Multi-constraint log cutting optimization method

Abstract

The invention belongs to the field of cutting optimization algorithms, and particularly relates to a multi-constraint log cutting optimization method. Comprising the following steps of sequentially performing peeling operation and peeling operation on two-dimensional log contour data to obtain a binary image I; in the image coordinate system, respectively extracting a Y coordinate value sequence TS of the upper contour of the binary image I and a Y coordinate value sequence BS of the lower contour of the binary image I from left to right; and a log sleeve cutting optimization model is constructed based on dynamic programming, TS and BS are optimized and solved in combination with various constraint conditions, and an optimal cutting scheme is determined. According to the method, the optimal cutting mode for cutting the log into the battens of different sizes at the same time can be solved, the main material is preferentially generated in the generated battens, and the mode with the minimum cutting frequency of the first channel saw is selected from the cutting modes with the same outturn percentage; the cutting mode with the closest left and right excess material thickness can be selected from the cutting modes with the same outturn percentage and cutting number.

Description

Technical Field

[0001] The invention belongs to the field of cutting optimization algorithms, in particular to a multi-constraint log cutting optimization method. Background Art

[0002] The log cutting equipment currently available on the market simply replaces human physical labor to saw logs into wooden blocks. It lacks calculation and optimization of sawing plans, and its sawing plans need to be designed by a sawyer. However, the end face of a log is not a regular shape. The actual outline of each log is a unique irregular shape. Even an experienced sawyer cannot guarantee to find a cutting plan with the highest yield on an irregular end face. Furthermore, when actual production requires "nesting", that is, cutting out multiple wooden blocks of different sizes from a log at the same time, human planning ability is unable to complete this level of task. In the current reality, sawyers usually cut the left and right sides into slices and the middle area into lumps based on their past experience. This simple design method often causes a certain degree of waste. Summary of the invention

[0003] Based on the above situation and in combination with the actual operation requirements of a log sawing table, the present invention proposes a multi-constraint log cutting optimization method to solve the above technical problems.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0005] A multi-constraint log cutting optimization method comprises the following steps:

[0006] 1) performing peeling and peeling operations on the two-dimensional log contour data in sequence to obtain a binary image I;

[0007] 2) In the image coordinate system, extract the Y coordinate value sequence TS of the upper contour and the Y coordinate value sequence BS of the lower contour of the binary image I from left to right respectively;

[0008] 3) Based on dynamic programming, a log cutting optimization model is constructed, and various constraints are combined to optimize TS and BS to determine the optimal cutting plan.

[0009] The peeling operation is specifically as follows:

[0010] Connect and fill the log contour points in sequence to form a closed area;

[0011] According to the peeling parameter D r Perform an erosion operation on the closed area. The structuring element of the erosion operation is a radius of D. r / δ, where δ is the pixel equivalent of the log end face contour point.

[0012] The peeling operation is specifically as follows:

[0013] In the peeled area image, the image coordinate system X coordinate is less than D xmin +D kl The sum of the points is greater than D xmax -D kr Delete all the points of D xmin Indicates the minimum X coordinate value of the point in the peeled area, D xmax Indicates the maximum value of the X coordinate value of the point in the peeled area, D kl Indicates the left side peeling parameter, D kr Indicates the right side peeling parameters.

[0014] The step 2) is specifically as follows:

[0015] TS(j)=min(Y), when I(X,Y)=1 and X=j

[0016] BS(j)=max(Y), when I(X,Y)=1 and X=j

[0017] Among them, I(X,Y) is the pixel value of the binary image, and j is the index of the column.

[0018] The step 3) comprises the following steps:

[0019] 3.1) Create a value matrix V and a state matrix FLAG respectively. Both matrices are L-row 2n-column matrices, where L is the length of the sequence TS and the sequence BS, and n is the number of categories of the size of the wood blocks to be cut;

[0020] 3.2) Initialize the value matrix V and the state matrix FLAG, set V(0,j) = 0, indicating that the current cut length is 0 and the generated value is 0; FLAG(0,j) = -1, indicating that the current cut position has no corresponding previous cut position;

[0021] 3.3) In the interval from 0 to L for i and from 1 to 2n for j, calculate the value matrix V and the state matrix FLAG, and when i is in the interval (PW 1 / 2, P+W 1 / 2) skips the search of all slices and sets V'=0, W 1 Indicates the width of the main wood, that is, the width of the wood with category number 1;

[0022] 3.4) Backtrack the node with the largest value in the value matrix V to obtain its corresponding cutting plan. If there are multiple nodes with the largest value, screen them according to the number of cuts and select the plan with the least number of cuts. If there are still multiple nodes with the largest value and the least number of cuts, select the plan with a more balanced size of the waste generated on the left and right sides of the log after cutting.

[0023] The step 3.3) is specifically as follows:

[0024] V(i,j) indicates that the cutting is performed at position i, and the cutting method is: when j is an even number,

[0025] V(i,j)=max(V(max(iW j / 2 -SW 1 ,0),:))+V'

[0026] FLAG(i,j)=W j / 2

[0027] Among them, V' represents the value of the new wood blocks produced in this cutting, W j / 2 Indicates the width of the lump produced by the current cutting, SW 1 Indicates the width of the first pass saw;

[0028] When j is an odd number,

[0029] V(i,j)=max(V(max(iH (j-1) / 2 -SW 1 ,0),:))+V'+σ

[0030] FLAG(i,j)=H (j-1) / 2

[0031] Among them, H (j-1) / 2 represents the thickness of the slice produced by the current cut, and σ represents the penalty term.

[0032] The calculation of the value V' of each new block of wood produced by cutting includes the following steps:

[0033] a) If the cut at position i produces a type C k of a lump, then according to category C k Determine its width W k , intercept TS'=TS(iW in TS and BS k -SW 1 :i) and BS'=BS(iW k -SW 1 :i); if the cut is made at position i and the resulting class is C k A piece of, then according to category C k Determine its thickness Hk , intercept TS'=TS(iH in TS and BS k -SW 1 :i) and BS'=BS(iH k -SW 1 :i), TS' and BS' represent the contour of a section of the left side of the current cutting position;

[0034] b) According to the value of TS' and the relevant parameters of the raw material, determine the upper limit of the current available position; according to the value of BS' and the relevant parameters of the raw material, determine the lower limit of the current available position;

[0035] c) Between the upper and lower limits, calculate how many wood blocks can be produced based on the cutting method and the width of the second saw, and calculate the total value V' of the newly produced multiple wood blocks.

[0036] In step b), the method for calculating the upper limit is: sort TS' according to the Y value from small to large, if the length of the TS' array is L, the raw material threshold is T w , then the sorted TS' is located in L*(1-T w ) The Y value of the point at which T That is the value of the upper limit;

[0037] The method for calculating the lower limit is: sort BS' by Y value from large to small. If the length of BS' array is L and the raw material threshold is T w , then the sorted BS' is located in L*(1-T w ) The Y value of the point at which B This is the value of the lower limit.

[0038] The step c) is specifically as follows:

[0039] Calculate the number of wood blocks n produced by different cutting methods and second-pass saw widths:

[0040] When the cutting method is cutting,

[0041] n=((Y B -Y T )+SW 2 ) / H k

[0042] Among them, Y B is the lower limit value, Y T is the upper limit value, SW 2 H is the width of the second pass saw. k is the thickness value of the wood block of category k;

[0043] When the cutting method is slice,

[0044] n=((Y B-Y T )+SW 2 ) / W k

[0045] Among them, Y B is the lower limit value, Y T is the upper limit value, SW 2 is the second pass saw width, W k is the width of the wood block of category k;

[0046] According to wood block category C k And the number of wood blocks generated calculates V':

[0047] V'=n*b k *W k *H k

[0048] Among them, b is the weighting coefficient, between 0 and 1, k is the category number, W k and H k is the width and height of the block.

[0049] The present invention has the following beneficial effects and advantages:

[0050] 1. The present invention designs a multi-constraint log cutting optimization method, which can optimize and solve according to the actual contour data of the log and the size of the required cutting wood, and obtain the cutting method with the highest yield rate. After actual use and testing, the multi-constraint log cutting optimization method designed by the present invention can increase the yield rate by 2%.

[0051] 2. The present invention designs a multi-constraint log cutting optimization method, which can meet multiple constraints in the process of optimization and solution, including peeling and left and right splitting of logs according to the specific conditions of the logs during the cutting process to ensure the quality of the produced wood blocks; it can limit 45% of the log diameter to be on the "lump" to ensure that the logs can be effectively fixed and smoothly sawed after turning over during the sawing process; it can select the method with the least number of first saw cuts in the cutting method with the same yield rate, and it can select the cutting method with the closest left and right residual thickness in the cutting method with the same yield rate and cutting number. The cutting method can be planned according to the set raw material parameters, so that the number of produced wood blocks is more and it is guaranteed to meet the raw material parameter standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Schematic diagram of the log cutting process.

[0053] Figure 2 This is a schematic diagram of the wool material effect.

[0054] Figure 3 Schematic diagram of the original log image and outline.

[0055] Figure 4 This is a schematic diagram of the contour data after peeling.

[0056] Figure 5 This is the effect of splitting the log into two parts.

[0057] FIG6 is a data diagram of the upper and lower profiles TS and BS of a log.

[0058] Figure 7 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0060] The method relates to a multi-constraint log cutting optimization method, which plans the optimal cutting plan under the condition of satisfying multiple constraints according to the actual contour shape of the log end face and the size data of multiple wood blocks that need to be cut.

[0061] The constraints include:

[0062] 1. When cutting logs, waste can only be generated on the far left and far right sides, and waste is not allowed in the middle area;

[0063] 2. During the cutting process of the log, first cut from left to right on the end face, then rotate the log 180 degrees and cut from left to right again. After the rotation, the log needs to be fixed on the saw table by the clamp, and the fixed clamp needs to occupy an area of ​​a certain thickness of the log, which requires that the area of ​​the fixed clamp must be planned as a "lump" in the first saw. In addition, if the position of the fixed clamp is planned as a "slice", the cutting trajectory may deviate from the straight line during the cutting process of the first saw due to insufficient support from the "slice". The timing of log rotation is: if the cutting position of the next knife from the current cutting position exceeds 45% of the diameter of the log, rotate the log at the current position; after the log is rotated, the rightmost piece of wood must be a "lump", that is, the position of 45% of the diameter of the log before rotation must be on the "lump";

[0064] 3. The bark around the end of the log cannot be used and needs to be excluded in the design, which is called "peeling";

[0065] 4. There may be a lot of unusable bark and scars on the left and right sides of the log end, which need to be excluded in the design, that is, "skinning";

[0066] 5. If the wood square produced after log cutting is located at the edge of the log, part of the wood square is allowed to exceed the log outline, that is, the end face of the wood square produced after cutting is not a complete rectangle. However, the position and size of the missing part must meet certain requirements;

[0067] This method needs to consider the following factors when evaluating the value of different cutting schemes:

[0068] 1. When planning a cutting method to produce multiple different-sized wood blocks from a single log at the same time, set priorities for different types of wood blocks according to the production requirements of different wood blocks, and adjust the output of different wood blocks;

[0069] 2. Plan the “sheets” and “lumps” of the material to be produced, adjust the weight of the “sheets” and “lumps” according to the actual production needs, increase the output of lumps, and reduce the workload of the second saw;

[0070] 3. The fewer the number of cuts in the first pass, the better;

[0071] The process of log cutting is as follows:

[0072] like Figure 1 As shown in the figure, log cutting needs to go through two cutting processes: the first saw and the second saw. The first saw first cuts the log along the vertical direction at the end face to form multiple wooden boards; the second saw further divides the wooden boards produced by the first saw to form wooden squares. The end face of the wooden square is rectangular. If the thickness of the wooden board produced by cutting is equal to the length of the long side of the wooden square, this wooden board is called a "lump"; similarly, if the thickness of the wooden board produced by cutting is equal to the length of the short side of the wooden square, this wooden board is called a "piece".

[0073] like Figure 2 As shown, the wood square does not have to be completely contained in the log area. If the wood square produced after log cutting is located at the edge of the log, part of the wood square is allowed to exceed the log outline, that is, the end face of the log produced after cutting may not be a complete rectangle. This kind of wood square is called "raw material". The position and size of the missing part of the raw material need to meet certain conditions: As shown in the figure, the long side of the wood square is set to W, and the short side is set to H, but one of the long sides is missing a part, and the remaining length is W', and the other short side is missing a part, and the remaining length is H', then W' / W>T must be satisfied. w , and H' / H>T h . T w ,T h are the thresholds for the proportion of the remaining parts of the long side and the short side respectively.

[0074] like Figure 7 As shown, the method comprises the following steps:

[0075] 1. The input of this method is the coordinates of the contour points and the pixel equivalent. The effect after drawing the contour coordinates onto the log image is as follows Figure 3 The white contour lines are the log contour coordinate points in the input data. The pixel equivalents of the image and the contour are fixed, that is, the actual physical size represented by each pixel in the image is fixed and known.

[0076] 2. When the log is peeled, the log contour points are first connected and filled in sequence to form a closed area. Then the resulting area is eroded. The structuring element of the erosion operation is a radius of D. r / δ. Where D r is the peeling parameter, which indicates the thickness of the epidermis to be removed, in mm; δ is the pixel equivalent, which indicates the actual physical size corresponding to each pixel, in mm. Figure 4 To give the log a "peeled" effect, the outside white outline around the log is the original log outline, and the slightly smaller inside outline is the peeled log outline.

[0077] 3. When performing the "peeling" operation on the log, first calculate the minimum value D of all points in the region obtained in step 2 in the X direction xmin and the maximum value D xmax Then, all the X coordinate values ​​in the area obtained in step 2 that are less than Dx min -D kl / δ point and X coordinate value is greater than Dx max +D kr / δ point deletion, where D kl The left peeling parameter indicates how many millimeters are removed from the left side of the log in the image, and its unit is mm. kr is the right peeling parameter, which indicates how many millimeters are removed from the right side of the log in the image, and its unit is mm. Figure 5 As shown, the white outline is the area of ​​the log after "peeling".

[0078] 4. From left to right, extract the Y value of the upper half of the binary image obtained in step 3 to form a sequence TS, and extract the Y value of the lower half to form a sequence BS. The following formula is used for extraction:

[0079] TS(j)=min(Y), when I(X,Y)=1 and X=j

[0080] BS(j)=max(Y), when I(X,Y)=1 and X=j

[0081] In this method, the origin of the image coordinate system is located in the upper left corner of the image. The extracted TS visualization effect is as follows Figure 6a BS visualization effect is as follows Figure 6b

[0082] 5. Set the parameters according to the cutting requirements, including: the width W of the wood to be cut 1 ,W 2 ,...,W n , the corresponding wood height H 1 ,H 2 ,...,Hn n is the number of the current wood size categories to be cut. The width of the first saw SW 1 , width SW of the second saw 2 (1) Create a value matrix V and a state matrix FLAG, both of which are L-row 2n-column matrices, where L is the length of the sequence TS and the sequence BS obtained in step 6. i and j are the indexes of the row and column respectively, and the state matrix FLAG represents the previous and next correspondence between each node.

[0083] 6. Initialize V and FLAG, set V(0,j) = 0, indicating that the current cut length is 0 and the generated value is 0; FLAG(0,j) = -1, indicating that the current cutting position has no corresponding previous cutting position.

[0084] 7. Iterate i from 0 to L, j from 1 to 2n, and calculate V and FLAG. The method is: V(i,j) represents the total value of the wood blocks produced after cutting at position i, and the cutting method is: when j is an even number, it means that the current cutting produces a new block with a width of W j / 2, at this time,

[0085] V(i,j)=max(V(max(iW j / 2-SW 1 ,0),:))+V';

[0086] Flag(i,j)=W j / 2

[0087] Among them, V' represents the value of the new wood blocks produced in this cutting.

[0088] When j is an odd number, it means that the current cutting produces a slice with a thickness of H. (j-1) / 2 ,at this time

[0089] V(i,j)=max(V(max(iH (j-1) / 2 -SW1,0),:))+V'+σ

[0090] Flag(i,j)=H(j-1) / 2

[0091] In the above formula, σ is the penalty term for producing a “slice” in this cutting.

[0092] 8. The V' in step 7 is calculated as follows:

[0093] If the cut at position i produces a type C k According to category C k Query its width W k , intercept TS'=TS(iW in TS and BSk -SW 1 :i) and BS'=BS(iW k -SW 1 :i). If the cut is made at position i and the resulting type is C k According to the category C k Determine its thickness H k , intercept TS'=TS(iH in TS and BS k -SW 1 :i) and BS'=BS(iH k -SW 1 :i). TS' and BS' represent the contour of a section of the left side of the current cutting position.

[0094] According to the value of TS' and the relevant parameters of the raw material, the upper limit of the current available position is determined; according to the value of BS' and the relevant parameters of the raw material, the lower limit of the current available position is determined. Between the upper and lower limits, the number of wood blocks that can be produced is calculated according to the distance between the upper and lower limits and the size of the wood block.

[0095] The method for calculating the upper limit based on Ts' is as follows: Taking the current wood block on the pile as an example, sort TS' from small to large according to the Y value. If the length of TS' array is L, the raw material threshold is T w , then the sorted TS' is located in L*(1-T w ) The Y value of the point at the position T The value of the upper limit is the same as that of the slice. The case of determining the lower limit is also similar, so I will not go into details.

[0096] When cutting a lump at the current position, the number of wood blocks that can be cut out of a lump in the second pass of the saw can be calculated as follows:

[0097] n=((Y B -Y T )+SW 2 ) / H k

[0098] Among them, YB is the lower limit value, YT is the upper limit value, SW 2 H is the width of the second saw. k is the thickness value of the wood block of category k;

[0099] The situation of slicing is similar and will not be described in detail.

[0100] Finally, according to the wood block category C k And the number of wood blocks generated is used to calculate V'. The details are as follows:

[0101] V'=n*b k *W k *Hk

[0102] Among them, n represents the number of new wood blocks generated in this step, b is the weighting coefficient, between 0 and 1, k is the category number, W k and H k is the width and height of the block. This formula indicates that the further back a category is in the category table, the lower its value per unit volume.

[0103] 9. In order to ensure that the 45% position of the log diameter must be located on the lump, the following method is used: let the 45% position of the log diameter be point P, then in step 7, when i is located at (PW 1 / 2, P+W 1 / 2) skips the search of all slices and sets V'=0;

[0104] Steps 7-9 can obtain the value matrix and state matrix. Each node in the value matrix represents the total value of the wood obtained after cutting at the current position. By backtracking the node with the largest total value in the value matrix, the cutting plan with the largest total value can be obtained. There is usually more than one cutting plan with the largest total value. After further counting the number of cuts in each plan, the plan with the least number of cuts is selected. There are often still multiple nodes that meet the requirements of both the maximum value and the least number of cuts. In this case, a plan with a relatively balanced size of waste generated on the left and right sides of the log after cutting is selected to facilitate the sawing operation.

Claims

1. A multi-constrained log cutting optimization method, It is characterized in that The following steps are involved: 1) performing peeling and peeling operations on the two-dimensional log contour data in sequence to obtain a binary image I; 2) In the image coordinate system, extract the Y coordinate value sequence TS of the upper contour and the Y coordinate value sequence BS of the lower contour of the binary image I from left to right respectively; 3) Based on dynamic programming, a log cutting optimization model is constructed, and various constraints are combined to optimize TS and BS to determine the optimal cutting plan.

2. A multi-constraint log cutting optimization method according to claim 1, It is characterized in that The peeling operation is specifically as follows: Connect and fill the log contour points in sequence to form a closed area; According to the peeling parameter D r Perform an erosion operation on the closed area. The structuring element of the erosion operation is a radius of D. r / δ, where δ is the pixel equivalent of the log end face contour point.

3. A multi-constraint log cutting optimization method according to claim 1, It is characterized in that The peeling operation is specifically as follows: In the peeled area image, the image coordinate system X coordinate is less than D xmin +D kl The sum of the points is greater than D xmax -D kr Delete all the points of D xmin Indicates the minimum X coordinate value of the point in the peeled area, D xmax Indicates the maximum value of the X coordinate value of the point in the peeled area, D kl Indicates the left side peeling parameter, D kr Indicates the right side peeling parameters.

4. A multi-constraint log cutting optimization method according to claim 1, It is characterized in that The step 2) is specifically as follows: TS(j)=min(Y), when I(X,Y)=1 and X=j BS(j)=max(Y), when I(X,Y)=1 and X=j Among them, I(X,Y) is the pixel value of the binary image, and j is the index of the column.

5. A multi-constraint log cutting optimization method according to claim 1, It is characterized in that The step 3) comprises the following steps: 3.1) Create a value matrix V and a state matrix FLAG respectively. Both matrices are L-row 2n-column matrices, where L is the length of the sequence TS and the sequence BS, and n is the number of categories of the size of the wood blocks to be cut; 3.2) Initialize the value matrix V and the state matrix FLAG, set V(0,j) = 0, indicating that the current cut length is 0 and the generated value is 0; FLAG(0,j) = -1, indicating that the current cut position has no corresponding previous cut position; 3.3) In the interval from 0 to L for i and from 1 to 2n for j, calculate the value matrix V and the state matrix FLAG, and when i is in the interval (PW 1 / 2, P+W 1 / 2) skips the search of all slices and sets V'=0, W 1 Indicates the width of the main wood, that is, the width of the wood with category number 1; 3.4) Backtrack the node with the largest value in the value matrix V to obtain its corresponding cutting plan. If there are multiple nodes with the largest value, screen them according to the number of cuts and select the plan with the least number of cuts. If there are still multiple nodes with the largest value and the least number of cuts, select the plan with a more balanced size of the waste generated on the left and right sides of the log after cutting.

6. A multi-constraint log cutting optimization method according to claim 5, It is characterized in that The step 3.3) is specifically as follows: V(i,j) indicates that the cutting is performed at position i, and the cutting method is: when j is an even number, V(i,j)=max(V(max(i-W j / 2 -SW 1 ,0),:))+V’ FLAG(i,j)=W j / 2 Among them, V' represents the value of the new wood blocks produced in this cutting, W j / 2 Indicates the width of the lump produced by the current cutting, SW 1 Indicates the width of the first pass saw; When j is an odd number, V(i,j)=max(V(max(i-H (j-1) / 2 -SW 1 ,0),:))+V’+σ FLAG(i,j)=H (j-1) / 2 Among them, H (j-1) / 2 represents the thickness of the slice produced by the current cut, and σ represents the penalty term.

7. A multi-constraint log cutting optimization method according to claim 6, It is characterized in that The calculation of the value V' of each new block of wood produced by cutting includes the following steps: a) If the cut at position i produces a type C k of a lump, then according to category C k Determine its width W k , intercept TS'=TS(iW in TS and BS k -SW 1 :i) and BS'=BS(iW k -SW 1 :i); if the cut is made at position i and the resulting class is C k A piece of, then according to category C k Determine its thickness H k , intercept TS'=TS(iH in TS and BS k -SW 1 :i) and BS'=BS(iH k -SW 1 :i), TS' and BS' represent the contour of a section of the left side of the current cutting position; b) According to the value of TS' and the relevant parameters of the raw material, determine the upper limit of the current available position; according to the value of BS' and the relevant parameters of the raw material, determine the lower limit of the current available position; c) Between the upper and lower limits, calculate how many wood blocks can be produced based on the cutting method and the width of the second saw, and calculate the total value V' of the newly produced multiple wood blocks.

8. A multi-constraint log cutting optimization method according to claim 7, It is characterized in that In step b), the method for calculating the upper limit is: sort TS' according to the Y value from small to large, if the length of the TS' array is L, the raw material threshold is T w , then the sorted TS' is located in L*(1-T w ) The Y value of the point at the position T That is the value of the upper limit; The method for calculating the lower limit is: sort BS' by Y value from large to small. If the length of BS' array is L and the raw material threshold is T w , then the sorted BS' is located in L*(1-T w ) The Y value of the point at the position B This is the value of the lower limit.

9. A multi-constraint log cutting optimization method according to claim 7, It is characterized in that The step c) is specifically as follows: Calculate the number of wood blocks n produced by different cutting methods and second-pass saw widths: When the cutting method is cutting, n=((Y B -Y T )+SW 2 ) / H k Among them, Y B is the lower limit value, Y T is the upper limit value, SW 2 H is the width of the second pass saw. k is the thickness value of the wood block of category k; When the cutting method is slice, n=((Y B -Y T )+SW 2 ) / IN k Among them, Y B is the lower limit value, Y T is the upper limit value, SW 2 is the second pass saw width, W k is the width of the wood block of category k; According to wood block category C k And the number of wood blocks generated calculates V': V’=n*b k *W k *H k Among them, b is the weighting coefficient, between 0 and 1, k is the category number, W k and H k is the width and height of the block.

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