Coordinate measuring device for unmanned aerial vehicle
By alternately illuminating the drone with RGB light sources and combining it with the LK optical flow method, the problem of slight brightness differences caused by the diversity of materials in optical flow positioning was solved, thus improving the accuracy and reliability of drone positioning.
Patent Information
- Application Number
- CN202520079962.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-01-14
AI Technical Summary
In optical flow positioning technology, the diversity of ground or environmental materials means that areas with the same reflectivity but different colors have slight differences in brightness on the grayscale image. This leads to corner detection and optical flow tracking algorithms having scarce feature points, too many duplicate features, or feature tracking errors, which in turn causes a decrease in positioning accuracy or even loss.
An RGB lighting module is used to alternately illuminate the area below the drone with red, green, and blue light. The image acquisition module acquires images under different color light sources, and coordinate information is estimated using the LK optical flow method. The PWM module controls the working mode and frequency of the light source to ensure that the frame rate and exposure time of the image acquisition module are aligned with the timing of the light source.
By alternating illumination with different colored light sources, the brightness difference in grayscale images is improved, enhancing the feasibility and accuracy of corner detection and optical flow tracking algorithms, and improving the precision and reliability of UAV positioning.
Smart Images
Figure CN223925753U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to unmanned plane positioning technology, especially relate to a kind of unmanned plane measurement coordinate device. BACKGROUND
[0002] When unmanned plane is autonomously hovering, navigating and avoiding obstacles in indoor and outdoor environment, light flow positioning technology is often used.
[0003] In the calculation process, light flow algorithm often only needs image brightness information to complete feature extraction and matching, so color image is often converted into gray image to reduce data volume and improve real-time performance and reliability;
[0004] In the practical application of light flow positioning, ground or environmental material often has diversified surface color and texture features, and surface materials of different colors have similar or same reflectivity under visible light, so the following problems may occur in the gray imaging of camera:
[0005] Regions with same reflectivity but different colors may show almost same brightness on gray image, leading to extremely weak or indistinguishable edge or texture contrast;
[0006] Common corner detection or light flow tracking algorithm relies on local brightness gradient or high-contrast feature points. When the difference is insufficient, these regions are prone to feature point scarcity, excessive repeated features or feature tracking errors, which further leads to positioning accuracy decline or even tracking loss. SUMMARY
[0007] The utility model aims at providing a kind of unmanned plane measurement coordinate device to solve the above technical problems.
[0008] The utility model provides a kind of unmanned plane measurement coordinate device, including flight control module, for the image collected according to image acquisition module, utilizes light flow method to carry out coordinate information estimation;
[0009] RGB light module, which can irradiate the area below the unmanned plane with colored light, and the irradiation area is larger than the collection area of the image acquisition module;
[0010] Image acquisition module is used to collect ground image.
[0011] PWM module is used to control the working mode and light-emitting timing of the RGB light module.
[0012] Height sensing module is used to detect the flight height of the unmanned plane and send height information to the flight control module.
[0013] Further, the flight control module processes the image collected by the image acquisition module based on LK light flow method to obtain the position information, speed information or attitude information of the unmanned plane.
[0014] Further, the frame rate of the image acquisition module is adjustable, and the working frequency of the PWM module is higher than the frame rate flicker perception threshold of the image acquisition module.
[0015] Further, the frequency of the PWM module is 1 kHz, and the frame rate of the image acquisition module is 61 FPS.
[0016] Further, the PWM module lights up red light, green light and blue light in turn in 1 / 3 of the single frame time.
[0017] Further, the exposure time of the image acquisition module is aligned with the lighting timing of the RGB light.
[0018] The beneficial effects achieved by the above structure of the present application are as follows:
[0019] The present application lights up red, green and blue light sources in different frames, and the reflection degree of different color ground materials on the corresponding light source is different, which can form a large brightness difference in the gray scale image. Even if the reflectivity of the ground material under visible light is close, it will also present obvious gray scale gradient because of different color matching with the RGB light source, thereby improving the feasibility and accuracy of the corner point detection or optical flow tracking algorithm. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 It is a schematic diagram of the working state of the RGB light module of the present application;
[0021] Figure 2 It is a schematic diagram of the non-working state of the RGB light module of the present application;
[0022] Figure 3 It is a schematic diagram of the non-working state of the RGB light module of the present application;
[0023] 1, flight control module; 2, RGB light module; 3, image acquisition module; 4, PWM module; 5, height sensing module. DETAILED DESCRIPTION
[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.
[0025] It should be noted that the words "front", "back", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the words "inner" and "outer" refer to the directions towards or away from the geometric center of a particular component.
[0026] In order to make the content of the utility model more easily and clearly understood, the technical solutions in the utility model embodiments will be clearly and completely described below in combination with the drawings in the utility model embodiments.
[0027] As shown in Figures 1-3 The utility model provides a kind of unmanned vehicle measurement coordinate device including flight control module 1, RGB light module 2, image acquisition module 3.
[0028] Flight control module 1 estimates the image collected by image acquisition module 3 by LK light flow method, and obtains the coordinate information of unmanned vehicle.
[0029] RGB light module 2 can irradiate the area below unmanned vehicle with colored light, and the irradiation area of RGB light module 2 is larger than the collection area of image acquisition module 3, and the area with the same color as RGB light can effectively reflect light, while the area with different color from RGB light absorbs most of the light;
[0030] When collecting images, the area that can reflect light has high brightness, while the area that cannot reflect light has low brightness;
[0031] RGB light module 2 is controlled by PWM module 4;
[0032] Preferably, the PWM frequency is 1kHz, and the frame rate of the camera is 60PFS, the PWM frequency is significantly higher than the flicker perception threshold of the camera, avoiding stroboscopic effect;
[0033] In each frame period, red, green and blue light sources are sequentially turned on, and the reflection texture of single color light is collected in each frame image;
[0034] Preferably, the frame rate of the camera is adjustable;
[0035] The frame rate of the camera can be adjusted by software, and it is adjusted to 59FPS or 61FPS, etc. which is not synchronized with the frequency of power grid and its multiples, and when indoor light is used as the only light source, stroboscopic effect of light can be avoided, so that the brightness of collected images is more uniform.
[0036] When the frame rate of the camera is 61FPS;
[0037] The duration of red light is set to T0 to T1, and T0 to T1 is 1 / 3 of the time of a single frame;
[0038] The green light duration is set as T1 to T2, T1 to T2 is 1 / 3 of a single frame time;
[0039] The blue light duration is set as T2 to T3, T2 to T3 is 1 / 3 of a single frame time;
[0040] The exposure time of each frame camera is aligned with the RGB timing to ensure that T0 to T1 collects the image under red light, T1 to T2 collects the image under green light, and T2 to T3 collects the image under blue light.
[0041] Further comprising a height sensing module 5, the flight control module 1 can receive the height information sent by the height sensing module;
[0042] As shown in Figure 1 When the height of the unmanned aerial vehicle is low, the collection range of the image acquisition module 3 is small, only S1 and S2, and at this time, the feature points contained in the S1 and S2 regions are less;
[0043] Suppose that at this time, the S1 region also contains the S1a region, the S1a region is blue, and the S1a region is only different in color from the S1 region and the S2 region;
[0044] Then under the blue light irradiation of the RGB light module 2, the gray level of the S1a region in the gray image will be significantly higher than that of other regions, which can be used as a feature point.
[0045] As shown in Figure 2 When the unmanned aerial vehicle flies at a high altitude, the collection range of the image acquisition module 3 is large, including S1, S2, S3, and S4, and the gray image contains more feature points, and the irradiation range of the RGB light module 2 is limited and cannot effectively cover the entire ground area photographed by the image acquisition module 3.
[0046] At this time, the flight control module 1 sets the duty cycle of the PWM signal module to 0%, and the RGB light module 2 is turned off.
[0047] The above only describes the preferred embodiment of the present patent, and does not limit the present patent, any modification, equivalent replacement and improvement made within the spirit and principle of the present patent should be included in the protection scope of the present patent.
Claims
1. A drone measuring coordinate device, characterized in that, The flight control module (1) is used to estimate coordinate information by using the optical flow method according to images collected by the image collection module (3); The RGB light module (2) can irradiate the area below the unmanned aerial vehicle with colored light, and the irradiation area is larger than the collection area of the image collection module (3); The image collection module (3) is used to collect ground images; The PWM module (4) is used to control the working mode and light-emitting timing of the RGB light module (2); The height sensing module (5) is used to detect the flight height of the unmanned aerial vehicle and send the height information to the flight control module (1). 2.The unmanned aerial vehicle coordinate measuring device of claim 1, wherein, The flight control module (1) processes the images collected by the image collection module (3) based on the LK optical flow method.
3. The unmanned aerial vehicle coordinate measuring device of claim 2, wherein, The frame rate of the image collection module (3) is adjustable, and the working frequency of the PWM module (4) is higher than the frame rate flicker perception threshold of the image collection module (3).
4. The unmanned aerial vehicle coordinate measuring device of claim 1, wherein, The frequency of the PWM module (4) is 1 kHz, and the frame rate of the image collection module (3) is 61 FPS.
5. The unmanned aerial vehicle coordinate measuring device of claim 1, wherein, The PWM module (4) lights up red light, green light and blue light in turn at 1 / 3 of the single frame time.
6. The unmanned aerial vehicle coordinate measuring device of claim 1, wherein, The exposure time of the image collection module (3) is aligned with the lighting timing of the RGB light module (2).