Two-dimensional code band coding method for long-distance high-precision visual positioning and application thereof

Abstract

The invention discloses a two-dimensional code band coding method for visual positioning of an absolute position of equipment. The method is suitable for all two-dimensional codes with limited number of unique IDs, and the core idea of the method is that a two-dimensional code group is divided into two parts, one part is used as an identification code group, and the other part is used as a positioning code plate. Specifically, IDs are divided into two parts from a two-dimensional code coding dictionary containing N unique IDs, one part comprises M IDs used for forming an identification code group, and the other part comprises N-M IDs used for forming a positioning code plate. When the identification code group is composed of K two-dimensional codes in a combined mode, the unique code number of the combination is (M / K) K, and therefore the code band coding range is remarkably expanded. The positioning code plates adopted in the two-dimensional code groups are the same in design and have fixed relative positions with the identification code groups. The system firstly identifies the identification code group to deduce the position of the positioning code plate, and then performs fine correction by using the positioning code plate, thereby realizing long-distance and high-precision visual positioning. The method has the advantages of being high in coding expansibility, high in positioning precision, easy to implement and wide in adaptability.

Description

Technical Field

[0001] The present invention relates to the technical field of visual positioning, and particularly relates to a technical solution for realizing long-distance and high-precision visual positioning through a QR code strip encoding method, which is applicable to the positioning systems of devices such as AGV (Automated Guided Vehicle), unmanned aerial vehicles, and large mechanical devices (such as gantry cranes). Background Art

[0002] In the prior art, visual positioning systems often use a single QR code or a fixed identifier for positioning. However, due to the limited number of unique encodings of QR codes, it is difficult to meet the requirements of large-scale and distributed positioning. At the same time, a single QR code is easily affected by occlusion, blurring, light changes, etc. in long-distance or complex environments, resulting in a decrease in recognition accuracy. Although there have been attempts to use multiple QR codes for joint encoding in the existing technology, there is often a lack of sufficient guarantee for positioning accuracy, or the identification part and the positioning part cannot be effectively separated, resulting in difficulty in balancing the encoding scalability and positioning accuracy of the system. Therefore, how to greatly expand the QR code encoding range without sacrificing positioning accuracy has become an urgent technical problem to be solved. Summary of the Invention

[0003] In view of the above technical problems, the present invention provides an encoding method that divides a QR code group into an identification code group and a positioning code plate. Its basic idea includes:

[0004] 1. Encoding scalability

[0005] Using a QR code dictionary containing N unique IDs, M of which are used to form an identification code group, and by jointly using K QR codes to form a combined encoding, the number of unique encodings is greatly expanded from the original limited value to (M / K)^K, so as to be applicable to large-scale positioning and distributed management.

[0006] 2. Guarantee of positioning accuracy

[0007] Adopting a positioning code plate composed of the remaining N - M IDs, and using the same design in each QR code group. There is a fixed relative position between the positioning code plate and the identification code group. The system first quickly identifies the position of the QR code group using the identification code group, and then performs fine correction based on the fixed geometric features of the positioning code plate to achieve high-precision positioning of the absolute position of the target device.

[0008] 3. Universality and applicability

[0009] The present invention is not limited to a specific type of two-dimensional code or visual positioning board. Any two-dimensional code with a small number of unique IDs and capable of expanding the coding range through combination can be adopted. At the same time, various high-precision visual positioning boards (such as boards designed based on specific patterns or geometric features) are applicable to this method, which has good versatility and popularization value.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] This method has a simple structure, strong expansion ability, and high positioning accuracy, and is applicable to the positioning requirements of various industrial and intelligent equipment. Specific embodiments

[0012] The following takes the adoption of Aruco codes as an example to illustrate the present invention in detail. However, this embodiment is only a preferred solution and does not limit the protection scope of the present invention.

[0013] Embodiment: Two-dimensional code strip coding method based on Aruco codes

[0014] 1. Selection and segmentation of two-dimensional code dictionary

[0015] Suppose the selected Aruco two-dimensional code dictionary is DICT_6X6_1000, which is the dictionary with the most unique IDs for Aruco two-dimensional codes and contains N = 1000 unique IDs.

[0016] According to the design requirements, the IDs in this dictionary are divided into two parts:

[0017] - Allocate M IDs to form an identification code group (for example, M is set to 900);

[0018] - The remaining N - M IDs (for example, 100) are used to form a positioning code board.

[0019] 2. Composition of identification code group

[0020] Taking Aruco codes as an example, each Aruco code has an independent unique ID.

[0021] It is set that the identification code group is composed of K Aruco codes combined (for example, K takes 2 or 3). Each two-dimensional code is arranged in sequence and each carries a unique ID, as shown in the identification code group when K = 2. Figure 1 As shown.

[0022] According to the combination formula of the present invention, if K = 2, the number of unique combinations is (M / 2)^2; if K = 3, the number of unique combinations is (M / 3)^3.

[0023] For example, if M = 900, then when K = 2, the number of unique combinations is (900 / 2)^2 = 450 2= 202500, and when K = 3, it is (900 / 3)^3 = 300 3 = 27000000.

[0024] In this way, by combining multiple Aruco codes, the encoding range of the QR code strip can be significantly expanded.

[0025] 3. Composition of the positioning code plate

[0026] Use the remaining N - M IDs to form a visual positioning plate.

[0027] In this embodiment, the positioning code plate adopts a pre-designed graphic style, such as the CharucoBoard marker graphic, as Figure 2 shown. This graphic has unique geometric features, facilitating accurate recognition by the image processing algorithm at different shooting angles and distances.

[0028] The design of the positioning code plate used in each QR code group is consistent, and its position relative to the identification code group is fixed (for example, on the right side of the identification code group, as Figure 3 shown), to facilitate subsequent positioning correction.

[0029] 4. Recognition and positioning process

[0030] a) Image acquisition: Use a camera device to acquire an image containing the QR code group.

[0031] b) Identification code group recognition: First, use the image processing algorithm to recognize the Aruco codes in the image, and decode the identification code group according to the preset combination relationship, so as to quickly determine the overall area of the QR code group.

[0032] c) Positioning code plate extraction and correction: After recognizing the identification code group, the system extracts the area where the positioning code plate is located according to the fixed relative position between the identification code group and the positioning code plate; then, using the unique geometric features of the positioning code plate, perform image geometric correction and calculate the absolute position of the target device.

[0033] d) Positioning output: Finally, output high-precision device position information through data fusion and correction algorithms to support navigation and control of AGV, drones, large mechanical devices, etc.

[0034] 5. Measures to enhance robustness

[0035] In practical applications, to improve the recognition stability of the system in low light, partial occlusion or dynamic environments, redundant check codes can be introduced into the identification code group, and multi-frame image fusion, filtering, and image enhancement algorithms can be used to further improve the positioning accuracy and system reliability. Description of the drawings

[0036] Figure 1This is the identification code group composed of two Aruco codes in the specific embodiment of the present invention.

[0037] Figure 2 This is the visual positioning board composed of the remaining IDs in the specific embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram of the two-dimensional code group structure in the specific embodiment of the present invention, which shows the fixed relative position relationship between the identification code group composed of two Aruco codes and the visual positioning board composed of the remaining IDs.

[0039] Invention effect

[0040] By dividing the two-dimensional code group into two parts: the identification code group and the visual positioning board, the present invention realizes the double improvement of coding scalability and positioning accuracy, and has the following remarkable advantages:

[0041] 1. Greatly expanded coding range: By combining a limited number of unique IDs through K two-dimensional codes to form an identification code group, the combined coding number is given by (M / K)^K, far exceeding the coding ability of a single two-dimensional code;

[0042] 2. High-precision positioning: The visually positioned board with a fixed design serves as a positioning correction reference, enabling high-precision absolute positioning even in long-distance and complex environments;

[0043] 3. Strong versatility: This method is not only applicable to Aruco codes, but can also be extended to all two-dimensional codes with limited unique IDs, and is also applicable to any graphic board that can achieve high-precision visual positioning;

[0044] 4. Simple structure and easy to implement: Based on the existing two-dimensional code and image processing technologies, the solution of the present invention can be realized at low cost on the existing hardware platform and is applicable to various industrial and intelligent equipment positioning systems.

[0045] In summary, the present invention has obvious innovation and practicality in expanding the coding range of two-dimensional codes and achieving high-precision visual positioning. It not only solves the problems of limited coding quantity and insufficient positioning accuracy in the prior art, but also provides a practical solution for the intelligent positioning of equipment such as AGVs, drones, and large mechanical devices.

Claims

1. A two-dimensional code band encoding method for long-distance high-precision visual positioning, characterized in that: The following steps are involved: a) Select a QR code dictionary containing N unique IDs; b) dividing the N unique IDs into two parts, one part including M IDs for constituting an identification code group, and the other part including N-M IDs for constituting a positioning code plate; c) using the identification code group formed by the M IDs, which is composed of K two-dimensional codes, the number of unique coding combinations that can be formed by each group is (M / K)^K; d) arranging the identification code group and the positioning code plate formed by the N-M IDs in each two-dimensional code group according to a predetermined and fixed relative position; e) Using an image acquisition device to obtain an image containing the above-mentioned two-dimensional code group, first identify the identification code group to determine the approximate position of the positioning code plate, and then perform fine correction based on the positioning code plate, thereby achieving high-precision visual positioning of the absolute position of the device.

2. The method according to claim 1, characterized in that When the identification code group is composed of K two-dimensional codes, each two-dimensional code carries a unique ID, and the unique code number formed by the combination is (M / K)^K.

3. The method according to claim 1, characterized in that The positioning code plate adopts any graphic plate capable of realizing high-precision visual positioning. The graphic plate adopts the same design in each two-dimensional code group and has a fixed relative position relationship with the identification code group.

4. The method according to claim 1, characterized in that The identification process of the two-dimensional code group includes: a) capturing an image containing a QR code group by a camera device; b) using image processing algorithms to identify and decode the identification code group and determine the position of the positioning code plate in the two-dimensional code group; c) Perform fine correction based on the fixed geometric features of the positioning code plate to calculate the absolute position of the device.

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