An irregular plot internal boundary planning method

Abstract

The application discloses an irregular plot internal boundary planning method and relates to the technical field of agricultural machinery, which comprises the following steps: adopting a shrink edge algorithm to shrink the plot boundary to obtain an internal boundary; judging whether impossible points exist on the internal boundary; if yes, removing the impossible points and adding boundary points to make the internal boundary closed to obtain a final internal boundary in sequence; otherwise, the internal boundary is the final internal boundary. The application finds out impossible points from the shrunk internal boundary, adds a boundary point Q to obtain a closed internal boundary, solves the self-intersection problem in the existing internal boundary calculation method, and realizes the planning of the internal boundary of the irregular plot.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery technology, specifically, a method for planning the internal boundaries of irregular plots of land. Background Technology

[0002] With the development of agricultural machinery automation, especially unmanned automated agricultural machinery, the entire process from field roads to entering and exiting the field is unmanned. The work area may be regular or irregular, and path planning needs to consider not only the plot boundaries but also the internal boundaries of the plots. Therefore, it is necessary to shrink the plot boundaries to the internal boundaries to accommodate the work path planning. However, the existing technology uses Bertrand curves from plane differential geometry to calculate plot boundary shrinkage, such as... Figure 1 As shown, Figure 1 (a) is the normal situation, but Figure 1 In the case of (b) shrinking the boundary, the boundary of the internal working area will be self-intersecting, and it will be impossible to form a closed internal boundary of the plot, which will affect the unmanned operation. Summary of the Invention

[0003] The purpose of this invention is to provide a method for planning the internal boundaries of irregular plots, which solves the problem that existing methods for calculating the internal boundaries of plots may result in self-intersections, making it impossible to form closed internal boundaries and affecting autonomous driving operations.

[0004] The present invention solves the above problems through the following technical solution:

[0005] A method for planning the internal boundaries of irregular land parcels, comprising:

[0006] The boundary of the land parcel is shrunk using an edge shrinking algorithm to obtain the inner boundary and the distance 'a' from the inner boundary to the land parcel boundary;

[0007] Determine whether there are impossible points on the internal boundary. If so, remove the impossible points and add boundary points that close the internal boundary, and connect them sequentially to obtain the final internal boundary; otherwise, the internal boundary is the final internal boundary.

[0008] This invention solves the problem of self-intersection in existing internal boundary calculation methods by finding impossible points on the shrunken internal boundary, adding boundary points Q, and using distance metrics to ensure that the index of point Q is added to the internal boundary in an orderly manner, thus obtaining a closed internal boundary. This invention realizes the planning of the internal boundary of irregular plots.

[0009] As a further improvement of the present invention, the method for determining whether there are impossible internal boundary points in the internal boundary is as follows:

[0010] Define any boundary point P on the internal boundary.i Any two boundary points F to the boundary of the plot j F j+1 The line segment F formed j F j+1 The distance d(i,j):

[0011] d(i,j)=dis_point_segment(P i ,F j ,F j+1 );

[0012] Calculate boundary point P i to line segment F j F j+1 The foot of the perpendicular H on the line is P If H P On segment F j F j+1 Above, then the boundary point P i to line segment F j F j+1 The distance d(i,j) = P i H P If H P On segment F j F j+1 On the extension of the boundary line, the boundary point P i to line segment F j F j+1 The distance is P i F j or P i F j+1 The smaller value in the middle, i.e., d(i,j)=min(P) i F j ,P i F j+1 );

[0013] When any line segment F exists j F j+1 If d(i,j) < a, then the boundary point P i P is an impossible point; otherwise, P i These are normal points on the internal boundary.

[0014] As a further improvement of the present invention, the method for adding boundary points to close the internal boundary is as follows:

[0015] Find all newly added boundary points Q on the internal boundary and assign values ​​to the positions of these points, including:

[0016] For the i-th edge of the internal boundary, i.e., line segment P i P i+1 Calculate its relationship with the (i+2)th edge, i.e., line segment P. i+2 Pi+3 The newly added boundary point Q i（i+2） :

[0017] Step A: Calculate line segment P separately. i P i+1 P i+2 P i+3 Given the slopes k1 and k2, if k1 and k2 are not equal, then calculate the slope of line segment P. i P i+1 The line and line segment P i+2 P i+3 The intersection point of the lines is cross_point. The cross_points that satisfy formula (1) are selected, that is, the new boundary points Q between the i-th edge and the (i+2)-th edge. i（i+2） :

[0018] (1)

[0019] in, The intersection point (cross_point) points to the boundary point (P). i ; The intersection point (cross_point) points to the boundary point (P). i+1 ; Represents the dot product of two vectors;

[0020] The intersection point (cross_point) points to the boundary point (P). i+2 The vector, The intersection point (cross_point) points to the boundary point (P). i+3 ; Represents the dot product of two vectors;

[0021] For the newly added boundary point Q between the i-th edge and the (i+2)-th edge i（i+2） Calculate the position assignment according to formula (2):

[0022] (2)

[0023] Step B: Following the method in Step A, find the new boundary point Q between the i-th edge and the (i+3)-th, (i+4)-th, ..., n-th edges. i（i+3） Q i（i+4） Q i（n） and the corresponding position assignment , , ..., , where n is the number of edges of the internal boundary;

[0024] Traverse the edges on the internal boundary, repeat the above steps, find all newly added boundary points Q on the internal boundary and assign values ​​to the positions of the newly added boundary points Q.

[0025] The new boundary points Q are added to the internal boundary sequentially according to the order in which they are assigned values ​​based on their positions.

[0026] As a further improvement to the present invention, formula (2) is replaced with:

[0027] .

[0028] As a further improvement of the present invention, it also includes removing boundary points on the internal boundary that are not inside the plot boundary.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] This invention identifies impossible points and new boundary points Q on the shrunken internal boundary, sorts Q, and inserts them into the internal boundary in sequence to obtain a closed internal boundary. This solves the problem of self-intersection in existing internal boundary calculation methods, realizes the planning of internal boundaries for irregular plots, and is applicable to the intelligent operation of intelligent agricultural machinery and equipment such as unmanned rice transplanters. Attached Figure Description

[0031] Figure 1 The diagram shows the calculation effect of the internal boundary of the land parcel in the prior art, where (a) is a normal shrinkage diagram and (b) is a diagram of the shrinkage with self-intersection.

[0032] Figure 2 This is a schematic diagram illustrating the existence of impossible boundary points and the need to add boundary points within the internal boundary in an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram illustrating the distance from any point on the internal boundary to any two boundary points of the land parcel in an embodiment of the present invention; wherein, (a) is a schematic diagram showing that the perpendicular foot of any point on the internal boundary and the land parcel boundary line segment falls on the line segment; (b) is a schematic diagram showing that the perpendicular foot of any point on the internal boundary and the land parcel boundary line segment falls on the extension line of the line segment.

[0034] Figure 4 This is a schematic diagram illustrating the positional relationship between line segment AB and line segment CD in an embodiment of the present invention, wherein (a) is a schematic diagram showing line segment AB and line segment CD forming an "X" shape; (b) is a schematic diagram showing line segment AB and line segment CD forming a "V" shape; (c) is a schematic diagram showing line segment AB and line segment CD forming a "\ / " shape; (d) is a schematic diagram showing line segment AB and line segment CD forming a "||" shape; and (e) is a schematic diagram showing line segment AB and line segment CD forming a "T" shape.

[0035] Figure 5 This is a schematic diagram illustrating the calculation of the newly added boundary point Q in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram illustrating the sorting of newly added boundary points Q in an embodiment of the present invention;

[0037] Figure 7 This is a diagram showing the effect of shrinking the first plot of land by the distance 'a' from the inner boundary to the plot boundary.

[0038] Figure 8 This is a diagram showing the effect of shrinking the inner boundary of a second plot of land, which has the same shape as the first plot but a larger area, by the distance 'a' from the inner boundary to the plot boundary.

[0039] Figure 9 This is a diagram showing the effect of shrinking the inner boundary of a third plot of land, which has the same shape as the first plot but a larger area than the second plot, by the distance 'a' from the inner boundary to the plot boundary. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0041] This invention provides a method for planning the internal boundaries of irregular land parcels, including:

[0042] An edge shrinking algorithm is used to shrink the boundaries of the land parcel to obtain the inner boundary. The distance from the inner boundary to the land parcel boundary is a fixed value. In this embodiment, the edge shrinking algorithm shrinks all points on the land parcel boundary inward by a distance a.

[0043] When self-intersections occur at internal boundaries, impossible internal boundary points must be removed (referred to as impossible points). Figure 2 As shown, point P j P j+1 P j+2 P j+3 P j+4 These are all impossible internal boundary points. Furthermore, boundary points Q1 and Q2 should be added to close the internal boundaries. For the most common case of self-intersecting internal boundaries, where all impossible points P are inside the plot boundary and the minimum distance from impossible points P to the plot boundary is less than a, the following algorithm is designed in this embodiment to obtain the impossible points P:

[0044] Define any boundary point P on the internal boundary. i Any two boundary points F to the boundary of the plot j F j+1 The line segment F formed j F j+1 The distance d(i,j):

[0045] d(i,j)=dis_point_segment(P i ,F j ,F j+1 );

[0046] dis_point_segment() is used to calculate boundary point P. i to line segment F j F j+1 The function of distance, and the underlying idea is as follows:

[0047] Calculate boundary point P i On segment F j F j+1 or line segment F j F j+1 The foot of the perpendicular H on the line is P If H P On segment F j F j+1 Between, then point P i to line segment F j F j+1 The distance d(i,j) = P i H P If H P On segment F j F j+1 On the extension of the boundary line, the boundary point P i to line segment F j F j+1 The distance is P i F j or P i F j+1 The smaller value in the middle, i.e., d(i,j)=min(P) i F j ,P i F j+1 ).

[0048] When there exists any line segment F j F j+1 If d(i,j) < a, then the boundary point P i P is an impossible point; otherwise, P i These are normal points on the internal boundary.

[0049] like Figure 3 As shown in (a), the perpendicular distance from boundary point P2 to line segment AB is d, and the foot of the perpendicular falls on line segment AB (including the case where the foot of the perpendicular coincides with point A or point B). Therefore, the distance from boundary point P2 to line segment AB is d. Figure 3 As shown in (b), the foot of the perpendicular from boundary point P1 to line segment AB falls on the extension of line segment AB. Therefore, the distance from boundary point P2 to line segment AB is the smaller value P1B between P1A and P1B.

[0050] For example, the inner boundary InnerEdge contains n boundary points P, and any boundary point P can be selected. i Calculate P i Let d(i,j), j=1,2,...,n, be the distance to any one of the n edges of the FieldEdge. If any one of d(i,1), d(i,2),..., d(i,n) is less than a, then the boundary point P... i If P is an impossible point, then P is not. i Let i be the normal points of the internal boundary. By iterating from 1 to n, we can obtain the internal boundary points P1, P2, ..., Pn. n Determining whether a point is within the normal range. This determination process needs to be run n × n = n times. 2 The dis_point_segment function.

[0051] Furthermore, the method for adding boundary points that close the internal boundary is as follows:

[0052] Set boundary point Q, [Q] = Q_Cross_Cal(InnerEdge); [Q] represents the set of points Q, and Q_Cross_Cal() is the function to calculate points Q.

[0053] like Figure 5 As shown, the segments_cross function is used to calculate the cross_point of the intersection of line segments AB and CD, where A, B, C, and D are boundary points on the inner boundary.

[0054] If AB∩CD has at most one point, then there are five possible cases:

[0055] (1) such as Figure 4 As shown in (a), AB and CD form an "X" shape;

[0056] (2) For example Figure 4 As shown in (b), B and C are at the same point, and AB and CD form a "v" shape;

[0057] (3) such as Figure 4 As shown in (c), AB and CD form a " / " shape;

[0058] (4) such as Figure 4 As shown in (d), AB and CD form a "||" shape;

[0059] (5) such as Figure 4 As shown in (e), AB and CD form a "T" shape;

[0060] Calculate the slopes k1 and k2 of AB and CD:

[0061] If k1=k2, then it is in the shape of "||" with no boundary point Q; that is, the situation in (4) above is not within the scope of this invention.

[0062] If k1 and k2 are not equal, then the above situations (1), (2), (3), and (5) may occur. This invention uses the following constraints to filter out the desired situation (1). Specifically:

[0063] Calculate the intersection point of AB and CD, the crosspoint of the "X" shape, satisfying formula (1). The crosspoint is Q:

[0064] (1)

[0065] in, This represents the vector pointing from point cross_point to point A; This represents the vector pointing from point cross_point to point B; This represents the dot product of the two vectors mentioned above;

[0066] This represents the vector pointing from point cross_point to point C. This represents the vector pointing from point cross_point to point D; This represents the dot product of the two vectors mentioned above;

[0067] Following the method described above, for the inner boundary InnerEdge, for the i-th edge P i P i+1 Calculate the Q values ​​of the inner boundary InnerEdge with the (i+2), (i+3), ..., (n)th edges (a total of ni-1 calculations), where i iterates from 1 to n, performing the segments_cross function (n-3) + (n-3) + (n-4) + (n-5) + ... + 2 + 1 = n * (n-3) / 2 times. This will find all the Q values ​​of the inner boundary InnerEdge.

[0068] For each calculated Q, the position is assigned using formula (2) or (3):

[0069] (2)

[0070] (3)

[0071] The position of Q is obtained and assigned as a distance metric for Q.

[0072] like Figure 5As shown, A,A+1 intersects A+2,A+3 at point Q1, and point Q1 is assigned a position value of 2.2, denoted as Q1(2.2). A,A+1 intersects A+5,A+6 at point Q2, and point Q2 is assigned a position value of 5.8, denoted as Q2(5.8). A+3,A+4 intersects A+5,A+6 at point Q3, and point Q3 is assigned a position value of 5.1 (placed before point Q2), denoted as Q3(5.1). The position values ​​are assigned accordingly. Sort by size and add Q1~Q3 to the inner boundary InnerEdge, as follows: Figure 6 As shown, the distance metric of point Q1 is 2.2, so it is added between A2 and A3. The distance metric of Q2 is 5.8 and that of Q3 is 5.1. So, we sort them according to A+5, Q3, Q2, and A+6 to obtain the final internal boundary, which is a closed and feasible internal boundary.

[0073] In this embodiment of the invention, the segments_cross function is executed n*(n-3) / 2 times. Let m be the number of newly added boundary points Q. The dis_point_segment function is executed (n+m)*n times. The total number of function calls is n*(n-3) / 2+(n+m)*n≈1.5*n. 2 .

[0074] This invention verifies the use of the same internal boundary to the boundary of plots of land with different sizes, employing a shrinkage test to measure the same distance 'a' between the internal boundary and the plot boundary.

[0075] Verification as Figure 7 As shown, Figure 7 The plot size factor (scale) is 0.05, resulting in:

[0076] num_Q=2 # num_Q represents the number of new boundary points, indicating that there are 2 new boundary points Q.

[0077] num_bad_P=5 # num_bad_P is the number of impossible points, indicating that there are 5 impossible points P.

[0078] Figure 7 In the diagram, the outer closed blue curve represents the plot boundary, and the closed green curve represents the final internal boundary. The blue dots on the blue curve inside the plot boundary represent impossible points P.

[0079] Verification 2 Figure 8 As shown, Figure 8 With a plot size factor (scale) of 0.1, we get:

[0080] num_Q=1 # Indicates that there is one new boundary point Q;

[0081] num_bad_P=2 # This means there are 2 impossible points P.

[0082] Figure 8 In the diagram, the closed blue curve represents the plot boundary, and the closed green curve represents the final internal boundary. The blue points inside the plot boundary represent impossible points P.

[0083] Verification of Three Figure 9 As shown, Figure 9 The plot size factor (scale) is 0.15, resulting in:

[0084] num_Q=0 # This indicates that there are 0 new boundary points Q.

[0085] num_bad_P=0 # This means there are 0 impossible points P.

[0086] Figure 9 In the diagram, the closed blue curve represents the plot boundary, and the closed green curve represents the final internal boundary. Figure 9 There is no point P that is impossible.

[0087] It can be seen that for plots of the same shape, the larger the plot, the fewer impossible P-values ​​will appear during edge shrinking.

[0088] Although the present invention has been described herein with reference to illustrative embodiments, the above embodiments are merely preferred embodiments of the present invention, and the implementation of the present invention is not limited to the above embodiments. It should be understood that those skilled in the art can devise many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A method for planning the internal boundaries of irregular land parcels, characterized in that, include: The boundary of the land parcel is shrunk using an edge shrinking algorithm to obtain the inner boundary and the distance 'a' from the inner boundary to the land parcel boundary; Determine whether there are impossible points on the internal boundary. If so, remove the impossible points and add boundary points that close the internal boundary, and connect them sequentially to obtain the final internal boundary; otherwise, the internal boundary is the final internal boundary.

2. The method for planning the internal boundaries of an irregular plot of land according to claim 1, characterized in that, The method for determining whether there are impossible internal boundary points is as follows: Define any boundary point P on the internal boundary. i Any two boundary points F to the boundary of the plot j F j+1 The line segment F formed j F j+1 The distance d(i,j): d(i,j)=dis_point_segment(P i ,F j ,F j+1 ); Calculate boundary point P i to line segment F j F j+1 The foot of the perpendicular H on the line is P If H P On segment F j F j+1 Above, then the boundary point P i to line segment F j F j+1 The distance d(i,j) = P i H P If H P On segment F j F j+1 On the extension of the boundary line, the boundary point P i to line segment F j F j+1 The distance is P i F j or P i F j+1 The smaller value in the middle, i.e., d(i,j)=min(P) i F j ,P i F j+1 ); When any line segment F exists j F j+1 If d(i,j)<a, then the boundary point P i P is an impossible point; otherwise, P i These are normal points on the internal boundary.

3. The method for planning the internal boundaries of an irregular plot of land according to claim 1, characterized in that, The method for adding boundary points to close the internal boundary is as follows: Find all newly added boundary points Q on the internal boundary and assign values ​​to the positions of these points; The new boundary points Q are added to the internal boundary sequentially according to the order in which they are assigned values ​​based on their positions.

4. The method for planning the internal boundaries of an irregular plot of land according to claim 3, characterized in that, The method for finding all newly added boundary points Q of the internal boundary and assigning the positions of the newly added boundary points Q is as follows: For the i-th edge of the internal boundary, i.e., line segment P i P i+1 Calculate its relationship with the (i+2)th edge, i.e., line segment P. i+2 P i+3 The newly added boundary point Q i（i+2） : Step A: Calculate line segment P separately. i P i+1 P i+2 P i+3 Given the slopes k1 and k2, if k1 and k2 are not equal, then calculate the slope of line segment P. i P i+1 The line and line segment P i+2 P i+3 The intersection point of the lines is cross_point. The cross_points that satisfy formula (1) are selected, that is, the new boundary points Q between the i-th edge and the (i+2)-th edge. i（i+2） : （1）； in, The intersection point (cross_point) points to the boundary point (P). i ; The intersection point (cross_point) points to the boundary point (P). i+1 ; Represents the dot product of two vectors; The intersection point (cross_point) points to the boundary point (P). i+2 The vector, The intersection point (cross_point) points to the boundary point (P). i+3 ; Represents the dot product of two vectors; For the newly added boundary point Q between the i-th edge and the (i+2)-th edge i（i+2） Calculate the position assignment according to formula (2): （2）； Step B: Following the method in Step A, find the new boundary point Q between the i-th edge and the (i+3)-th, (i+4)-th, ..., n-th edges. i（i+3） Q i（i+4） Q i（n） and the corresponding position assignment , , ..., , where n is the number of edges of the internal boundary; Repeat the above steps to traverse the edges on the internal boundary, find all newly added boundary points Q on the internal boundary and assign values ​​to the positions of the newly added boundary points Q.

5. The method for planning the internal boundaries of an irregular plot of land according to claim 4, characterized in that, The formula (2) is replaced by .

6. The method for planning the internal boundaries of an irregular plot of land according to claim 1, characterized in that, This also includes removing boundary points on the internal boundary that are not inside the plot boundary.

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