Angle measurement method and system for culvert construction in high altitude areas

Abstract

The present application relates to the technical field of image processing, in particular to a kind of angle measurement method and system for culvert construction in high altitude area.The method is collected after the laser spot image after the reflection of total station instrument, and the real spot center point is screened out.The connection between two real spot center points is carried out, and the overlapping region of spot is determined by analyzing the change of brightness value.Based on the brightness value decay law embodied by each real spot center point, the pixel points in the spot overlapping region are simulated, and the simulated brightness value is determined.Combining two simulated brightness values and distance information, the brightness value of the pixel points in the spot overlapping region is adjusted, and then the spot region fitting is carried out, the infrared spot region is obtained and the culvert construction angle measurement is carried out.The present application eliminates the influence of the brightness of the overlapping region in the infrared spot region, so that the information of the infrared spot region is more referential, to improve the accuracy of the total station for culvert construction angle measurement in high altitude area.

Description

Technical Field

[0001] This invention relates to the field of image processing technology, and specifically to an angle measurement method and system for culvert construction in high-altitude areas. Background Technology

[0002] The common equipment used for measuring angles during culvert construction is a total station. When using a total station and the polar coordinate method for measurement, it is necessary to determine whether the angle between the culvert axis and the centerline of the route is orthogonal. During culvert construction, timely measurements and judgments are also required to pre-determine the construction location and, after construction, determine whether the angle conforms to the predetermined value in the culvert design.

[0003] In current technology, angle measurements using a total station typically involve selecting areas where direct sunlight is avoided or using obstructions to reduce the impact of ambient light. However, at high altitudes, the light intensity is high, and the scattering of natural light is low. When the total station receives reflected light, it cannot completely avoid the influence of strong light. This means that the receiving camera may receive not only its own emitted infrared light but also sunlight and other light sources, resulting in multiple light spots. The overlapping of these light spots can create irregular shapes that affect the total station's measurements, leading to errors in the accuracy of the data obtained by the camera. Summary of the Invention

[0004] To address the technical problem of existing technologies using total stations for angle measurement in culvert construction at high altitudes, which cannot avoid the influence of strong sunlight, resulting in overlapping light spot areas and making it impossible to determine the effective light spot area, thus affecting the actual measurement accuracy, the present invention aims to provide an angle measurement method and system for culvert construction in high-altitude areas. The specific technical solution adopted is as follows:

[0005] This invention proposes an angle measurement method for culvert construction in high-altitude areas, the method comprising:

[0006] Obtain the laser spot image on the total station after reflection from the target point; select the true center point of the laser spot from the laser spot image based on the brightness value characteristics;

[0007] The line connecting the center points of the real light spots is taken as the first line to be analyzed. The first line to be analyzed is scanned along the vertical direction. Each scan selects the pixels in the overlapping area of ​​the light spots according to the trend of brightness value change, and obtains the overlapping area of ​​the light spots.

[0008] For any pixel in the overlapping area of ​​light spots, connect the corresponding real light spot center point to obtain two calibration lines. For any calibration line, according to the brightness decrease law of the real light spot center point and the length of the calibration line, obtain the simulated brightness value of the pixel in the overlapping area of ​​light spots.

[0009] The brightness difference between two simulated brightness values ​​and the actual brightness value of the pixels in the overlapping area of ​​the light spot is obtained. A distance weight is obtained based on the calibration connection length. The brightness differences are then weighted and fused according to the distance weight to obtain the corrected brightness. The center point of the real light spot closest to the pixels in the overlapping area is selected as a reference point. A base brightness value is obtained based on the distance weight corresponding to the reference point and the simulated brightness value. The adjusted brightness of the pixels in the overlapping area is obtained based on the base brightness value and the corrected brightness.

[0010] The laser spot area is fitted based on the adjusted laser spot image, and the angle is measured based on the obtained infrared spot area.

[0011] Furthermore, the method for obtaining the center point of the actual light spot includes:

[0012] Each pixel in the laser spot image is filtered based on its brightness value, and all maximum values ​​in the laser spot image are taken as suspected spot center points. The lines connecting each pair of suspected spot center points are taken as second lines to be analyzed. The brightness value change characteristics between the two endpoints of the second lines to be analyzed, and the true spot center points are selected from the suspected spot center points.

[0013] Furthermore, the step of filtering out the true center point of the light spot from the suspected center points includes:

[0014] For the second line to be analyzed, take any endpoint as the starting point and count the brightness value sequence on the second line to be analyzed. In the brightness value sequence, subtract the next element from the previous element to obtain the difference sequence. If the number of positive elements in the difference sequence is greater than the preset first threshold, then the suspected light spot center point corresponding to the starting point is taken as the real light spot center point.

[0015] Furthermore, the method for selecting pixels in the overlapping area of ​​the light spots includes:

[0016] The consecutive positive elements starting from the first element in the statistical difference sequence are taken as normal spot pixels; the normal spot pixels corresponding to the two endpoints of the first line to be analyzed are obtained and removed to obtain the cut line segment, and the pixels on the cut line segment are the pixels in the overlapping area of ​​the spot.

[0017] Furthermore, the stopping condition for the scan is:

[0018] Starting from the initial position of the first line to be analyzed, scan along the perpendicular bisector in two directions. For each scanning direction, stop scanning when the length of the intercepted line segment is less than a preset second threshold.

[0019] Furthermore, the method for obtaining the brightness decrease pattern includes:

[0020] The intersection of the calibration line and the overlapping area of ​​the light spot is taken as the transition point; the difference in brightness value between the center point of the actual light spot corresponding to the calibration line and the transition point is obtained. The difference in brightness value is used as the numerator, and the distance between the center point of the actual light spot and the transition point is used as the denominator to obtain the brightness decrease rule.

[0021] Furthermore, the method for obtaining the simulated brightness value includes:

[0022] For each calibration line, the product of the length of the calibration line and the brightness decrease rule is used as the simulated brightness decay value. The simulated brightness decay value is then subtracted from the brightness value of the corresponding real spot center point to obtain the simulated brightness value.

[0023] Furthermore, the method for obtaining the corrected brightness includes:

[0024] For any calibration connection, the length of the calibration connection is negatively correlated and normalized to obtain the distance weight; the brightness difference is weighted and summed with the corresponding distance weight to obtain the corrected brightness.

[0025] Furthermore, the method for obtaining the basic brightness value includes:

[0026] The base brightness value is obtained by multiplying the distance weight corresponding to the reference point by the simulated brightness value.

[0027] Furthermore, the adjusted brightness is the sum of the base brightness value and the corrected brightness value.

[0028] The present invention also proposes an angle measurement system for culvert construction in high-altitude areas, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of any one of the angle measurement methods for culvert construction in high-altitude areas.

[0029] The present invention has the following beneficial effects:

[0030] After acquiring the laser spot image after reflection from a total station, this invention first identifies the center points of the actual laser spots. This is because overlapping areas between two actual laser spot center points can alter the brightness trend from the inside out of the spot area. Therefore, this invention connects each pair of actual laser spot center points and analyzes the brightness changes along these lines to determine the overlapping areas. To ensure that each independent spot area is not affected by the overlapping areas, the pixel values ​​of the pixels within these overlapping areas are corrected after locating them, ensuring that the final spot area is not affected by the overlap and thus determining effective edge information. This invention first simulates the attenuation of pixels in the overlapping areas based on the brightness attenuation pattern exhibited by each actual laser spot center point, determining the simulated brightness values. Furthermore, considering that pixels in the overlapping areas are more significantly affected by the nearest actual laser spot center point, the brightness values ​​of the pixels in the overlapping areas can be effectively adjusted by combining the two simulated brightness values ​​and distance information. The adjusted brightness value eliminates the influence of overlapping areas, allowing for spot area fitting to obtain accurate and independent infrared spot areas. At the same time, the information within the area is more complete, thus improving the accuracy of the total station in measuring the angle of culvert construction in high-altitude areas. Attached Figure Description

[0031] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of an angle measurement method for culvert construction in high-altitude areas, provided as an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of a light spot overlap region provided in one embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of a scanning process provided in one embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of a brightness attenuation simulation analysis provided in one embodiment of the present invention. Detailed Implementation

[0036] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an angle measurement method and system for culvert construction in high-altitude areas proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0038] The following description, in conjunction with the accompanying drawings, details a specific scheme for an angle measurement method and system for culvert construction in high-altitude areas provided by the present invention.

[0039] Please see Figure 1 The diagram illustrates a flowchart of an angle measurement method for culvert construction in high-altitude areas, provided by an embodiment of the present invention. The method includes:

[0040] Step S1: Obtain the laser spot image after reflection from the target point on the total station; select the true center point of the laser spot from the laser spot image based on the brightness value characteristics.

[0041] This invention addresses the scenario of measuring construction angles using a total station in high-altitude bridge and culvert construction areas. In high-altitude regions, the intensity of natural light is high, and the use of a total station to receive reflected light can cause interference from natural light, generating additional light spots in the laser beam image. This leads to overlap between beam areas and a decrease in information accuracy. This invention, after determining the construction area and designing the bridge and culvert, selects a suitable location within the construction area, erects a tripod, and sets up the total station. A reference point is determined at the target location, and a reflector is installed at the reference point to ensure the total station can accurately measure the coordinates of that point. A polar coordinate system is established with this point as the origin. After setup, distance measurement and coordinate determination are performed on each target point. The total station emits an infrared beam towards the target point. After reflection from the target, the beam is projected onto the total station's built-in CCD camera, forming a laser beam image. This image is acquired for subsequent calculation and analysis. It should be noted that the specific working principle of the total station and the technical means used for its setup are well-known to those skilled in the art and will not be elaborated upon here.

[0042] Due to the high altitude and thin cloud cover in high-altitude areas, the refraction and absorption of sunlight as it passes through the atmosphere are greatly reduced, making the sunlight reaching the ground more direct and intense. This means that the receiving camera of a total station may receive not only its own emitted infrared radiation but also other light sources such as sunlight, resulting in multiple light spots. These infrared light spots in the image may overlap with natural light spots, creating irregularly shaped spots that affect total station measurements. This invention aims to reconstruct the true and effective infrared light spot area for angle measurement by locating, analyzing, and adjusting the brightness of the overlapping areas. Considering that the light spot area is brightest at the center and gradually decreases in brightness outwards, the true center point of the laser light spot can be directly selected from all pixels in the laser light spot image based on its brightness characteristics. That is, the true center point is a point with a large brightness value and a significant decrease in brightness outwards.

[0043] Preferably, in this embodiment of the invention, considering that overlapping areas will also produce some brighter points due to brightness overlap, the points obtained by filtering by brightness value cannot be directly used as the true center point of the light spot. Therefore, the method for obtaining the true center point of the light spot in this embodiment of the invention includes:

[0044] Each pixel in the laser spot image is filtered based on its brightness value, and all maxima in the laser spot image are selected as potential spot center points. It should be noted that the brightness value can be obtained from the V channel pixel value in the HSV color space. The method for obtaining local maxima in an image is a well-known technique and will not be elaborated upon here.

[0045] Please see Figure 2 This illustration shows a schematic diagram of a light spot overlap region provided by an embodiment of the present invention. Because of the overlap region, the suspected light spot center point obtained through maximum value filtering will also exist within the overlap region and is not the actual light spot center point. For example... Figure 2 As shown, points Q and E are the true center points of the light spot. A regular brightness attenuation phenomenon occurs in the region between the overlapping area and the true center point. However, the neighborhood of the overlapping area is affected by the overlap and does not exhibit effective brightness attenuation. Therefore, it is possible to determine whether a suspected light spot center point is a true center point by analyzing the brightness value change characteristics in a fixed direction. In this embodiment of the invention, the line connecting each pair of suspected light spot center points is used as the second line to be analyzed. The brightness value change characteristics between the two endpoints of the second line to be analyzed are then used to filter out the true light spot center points from the suspected light spot center points.

[0046] Furthermore, in order to effectively quantify the brightness value change characteristics at the endpoint of the second connection to be analyzed, this embodiment of the invention filters out the true center point of the light spot from the suspected center points, including:

[0047] For the second connection to be analyzed, starting from any endpoint, the brightness value sequence along the second connection is statistically analyzed. If the starting point is the center point of the actual light spot, the brightness value sequence should be a stable decreasing sequence at the beginning. If the starting point is a pixel in the overlapping area, the brightness value sequence may exhibit a uniform characteristic or an increasing characteristic, which are different from the brightness value change characteristics of the actual light spot center point. Therefore, in this embodiment of the invention, the previous element is subtracted from the next element in the brightness value sequence to obtain a difference sequence. If the number of positive elements in the difference sequence is greater than a preset first threshold, it indicates that the brightness value sequence exhibits a stable brightness decay at the beginning position, and the suspected light spot center point corresponding to the starting point is taken as the actual light spot center point.

[0048] In one specific implementation of this invention, after obtaining the number of positive elements, this number is used as the numerator, and the total number of elements in the brightness value sequence is used as the denominator to obtain a normalized result. A first threshold is set to 0.23. If the normalized result is greater than 0.23, it indicates that the brightness value sequence exhibits stable brightness decay at the beginning, and the suspected light spot center point corresponding to the starting point is taken as the actual light spot center point. Similarly, if the number of positive elements is not normalized, the result of rounding down 23% of the number of elements can be selected as the first threshold.

[0049] Step S2: Take the line connecting the center points of each pair of real light spots as the first line to be analyzed, scan the first line to be analyzed along the vertical direction, and select the pixels in the overlapping area of ​​the light spots according to the trend of brightness value change in each scan to obtain the overlapping area of ​​the light spots.

[0050] It should be noted that, at the center point of the actual light spot, because the infrared laser energy emitted by the total station is highly concentrated, the natural light in the environment is relatively diffuse and, when received by the total station camera, will not present a concentrated, high-intensity light spot. Therefore, the center point of the actual light spot with the highest brightness value is the center point of the light spot area formed by infrared reflection. It is necessary to further locate the overlapping area between the infrared light spot area and other noisy light spot areas and eliminate the overlap effect. Considering that the center point of the infrared light spot area is also a type of actual light spot center point, and the method for obtaining the overlapping area between light spot areas is the same, the method described in the embodiments of this invention is a universal method for locating and analyzing overlapping areas. In actual implementation, only the center point of the infrared light spot area can be used as the analysis object to analyze its overlapping area.

[0051] For the two light spot regions, considering that the overlapping area is between the center points of the two light spots, the brightness values ​​in this area are relatively random, while the brightness values ​​at the center points of the two actual light spots exhibit a regular outward decay characteristic. Therefore, this embodiment of the invention uses the line connecting the center points of the actual light spots as the first line to be analyzed. By extracting the regular brightness decay portion of the light spot region from the first line to be analyzed, a segment belonging to the overlapping area can be obtained. The pixels on this segment are the pixels of the overlapping area. Therefore, this embodiment of the invention uses a scanning method, scanning the first line to be analyzed along the perpendicular bisector direction, with a scanning step size of 1 pixel. Each scan requires filtering out the overlapping area based on the brightness value change trend, and the overlapping area can be obtained after the scan is completed.

[0052] Preferably, in this embodiment of the invention, the method for selecting pixels in the overlapping area of ​​light spots includes:

[0053] The consecutive positive elements starting from the first element in the statistical difference sequence are taken as normal spot pixels; the normal spot pixels corresponding to the two endpoints of the first line to be analyzed are obtained and removed to obtain the truncated line segment. The pixels on the truncated line segment are the pixels in the overlapping area of ​​the spots.

[0054] Further, please refer to Figure 3 This diagram illustrates a scanning process according to an embodiment of the present invention, where points Z and J are the center points of two actual light spots, and point Z is the center point of the infrared light spot region. The line ZJ can be used to scan both sides along the perpendicular bisector. In this embodiment of the invention, the scanning stops under the following conditions:

[0055] Starting from the initial position of the first line to be analyzed, scanning is performed along the perpendicular bisector in two directions. For each scanning direction, scanning stops when the length of the intercepted line segment is less than a preset second threshold. This embodiment of the invention considers that the overlapping area will eventually intersect with two related spot areas at two points, respectively located on the two segments of the first line to be analyzed. Therefore, the second threshold is set to 1, meaning that scanning stops when only one intersection point with the irregularly shaped spot area is reached.

[0056] It should be noted that, for the center point Z of the infrared spot region, all the spot overlap areas between it and the noise spot region can be obtained through the method in step S2, and then each spot overlap area can be adjusted in a targeted manner in subsequent steps.

[0057] Step S3: For any pixel in the overlapping area of ​​light spots, connect the corresponding real light spot center point to obtain two calibration lines. For any calibration line, according to the brightness decrease law of the real light spot center point and the length of the calibration line, obtain the simulated brightness value of the pixel in the overlapping area of ​​light spots.

[0058] For each pixel in each overlapping region of a light spot, the generation of the pixel in the overlapping region is due to the overlap of the two light spot regions involved. This embodiment of the invention first uses simulation to simulate the brightness value that the pixel in the overlapping region should exhibit in each of the two light spot regions if it were not affected by the overlap.

[0059] This invention considers that brightness attenuation is related to distance; the farther a point is from the center of the actual light spot, the greater the brightness attenuation, i.e., the smaller the brightness value. Therefore, to measure this characteristic, this invention also uses a connection method for quantitative analysis. For any pixel in the overlapping area of ​​the light spots, the corresponding center point of the actual light spot is connected to obtain two calibration lines. Each calibration line corresponds to a simulation process; that is, analyzing the two calibration lines yields the simulated brightness value of the pixel in the overlapping area of ​​the light spots relative to the two center points of the actual light spots.

[0060] The brightness decrease rule of the real spot center point can be obtained according to the brightness value change in the neighborhood. Then, combined with the length of the calibration line, the simulated brightness value of the pixel in the spot area of ​​the real spot center point can be obtained without the influence of overlap.

[0061] Preferably, in this embodiment of the invention, the method for obtaining the brightness decrease pattern includes:

[0062] The intersection of the calibration line and the overlapping area of ​​the light spot is taken as the transition point; the difference in brightness value between the center point of the actual light spot corresponding to the calibration line and the transition point is obtained. This difference in brightness value is used as the numerator, and the distance between the center point of the actual light spot and the transition point is used as the denominator to obtain the brightness reduction law. That is, the brightness reduction law represents the value of brightness decay per unit distance.

[0063] Please see Figure 4 This illustrates a schematic diagram of a brightness attenuation simulation analysis provided by an embodiment of the present invention. Figure 4 In the diagram, point Z is the center point of the infrared spot region, point J is the center point of the analyzed noise spot region, point E is the pixel in the analyzed spot overlap region, point A is the transition point between the calibration line corresponding to the infrared spot region center point Z and the spot overlap region, and point B is the transition point between the noise spot region center point J and the spot overlap region. Taking the infrared spot region center point Z as an example, the brightness decreases according to the following pattern. Expressed as a formula: ;in The value of Z, which is the center point of the infrared spot region. Let A be the brightness value of the transition point A formed by the calibration line corresponding to the center point Z of the infrared spot region and the overlapping area of ​​the spot. Let Z be the distance between the center point Z of the infrared spot region and the transition point A. Similarly, the brightness decreases at point J. No further explanation needed.

[0064] Preferably, in this embodiment of the invention, the method for obtaining the simulated brightness value includes:

[0065] For each calibration line, the product of the calibration line length and the brightness decrease rule is used as the simulated brightness attenuation value. The simulated brightness attenuation value is then subtracted from the brightness value of the corresponding real light spot center point to obtain the simulated brightness value. Figure 4 For example, the simulated brightness value can be expressed by the formula: ;in The simulated brightness value of point E relative to point Z. This is the length of the calibration line connecting point Z and point E. The simulated brightness attenuation value is the simulated brightness reduction that point E should experience in the spot area corresponding to point Z. Subtracting the simulated brightness attenuation value from the brightness value of point Z yields the simulated brightness value of point E relative to point Z. Similarly, the simulated brightness value of point E relative to point J can be obtained. .

[0066] Step S4: Obtain the brightness difference between the two simulated brightness values ​​and the actual brightness value of the pixels in the overlapping area of ​​the light spots. Obtain the distance weight based on the calibration connection length. Perform weighted fusion on the brightness difference based on the distance weight to obtain the corrected brightness. Select the center point of the real light spot that is closest to the pixels in the overlapping area of ​​the light spots as the reference point. Obtain the base brightness value based on the distance weight corresponding to the reference point and the simulated brightness value. Obtain the adjusted brightness of the pixels in the overlapping area of ​​the light spots based on the base brightness value and the corrected brightness.

[0067] Because pixels in the overlapping area of ​​light spots are simultaneously affected by two light spot areas, and the distance between pixels in the overlapping area and the center point of the real light spot varies, the impact varies accordingly. That is, the closer the distance, the greater the impact, and therefore the corresponding simulated brightness value should be more reliable. Therefore, in the process of fusing two simulated brightness values, this embodiment of the invention first obtains a distance weight based on the length of the calibration connection line; that is, the shorter the calibration connection line, the greater the distance weight, and the stronger the reliability of the corresponding simulated brightness value. This embodiment of the invention first obtains the brightness difference between each simulated brightness value and the actual brightness value of the pixels in the overlapping area of ​​light spots. This brightness difference reflects the amount of adjustment that should be made. Further, the two brightness differences are weighted and fused according to the distance weight to obtain the corrected brightness. The corrected brightness represents the change in actual brightness after removing the influence of other light spots; therefore, it should also be fused with a basic value to obtain the final adjusted brightness. This embodiment of the invention uses the center point of the real light spot closest to the pixels in the overlapping area of ​​light spots as a reference point, and obtains a basic brightness value based on the distance weight corresponding to the reference point and the simulated brightness value. Then, by fusing the base brightness value and the corrected brightness, the adjusted brightness of the pixels in the overlapping area of ​​the light spot can be obtained.

[0068] Preferably, in this embodiment of the invention, the method for obtaining the corrected brightness includes:

[0069] For any calibration connection, the length of the calibration connection is negatively correlated and normalized to obtain the distance weight; the brightness difference is weighted and summed with the corresponding distance weight to obtain the corrected brightness. As an example, let's take... Figure 4 Taking content as an example, the formula for adjusting brightness is: ;in The corrected brightness for point E; The distance between point Z and point E is the length of the corresponding calibration line; The distance between point J and point E is the length of the corresponding calibration line; for and The sum of; This represents the actual brightness value of point E. That is, in this formula, for The result of negative correlation mapping and normalization is that the closer the distance, the greater the weight. And... and The sum of is 1.

[0070] Preferably, in this embodiment of the invention, the method for obtaining the basic brightness value includes:

[0071] The base brightness value is obtained by multiplying the distance weight corresponding to the reference point by the simulated brightness value. Figure 4 Taking the content as an example, it can be expressed as a formula: .

[0072] Preferably, in this embodiment of the invention, the brightness is adjusted to be the sum of the base brightness value and the corrected brightness value.

[0073] Step S5: Fit the laser spot area based on the adjusted laser spot image, and measure the angle based on the obtained infrared spot area.

[0074] Based on the above steps, the brightness values ​​of the center point of the infrared spot region and its related overlapping areas can be adjusted. The adjusted results can then be used for spot region fitting, specifically circular region fitting, to obtain the infrared spot region. Angle measurements are then performed based on the obtained infrared spot region. Furthermore, the asymmetric speckle problem caused by diffraction at the edge of the infrared spot region can be analyzed symmetrically using the adjusted brightness of the infrared spot region to obtain precise spot regions for subsequent angle measurements. The specific angle measurement method is a technique well-known to those skilled in the art. After obtaining the infrared spot region, calculations can be performed in polar coordinates to determine the angle between the culvert axis and the route centerline. The calculated angle value is compared with the predetermined value during culvert design. Based on the comparison results, subsequent bridge and culvert construction is rationally arranged. The specific angle measurement content is a technique well-known to those skilled in the art and will not be elaborated here. Circular region fitting can be implemented using algorithms such as Hough transform for circle detection. Other techniques can also be used in this embodiment of the invention, which will not be elaborated or limited further.

[0075] During the angle measurement of culvert construction using a total station, the size symmetry and clarity of the reflected infrared spot area are important factors causing measurement accuracy errors. This invention can effectively compensate and optimize the brightness of the overlapping area by dynamically adjusting the brightness value of the pixels in the overlapping area. Using the adjusted infrared spot area for angle measurement can improve the measurement accuracy.

[0076] In summary, this invention acquires the laser spot image after reflection from the total station and then filters out the true center points of the laser spots. Lines are drawn between each pair of true laser spot center points, and the changes in brightness values ​​along these lines are analyzed to determine the overlapping areas of the laser spots. Based on the brightness attenuation pattern exhibited by each true laser spot center point, the pixels in the overlapping areas are simulated to determine simulated brightness values. By combining the two simulated brightness values ​​and information such as distance, the brightness values ​​of the pixels in the overlapping areas can be effectively adjusted. Then, laser spot region fitting is performed to obtain the infrared laser spot region, which is then used to measure the culvert construction angle. This invention eliminates the influence of brightness in the overlapping areas of the infrared laser spot region, making the information in the infrared laser spot region more reliable and improving the accuracy of total station measurements of culvert construction angles in high-altitude areas.

[0077] The present invention also proposes an angle measurement system for culvert construction in high-altitude areas, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of any one of the angle measurement methods for culvert construction in high-altitude areas.

[0078] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0079] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. An angle measurement method for culvert construction in high-altitude areas, characterized in that, The method includes: Obtain the laser spot image on the total station after reflection from the target point; select the true center point of the laser spot from the laser spot image based on the brightness value characteristics; The line connecting the center points of the real light spots is taken as the first line to be analyzed. The first line to be analyzed is scanned along the vertical direction. Each scan selects the pixels in the overlapping area of ​​the light spots according to the trend of brightness value change, and obtains the overlapping area of ​​the light spots. For any pixel in the overlapping area of ​​light spots, connect the corresponding real light spot center point to obtain two calibration lines. For any calibration line, according to the brightness decrease law of the real light spot center point and the length of the calibration line, obtain the simulated brightness value of the pixel in the overlapping area of ​​light spots. The brightness difference between two simulated brightness values ​​and the actual brightness value of the pixels in the overlapping area of ​​the light spot is obtained. A distance weight is obtained based on the calibration connection length. The brightness differences are then weighted and fused according to the distance weight to obtain the corrected brightness. The center point of the real light spot closest to the pixels in the overlapping area is selected as a reference point. A base brightness value is obtained based on the distance weight corresponding to the reference point and the simulated brightness value. The adjusted brightness of the pixels in the overlapping area is obtained based on the base brightness value and the corrected brightness. The laser spot image is fitted to the spot region, and the angle is measured based on the obtained infrared spot region. The method for obtaining the center point of the actual light spot includes: Each pixel in the laser spot image is filtered based on its brightness value, and all maximum values ​​in the laser spot image are taken as suspected spot center points. The lines connecting each pair of suspected spot center points are taken as second lines to be analyzed. The brightness value change characteristics between the two endpoints of the second lines to be analyzed, and the true spot center points are selected from the suspected spot center points.

2. The angle measurement method for culvert construction in high-altitude areas according to claim 1, characterized in that, The process of filtering out the true center point of the light spot from the suspected center points includes: For the second line to be analyzed, take any endpoint as the starting point and count the brightness value sequence on the second line to be analyzed. In the brightness value sequence, subtract the next element from the previous element to obtain the difference sequence. If the number of positive elements in the difference sequence is greater than the preset first threshold, then the suspected light spot center point corresponding to the starting point is taken as the real light spot center point.

3. The angle measurement method for culvert construction in high-altitude areas according to claim 2, characterized in that, The method for selecting pixels in the overlapping area of ​​the light spots includes: The consecutive positive elements starting from the first element in the statistical difference sequence are taken as normal spot pixels; the normal spot pixels corresponding to the two endpoints of the first line to be analyzed are obtained and removed to obtain the cut line segment, and the pixels on the cut line segment are the pixels in the overlapping area of ​​the spot.

4. The angle measurement method for culvert construction in high-altitude areas according to claim 3, characterized in that, The scanning stop condition is: Starting from the initial position of the first line to be analyzed, scan along the perpendicular bisector in two directions. For each scanning direction, stop scanning when the length of the intercepted line segment is less than a preset second threshold.

5. The angle measurement method for culvert construction in high-altitude areas according to claim 1, characterized in that, The method for obtaining the brightness decrease pattern includes: The intersection of the calibration line and the overlapping area of ​​the light spot is taken as the transition point; the difference in brightness value between the center point of the actual light spot corresponding to the calibration line and the transition point is obtained. The difference in brightness value is used as the numerator, and the distance between the center point of the actual light spot and the transition point is used as the denominator to obtain the brightness decrease rule.

6. The angle measurement method for culvert construction in high-altitude areas according to claim 5, characterized in that, The method for obtaining the simulated brightness value includes: For each calibration line, the product of the length of the calibration line and the brightness decrease rule is used as the simulated brightness decay value. The simulated brightness decay value is then subtracted from the brightness value of the corresponding real spot center point to obtain the simulated brightness value.

7. The angle measurement method for culvert construction in high-altitude areas according to claim 1, characterized in that, The method for obtaining the corrected brightness includes: For any calibration connection, the length of the calibration connection is negatively correlated and normalized to obtain the distance weight; the brightness difference is weighted and summed with the corresponding distance weight to obtain the corrected brightness.

8. The angle measurement method for culvert construction in high-altitude areas according to claim 1, characterized in that, The method for obtaining the basic brightness value includes: The base brightness value is obtained by multiplying the distance weight corresponding to the reference point by the simulated brightness value.

9. An angle measurement system for culvert construction in high-altitude areas, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the angle measurement method for culvert construction in high-altitude areas as described in any one of claims 1 to 8.

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