A parcel posture recognition method based on a non-parametric passive label group structure

Abstract

The present application relates to a kind of parcel posture identification method based on non-parametric passive label group structure, comprising the following steps: S1: each parcel adopts three groups of component orthogonal structure label group to parcel and does pretreatment;S2: according to warehouse shelf, antenna and guide rail are arranged, the transverse movement trajectory and longitudinal movement trajectory of antenna are determined, and several reference label arrays are arranged in the region to be detected;S3: the corresponding phase sequence of each reference label and parcel label on the whole antenna scanning trajectory sampling point is obtained;S4: according to the phase sequence of reference label and parcel label on scanning trajectory, using the method based on AOA angle of arrival is handled;S5: based on the spatial information of reference label, two relative coordinate systems under the transverse movement trajectory and longitudinal movement trajectory of antenna are coupled into the absolute coordinate system under the positioning area respectively;S6: the absolute positioning coordinate of parcel label in the absolute coordinate system of the region to be detected is solved;S7: parcel posture identification is carried out.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency identification positioning and intelligent logistics passive sensing technology, and relates to a passive package attitude recognition method based on ultra-high frequency radio frequency identification and synthetic aperture scanning, and utilizing a non-parametric tag group structure and reference tag array.

[0002] This invention can be used in logistics warehousing, parcel sorting, shelf inventory, parcel orientation correction, parcel stacking status judgment, and other application scenarios that require obtaining target posture information through passive tags. Background Technology

[0003] In logistics warehousing and parcel sorting, the spatial location, orientation, and stacking status of parcels directly impact cargo safety, sorting efficiency, and warehouse management quality. In recent years, parcel posture recognition has increasingly been recognized as a three-dimensional state perception problem in intelligent logistics systems. Its goal is not only to determine whether a parcel is inverted, tilted, or otherwise abnormally oriented, but also to estimate the parcel's bottom orientation, spatial rotation angle, 3D bounding box, and stacking relationship with other parcels. In single-parcel scenarios, posture recognition focuses on the relative relationship between the parcel's coordinate system and the warehouse coordinate system to determine if the parcel is placed in the prescribed orientation. In multi-parcel scenarios, it further focuses on the vertical, front-back, and horizontal positional relationships between parcels, as well as whether there are misalignments, obstructions, misalignments, or abnormal stacking. This posture and stacking information is a crucial foundation for achieving 3D parcel reconstruction, warehouse status monitoring, robotic sorting, and automated loading decisions.

[0004] Radio frequency identification (RFID) technology features low tag cost, no battery required, easy mass deployment, and non-line-of-sight reading capabilities, making it suitable for target identification and positioning in warehousing scenarios. By forming a synthetic aperture through a moving reader antenna, spatial information about the tag's trajectory relative to the antenna can be obtained by utilizing phase and angle-of-arrival changes in the tag's returned signal, thereby achieving target attitude recognition.

[0005] However, existing parcel posture recognition methods based on tag arrays or tag groups typically suffer from the following shortcomings: First, the geometric layout of the tag group needs to be customized according to the parcel size, shape, or target scale, making it difficult to apply to parcels with large size differences and resulting in high deployment costs. Second, the coupling of tag features in different scanning dimensions often heavily relies on internal geometric information such as the precise spacing between tag groups. This rigid constraint leads to extremely low system fault tolerance, and in practical logistics applications (such as spatial deviations introduced by rapid manual labeling, or physical deformations caused by stacking and squeezing of cardboard boxes and soft-packed goods), parcel posture recognition is easily misjudged due to damage to the internal geometric structure. Third, when reading the phase data of the tags, the reader antenna needs to know the precise position of each reader antenna scanning trajectory relative to the global coordinate system, resulting in complex system calibration, low flexibility, and unfavorable conditions for distributed collaborative processing. Therefore, a new method for package posture recognition needs to be proposed so that the tag group structure does not need to be customized according to the package size, the positioning algorithm does not depend on the pre-calibrated position of each scanning trajectory in the global coordinate system, and the package posture recognition can be completed quickly and stably after obtaining the three-dimensional positioning results of the tag. Summary of the Invention

[0006] The purpose of this invention is to propose a package posture recognition method based on a non-parametric tag group structure. This method first sets a non-parametric tag group structure on the package surface, eliminating the need for customized design based on package size, dimensions, or actual distances between tags, greatly simplifying the tag layout process and placing the package within the detection area. Second, a reference tag array is set within the detection area. Utilizing the external information provided by the reference tag array, the constraint of requiring internal information for feature vector coupling is removed, and multi-local coordinate system coupling positioning is performed based on the reference tag array. Finally, based on the 3D positioning results of the target tag, a joint discrimination of absolute and relative positioning is used to achieve robustness to the z-coordinate with large errors, and fast package posture recognition is achieved by querying an enumeration table.

[0007] A package pose recognition method based on a non-parametric passive tag group structure includes the following steps: S1: Pre-process the package: Each package uses three sets of orthogonal tag groups, each positioned at a corner of the package. With the package in its normal orientation, each orthogonal tag group contains three orthogonal tags positioned at a corner: the first set is located at the top left corner of the front surface; the second set at the bottom right corner; and the third set at the bottom left corner of the rear surface. The tag group at the top left corner of the front surface is abstracted as... Abstract the lower right corner label group on the front surface of the package as... Abstract the lower left corner label group on the back surface of the package as... .

[0008] S2: Based on the storage rack, arrange the antenna and guide rail, determine the lateral and longitudinal movement trajectories of the antenna, and arrange several reference tag arrays in the area to be detected; S3: Determine the starting point of the antenna movement, use the antenna to extract the tag phase sequence of the package in the area to be detected, move the antenna on the guide rail at equal intervals in the horizontal and vertical directions and collect the phase data of the reference tag and the package tag at each sampling point. The spacing between adjacent sampling points is the same, and obtain the phase sequence of each reference tag and the package tag on the sampling points of the entire antenna scanning trajectory. The package tag of the package in the area to be detected includes the phase sequence collected on the scanning trajectory at the three package corners respectively. S4: Based on the phase sequence of the reference tag and the package tag on the scanning trajectory, process them using the AOA-based angle of arrival method; obtain the vertical distance of the reference tag and the package tag from the current antenna trajectory. Horizontal distance from the starting point of the antenna's motion To obtain the spatial distance information of the reference tag relative to the antenna's motion trajectory. , ); S5: Based on the spatial information of the reference tag, the antenna is coupled to the absolute coordinate system of the positioning area along its horizontal and vertical motion trajectories, using the following method: Three coordinate systems are defined: Relative coordinate system under the antenna's lateral motion trajectory Let its starting point of motion be the origin, denoted as ; Relative coordinate system of antenna along its trajectory in depth Taking its starting point as the origin, denoted as ; The absolute coordinate system of the area to be detected Using the index value in the reference tag array The reference label is the origin, denoted as Define two relative coordinate systems for the antenna's lateral and longitudinal motion trajectories, respectively. Direction: All directions are based on the lateral movement direction of the antenna. Direction, the direction of movement in depth is Direction, vertically upward. direction; Define the relative coordinate system Coupled to absolute coordinate system The required lateral movement distance is The depth of movement is The vertical movement distance is ; Relative coordinate system Coupled to absolute coordinate system The required lateral movement distance is The depth of movement is The vertical movement distance is ; Solve by using relative coordinate systems respectively and relative coordinate system Coupled to absolute coordinate system The required lateral movement distance ( , ), ( , ); S6: Solving the absolute positioning coordinates of the package label in the absolute coordinate system of the area to be detected: Based on... and Find the absolute positioning of the package label Coordinates; then according to ( , ), ( , ), The optimization function is used to solve for the absolute positioning of the package label. coordinate: S7: For the package to be located, set... The absolute positioning coordinates are ; The absolute positioning coordinates are ; The absolute positioning coordinates are ; 3D positioning results based on package tags The method for package pose recognition is as follows: S71: Relative positioning discrimination is used to determine if a package is upside down; S711: Differentiate between top and bottom labels on packages; use clustering methods to... Divided into two groups: and After clustering, the absolute coordinates of the three package labels are as follows: ( , , ),( , , ),( , , ); Compare and Size, and sort the corresponding items in ascending order of size. and This yields two possible results: when When, the sorting result is , The bottom label of the package is the vertical axis. The label is on the front of the package, and the other two package labels are located on the top surface of the package; when When, the sorting result is The top label of the package is the vertical axis. The first label is located on the bottom of the package; the other two labels are located on the bottom of the package. S712: Determine if the package is upside down as follows; 1) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package will not be turned upside down; 2) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 3) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 4) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 5) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 6) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; S72: Absolute positioning discrimination is used to determine the planar rotational attitude of the package in the absolute coordinate system and obtain the package rotation angle. ; S8: Based on the package's inverted and rotated postures obtained in S71 and S72, perform posture correction on the package, including package rotation posture correction and package inverted posture correction.

[0009] Furthermore, the method for step S2 is as follows: S21: The reference tag array is composed of OK Total The array consists of a regular arrangement of UHF passive RFID tags, where each passive RFID tag has a unique row and column two-dimensional index denoted as . ,satisfy , ; S22: Geometrically, the reference tag array has a fixed, equidistant spacing between the tag centers in the lateral dimension. The vertical spacing between the center points of the labels is a fixed, equidistant distance. .

[0010] Furthermore, the method for obtaining the phase sequence on the scanning trajectory of the package tag located in the area to be detected, which includes the three package corners respectively, is as follows: For each group of orthogonal tags at the package corner, the tag whose phase can be acquired by the antenna at the sampling point is called a high-quality tag. High-quality tags at the same package corner are considered to belong to the same position in space. Then, the phase of the high-quality tags at the package corner is weighted and averaged to obtain the phase sequence on the scanning trajectory for that package corner.

[0011] Furthermore, the solution involves resolving the relative coordinate systems separately. and relative coordinate system Coupled to absolute coordinate system The required lateral movement distance ( , ), ( , The method is as follows: S51: Solve : For the reference label array, the index value is The horizontal distance of the tag from the starting point of the antenna movement along its lateral trajectory; S52: Solve : For the reference label array, the index value is The horizontal distance of the tag from the starting point of the antenna movement in the longitudinal motion trajectory; S53: Solving based on reference tag array , For index value The reference label, whose vertical distance relative to the lateral movement trajectory is... Its relative lateral trajectory The vertical distance in the plane is ; and the location of the reference label in the lateral movement trajectory The distance between the projection point on the plane and the foot of the perpendicular from its horizontal trajectory is... ; Establish and solve , The optimization function for the optimal value problem is: that is, finding the solution that satisfies the condition that... smallest , value: ,and ; S54: Solving based on reference tag array , For index value The reference label, whose vertical distance relative to the depth motion trajectory is Its trajectory relative to depth Vertical distance in a plane The reference label is located in the depth of the movement trajectory. The distance between the projection point on the plane and the foot of the perpendicular from its trajectory in the depth is... ; Establish and solve , The optimization function for the optimal value problem is: that is, finding the solution that satisfies the condition that... smallest , value: ,and .

[0012] Furthermore, the vertical distance of the package label from the lateral movement trajectory is defined as... The horizontal distance from the starting point of the antenna movement is The vertical distance between the package label and the trajectory of its movement is... The horizontal distance from the starting point of the antenna movement is The method for solving the absolute positioning coordinates of the package label in the absolute coordinate system of the area to be detected is as follows: S61: Solve ,according to Couple the horizontal spatial information of the package label in the relative coordinate system to the absolute coordinate system: the horizontal distance of the horizontal movement trajectory of the package label. minus This allows us to obtain the absolute coordinates of the package label in the absolute coordinate system: ; S62: Solve ,according to Couple the horizontal spatial information of the package label along its depth in the relative coordinate system to the absolute coordinate system: the horizontal distance of the package label's movement trajectory along its depth. minus This allows us to obtain the package label in the absolute coordinate system. Absolute coordinates: ; S63: Solve According to S5 ( , , , S61 and S62 The optimization functions are solved for the horizontal and vertical movement trajectories respectively, and the solution for the package label in the absolute coordinate system is obtained. Value; Thus, the absolute positioning coordinates of the package have been determined: .

[0013] 10. The package posture recognition method based on a non-parametric passive tag group structure according to claim 5, characterized in that, in step S63, the solution is... The method is as follows: S631: Optimize the function based on the geometric relationship of the package label on the horizontal movement trajectory: the vertical distance of the package label relative to the horizontal movement trajectory. The location of the package label relative to its lateral movement trajectory The vertical distance in the plane is The location of the package label in its lateral movement trajectory The distance between the projection point of the plane and the foot of its perpendicular to the transverse trajectory. ); S632: Based on the geometric relationship of the package tag on the longitudinal movement trajectory, optimize the function. The vertical distance of the package tag relative to the longitudinal movement trajectory is... The location of the package label's movement relative to the depth of the package. The vertical distance in the plane is The location of the package tag's movement trajectory in the depth The distance between the projection point on the plane and the foot of the perpendicular on its trajectory in the depth is ; S633: Establish and solve the parcel label in the absolute coordinate system Optimization function for the value problem: and ; Furthermore, in S72, the package rotation angle is obtained. The method is as follows: rotate the package by the following angle. Defined as the angle of rotation within the XY plane, while the Z coordinate remains unchanged; the rotation angle is then calculated using the following formula. ,in Indicates along Starting from the positive direction of the axis, rotate counterclockwise to the origin and then to the next point. The angle that the rays sweep across.

[0014] Furthermore, in S8, the method for correcting the package rotation posture is as follows: 1) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 2) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 3) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 4) At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 5) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 6) At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 7) When At this time, it is necessary to rotate the package counterclockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 8) When At this time, it is necessary to rotate the package counterclockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged.

[0015] Furthermore, in S8, the method for correcting the inverted posture of the package is as follows: 1) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; further in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; 2) When the clustering ranking result is and At this time, the package is in good posture and requires no correction; 3) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; 4) When the clustering ranking result is and At that time, the package needs to be placed in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; further in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; 5) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; 6) When the clustering ranking result is and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; further work is needed. Rotate clockwise in the plane ,at the same time The coordinates remain unchanged. Attached Figure Description

[0016] Figure 1 Schematic diagram of a passive wrapping 3D pose recognition system.

[0017] Figure 2 : Schematic diagram of nonparametric label group structure.

[0018] Figure 3 : Refer to the label array diagram.

[0019] Figure 4 A diagram based on AOA positioning.

[0020] Figure 5: Lateral trajectory coupling model.

[0021] Figure 6 : In-depth trajectory coupling model.

[0022] Figure 7 Package label location model.

[0023] Figure 8 Orientation correction flowchart. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings. The following embodiments are used to illustrate the technical solution of the present invention.

[0025] System composition: The system described in this invention is as follows Figure 1 As shown, it mainly consists of four core parts: the main structure unit of the package tag, the reference tag unit, the reader antenna, and the moving guide rail.

[0026] Step 1. The detailed method of S1 is as follows: Its purpose is to construct a non-parametric tag group structure for the package: arrange the package tags according to a pyramid structure, such as... Figure 2 As shown, the labels are affixed to the package, with each corner label arranged in an orthogonal structure. The three orthogonal labels at each corner are then abstracted into a single label, corresponding to... Figure 2 In Specific examples are as follows: Figure 2 As shown: The long shaded area in the figure is the package label. The label at each corner is orthogonally attached to the package. The three corners of the package with attached labels form a pyramidal topology. The basic orientation of the package is defined as facing the vertical plane where the antenna's lateral movement trajectory is located.

[0027] Step 2. The detailed method of S2 is as follows: Its purpose is to arrange a reference tag array in the area to be detected: such as Figure 3 The reference tag array shown is deployed in a planar manner in the area to be located. The reference tag array consists of... OK Total The array consists of a regular arrangement of UHF passive RFID tags, where each passive RFID tag has a unique row and column two-dimensional index denoted as . ,satisfy , In terms of geometric dimensions, the reference label array has a fixed, equidistant spacing between the center points of the labels in the lateral dimension. The vertical spacing between the center points of the labels is a fixed, equidistant distance. Using the index of the bottom left corner of the array as... The reference label is the origin, and any index is... The relative known physical space coordinates of the reference label with respect to the origin of the reference point can be quantitatively expressed as follows: All tags in the entire array use antenna tags in the same frequency band to ensure spatial consistency in their reflection phase characteristics.

[0028] This concludes the preprocessing steps for the package and the area to be detected. Next, the package and reference tag array can be placed in the area to be detected, and the antenna can be used to locate and identify the package's orientation. The specific implementation method is as follows: Step 3. The detailed method of S3 is as follows: Its purpose is to arrange the antenna sampling direction and collect the phase of each tag acquired by the antenna at each sampling point. The antenna is arranged in scanning dimensions 1 and 2, which in the actual scenario are the x and y orthogonal directions, to scan the packaged tags and the reference tag array, reading the phase data of each tag at each sampling point. The antenna should be scanned every [time period] during the scanning process. Perform a tag phase sampling. The sampling interval is limited by the antenna's transmission wavelength. , With wavelength The constraints between them have been detailed in the existing AOA (Angle of Arrival) method, and the AOA angle of arrival model is as follows: Figure 4 As shown. At this point, we have obtained the phase sequence corresponding to each tag across all sampling points of the scanning trajectory.

[0029] Step 4. The detailed method for S4 is as follows: The ultimate goal is to obtain the spatial information of the tag on the current motion trajectory. The method sequence is as follows: First, the discontinuous phase sequence of each tag acquired in S4 is unwrapped to obtain two continuous phase sequences, corresponding to the phase sequences under scanning trajectory 1 and scanning trajectory 2, respectively. Then, the spatial information of the tag on the current motion trajectory is calculated using the AOA angle of arrival method, which is a mature existing technology. The phase processing methods for the reference tag array and the wrapping tag are explained by the following sub-steps: 1) Reference Tag Array Processing Method: This involves two steps. First, the discontinuous phase sequences of the reference tag array at each sampling point on both scanning trajectories are unwrapped to make them continuous. The phase information read by the antenna from the tag is... This causes the phase to change at certain sampling points. Nearby Nearby or from the opposite Nearby Nearby abrupt changes. Therefore, phase information needs to be unwrapped. The method is as follows: if the phase difference between adjacent sampling points is... or This indicates a phase jump, requiring adjustments to all subsequent phases. To ensure the tag phase continuity: the previous sampling point With the next sampling point Position difference , need to All subsequent phases Previous sampling point With the next sampling point , need to All subsequent phases Finally, based on the unwrapped phase sequence under each scan trajectory, the spatial information of the reference tag under the current trajectory is obtained using the AOA angle of arrival method: the horizontal distances of the reference tag in scan dimensions 1 and 2 are respectively and the vertical distance are respectively ,like Figure 2 As shown.

[0030] 2) Package label handling method: For labels located at the corners of packages For each set of orthogonal tags at a given location, the tag whose phase can be acquired by the antenna at the sampling point is called a high-quality tag. For tags located at... The method for processing the phase of high-quality tags at the same pyramidal vertex is as follows: High-quality tags located at the same vertex of the pyramidal structure are considered to belong to the same spatial position. Therefore, a weighted average of the phases of the high-quality tags at that vertex is applied to re-obtain the phases of the tags at that pyramidal vertex. The phase sequence is then used to calculate the package label based on the untangling process and AOA angle of arrival method in 1). The horizontal and vertical distances relative to the antenna's trajectory.

[0031] Step 5. The detailed method of S5 is as follows: Its purpose is to couple the relative coordinate system where the antenna's motion trajectory is located to the absolute coordinate system, thereby positioning the package in the absolute coordinate system: Based on the two-dimensional scan results, the reference tag feature vector can be obtained as follows: We need to couple the relative coordinate system to the absolute coordinate system, i.e., wrap the area to be located, based on the feature vector of the reference label array.

[0032] The relative coordinate system along the antenna's lateral trajectory is defined as follows. Taking its starting point as the origin, denoted as Similarly, the relative coordinate system under the antenna's trajectory along the depth path. Taking its starting point as the origin, denoted as The absolute coordinate system of the positioning area Using the index value in the reference tag array The label, i.e., the reference label in the lower left corner, is the origin, denoted as . And define two relative coordinate systems for the antenna's lateral and longitudinal motion trajectories, respectively. Direction: All directions are based on the lateral movement direction of the antenna. Direction, the direction of movement in depth is Direction, vertically upward. direction; To couple the relative coordinate system to the absolute coordinate system, it is necessary to calculate the relative translation distance between the relative and absolute coordinate systems: Define the relative coordinate system Coupled to absolute coordinate system The required lateral movement distance is The depth of movement is The vertical movement distance is ; Relative coordinate system Coupled to absolute coordinate system The required lateral movement distance is The depth of movement is The vertical movement distance is ; The current goal is to solve ( , ), ( , The process is divided into the following sub-steps: 1): Solve .like Figure 5 As shown, For the reference label array, the index value is The horizontal distance of the tag from the starting point of the antenna movement along its lateral trajectory; 2): Solving based on reference label array , .like Figure 5 As shown, for an index value of The reference label, its vertical distance relative to the lateral movement trajectory. for Its relative lateral trajectory Vertical distance in a plane for ; and the location of the reference label in the lateral movement trajectory Projection point of the plane The foot of its perpendicular to the lateral trajectory Distance between for The three elements together form the three sides of a right triangle; simultaneously, the index value is... The square of the vertical distance between the reference labels in the same row and the reference labels relative to the lateral motion trajectory is updated as follows: ; Then, by utilizing the geometric relationships of all reference labels, the Pythagorean theorem is transformed into an optimization function for solution. , Optimal value problem: that is, finding the solution that satisfies the condition that... smallest , value: , and ; 3): Solve .like Figure 6 As shown, For the reference label array, the index value is The horizontal distance of the tag from the starting point of the antenna movement in the longitudinal motion trajectory; 4): Solving based on reference label array , .like Figure 6 As shown, for an index value of The reference label, its vertical distance relative to the depth motion trajectory. for Its trajectory relative to depth Vertical distance in a plane for The reference label is located in the depth of the movement trajectory. Projection point of the plane The foot of its vertical trajectory in the depth of motion The distance between them is The three elements together form the three sides of a right triangle; then, by utilizing the geometric relationships of all reference labels, the Pythagorean theorem is transformed into an optimization function solution. , Optimal value problem: that is, finding the solution that satisfies the condition that... smallest , value:

[0033] ,and ; At this point, the coupling between the coordinate systems has been obtained.

[0034] Step 6. The detailed method of S6 is as follows: Its purpose is to use the coordinate coupling amount in step 5 to position the package label in the absolute coordinate system. Below. According to and Find the absolute positioning of the package label Coordinates; then according to ( , ), ( , ), The absolute positioning region of the package label is solved using an optimization function. Coordinates. Defined as the vertical distance between the package label and its horizontal movement trajectory. Meanwhile, the horizontal distance from the starting point of the antenna movement is Similarly, the vertical distance between the package label and the trajectory of its movement is... Meanwhile, the horizontal distance from the starting point of the antenna movement is The following steps will now be explained.

[0035] 1) Solve :like Figure 7 As shown, based on coordinate coupling... The horizontal distance of the package label relative to the lateral movement trajectory minus This allows us to obtain the absolute coordinates of the package label in the absolute coordinate system: 2) Solve :like Figure 7 As shown, based on coordinate coupling... The horizontal distance of the movement trajectory of the package label in the depth. minus This allows us to obtain the package label in the absolute coordinate system. Absolute coordinates: 3) Solve It is based on ( , , , Solve the optimization functions on the horizontal and vertical movement trajectories respectively, and find the package label in the absolute coordinate system. value; 3.1) Optimize the function based on the geometric relationship of the package label on the horizontal movement trajectory: the vertical distance of the package label relative to the horizontal movement trajectory. for The location of the package label relative to its lateral movement trajectory Vertical distance in a plane for The location of the package label in its lateral movement trajectory Projection point of the plane Rather than the foot of the perpendicular in the lateral movement trajectory Distance between for The three elements together form the three sides of a right triangle, thus transforming the Pythagorean theorem into an optimization function solution. Optimal value problem: that is, finding the solution that satisfies the condition that... smallest value; 3.2) Based on the geometric relationship of the package tag on the longitudinal movement trajectory, optimize the function to determine the vertical distance of the package tag relative to the longitudinal movement trajectory. for The location of the package label's movement relative to the depth of the package. Vertical distance in a plane for The location of the package tag's movement trajectory in the depth Projection point of the plane Rather than the foot of the perpendicular in the trajectory of the depth movement Distance between for The three elements together form the three sides of a right triangle, thus transforming the Pythagorean theorem into an optimization function solution. Optimal value: that is, finding the value that satisfies the condition that... smallest value Therefore, 3.1) and 3.2) are combined into a joint optimization solution. The value problem yields the following formula: and ; The coordinates of the package within the absolute positioning region have now been determined. ; Step 7: Its purpose is to obtain the absolute positioning result based on the package label. The package orientation is determined using absolute and relative positioning. Based on the intrinsic information provided by the non-parametric tag group structure constructed in step 1, it is known that one of the three tags on the package must be located on the top / bottom surface, and the other two tags must be located on the bottom / top surface; the three tags are... The projection onto the plane is a right-angled triangle.

[0036] remember The absolute positioning coordinates are ; The absolute positioning coordinates are ; The absolute positioning coordinates are According to the basic parcel form specified in S11, Located on the top surface, Located on the bottom surface. We divide the package posture judgment and correction method, and the multi-package stacking judgment into the following sub-steps. 1) Determine the inverted status of a single package based on its relative positioning.

[0037] 1.1): Distinguish between the top and bottom labels of the package. In order to obtain... The relative positional relationships need to be determined using clustering methods. Divided into two groups: and .Compare and Size, and sort the corresponding items in ascending order of size. and This yields two possible results: when When, the sorting result is , The bottom label of the package is the vertical axis. The first label is located on the top of the package, while the other two labels are located on the top surface. When, the sorting result is The top label of the package is the vertical axis. The first label is on the package, and the other two labels are located on the bottom of the package.

[0038] 1.2): Based on the results of S711 and the basic orientation of the package specified in S11, the package inversion situation is determined as follows.

[0039] 1.2.1) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package will not be turned upside down; 1.2.2) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 1.2.3) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 1.2.4) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 1.2.5) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 1.2.6) When the result of ascending sort is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; 2): Absolute positioning is used to determine the planar rotational attitude of the package in the absolute coordinate system. Based on the sorting results of the vertical coordinates of the package label in S712, the vertical coordinates are obtained as follows: The labels, with corresponding x and y coordinates as follows: , The vertical coordinate is The labels, with corresponding x and y coordinates as follows: , The vertical coordinate is The labels, with corresponding x and y coordinates as follows: , Package rotation angle The calculations are shown below.

[0040] 2.1) Calculate the package rotation angle Let this be defined as the angle of rotation within the XY plane, while the Z coordinate remains unchanged. The rotation angle can then be calculated using the following formula: ,in Indicates along Starting from the positive direction of the axis, rotate counterclockwise to the origin and then to the next point. The angle that the rays sweep across.

[0041] The package posture has been identified using the method described in step 7. The following section explains how to correct the package posture to the basic package posture in S11.

[0042] Step 8: Correction of Wrapped Inverted and Rotated Postures. This can be divided into two steps: first, correct the wrapped wrapping rotation posture, and then correct the wrapped wrapping inverted posture.

[0043] 1): Package rotation attitude correction. After obtaining the package rotation angle based on the S72 method, the package rotation correction method can be obtained as follows: 1.1) When or To satisfy either condition, the object must be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged.

[0044] 1.2) When or To satisfy either condition, the object must be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged.

[0045] 1.3) When or To satisfy either condition, the object must be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged.

[0046] 1.4) When or If one of these conditions is met, the object must be rotated counterclockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged.

[0047] This concludes the correction of the package's rotational posture.

[0048] 2): Package inverted posture correction. After the package rotation posture is corrected in S81, based on the package inverted status obtained in S71, the package inverted posture correction method is as follows.

[0049] 2.1) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; further in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; 2.2) When the clustering ranking result is and At this time, the package is in good posture and requires no correction; 2.3) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; 2.4) When the clustering ranking result is and At that time, the package needs to be placed in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; further in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; 2.5) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; 2.6) When the clustering ranking result is and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; further work is needed. Rotate clockwise in the plane ,at the same time Coordinates remain unchanged The process of correcting the orientation of the package is now complete.

Claims

1. A method for package pose recognition based on a non-parametric passive tag group structure, comprising the following steps: S1: Pre-process the package: Each package uses three sets of orthogonal tag groups, each positioned at a corner of the package. With the package in its normal orientation, each orthogonal tag group contains three orthogonal tags positioned at a corner: the first set is located at the top left corner of the front surface; the second set at the bottom right corner; and the third set at the bottom left corner of the rear surface. The tag group at the top left corner of the front surface is abstracted as... Abstract the lower right corner label group on the front surface of the package as... Abstract the lower left corner label group on the back surface of the package as... ; S2: Based on the storage rack, arrange the antenna and guide rail, determine the lateral and longitudinal movement trajectories of the antenna, and arrange several reference tag arrays in the area to be detected; S3: Determine the starting point of the antenna movement, use the antenna to extract the tag phase sequence of the package in the area to be detected, move the antenna on the guide rail at equal intervals in the horizontal and vertical directions and collect the phase data of the reference tag and the package tag at each sampling point. The spacing between adjacent sampling points is the same, and obtain the phase sequence of each reference tag and the package tag on the sampling points of the entire antenna scanning trajectory. The package tag of the package in the area to be detected includes the phase sequence collected on the scanning trajectory at the three package corners respectively. S4: Based on the phase sequence of the reference tag and the package tag on the scanning trajectory, the method based on the angle of arrival (AOA) is used to process the data and obtain the vertical distance between the reference tag and the package tag and the antenna trajectory under the current antenna trajectory. Horizontal distance from the starting point of the antenna's motion To obtain the spatial distance information of the reference tag relative to the antenna's motion trajectory. , ); S5: Based on the spatial information of the reference tag, the antenna is coupled to the absolute coordinate system of the positioning area along its horizontal and vertical motion trajectories, using the following method: Three coordinate systems are defined: Relative coordinate system of the antenna along its lateral motion trajectory Taking its starting point as the origin, denoted as ; Relative coordinate system of antenna along its trajectory in depth Taking its starting point as the origin, denoted as ; The absolute coordinate system of the area to be detected Using the index value in the reference tag array The reference label is the origin, denoted as Define two relative coordinate systems for the antenna's lateral and longitudinal motion trajectories, respectively. Direction: All directions are based on the lateral movement direction of the antenna. Direction, the direction of movement in depth is Direction, vertically upward. direction; Define the relative coordinate system Coupled to absolute coordinate system The required lateral movement distance is The depth of movement is The vertical movement distance is ; Relative coordinate system Coupled to absolute coordinate system The required lateral movement distance is The depth of movement is The vertical movement distance is ; Solve by using relative coordinate systems respectively and relative coordinate system Coupled to absolute coordinate system The required lateral movement distance ( , ), ( , ); S6: Solving the absolute positioning coordinates of the package label in the absolute coordinate system of the area to be detected: Based on... and Find the absolute positioning of the package label Coordinates; then according to ( , ), ( , ), The optimization function is used to solve for the absolute positioning of the package label. coordinate: S7: For the package to be located, set... The absolute positioning coordinates are ; The absolute positioning coordinates are ; The absolute positioning coordinates are ; 3D positioning results based on package tags The method for package pose recognition is as follows: S71: Determine package inversion status using relative positioning method: S711: Differentiate between top and bottom labels on packages; use clustering methods to... Divided into two groups: and After clustering, the absolute coordinates of the three package labels are as follows: ( , , ),( , , ),( , , ); Compare and Size, and sort the corresponding items in ascending order of size. and This yields two possible results: when When, the sorting result is , The bottom label of the package is the vertical axis. The label is on the front of the package, and the other two package labels are located on the top surface of the package; when When, the sorting result is The top label of the package is the vertical axis. The first label is located on the bottom of the package; the other two labels are located on the bottom of the package. S712: Determine if the package is upside down as follows; S7121: When the ascending sort result is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package will not be turned upside down; S7122: When the ascending sort result is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; S7123: When the ascending sort result is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; S7124: When the ascending sort result is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; S7125: When the ascending sort result is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; S7126: When the ascending sort result is and At that time, the package had three labels on it. The vertex of the right triangle in the plane projection is The package was turned upside down; S72: Determine the planar rotation attitude of the package in the absolute coordinate system using the absolute positioning discrimination method, and obtain the package rotation angle. .

2. The package posture recognition method based on a non-parametric passive tag group structure according to claim 1, characterized in that, The method for step S2 is as follows: S21: The reference tag array is composed of OK Total The array consists of a regular arrangement of UHF passive RFID tags, where each passive RFID tag has a unique row and column two-dimensional index denoted as . ,satisfy , ; S22: Geometrically, the reference tag array has a fixed, equidistant spacing between the tag centers in the lateral dimension. The vertical spacing between the center points of the labels is a fixed, equidistant distance. .

3. The package posture recognition method based on a non-parametric passive tag group structure according to claim 1, characterized in that, The method for obtaining the phase sequence on the scanning trajectory of the package tag located in the area to be detected, which includes the three package corners respectively, is as follows: For each group of orthogonal tags at the package corner, the tag whose phase can be acquired by the antenna at the sampling point is called a high-quality tag. High-quality tags at the same package corner are considered to belong to the same position in space. Then, the phase of the high-quality tags at the package corner is weighted and averaged to obtain the phase sequence on the scanning trajectory for that package corner.

4. The package posture recognition method based on a non-parametric passive tag group structure according to claim 1, characterized in that, Solve by using relative coordinate systems respectively and relative coordinate system Coupled to absolute coordinate system The required lateral movement distance ( , ), ( , The method is as follows: S51: Solve : For the reference label array, the index value is The horizontal distance of the tag from the starting point of the antenna movement along its lateral trajectory; S52: Solve : For the reference label array, the index value is The horizontal distance of the tag from the starting point of the antenna movement in the longitudinal motion trajectory; S53: Solving based on reference tag array , For index value The reference label, whose vertical distance relative to the lateral movement trajectory is... Its relative lateral movement trajectory The vertical distance in the plane is ; And the location of the reference label in the lateral movement trajectory The distance between the projection point on the plane and the foot of the perpendicular from its horizontal trajectory is... ; Establish and solve , The optimization function for the optimal value problem is: that is, finding the solution that satisfies the condition that... smallest , value: ,and ; S54: Solving based on reference tag array , For index value The reference label, whose vertical distance relative to the depth motion trajectory is Its trajectory relative to depth Vertical distance in a plane ; The reference label is located in the depth movement trajectory. The distance between the projection point on the plane and the foot of the perpendicular from its trajectory in the depth is... ; Establish and solve , The optimization function for the optimal value problem is: that is, finding the solution that satisfies the condition that... smallest , value: ,and .

5. The package posture recognition method based on a non-parametric passive tag group structure according to claim 1, characterized in that, Define the vertical distance of the package label from the horizontal movement trajectory as The horizontal distance from the starting point of the antenna movement is ; The vertical distance between the package tag and the trajectory of the deep movement is The horizontal distance from the starting point of the antenna movement is The method for solving the absolute positioning coordinates of the package label in the absolute coordinate system of the area to be detected is as follows: S61: Solve ,according to Couple the horizontal spatial information of the package label in the relative coordinate system to the absolute coordinate system: the horizontal distance of the horizontal movement trajectory of the package label. minus This allows us to obtain the absolute coordinates of the package label in the absolute coordinate system: ; S62: Solve ,according to Couple the horizontal spatial information of the package label along its depth in the relative coordinate system to the absolute coordinate system: the horizontal distance of the package label's movement trajectory along its depth. minus This allows us to obtain the package label in the absolute coordinate system. Absolute coordinates: ; S63: Solve According to S5 ( , , , S61 and S62 The optimization functions are solved for the horizontal and vertical movement trajectories respectively, and the solution for the package label in the absolute coordinate system is obtained. Value; Thus, the absolute positioning coordinates of the package have been determined: .

6. The package posture recognition method based on a non-parametric passive tag group structure according to claim 5, characterized in that, S63 solution The method is as follows: S631: Optimize the function based on the geometric relationship of the package label on the horizontal movement trajectory: the vertical distance of the package label relative to the horizontal movement trajectory. The location of the package label relative to its lateral movement trajectory The vertical distance in the plane is The location of the package label in its lateral movement trajectory The distance between the projection point of the plane and the foot of its perpendicular to the transverse trajectory. ); S632: Based on the geometric relationship of the package tag on the longitudinal movement trajectory, optimize the function. The vertical distance of the package tag relative to the longitudinal movement trajectory is... The location of the package label's movement relative to the depth of the package. The vertical distance in the plane is The location of the package tag's movement trajectory in the depth The distance between the projection point on the plane and the foot of the perpendicular on its trajectory in the depth is ; S633: Establish and solve the parcel label in the absolute coordinate system Optimization function for the value problem: and .

7. The package posture recognition method based on a non-parametric passive tag group structure according to claim 1, characterized in that, In S72, the package rotation angle is obtained. The method is as follows: rotate the package by the following angle. Defined as the angle of rotation within the XY plane, while the Z coordinate remains unchanged; the rotation angle is then calculated using the following formula. ,in Indicates along Starting from the positive direction of the axis, rotate counterclockwise to the origin and then to the next point. The angle that the rays sweep across.

8. The package posture recognition method based on a non-parametric passive tag group structure according to claim 7, characterized in that, This also includes obtaining the package's inverted and rotated postures, and correcting the package's rotational posture using the following method: 1) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 2) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 3) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 4) At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 5) When At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 6) At this time, it needs to be rotated clockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 7) When At this time, it is necessary to rotate the package counterclockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged; 8) When At this time, it is necessary to rotate the package counterclockwise within the XY plane. Meanwhile, the Z coordinate remains unchanged.

9. The package posture recognition method based on a non-parametric passive tag group structure according to any one of claims 7 or 8, characterized in that, It also includes correcting the package's inverted posture based on the obtained inverted and rotated postures, using the following method: 1) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; further in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; 2) When the clustering ranking result is and At this time, the package is in good posture and requires no correction; 3) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; 4) When the clustering ranking result is and At that time, the package needs to be placed in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; further in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; 5) When the clustering ranking result is , and At that time, the package needs to be placed in Rotate counterclockwise in the plane ,at the same time The coordinates remain unchanged; 6) When the clustering ranking result is and At that time, the package needs to be placed in Rotate clockwise in the plane ,at the same time The coordinates remain unchanged; further work is needed. Rotate clockwise in the plane ,at the same time The coordinates remain unchanged.

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