore, the preferred value Ak of ​​the video corresponding to the same preselected measurement point is obtained by the following steps: converting the video corresponding to the same preselected measurement point into an image frame, obtaining the average grayscale value of each image frame and marking it as Pv, setting the low grayscale threshold of the image frame as Lm, setting the high grayscale threshold of the image frame as Yp, when the grayscale value of the grayscale point of the image frame is less than the low grayscale threshold Lm, then the grayscale point is marked as a low grayscale point, when the grayscale value of the grayscale point of the image frame is greater than the high grayscale threshold Yp, then the grayscale point is marked as a high grayscale point, the number of low grayscale points and the number of high grayscale points are summed to obtain the number of abnormal gray points, the ratio of the number of abnormal gray points to the number of pixels in the image frame is calculated, the abnormal grayscale ratio is obtained and marked as Ve, and the formula is used. The sigmoid value Qj of the image frame is obtained, and the sigmoid values ​​of the image frame at the same preselected measurement point are summed and averaged to obtain the preferred value Ak of ​​the video corresponding to the same preselected measurement point, where n1 and n2 are both preset proportional coefficients.

[0022] Furthermore, the return time difference Js is obtained by the following steps: the laser transmission time and the laser reception time corresponding to the n laser pulses are sorted in chronological order, the laser transmission time of the latter laser pulse of the two adjacent laser pulses is marked as Lg, the laser reception time of the latter laser pulse is marked as Lh, the laser transmission time of the former laser pulse of the two adjacent laser pulses is marked as Lz, the laser reception time of the former laser pulse is marked as Lr, and the formula is used. The return time difference Js is obtained, where a1 and a2 are both preset proportional coefficients.

[0023] Furthermore, when the laser transmitter sends a laser pulse toward the target object at the measurement point, the moment is marked as the laser sending moment, and when the ranging processing module receives the laser pulse returned from the target object, the moment is marked as the laser receiving moment. Beneficial effects

[0024] 1. Set up a laser emission module, which can control n laser emitters to send laser pulses from the measurement point toward the target object at the same time interval, providing a reference basis for the judgment of subsequent measurement points. Set up a ranging processing module, which can determine whether the measurement point can perform normal and accurate laser ranging. When the measurement point is judged to be normal, there is no need to select other measurement points for laser ranging. When the measurement point is judged to be abnormal, other measurement points are selected for laser ranging in time.

[0025] 2. Set up the measurement point reselection module, which can quickly select measurement points based on abnormal measurement points, ensuring that the appropriate measurement points are selected for remeasurement each time, greatly reducing the number of measurement point reselections and improving the efficiency and accuracy of laser ranging. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a block diagram of a distance measurement processing module according to the present invention;

[0027] FIG2 is a block diagram of the principle of the measuring point reselection module of the present invention;

[0028] FIG3 is a block diagram showing the principle of the present invention. Modes for Carrying Out the Invention

[0029] Example 1

[0030] 1 , a geodetic measurement system based on laser ranging includes a laser emission module and a ranging processing module.

[0031] The laser transmitter module controls n laser transmitters to send laser pulses from the measurement point toward the target object at the same time interval. For example, a geodetic measurement system includes 10 laser transmitters, each of which sends laser pulses toward the target every 5 minutes.

[0032] The measuring points are selected manually, usually at locations with a wide field of view.

[0033] The ranging processing module is used to determine whether the measurement point can be used for normal laser ranging. Specifically:

[0034] Step 1: Obtain the return time difference Js. The return time difference Js is obtained by the following steps: sort the laser transmission time and laser reception time corresponding to n laser pulses in chronological order, mark the laser transmission time of the latter laser pulse in the two adjacent laser pulses as Lg, and the laser reception time of the latter laser pulse as Lh, mark the laser transmission time of the former laser pulse in the two adjacent laser pulses as Lz, and the laser reception time of the former laser pulse as Lr, and use the formula Obtain the return time difference Js, where a1 and a2 are preset proportional coefficients, with a1 set to 0.1 and a2 set to 0.2. For example, if the laser transmission time of the second laser pulse is 12:00:00 and the laser reception time of the second laser pulse is 12:00:30, and the laser transmission time of the first laser pulse is 11:55:00 and the laser reception time of the first laser pulse is 11:55:25, then the return time difference Js is 45.55.

[0035] Step 2: Each return time difference is assigned a return time difference value Gi. The return time difference value is obtained by the following steps: the ranging processing module controls the camera component to take a photo of the target object and preprocesses the photo to obtain a preprocessed photo. The photo preprocessing includes image denoising, grayscale conversion, and sharpening. The image analysis model is implemented by the following steps: obtaining N image materials, which can be downloaded from the Internet; marking the image materials as training images; dividing the training images into multiple identical grids using multiple equally spaced horizontal and vertical lines, and assigning an image label to each grid; dividing the training images into a training set and a validation set according to a set ratio; constructing a neural network model; iteratively training the neural network model using the training set and validation set. When the number of training iterations exceeds a threshold, the neural network model is deemed to have completed training and marked as the image analysis model. The pre-processed photos are used as the input data of the image analysis model to obtain the output data of the image analysis model, and the output data is marked as the target label; the target label is the image label corresponding to each grid; the value range of the image label is set to [0-3], where the larger the value of the image label, the larger the area occupied by the target object in the grid. All image labels are summed up to obtain the total value of the image label and marked as Tb. The formula is used The return time difference is obtained, where m1 is the preset proportional coefficient and m1 is 0.5. When the total value of the image label of the measurement point a is 15, the return time difference Gi of the measurement point a is obtained by using the formula to be 7.5.

[0036] Compare the general return time difference with the return time difference value. When the general return time difference is less than the return time difference value, mark the general return time difference as the return time difference low value. Calculate the difference between the return time difference value and the return time difference low value to obtain the low value standard deviation; sum up all the low value standard deviations to obtain the low value total standard deviation and mark it as Rw; obtain the total number of low value return time difference occurrences and mark it as Ky.

[0037] Step 3: If the normal return time difference is greater than the return time difference value, mark the normal return time difference as an excess return time difference. Calculate the difference between the excess return time difference value and the return time difference value to obtain the excess standard deviation. Sum all excess standard deviations to obtain the total excess standard deviation and label it Ej. Obtain the total number of excess return time difference occurrences and label it Sc.

[0038] Using the formula The laser low accuracy value Hm is obtained; where b1 and b2 are preset proportional coefficients, the laser low accuracy value Hm of measurement point a is 18, and the laser low accuracy value Hm of measurement point b is 10. Using the formula Obtain the laser super-measurement accuracy value Bk; where c1 and c2 are preset proportional coefficients. The laser super-measurement accuracy value Bk of measurement point a is 15, and the laser super-measurement accuracy value Bk of measurement point b is 9. Using the formula Obtain the laser warning accuracy value Pe for the measurement point, where d1 and d2 are preset proportional coefficients. Set the laser warning accuracy threshold to Cz. When the laser warning accuracy value Pe ≥ Cz, mark the measurement point as abnormal. When the laser warning accuracy value Pe < Cz, mark the measurement point as normal. If the laser warning accuracy value Pe of measurement point a is 30 and the laser warning accuracy threshold Cz is 28, measurement point a is marked as abnormal. If the laser warning accuracy value Pe of measurement point b is 25, mark measurement point b as normal.

[0039] Example 2

[0040] 2-3 , on the basis of Example 1, a measuring point reselection module is further included. The measuring point reselection module is used to reselect measuring points based on abnormal measuring points. Specifically,

[0041] Step 1: Obtain the location of the abnormal measurement point, and draw a circle with a preset radius with the current location as the center to obtain the fixed point range. Mark the unmeasured points within the fixed point range as pre-selected measurement points. Unmeasured points are manually selected measurement points that have not been measured yet.

[0042] Step 2: The measurement point determination module controls the drone to reach the preselected measurement point and capture a video of the target object. This module then obtains the preferred value Ak for the video corresponding to the preselected measurement point. The preferred value Ak for the video corresponding to the preselected measurement point is obtained by: When the laser transmitter sends a laser pulse toward the target object at the measurement point, this moment is marked as the laser transmission moment. When the ranging processing module receives the return laser pulse from the target object, this moment is marked as the laser reception moment. The video corresponding to the same preselected measurement point is converted into an image frame, and the average grayscale value of each image frame is obtained and marked as Pv. The low grayscale threshold of the image frame is set to Lm, and the high grayscale threshold of the image frame is set to Yp. When the grayscale value of the grayscale point of the image frame is less than the low grayscale threshold Lm, the grayscale point is marked as a low grayscale point. When the grayscale value of the grayscale point of the image frame is greater than the high grayscale threshold Yp, the grayscale point is marked as a high grayscale point. The number of low grayscale points and the number of high grayscale points are summed to obtain the number of abnormal gray points. The ratio of the number of abnormal gray points to the number of pixels in the image frame is calculated to obtain the abnormal grayscale ratio and marked as Ve. The formula is used Obtain the image frame's outlier value Qj. Sum and average the outlier values ​​for the image frames at the same preselected measurement point to obtain the preferred value Ak for the video corresponding to that preselected measurement point, where n1 and n2 are preset scaling factors. Mark the preselected measurement point with the smallest preferred value Ak as the final measurement point. If the preferred value Ak for the video corresponding to measurement point x is 5, the preferred value Ak for the video corresponding to measurement point y is 3, and the preferred value Ak for the video corresponding to measurement point z is 6, mark measurement point y as the final measurement point. How it works

[0043] Setting up a laser emission module can control n laser emitters to send laser pulses from the measuring point toward the target object within the same time interval, providing a reference basis for the judgment of subsequent measuring points. Setting up a ranging processing module can determine whether the measuring point can perform normal and accurate laser ranging. When the measuring point is judged to be normal, there is no need to select other measuring points for laser ranging. When the measuring point is judged to be abnormal, other measuring points are selected for laser ranging in time. Setting up a measuring point reselection module can quickly select measuring points based on abnormal measuring points, ensuring that the appropriate measuring point is selected for re-measurement each time, greatly reducing the number of reselection times of measuring points, and improving the efficiency and accuracy of laser ranging.

[0044] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, certain improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of this template.

[0045] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", etc. indicating directions or positional relationships are based on the directions 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 direction, and a specific direction structure and operation, and therefore, cannot be understood as limiting the present invention. In addition, "first" and "second" are only 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" and "second" 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.

[0046] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0047] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A geodetic surveying system based on laser ranging, characterized in that, It includes a laser emission module, a ranging processing module, and a measurement point re-selection module; The laser emission module is used to control n laser emitters to send laser pulses from the measurement point towards the target object at the same time interval; The ranging processing module is used to judge the measurement point to determine whether normal laser ranging can be performed on the measurement point. Specifically: Step 1: Obtain the round-trip time difference Js; Step 2: Set each round-trip time difference to correspond to a round-trip time value Gi. Compare the round-trip time difference with the round-trip time value. When the round-trip time difference is less than the round-trip time value, mark this round-trip time difference as the low round-trip time difference value. Calculate the difference between the round-trip time value and the low round-trip time difference value to obtain the low standard deviation; Sum up all the low standard deviations to obtain the total low standard deviation and mark it as Rw; obtain the total number of occurrences of the low round-trip time difference value and mark it as Ky; Step 3: When the round-trip time difference is greater than the round-trip time value, mark this round-trip time difference as the high round-trip time difference value. Calculate the difference between the high round-trip time difference value and the round-trip time value to obtain the high standard deviation; sum up all the high standard deviations to obtain the total high standard deviation and mark it as Ej; obtain the total number of occurrences of the high round-trip time difference value and mark it as Sc; Using the formula Obtain the low laser measurement accuracy value Hm; where b1 and b2 are both preset proportionality coefficients; Using the formula Obtain the high laser measurement accuracy value Bk; where c1 and c2 are both preset proportionality coefficients; Using the formula Obtain the laser warning accuracy value Pe of this measurement point. Where d1 and d2 are both preset proportionality coefficients. Set the laser warning accuracy value threshold as Cz. When the laser warning accuracy value Pe ≥ the laser warning accuracy value threshold Cz, mark the measurement point as an abnormal measurement point. When the laser warning accuracy value Pe < the laser warning accuracy value threshold Cz, mark this measurement point as a normal measurement point; The measurement point re-selection module is used to re-select the measurement point based on the abnormal measurement point. Specifically: Step 1: Obtain the position of the abnormal measurement point, draw a circle with the current position as the center and a preset radius to obtain a fixed-point range, and mark the unmeasured points within the fixed-point range as preselected measurement points; Step 2: The measurement point determination module controls the drone to reach the preselected measurement point and then takes a video of the target object to obtain the preferred value Ak of the video corresponding to the same preselected measurement point; Step 3: Mark the preselected measurement point with the smallest preferred value Ak as the final selected measurement point; The time difference during return is obtained through the following steps: The ranging processing module controls the photographing component to take a picture of the target object, preprocesses the picture to obtain a preprocessed picture, uses the preprocessed picture as the input data of the image analysis model to obtain the output data of the image analysis model, and marks the output data as a target label; the target label is the image label corresponding to each grid; the value range of the image label is set to [0 - 3], where the larger the value of the image label, the larger the area occupied by the target object in the grid. Sum all the image labels to obtain the total value of the image labels and mark it as Tb, and use the formula Obtain the round-trip time value, where m1 is a preset proportionality coefficient; The time difference during return is obtained through the following steps: The ranging processing module controls the photographing component to take a photo of the target object, preprocesses the photo to obtain a preprocessed photo, uses the preprocessed photo as the input data of the image analysis model to obtain the output data of the image analysis model, and marks the output data as the target label; the target label is the image label corresponding to each grid; the value range of the image label is set to [0-3], where the larger the value of the image label, the larger the area occupied by the target object in the grid. Sum all the image labels to obtain the total value of the image labels and mark it as Tb, and use the formula Obtain the round-trip time value, where m1 is a preset proportionality coefficient; The preferred value Ak of the video corresponding to the same preselected measurement point is obtained through the following steps: Convert the video corresponding to the same preselected measurement point into image frames, obtain the average gray value of each image frame and label it as Pv, set the low abnormal gray threshold of the image frame as Lm, set the high abnormal gray threshold of the image frame as Yp. When the gray value of a gray point in the image frame < the low abnormal gray threshold Lm, then label this gray point as a low abnormal gray point. When the gray value of a gray point in the image frame > the high abnormal gray threshold Yp, then label this gray point as a high abnormal gray point. Sum up the number of low abnormal gray points and the number of high abnormal gray points to obtain the number of abnormal gray points. Calculate the ratio of the number of abnormal gray points to the number of pixel points in the image frame to obtain the abnormal gray ratio and label it as Ve. Use the formula to obtain the abnormal value Qj of the image frame. Sum up the abnormal values of the image frames of the same preselected measurement point and take the average value to obtain the preferred value Ak of the video corresponding to the same preselected measurement point, where n1 and n2 are both preset proportionality coefficients; The return travel time difference Js is obtained through the following steps: Sort the laser emission times and laser reception times corresponding to n laser pulses in chronological order. Mark the laser emission time of the latter laser pulse among two adjacent laser pulses as Lg, and the laser reception time of the latter laser pulse as Lh. Mark the laser emission time of the former laser pulse among two adjacent laser pulses as Lz, and the laser reception time of the former laser pulse as Lr. Use the formula Obtain the return time difference Js, where a1 and a2 are both preset proportionality coefficients.

2. The geodetic surveying system based on laser ranging according to claim 1, wherein, The preprocessing of the photo includes image denoising, gray transformation, and sharpening of the photo.

3. A geodetic surveying system based on laser ranging according to claim 2, characterized in that, The image analysis model is obtained through the following steps: Obtain N image materials, label the image materials as training images, divide the training images into multiple identical grids by multiple equally spaced horizontal lines and multiple equally spaced vertical lines, and assign image labels to each grid; Divide the training images into a training set and a validation set according to a set ratio; Construct a neural network model; Iteratively train the neural network model through the training set and the validation set. When the number of iterative training times is greater than the iteration number threshold, then determine that the neural network model is trained, and label the trained neural network model as the image analysis model.

4. [Corrected according to Rule 26 on 04.01.2024] A geodetic surveying system based on laser ranging according to claim 3, characterized in that, When the laser emitter sends a laser pulse towards the target object at the measurement point, mark this moment as the laser sending moment. When the ranging processing module receives the laser pulse returned from the target object, mark this moment as the laser receiving moment.

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