A method for gradually changing color leather wrapping of a steering wheel

Abstract

The present invention provides a method for covering a steering wheel with gradient-color leather, and the method comprises the following steps: selecting gradient-color leather materials; partitioning a steering wheel skeleton based on the gradient-color leather covering area, and representing each partition with a closed geometric figure; analyzing the color distribution and gradient rule on the surface of the gradient-color leather, determining the ideal color distribution and transition effect of covering the gradient-color leather on each partition of the steering wheel skeleton, and generating a color transition template; according to the color transition template, depicting a cutting path on the gradient-color leather, and using a numerical control cutting machine to cut the gradient-color leather so that it corresponds to the geometric shape of each partition of the steering wheel skeleton; fitting the cut gradient-color leather onto the surface of the glue-coated steering wheel skeleton, sewing, shaping, and post-processing. The present invention specifically designs and optimizes the color distribution and transition effect of each partition, effectively avoiding the phenomenon of discontinuous color transition that occurs when covering a steering wheel skeleton with a complex shape with gradient-color leather.

Description

Technical Field

[0001] The invention relates to a steering wheel leather covering method, in particular to a steering wheel gradient color leather covering method, belonging to the technical field of digital industrial production process design. Background Art

[0002] At present, the leather covering of car steering wheels usually adopts a single color or a color matching design. Although it can meet the basic aesthetic and functional requirements of users, it still has great limitations in terms of visual effects and personalization. In order to enhance the visual impact and luxury of the steering wheel, mid-to-high-end car brands have tried to use gradient color leather to cover the steering wheel. However, achieving a better covering effect of gradient color leather for steering wheels still faces the following technical problems.

[0003] In the prior art, the process of gradient leather covering steering wheels, during its production stage, is a major technical challenge in how to accurately convert the color scheme in the design stage into the actual effect and ensure that the steering wheels produced in different batches have a consistent color transition effect. Although the existing leather cutting and stitching process is based on digital industrial production and uses computer-aided design and manufacturing technology, it is still difficult to accurately control the color distribution of the steering wheel covering surface due to the lack of a method specifically for gradient leather covering of complex-shaped steering wheels, especially the gradient color transition at the junction between different partitions of the steering wheel. Therefore, it is very easy to have problems such as color deviation on the surface of the finished steering wheel, uneven gradient color transition, discontinuous color transition or abrupt transition. Summary of the invention

[0004] Based on the above background, the purpose of the present invention is to provide a method for gradient color leather covering of a steering wheel. Based on digital industrial production technology, a method for gradient color leather covering of a steering wheel is designed to improve color reproduction accuracy and optimize the leather cutting path, thereby solving the problems described in the background technology.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for covering a steering wheel with gradient leather, the method comprising the following steps:

[0007] Choose gradient leather material, and glue lining fabric on the back of gradient leather;

[0008] The steering wheel skeleton is divided into zones based on the gradient leather covering area, and each zone is represented by a closed geometric figure;

[0009] Analyze the color distribution and gradient law of the gradient leather surface, determine the ideal color distribution and transition effect of the gradient leather covering each partition of the steering wheel frame, and generate a color transition template;

[0010] According to the color transition template, depict the cutting path on the gradient leather, and use a numerically controlled cutting machine to cut the gradient leather so that it corresponds to the geometric shape of each partition of the steering wheel skeleton;

[0011] Mark the cut gradient leather and align it with the steering wheel skeleton;

[0012] Attach the cut gradient leather to the surface of the glue-coated steering wheel skeleton, sew, shape, and perform post-treatment;

[0013] Among them, the method for generating the color transition template specifically includes:

[0014] Establish a color gradient model on the surface of the gradient leather;

[0015] Calculate the color distribution of each partition of the steering wheel skeleton;

[0016] Optimize the color transition between adjacent partitions of the steering wheel skeleton;

[0017] Generate a color transition template for guiding the cutting of the gradient leather.

[0018] Preferably, the establishment of the color gradient model on the surface of the gradient leather specifically includes:

[0019] For the linear gradient mode, use the following mathematical expression for modeling,

[0020]

[0021] In the formula, C(x,y) represents the color value at the coordinate position (x,y), C 1 represents the starting color value, C 2 represents the ending color value, a and b represent the color gradient direction vectors, c represents the intercept of the color gradient, that is, the distance between the color gradient direction vector and the starting point of the color change, and d represents the range of the color gradient, that is, the length of the color gradient direction vector.

[0022] For the radial gradient mode, use the following mathematical expression for modeling,

[0023]

[0024] In the formula, (x 0 ,y 0 ) represents the coordinates of the center point of the color gradient, and r represents the radius of the color gradient range.

[0025] For the angular gradient mode, use the following mathematical expression for modeling,

[0026]

[0027] In the formula, arctan2 represents the arctangent function, which is used to calculate the angle of the position (x, y) relative to the center point (x 0 , y 0 ) of the color gradient.

[0028] Preferably, calculating the color distribution of each partition of the steering wheel skeleton specifically includes:

[0029] Dividing the partition into several fan-shaped sub-regions;

[0030] Within each fan-shaped sub-region, select the center point of the fan as the integration point. The coordinates (x i,c , y i,c ) of the center point of the fan are calculated through the following mathematical expression,

[0031]

[0032]

[0033] In the formula, r represents the radius of the fan, and θ i represents the starting angle of the fan, and θ i+1 represents the ending angle of the fan;

[0034] For the center point (x i,c , y i,c ) of each fan-shaped sub-region, calculate the color value of the center point of the fan according to the gradient model corresponding to the gradient mode of the partition where it is located;

[0035] For each fan-shaped sub-region, use the following mathematical expression to calculate the color integral value within the fan-shaped sub-region,

[0036] I i = A i · C(x i,c , y i,c )

[0037] In the formula, A i represents the area of the fan-shaped sub-region;

[0038] Accumulate the color integral values I i of all fan-shaped sub-regions within the partition to obtain the color integral value I of the partition. According to the color integral value I of the partition and the partition area A, calculate the average color value C avg of each point within the partition.

[0039] Preferably, optimizing the color transition between adjacent partitions of the steering wheel skeleton specifically includes:

[0040] Set a certain range at the junction of adjacent partitions as the transition area. For each point in the transition area, calculate the distances from this point to the boundaries of the two adjacent partitions, and substitute the distance value d into the following mathematical expression to calculate the transition weight coefficient W(d) of this point.

[0041]

[0042] In the formula, σ represents the parameter controlling the transition speed, and the value of σ is set to one-third to one-half of the width of the transition area.

[0043] Using the transition weight coefficient, perform weighted averaging on the colors of adjacent partitions, and use the following mathematical expression to calculate the transition color value C(x GD ,y GD ) of each point in the transition area.

[0044] C(x GD ,y GD ) = W(d)·C 1 (x GD ,y GD )+(1 - W(d))·C 2 (x GD ,y GD )

[0045] In the formula, C 1 (x GD ,y GD ) and C 2 (x GD ,y GD ) respectively represent the color values at the position (x GD ,y GD ) in the transition area of the two adjacent partitions.

[0046] Preferably, the optimization of the color transition between adjacent partitions of the optimized steering wheel skeleton further includes:

[0047] According to the transition color value C(x GD ,y GD ) of each point in the transition area, inversely calculate and obtain the optimized color value of each point in the adjacent partitions.

[0048] Preferably, the inversely calculating and obtaining the optimized color value of each point in the adjacent partitions specifically includes:

[0049] For each point in the partition, find the corresponding reference point in the transition area and obtain the transition color value of this reference point;

[0050] Calculate the color difference between the point in the partition and the reference point according to the color gradient model;

[0051] Add the transitional color value of the reference point to the color difference to obtain the optimized color value of the point within the partition.

[0052] Preferably, the generation of the color transition template for guiding the cutting of the gradient leather specifically includes:

[0053] Create a digital image or matrix with the same size as the gradient leather as the substrate of the color transition template;

[0054] For each pixel point on the gradient leather, use the mapping method to determine the corresponding partition point position of the steering wheel skeleton, and obtain the optimized color value of each point in the steering wheel skeleton partition, and assign it to the corresponding pixel point on the gradient leather;

[0055] Repeat the above steps until the color values of each point in the steering wheel skeleton partition are assigned to the gradient leather to form a color transition template.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] The method for covering a steering wheel with gradient leather of the present invention is based on digital industrial production technology. By partitioning the steering wheel skeleton and establishing a color gradient model on the surface of the gradient leather, the color distribution and transition effect of each partition are specifically designed and optimized, the color distribution law on the leather surface is quantitatively described, the accuracy of color restoration is improved, and the leather cutting path is optimized, effectively avoiding the phenomenon of discontinuous or abrupt color transition when covering the gradient leather on the steering wheel with a complex shape, and minimizing material waste and improving leather utilization rate to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0059] Figure 1 is a schematic flow chart of the method for covering a steering wheel with gradient leather of the present invention;

[0060] Figure 2 is a schematic diagram of the partition of the steering wheel skeleton in the present invention.

[0061] In the figure: 1, central area; 2, edge area; 3, spoke area; 4, fan-shaped sub-area; 5, transition area. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] The technical solution of the present invention will be further specifically described below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any formal modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0063] In the present invention, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments are conventional methods in the art unless otherwise specified. The components or equipment in the following embodiments are general standard parts or components known to those skilled in the art unless otherwise specified, and their structures and principles can all be known by those skilled in the art through technical manuals or obtained through conventional experimental methods.

[0064] The following will make a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments can also be implemented by those skilled in the art without these specific details.

[0065] An embodiment of the present invention discloses a method for covering a steering wheel with gradient-color leather, and the method includes the following steps:

[0066] S1. Select gradient-color leather material and bond a lining cloth to the back of the gradient-color leather;

[0067] S2. Divide the steering wheel skeleton into zones based on the gradient-color leather covering area, divide it into a central zone 1, an edge zone 2, and a spoke zone 3, and represent each zone with a closed geometric figure;

[0068] S3. Analyze the color distribution and gradient rule on the surface of the gradient-color leather, determine the ideal color distribution and transition effect of covering the gradient-color leather on each zone of the steering wheel skeleton, and generate a color transition template;

[0069] S3.1. Establish a color gradient model on the surface of the gradient-color leather;

[0070] S3.2. Calculate the color distribution of each zone of the steering wheel skeleton;

[0071] S3.3. Optimize the color transition between adjacent zones of the steering wheel skeleton;

[0072] S3.4. Generate a color transition template for guiding the cutting of the gradient-color leather;

[0073] S4. According to the color transition template, draw a cutting path on the gradient-color leather, and use a numerical control cutting machine to cut the gradient-color leather so that it corresponds to the geometric shapes of each zone of the steering wheel skeleton;

[0074] S5. Mark the cut gradient leather and align it with the steering wheel skeleton;

[0075] S6. Bond the cut gradient leather to the surface of the glued steering wheel skeleton, sew, shape, and perform post-treatment.

[0076] By partitioning the steering wheel skeleton and establishing a color gradient model on the surface of the gradient leather, the color distribution and transition effect of each partition are designed and optimized specifically, the color distribution law on the leather surface is quantitatively described, the accuracy of color restoration is improved, the leather cutting path is optimized, the phenomenon of discontinuous or abrupt color transition that occurs when covering the gradient leather on the steering wheel skeleton with a complex shape is effectively avoided, and the material waste is minimized and the leather utilization rate is increased to the greatest extent.

[0077] The above steps are described in detail below.

[0078] As Figure 2 shown, based on the gradient leather covering area, the steering wheel skeleton is partitioned into a central area 1, an edge area 2, and a spoke area 3. The central area 1 specifically refers to the central area 1 of the steering wheel skeleton, on the surface of which a horn button and a logo are designed, and the area surface except the logo is relatively flat. The edge area 2 specifically refers to the peripheral area of the steering wheel skeleton, and its shape is a single ring or a segmented ring. The spoke area 3 specifically refers to the bridge area connecting the central area 1 and the edge area 2, and usually includes two or three separate spokes.

[0079] After determining the partitions, a mathematical model is established according to the color gradient law on the surface of the gradient leather to describe its color distribution, and corresponding gradient models are established according to different gradient patterns.

[0080] For the linear gradient pattern, that is, the color changes linearly along one direction, the following mathematical expression is used for modeling,

[0081]

[0082] In the formula, C(x,y) represents the color value at the coordinate position (x,y), C 1 represents the starting color value, C 2 represents the ending color value, a and b represent the color gradient direction vector, c represents the intercept of the color gradient, that is, the distance between the color gradient direction vector and the starting point of the color change, and d represents the range of the color gradient, that is, the length of the color gradient direction vector.

[0083] For the radial gradient pattern, that is, the color radiates and changes from a central point to the surrounding, the following mathematical expression is used for modeling,

[0084]

[0085] In the formula, (x0 , y 0 ) represents the coordinates of the center point of the color gradient, and r represents the radius of the color gradient range.

[0086] For the angular gradient mode, that is, the color changes along an angular direction to form a circular or fan-shaped gradient effect, the following mathematical expression is used for modeling.

[0087]

[0088] In the formula, arctan2 represents the arctangent function, which is used to calculate the angle of the position (x, y) relative to the center point (x 0 , y 0 ) of the color gradient.

[0089] After that, calculate the color distribution of each partition of the steering wheel skeleton. According to the geometric shape and position of each partition, the following method is used to calculate the ideal color value of each point inside each partition:

[0090] Divide the partition into several fan-shaped sub-regions 4. Among them, the central angle of the fan should be small to ensure that the color change within each sub-region is relatively gentle. For each partition of the steering wheel skeleton, it is more appropriate to divide it into 20 - 50 fan-shaped sub-regions 4, which can obtain better calculation accuracy and balance the calculation efficiency;

[0091] Inside each fan-shaped sub-region 4, select the center point of the fan as the integration point. The coordinates (x i,c , y i,c ) of the center point of the fan are calculated by the following mathematical expression.

[0092]

[0093]

[0094] In the formula, r represents the radius of the fan, and θ i represents the starting angle of the fan, and θ i+1 represents the ending angle of the fan.

[0095] For the center point (x i,c , y i,c ) of each fan-shaped sub-region 4, calculate the color value of the center point of the fan according to the gradient model corresponding to the gradient mode of the partition where it is located. For example, for the angular gradient mode, the color value of the center point (x i,c , y i,c ) of each fan-shaped sub-region 4 can be calculated by the following mathematical expression.

[0096]

[0097] For each sector sub-region 4, the following mathematical expression is used to calculate the color integral value within the sector sub-region 4.

[0098] I i = A i · C(x i,c , y i,c )

[0099] In the formula, A i represents the area of the sector sub-region 4.

[0100] The color integral values Ii of all the sector sub-regions 4 within the partition are accumulated to obtain the color integral value I of the partition. According to the color integral value I of the partition and the partition area A, the following mathematical expression is used to calculate the average color value C at each point within the partition. avg ,

[0101]

[0102] After that, the color transition between adjacent partitions is optimized to ensure visual continuity and aesthetics. A certain range at the junction of adjacent partitions is set as the transition region 5. For each point in the transition region 5, the distances from the point to the boundaries of the two adjacent partitions are calculated, and the distance value d is substituted into the following mathematical expression to calculate the transition weight coefficient W(d) of the point.

[0103]

[0104] In the formula, σ represents the parameter controlling the transition speed, and the value of σ is set to one-third to one-half of the width of the transition region 5.

[0105] Using the transition weight coefficient, the colors of adjacent partitions are weighted and averaged, and the following mathematical expression is used to calculate the transition color value C(x GD , y GD ) at each point within the transition region 5.

[0106] C(x GD , y GD ) = W(d) · C 1 (x GD , y GD ) + (1 - W(d)) · C 2 (x GD , y GD )

[0107] In the formula, C 1 (x GD , y GD ) and C 2 (x GD , y GD ) respectively represent the positions (xGD , y GD the color value at

[0108] In this way, the transitional color values of each point in the transition region 5 can be obtained. Since a part of the transition region 5 must be located in one of the adjacent partitions, and the other part of the transition region 5 must be located in the other adjacent partition, after the transitional color values of each point in the transition region 5 are determined, the optimized color values of each point in these two partitions can be deduced inversely. Specifically, for each point in the partition, find its corresponding reference point in the transition region 5 and obtain the transitional color value of this reference point. Then, calculate the color difference between the point in the partition and the reference point according to the gradient model function. Finally, add the transitional color value of the reference point and the color difference to obtain the optimized color value of the point in the partition.

[0109] By first obtaining the color values of the transition region 5 and then inversely deducing the color values within the partition, precise color transition control is achieved, the accuracy of color restoration is improved, ensuring that within the transition region 5 between adjacent partitions, the color can transition smoothly, avoiding abrupt color changes, and reducing the complexity of color optimization calculations.

[0110] Create a digital image or matrix with the same size as the leather as the color transition template substrate. For each pixel point on the leather, use the mapping method to determine its corresponding partition point position on the steering wheel skeleton, and obtain the optimized color value of each point in the steering wheel skeleton partition, and assign it to the corresponding pixel point on the leather. Repeat the above steps until the color values of each point in the steering wheel skeleton partition are assigned to the leather to form a color transition template.

[0111] According to the color transition template, depict the cutting path on the gradient-color leather, and use a numerical control cutting machine to cut the gradient-color leather so that it corresponds to the geometric shape of each partition of the steering wheel skeleton.

[0112] After that, mark the cut gradient-color leather and align it with the steering wheel skeleton. Specifically, use a special marking tool to mark information such as the corresponding partition number and direction indication on the back of the cut gradient-color leather segment. Align it with the corresponding partition of the steering wheel skeleton according to the indication of the mark.

[0113] Attach the cut gradient-color leather to the surface of the glue-coated steering wheel skeleton, and use a special sewing machine to sew along the edge of the gradient-color leather segment to make the leather close and wrap the steering wheel skeleton. Finally, heat for shaping, clean, and polish.

[0114] In this article, specific examples are used to illustrate the principles and implementation modes of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for covering a steering wheel with gradient leather, characterized in that: The method comprises the following steps: Choose gradient leather material, and glue lining fabric on the back of gradient leather; The steering wheel skeleton is divided into zones based on the gradient leather covering area, and each zone is represented by a closed geometric figure; Analyze the color distribution and gradient law of the gradient leather surface, determine the ideal color distribution and transition effect of the gradient leather covering each partition of the steering wheel frame, and generate a color transition template; According to the color transition template, draw the cutting path on the gradient leather, and use the CNC cutting machine to cut the gradient leather to correspond to the geometric shapes of each partition of the steering wheel frame; Mark the cut gradient leather and align it with the steering wheel frame; Laminating the cut gradient leather to the surface of the glue-coated steering wheel frame, stitching, shaping, and post-processing; The method for generating a color transition template specifically includes: Establish a color gradient model for gradient leather surface; Calculate the color distribution of each partition of the steering wheel skeleton; Optimize the color transition between adjacent partitions of the steering wheel frame; Generate a color transition template to guide the cutting of gradient leather.

2. The method for covering a steering wheel with gradient leather according to claim 1, characterized in that: The step of establishing a color gradient model for the gradient color leather surface specifically includes: For the linear gradient mode, the following mathematical expression is used to model it, Where, C(x,y) represents the color value at the coordinate position (x,y), C1 represents the starting color value, C2 represents the ending color value, a and b represent the color gradient direction vectors, c represents the intercept of the color gradient, that is, the distance between the color gradient direction vector and the starting point of the color change, and d represents the range of the color gradient, that is, the length of the color gradient direction vector; For the radial gradient pattern, the following mathematical expression is used to model it, In the formula, (x0, y0) represents the coordinates of the center point of the color gradient, and r represents the radius of the color gradient range; For the angle gradient mode, the following mathematical expression is used for modeling: Wherein, arctan2 represents the inverse tangent function, which is used to calculate the angle of the position (x, y) relative to the center point (x0, y0) of the color gradient.

3. The method for covering a steering wheel with gradient leather according to claim 1, characterized in that: The calculating the color distribution of each partition of the steering wheel skeleton specifically includes: Divide the partition into a number of sector-shaped sub-regions (4); In each sector sub-region (4), the sector center point is selected as the integration point. The coordinates of the sector center point (x i,c ,y i,c ) is calculated by the following mathematical expression, In the formula, r represents the radius of the sector, θ i Indicates the starting angle of the sector, θ i+1 Indicates the end angle of the sector; For each sector sub-area (4), the sector center point (x i,c ,y i,c ), calculate the color value of the center point of the sector according to the gradient model corresponding to the gradient mode of the partition where it is located; For each sector-shaped sub-region (4), the color integral value within the sector-shaped sub-region (4) is calculated using the following mathematical expression: I i =A i ·C(x i,c ,y i,c ) In the formula, A i represents the area of ​​the sector-shaped sub-region (4); The color integral value I of all the fan-shaped sub-areas (4) in the partition i Accumulate and get the color integral value I of the partition. According to the color integral value I of the partition and the partition area A, calculate the average color value C of each point in the partition. avg .

4. The method for covering a steering wheel with gradient leather according to claim 1, characterized in that: The step of optimizing the color transition between adjacent partitions of the steering wheel skeleton specifically includes: A certain range of the intersection of adjacent partitions is set as the transition area (5). For each point in the transition area (5), the distance from the point to the boundaries of two adjacent partitions is calculated. The distance value d is substituted into the following mathematical expression to calculate the transition weight coefficient W(d) of the point: In the formula, σ represents the parameter controlling the transition speed, and the value of σ is set to one third to one half of the width of the transition region (5); Using the transition weight coefficient, the colors of adjacent partitions are weighted averaged, and the transition color value C(x) of each point in the transition area (5) is calculated using the following mathematical expression: GD ,y GD ), C(x GD ,y GD )=W(d)·C1(x GD ,y GD )+(1-W(d))·C2(x GD ,y GD ) In the formula, C1(x GD ,y GD ) and C2(x GD ,y GD ) respectively represent the positions (x) of two adjacent partitions in the transition region (5) GD ,y GD ) is the color value at .

5. The method for covering a steering wheel with gradient leather according to claim 4, characterized in that: The method of optimizing the color transition between adjacent partitions of the steering wheel skeleton further includes: According to the transition color value C(x GD ,y GD ), and reversely calculate to obtain the optimized color value of each point in the adjacent partition.

6. The method for covering a steering wheel with gradient leather according to claim 5, characterized in that: The reverse calculation to obtain the optimized color value of each point in the adjacent partitions specifically includes: For each point in the partition, find the corresponding reference point in the transition area (5), and obtain the transition color value of the reference point; Calculate the color difference between the points in the partition and the reference point according to the color gradient model; The transition color value of the reference point is added to the color difference to obtain the optimized color value of the point in the partition.

7. The method for covering a steering wheel with gradient leather according to claim 1, characterized in that: The generating of the color transition template for guiding the cutting of gradient color leather specifically includes: Create a digital image or matrix of the same size as the gradient leather to serve as a color transition template substrate; For each pixel point on the gradient color leather, a mapping method is used to determine the corresponding partition point of the steering wheel skeleton, and the optimized color value of each point of the steering wheel skeleton partition is obtained, and the color value is assigned to the corresponding pixel point on the gradient color leather; Repeat the above steps until the color value of each point in the steering wheel skeleton partition is assigned to the gradient leather to form a color transition template.

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