Unmanned aerial vehicle land survey system and survey method based on multi-source sensor fusion

Abstract

The invention relates to the technical field of unmanned aerial vehicle land exploration, in particular to an unmanned aerial vehicle land exploration system and method based on multi-source sensor fusion, and the method comprises the steps: driving an image collection module of an unmanned aerial vehicle to carry out the collection of a land exploration image of a target exploration land; positioning a blade loss position based on a noisy point distribution area of the land survey image acquired by the unmanned aerial vehicle, and adjusting a blade position when the unmanned aerial vehicle advances; the attenuation of the movement speed of the unmanned aerial vehicle is obtained, and the relative positions of blades of the unmanned aerial vehicle and external wind power are adjusted; acquiring the ambient humidity around the unmanned aerial vehicle; acquiring the image contrast of the environment humidity abnormal area; adjusting the rotating speed of the corresponding blade according to the deterioration direction of the image contrast; and according to the adjusted rotating speed of the blades and the adjusted rotating speed of the corresponding blades, the unmanned aerial vehicle is controlled to continue to advance so as to complete exploration of the target exploration land. According to the invention, the stability and picture definition of the unmanned aerial vehicle land survey process are improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of unmanned aerial vehicle land survey, and in particular to an unmanned aerial vehicle land survey system and method based on multi-source sensor fusion. BACKGROUND

[0002] The unmanned aerial vehicle land survey system mainly relies on a high-resolution camera to obtain ground surface images, and generates topographic maps, three-dimensional models and other results through subsequent image processing and photogrammetry technology. However, the rotor blades, as the core power components of the unmanned aerial vehicle, will be worn and out of balance after a long time of high-speed operation. The blade wear will destroy the stability of the downflow, generate aerodynamic turbulence in a specific direction, and appear as directional stripe noise points on the image, which seriously reduces the image quality and affects the accuracy of subsequent feature point matching and model splicing. In addition, the wind flow encountered by the unmanned aerial vehicle during operation will cause the unmanned aerial vehicle to shake, resulting in image blurring. At the same time, when the environmental humidity is too high, water vapor is easy to form microdroplets or mist in front of the camera lens, causing the image contrast to decrease. Therefore, there is an urgent need for an unmanned aerial vehicle land survey system and method that fuses multi-source sensors and actively adapts to the environment.

[0003] Chinese Patent Publication No. CN215767057U discloses a dynamic adjustment device for improving the precision of unmanned aerial vehicle investigation of complex slope rock mass, which comprises an unmanned aerial vehicle body, a high-definition camera and a control system, and further comprises a laser ranging module installed on the high-definition camera. The laser ranging module is provided with three laser ranging devices, each of which measures the distance value of the shooting area. The laser reverse extension lines of each laser ranging device intersect at L behind the lens. The intersection point of the laser reverse extension lines is taken as the coordinate system origin O, the X-axis direction is the long side direction of the high-definition camera of the unmanned aerial vehicle, the Y-axis direction is the short side direction of the high-definition camera, the Z-axis direction is the same as the lens direction of the high-definition camera, and the XOY plane is perpendicular to the lens direction of the high-definition camera. It can be seen that the dynamic adjustment device for improving the precision of unmanned aerial vehicle investigation of complex slope rock mass has the problems that when the unmanned aerial vehicle blades are worn, the downflow stability is unbalanced, resulting in aerodynamic turbulence in a specific direction, and further causing stripe noise points in the collected land survey images. In addition, due to the high environmental humidity of the unmanned aerial vehicle body, water vapor is wrapped and adsorbed by the downflow aerodynamic turbulence, forming microdroplets or mist in front of the camera lens, which causes the clarity of the land survey image to decrease. SUMMARY

[0004] To address this, the present invention provides a UAV land surveying system and method based on multi-source sensor fusion, which overcomes the problems in the prior art where wear of UAV blades leads to an imbalance in the downward airflow stability, resulting in aerodynamic turbulence in a specific direction, which in turn causes stripe noise in the acquired land surveying images. It also addresses the problem that when the UAV body is in a high-humidity environment, water vapor is carried and adsorbed by the downward aerodynamic turbulence, forming micro-droplets or mist in front of the camera lens, thus reducing the clarity of the land surveying images.

[0005] On the one hand, the present invention provides a UAV land surveying method based on multi-source sensor fusion, comprising: The image acquisition module that drives the drone acquires land survey images of the target land. The location of blade wear on the UAV is determined based on the noise distribution area in the land survey image. Adjust the blade position of the UAV as it moves forward based on the location of blade wear. Obtain the amount of speed reduction of the drone as it moves forward according to the position of the blades when it is moving forward; Adjust the relative position of the drone's blades to the external wind force according to the attenuation amount; The humidity sensor installed on the drone collects the ambient humidity around the drone during the survey process according to the relative position. Image contrast of areas with abnormal environmental humidity in land survey images; Adjust the rotational speed of the corresponding blades according to the direction of deterioration in the image contrast; The drone continues to move forward according to the adjusted rotation speed of the corresponding blades in order to complete the survey of the target land.

[0006] Further, locating the blade wear location of the UAV based on the noise distribution area of ​​the land survey image collected by the UAV includes: The largest area enclosed by a straight line connecting the sampling points in the land survey image that have a noise intensity value greater than a preset noise intensity is defined as the abnormal noise area. The blade corresponding to the blade partition with the largest area proportion of the abnormal noise region within each blade partition is identified as the target blade generating the noise feature. The area ratio of the abnormal noise region in each leaf partition is the ratio of the image area occupied by the abnormal noise region in each leaf partition to the total area of ​​that leaf partition.

[0007] Furthermore, adjusting the blade position of the UAV during forward movement based on the wear location includes: If the target blade is on the opposite side of the UAV's forward direction, the blade position of the UAV will not be adjusted while it is moving forward. If the target blade is on a side other than the direction of travel of the UAV, then the position of the target blade as the UAV moves forward will be adjusted from the side other than the direction of travel to the side opposite to the direction of travel of the UAV.

[0008] Furthermore, adjusting the relative position of the UAV blades to the external wind force based on the attenuation amount includes: The decrease in the speed of the drone is compared with a preset decrease. If the attenuation amount is greater than the preset attenuation amount, then the target blade is set perpendicular to the wind direction of the external wind force that meets the preset wind force conditions, wherein, The direction of the external wind force is the angle between the direction of the sum of all wind speed vectors around the drone as it moves forward and the horizontal plane, where, The decrease in the drone's speed is the difference between the drone's speed at the beginning and the speed at the end of a unit monitoring period.

[0009] Furthermore, the preset wind condition is that the wind speed value of the external wind force collected by the wind speed sensor installed on the drone is greater than the preset wind speed value.

[0010] Furthermore, the image contrast of areas with abnormal environmental humidity in the acquired land survey images includes: The area around the drone body that meets the preset humidity conditions is defined as an area with abnormal environmental humidity. Contrast of the land survey image closest to the area of ​​abnormal environmental humidity.

[0011] Furthermore, the preset humidity condition is that the ambient humidity around the drone body is greater than the preset humidity.

[0012] Further, adjusting the rotational speed of the corresponding blade according to the direction of deterioration in the image contrast includes: If the change in contrast is greater than the preset change, then the contrast sampling points are connected according to the size of each contrast, and the vector sum of all vector segments formed by each contrast sampling point and its neighbors is determined as the deterioration direction. Increase the rotational speed of the blades corresponding to the direction of deterioration, wherein, The change in contrast is the difference between the contrast at the end of a unit monitoring period and the contrast at the beginning of the period.

[0013] Furthermore, the rotational speed of the blade corresponding to the direction of deterioration is positively correlated with the change in contrast, wherein, The blade corresponding to the deterioration direction is the blade with the smallest angle between the straight line containing the vector sum of all vector segments and the baseline segment, wherein the baseline segment is the line segment connecting the farthest end of the UAV blade and the rotation center of the UAV blade.

[0014] On the other hand, the present invention provides a UAV land surveying system based on multi-source sensor fusion, including the UAV body and further comprising: The drive module, which is connected to the UAV body, includes several blades connected to the UAV body for generating lift and thrust, and a speed drive motor connected to the blades for adjusting the speed of the UAV blades. An image acquisition module, which is mounted on a gimbal below the drone body, is used to acquire land survey images of the land to be photographed. The detection module, which is connected to the image acquisition module, includes a wind speed sensor located below the drone body to acquire the wind speed around the drone, and a humidity sensor located on the drone body to acquire the ambient humidity around the drone. The control module, which is connected to the drive module, the image acquisition module, and the detection module, is used to adjust the position of the UAV's blades when moving forward based on the noise intensity value in the land survey image, adjust the relative position of the UAV's blades to the external wind force based on the attenuation of the UAV's movement speed, determine the abnormal humidity area based on the ambient humidity around the UAV, and adjust the rotation speed of the corresponding blades based on the direction of contrast deterioration corresponding to the abnormal humidity area.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention determines the location of blade wear on a UAV based on the noise distribution area of ​​land survey images collected by the UAV. When the noise intensity value in the land survey image is greater than a preset noise intensity, it indicates that there is a directional and continuous disturbance in the downdraft of the UAV. The area enclosed by all sampling points with noise intensity values ​​greater than the preset noise intensity is defined as an abnormal noise area. The target blade generating the noise feature is determined based on the extended area of ​​the abnormal noise area. The extended area is a semi-closed area formed by the two tangents corresponding to the maximum width connecting line segment of the abnormal noise area and the maximum width connecting line segment. This semi-closed area represents the complete projection range of the directional airflow disturbance caused by blade wear on the image sensor. When there is at least one target blade generating noise features, the main axis direction of the semi-closed area will cover the projection orientation of the corresponding target blade on the image plane, indicating that the noise energy exhibits obvious directional distribution characteristics on the image. The extended area corresponding to the abnormal noise area represents the aerodynamic disturbance caused in the image. Regarding the extension direction of noise on the acquisition module, when there is an abnormal noise area corresponding to the blade with the largest area ratio in each blade partition, it indicates that the rotation plane of the corresponding blade is highly coincident with the direction of aerodynamic disturbance. This blade, which is highly coincident with the direction of aerodynamic disturbance, is strongly correlated with the main source of abnormal noise. Therefore, the corresponding blade in the extension area corresponding to the abnormal noise area is identified as the target blade generating noise characteristics. Adjusting the target blade to the opposite side of the UAV's forward direction is to make the rotation plane of the damaged blade approximately parallel to the relative airflow direction during the UAV's cruise state. This minimizes the direct impact of the generated aerodynamic noise on the imaging system, solves the image directional stripe noise caused by the asymmetry of the downward airflow due to the structural loss of a single blade, and further improves the overall stability of the air curtain formed by the UAV rotor. This further provides the execution basis for subsequent active dehumidification control based on the air curtain and avoids the failure of the dehumidification barrier due to local airflow instability.

[0016] Furthermore, this invention sets non-compliant blades perpendicular to the wind direction where the external wind force is greater than a preset wind force, based on the location of blade damage. When the external wind force is greater than the preset wind force, it indicates that the damaged blades of the UAV are at risk of structural failure under wind load. When the ambient humidity around the UAV is greater than the preset humidity, it indicates that there is a potential condition for water vapor to condense on the lens surface, leading to a decrease in image optical performance. At this time, the contrast of the land survey image closest to the area of ​​abnormal ambient humidity (greater than the preset humidity) is collected. The contrast further reflects the severity of the loss of image detail information caused by humidity in the imaging area corresponding to the land survey image directly in contact with the area of ​​abnormal ambient humidity in front of the lens.

[0017] Furthermore, this invention calculates the contrast of the land survey image within a unit monitoring period, and determines the direction of contrast degradation based on the change in contrast and the direction of the contrast gradient vector. The change in contrast represents the degree of image quality degradation. When the change in contrast is greater than a preset change, it indicates that humidity interference is in an accelerated degradation stage. By connecting the contrast sampling points according to the magnitude of each contrast, the vector sum of all vector segments formed by each contrast sampling point and its neighbors is determined as the degradation direction. This quantifies and locks the main axis of contrast degradation with the strongest correlation caused by uneven spatial distribution of moisture, further clarifying the source location and main transmission path of moisture invasion. At this time, the rotation speed of the blades corresponding to the degradation direction is increased according to the change in contrast. Without changing the overall flight attitude and trajectory of the UAV, the problem of image clarity reduction caused by environmental moisture interfering with the lens in a specific direction is solved. This further realizes the adaptive control of the imaging microenvironment, thereby improving the quality and reliability of UAV land survey under corresponding humidity conditions. Attached Figure Description

[0018] Figure 1 This is an overall flowchart of the UAV land survey method based on multi-source sensor fusion according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the UAV in the UAV land survey system based on multi-source sensor fusion, according to an embodiment of the present invention. Figure 3 This is a schematic diagram showing the location of noise anomaly regions in a land survey image of an UAV land survey system based on multi-source sensor fusion, according to an embodiment of the present invention. Figure 4 This is a flowchart illustrating the adjustment of the rotational speed of corresponding blades in the UAV land surveying method based on multi-source sensor fusion, as described in an embodiment of the present invention. Figure labeling: 1-High resolution camera, 2-Blade, 3-Humidity sensor, 4-Baseline segment, 5-UAV body, 6-Blade rotation center, 7-Blade partition, 8-Noise abnormality area. Detailed Implementation

[0019] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0020] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0021] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0022] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Please see Figure 1 The diagram shown is an overall flowchart of the UAV land surveying method based on multi-source sensor fusion according to an embodiment of the present invention. The UAV land surveying method based on multi-source sensor fusion according to an embodiment of the present invention includes: The image acquisition module that drives the drone acquires land survey images of the target land. The location of blade wear on the UAV is determined based on the noise distribution area in the land survey image. Adjust the blade position of the UAV as it moves forward based on the location of blade wear. Obtain the amount of speed reduction of the drone as it moves forward according to the position of the blades when it is moving forward; Adjust the relative position of the drone's blades to the external wind force according to the attenuation amount; The humidity sensor installed on the drone collects the ambient humidity around the drone during the survey process according to the relative position. Image contrast of areas with abnormal environmental humidity in land survey images; Adjust the rotational speed of the corresponding blades according to the direction of deterioration in the image contrast; The drone continues to move forward according to the adjusted rotation speed of the corresponding blades in order to complete the survey of the target land.

[0024] In implementation, this invention determines the location of blade wear on a UAV based on the noise distribution area of ​​land survey images acquired by the UAV. When the noise intensity value in the land survey image is greater than a preset noise intensity, it indicates that there is a directional and continuous disturbance in the downdraft of the UAV. The area enclosed by all sampling points with noise intensity values ​​greater than the preset noise intensity is defined as an abnormal noise region. The target blade generating the noise feature is determined based on the extended region of the abnormal noise region. The extended region is a semi-enclosed area formed by the two tangents corresponding to the maximum width of the connecting line segment of the abnormal noise region and the maximum width connecting line segment. This semi-enclosed region represents the complete projection range of the directional airflow disturbance caused by blade wear on the image sensor. When there is at least one target blade generating noise features, the main axis direction of the semi-enclosed region will cover the projection orientation of the corresponding target blade on the image plane, indicating that the noise energy exhibits a clear directional distribution feature on the image. The extended region corresponding to the abnormal noise region represents the noise generated by the aerodynamic disturbance on the image acquisition module. The direction of sound extension indicates that when the blade corresponding to the blade with the largest area proportion in each blade partition 7 has an abnormal noise region, it means that the rotation plane of the corresponding blade is highly coincident with the direction of aerodynamic disturbance. This blade, which is highly coincident with the direction of aerodynamic disturbance, is strongly correlated with the main source of abnormal noise. Therefore, the blade corresponding to the extension area of ​​the abnormal noise region is identified as the target blade that generates noise characteristics. Adjusting the target blade to the opposite side of the forward direction of the UAV is to make the rotation plane of the damaged blade approximately parallel to the relative airflow direction during the UAV's cruise state. This minimizes the direct impact of the generated aerodynamic noise on the imaging system and solves the image directional stripe noise caused by the asymmetry of the downward airflow due to the structural loss of a single blade. This further improves the overall stability of the air curtain formed by the UAV rotor and provides a basis for subsequent active dehumidification control based on the air curtain, avoiding the failure of the dehumidification barrier due to local airflow instability.

[0025] Please see Figure 2 as well as Figure 3 The figures shown are schematic diagrams of the structure of the UAV in the UAV land survey system based on multi-source sensor fusion according to an embodiment of the present invention, and schematic diagrams of the location of noise anomaly areas in the land survey image. The step of locating the wear location of the UAV's blades 2 based on the noise distribution area of ​​the land survey image 7 acquired by the UAV includes: The largest area enclosed by a straight line connecting the sampling points in the land survey image that have a noise intensity value greater than a preset noise intensity is defined as the abnormal noise area. The blade corresponding to the blade partition 7 with the largest area proportion of the abnormal noise region within each blade partition 7 is determined as the target blade generating the noise feature. The area ratio of the abnormal noise region in each leaf partition 7 is the ratio of the image area occupied by the abnormal noise region in each leaf partition 7 to the total area of ​​that leaf partition 7.

[0026] Optionally, the preset noise intensity can be selected in the range of [10 gray levels, 30 gray levels].

[0027] Preferably, the preferred embodiment of the preset noise intensity is 15 gray levels.

[0028] Specifically, adjusting the position of blade 2 of the UAV during forward movement based on the wear location includes: If the target blade is on the opposite side of the UAV's forward direction, the blade position of the UAV will not be adjusted while it is moving forward. If the target blade is on a side other than the direction of travel of the UAV, then the position of the target blade as the UAV moves forward will be adjusted from the side other than the direction of travel to the side opposite to the direction of travel of the UAV.

[0029] Specifically, adjusting the relative position of the UAV blades 2 with the external wind force according to the attenuation amount includes: The decrease in the speed of the drone is compared with a preset decrease. If the attenuation amount is greater than the preset attenuation amount, then the target blade is set perpendicular to the wind direction of the external wind force that meets the preset wind force conditions, wherein, The direction of the external wind force is the angle between the direction of the sum of all wind speed vectors around the drone as it moves forward and the horizontal plane, where, The decrease in the drone's speed is the difference between the drone's speed at the beginning and the speed at the end of a unit monitoring period.

[0030] Optionally, the preset attenuation range is [0.8 m / s, 1.5 m / s].

[0031] Preferably, the preferred embodiment of the preset attenuation amount is 1.0 m / s.

[0032] Specifically, the preset wind condition is that the wind speed of the external wind force is greater than the preset wind speed value.

[0033] Optionally, the preset wind speed value can be selected within the range of [5.6m / s, 8.8m / s].

[0034] Preferably, the preset wind speed value in the preferred embodiment is 7 m / s.

[0035] In implementation, a specific embodiment of the present invention is as follows: the attenuation of the drone's movement speed is 1.2 m / s. The target blade 2 is set to be perpendicular to the wind direction of the external wind force that meets the preset wind force conditions. At this time, the wind speed of the external wind force is 7.5 m / s. Based on the fact that the angle between the direction of the sum of all wind speed vectors around the drone and the horizontal plane is 135° when the drone is moving forward, the target blade 2 is set at a direction perpendicular to the horizontal plane at 135°, i.e., 45° or 225°. Based on adjusting the position of the blade 2 of the drone when it is moving forward according to the loss position, the target blade 2 is set at 45° perpendicular to the horizontal plane.

[0036] In practice, this invention sets non-compliant blades perpendicular to the wind direction where the external wind force is greater than the preset wind force, based on the location of blade damage. When the external wind force is greater than the preset wind force, it indicates that the damaged blades of the UAV are at risk of structural failure under wind load. When the ambient humidity around the UAV body 5 is greater than the preset humidity, it indicates that there is a potential condition for water vapor to condense on the lens surface, leading to a decrease in image optical performance. At this time, the contrast of the land survey image closest to the area of ​​abnormal ambient humidity (greater than the preset humidity) is collected. The contrast further reflects the severity of the loss of image detail information caused by humidity in the imaging area corresponding to the land survey image directly in contact with the area of ​​abnormal ambient humidity in front of the lens.

[0037] Please see Figure 4 As shown, this is a flowchart illustrating the adjustment of the rotational speed of corresponding blades in the UAV land surveying method based on multi-source sensor fusion according to an embodiment of the present invention. The image contrast of the abnormal environmental humidity areas in the acquired land survey images includes: The area around the drone body 5 that meets the preset humidity conditions is defined as an area with abnormal environmental humidity. Contrast of the land survey image closest to the area of ​​abnormal environmental humidity.

[0038] Specifically, the preset humidity is the ratio of water vapor partial pressure to saturated water vapor pressure at the same temperature, i.e., relative humidity.

[0039] Specifically, the preset humidity condition is that the ambient humidity around the drone body 5 is greater than the preset humidity.

[0040] Optionally, the preset humidity range is [65%RH, 80%RH].

[0041] Preferably, the preset humidity is 70%RH.

[0042] Please continue reading. Figure 4 As shown, adjusting the rotational speed of the corresponding blade according to the direction of deterioration in the image contrast includes: If the change in contrast is greater than the preset change, then the contrast sampling points are connected according to the size of each contrast, and the vector sum of all vector segments formed by each contrast sampling point and its neighbors is determined as the deterioration direction. Increase the rotational speed of the blades corresponding to the direction of deterioration, wherein, The change in contrast is the difference between the contrast at the end of a unit monitoring period and the contrast at the beginning of the period.

[0043] Optionally, the preset range of variation is [3%, 8%].

[0044] Preferably, the preferred embodiment of the preset variation amount is 5%.

[0045] Specifically, the rotational speed of the blade corresponding to the direction of deterioration is positively correlated with the change in contrast, wherein, The blade corresponding to the deterioration direction is the blade with the smallest angle between the straight line containing the vector sum of all vector segments and the baseline segment, wherein the baseline segment is the line segment connecting the farthest end of the UAV blade and the rotation center of the UAV blade.

[0046] In implementation, when the change in contrast is greater than the preset change value within 0.5%, the rotation speed of the corresponding blade 2 upstream in the deterioration direction is adjusted to 1.1 times the current rotation speed. When the change in contrast is greater than the preset change value greater than 0.5%, for every 0.1% exceeding 0.5%, the rotation speed of the corresponding blade 2 upstream in the deterioration direction is increased by 0.05%. In a specific embodiment, the current change in contrast is 6%, and the current rotation speed of the corresponding blade 2 upstream in the deterioration direction is 1000 rpm. Then the increased rotation speed is 1000 rpm × 1.1 × (1 + 0.25%) ≈ 1102 rpm. When the calculated rotation speed of blade 2 has more than one decimal place, it is rounded to the nearest integer, i.e., 1102 rpm.

[0047] In implementation, this invention calculates the contrast of the land survey image within a unit monitoring period. Based on the change in contrast and the direction of the contrast gradient vector, the direction of contrast degradation is determined. The change in contrast represents the degree of image quality degradation. When the change in contrast is greater than a preset change, it indicates that humidity interference is in an accelerated degradation stage. By connecting the contrast sampling points according to the magnitude of each contrast, the vector sum of all vector segments formed by each contrast sampling point and its neighbors is determined as the degradation direction. This quantifies and locks the main axis of contrast degradation with the strongest correlation caused by uneven spatial distribution of moisture, further clarifying the source location and main transmission path of moisture invasion. At this time, the rotation speed of the blades corresponding to the degradation direction is increased according to the change in contrast. Without changing the overall flight attitude and trajectory of the UAV, the problem of image clarity reduction caused by environmental moisture interfering with the lens in a specific direction is solved. This further realizes the adaptive control of the imaging microenvironment, thereby improving the quality and reliability of UAV land survey under corresponding humidity conditions.

[0048] Please see Figure 4 As shown, this is an overall module diagram of the surveying system of the UAV land surveying method based on multi-source sensor fusion according to an embodiment of the present invention. The surveying system of the UAV land surveying method based on multi-source sensor fusion according to an embodiment of the present invention includes the UAV body 5, and also includes: The drive module is connected to the UAV body 5 and includes a number of blades 2 connected to the UAV body 5 to generate lift and thrust, and a speed drive motor connected to the blades 2 to adjust the speed of the UAV blades. An image acquisition module is mounted on a gimbal below the UAV body 5 to acquire land survey images 7 of the land to be photographed. The detection module, which is connected to the image acquisition module, includes a wind speed sensor located below the drone body 5 to acquire the wind speed around the drone, and a humidity sensor located on the drone body 5 to acquire the ambient humidity around the drone. The control module, which is connected to the drive module, the image acquisition module, and the detection module respectively, is used to adjust the position of the UAV's blades when moving forward according to the noise intensity value in the land survey image 7, adjust the relative position of the UAV's blades and the external wind force according to the attenuation of the UAV's movement speed, determine the abnormal humidity area according to the ambient humidity around the UAV, and adjust the rotation speed of the corresponding blades according to the direction of the deterioration of the contrast corresponding to the abnormal humidity area.

[0049] Specifically, the drone refers to a professional surveying drone.

[0050] Specifically, the drive motor has a power of 2.5kW and an output speed range of 200 to 3000 rpm.

[0051] Specifically, the image acquisition module includes a high-resolution camera 1.

[0052] Specifically, by controlling the orientation of the drone's fuselage, the yaw angle of the drone can be changed, thereby causing all blades to change their spatial orientation relative to the direction of travel and the external wind field as a whole, thus adjusting the target blade to the opposite side of the drone's direction of travel.

[0053] Specifically, when adjusting the relative position of the UAV blade 2 with the external wind force, only the orientation of the blade 2, i.e. the yaw angle, is adjusted, while the acquisition position for collecting the land survey image 7 of the target land remains unchanged.

[0054] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A UAV land surveying method based on multi-source sensor fusion, characterized in that, include: The image acquisition module that drives the drone acquires land survey images of the target land. The location of blade wear on the UAV is determined based on the noise distribution area in the land survey image. Adjust the blade position of the UAV as it moves forward based on the location of blade wear. Obtain the amount of speed reduction of the drone as it moves forward according to the position of the blades when it is moving forward; Adjust the relative position of the drone's blades to the external wind force according to the attenuation amount; The humidity sensor installed on the drone collects the ambient humidity around the drone during the survey process according to the relative position. Image contrast of areas with abnormal environmental humidity in land survey images; Adjust the rotational speed of the corresponding blades according to the direction of deterioration in the image contrast; The drone continues to move forward according to the adjusted rotation speed of the corresponding blades in order to complete the survey of the target land.

2. The UAV land survey method based on multi-source sensor fusion according to claim 1, characterized in that, Locating the blade wear location of the UAV based on the noise distribution area of ​​the land survey image acquired by the UAV includes: The largest area enclosed by a straight line connecting the sampling points in the land survey image that have a noise intensity value greater than a preset noise intensity is defined as the abnormal noise area. The blade corresponding to the blade partition with the largest area proportion of the abnormal noise region within each blade partition is identified as the target blade generating the noise feature. The area ratio of the abnormal noise region in each leaf partition is the ratio of the image area occupied by the abnormal noise region in each leaf partition to the total area of ​​that leaf partition.

3. The UAV land survey method based on multi-source sensor fusion according to claim 2, characterized in that, The step of adjusting the blade position of the UAV during forward movement based on the wear location includes: If the target blade is on the opposite side of the UAV's forward direction, the blade position of the UAV will not be adjusted while it is moving forward. If the target blade is on a side other than the direction of travel of the UAV, then the position of the target blade as the UAV moves forward will be adjusted from the side other than the direction of travel to the side opposite to the direction of travel of the UAV.

4. The UAV land survey method based on multi-source sensor fusion according to claim 3, characterized in that, Adjusting the relative position of the UAV blades to the external wind force based on the attenuation amount includes: The decrease in the speed of the drone is compared with a preset decrease. If the attenuation amount is greater than the preset attenuation amount, then the target blade is set perpendicular to the wind direction of the external wind force that meets the preset wind force conditions, wherein, The direction of the external wind force is the angle between the direction of the sum of all wind speed vectors around the drone as it moves forward and the horizontal plane, where, The decrease in the drone's speed is the difference between the drone's speed at the beginning and the speed at the end of a unit monitoring period.

5. The UAV land survey method based on multi-source sensor fusion according to claim 4, characterized in that, The preset wind condition is that the wind speed value of the external wind force collected by the wind speed sensor installed on the drone is greater than the preset wind speed value.

6. The UAV land survey method based on multi-source sensor fusion according to claim 5, characterized in that, The image contrast of areas with abnormal environmental humidity in the acquired land survey images includes: The area around the drone body that meets the preset humidity conditions is defined as an area with abnormal environmental humidity. Contrast of the land survey image closest to the area with abnormal environmental humidity.

7. The UAV land survey method based on multi-source sensor fusion according to claim 6, characterized in that, The preset humidity condition is that the ambient humidity around the drone body is greater than the preset humidity.

8. The UAV land survey method based on multi-source sensor fusion according to claim 7, characterized in that, The step of adjusting the rotational speed of the corresponding blade according to the direction of deterioration in the image contrast includes: If the change in contrast is greater than the preset change, then the contrast sampling points are connected according to the size of each contrast, and the vector sum of all vector segments formed by each contrast sampling point and its neighbors is determined as the deterioration direction. Increase the rotational speed of the blades corresponding to the direction of deterioration, wherein, The change in contrast is the difference between the contrast at the end of a unit monitoring period and the contrast at the beginning of the period.

9. The UAV land survey method based on multi-source sensor fusion according to claim 8, characterized in that, The rotational speed of the blade corresponding to the direction of deterioration is positively correlated with the change in contrast, wherein, The blade corresponding to the deterioration direction is the blade with the smallest angle between the straight line containing the vector sum of all vector segments and the baseline segment, wherein the baseline segment is the line segment connecting the farthest end of the UAV blade and the rotation center of the UAV blade.

10. A surveying system using the UAV land surveying method based on multi-source sensor fusion as described in any one of claims 1 to 9, comprising a UAV body, characterized in that, Also includes: The drive module, which is connected to the UAV body, includes several blades connected to the UAV body for generating lift and thrust, and a drive motor connected to the blades for adjusting the rotational speed of the UAV blades. An image acquisition module, which is mounted on a gimbal below the drone body, is used to acquire land survey images of the land to be photographed. The detection module, which is connected to the image acquisition module, includes a wind speed sensor located below the drone body to acquire the wind speed around the drone, and a humidity sensor located on the drone body to acquire the ambient humidity around the drone. The control module, which is connected to the drive module, the image acquisition module, and the detection module, is used to adjust the position of the UAV's blades when moving forward based on the noise intensity value in the land survey image, adjust the relative position of the UAV's blades to the external wind force based on the attenuation of the UAV's movement speed, determine the abnormal humidity area based on the ambient humidity around the UAV, and adjust the rotation speed of the corresponding blades based on the direction of contrast deterioration corresponding to the abnormal humidity area.

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