Female breast volume quantitative calculation method based on boundary mixing characteristics

Abstract

The invention discloses a female breast volume quantitative calculation method based on boundary mixed features, which comprises the following steps: acquiring three-dimensional point cloud data of a human chest through a three-dimensional human body scanner, and constructing a breast three-dimensional model through a point cloud stage, a polygon stage and a curved surface stage according to a reverse engineering method. And determining breast boundaries on the three-dimensional human body model through a curvature distribution method in combination with the feature points. Curvature differentiation is carried out on the breast bottom contour line on the breast boundary, large deformation is converted into tiny change curvature, and the breast bottom boundary conforming to the human body curved surface is obtained. On the premise of ensuring smooth transition of the bottom of the breast along the boundary, the breast bottom closed area is filled in sequence, so that the bottom of the breast can conform to the human body spatial form, and the volume of the breast three-dimensional model is calculated through calculus. The problem that the three-dimensional breast space volume is calculated under the condition that the breast bottom in the human body cannot be clearly known is solved, and the breast volume calculation precision can be improved while the breast shape of the human body can be better met.

Description

Technical Field

[0001] The invention relates to the technical field of human body measurement, and in particular to a method for quantitatively calculating female breast volume based on boundary mixing features. Background Art

[0002] In the clothing industry, especially the underwear industry, breast volume is closely related not only to the shape of the chest, but also to the fit of the clothing, especially the matching degree between the bra cup and the breast. As a covering material for the breast, the bra matches the breast mainly in two aspects: on the one hand, the coverage of the breast boundary, and on the other hand, the coverage of the breast volume. For the underwear industry, especially the design of bras, the matching of the cup volume and the breast not only affects the comfort of wearing, but also directly affects the fit of the product. Therefore, being able to objectively and accurately obtain the breast volume is of great significance to solving the fit of the bra. However, since the breast is a complex three-dimensional human body shape, it is indeed faced with many technical difficulties to obtain its true volume and boundary. Moreover, the calculation of volume is not only based on the external shape, but also directly affects the shape of the bottom. However, the bottom of the breast is located inside the breast and cannot be directly measured by instruments or equipment. The bottom of the breast cannot be directly obtained by plane interception method, three-dimensional scanning method, etc., which directly increases the difficulty of calculating the breast volume.

[0003] At present, the measurement methods of breast volume are mainly divided into statistical calculation method, mold design method, imaging measurement and three-dimensional measurement method. Among them, Tian Shuliang summarized the research progress of breast volume measurement methods and analyzed the advantages and disadvantages of the above measurement methods. CN 103690172 discloses a breast volume measurement method, which constructs a three-dimensional model of the breast bottom surface according to the shape of the ribs where the breast bottom is located, and seals and combines the three-dimensional model of the breast bottom surface with the three-dimensional model of the breast surface to obtain a closed three-dimensional model of the breast area to be measured, and further calculates the volume of the three-dimensional model of the breast area to be measured. Its characteristic is that the breast bottom is based on the shape of the ribs where the breast bottom is located, but because the ribs are inside the breast, it is difficult to effectively obtain internal information of the breast based on the external morphology. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for quantitatively calculating the volume of female breasts based on boundary mixing features, which can ensure that the three-dimensional breast model can be filled under the premise that the bottom of the breast can smoothly transition along the boundary, so that the bottom of the breast can conform to the spatial form of the human body, and calculate the volume of the three-dimensional breast model through calculus, thereby solving the problem of accurately calculating the three-dimensional breast volume when the bottom of the breast located inside the human body cannot be clearly known, and compared with the breast volume actually measured by the white latex method, the calculation error is smaller.

[0005] The present invention also provides a method for quantitatively calculating the volume of female breasts based on the above-mentioned boundary mixing feature, comprising the following steps:

[0006] S1. Concrete human body 3D model: obtain the 3D point cloud data of the whole body through the 3D human body scanner, and then use reverse engineering to transform the breast point cloud data through the point cloud stage, polygon stage and surface stage to construct a human body 3D model based on NURBS surface fitting;

[0007] S2. Establishing the human breast boundary: Based on the human body three-dimensional model obtained in S1, the breast boundary is determined by combining curvature distribution with feature point positioning method;

[0008] S3. Breast boundary closed filling: The curvature of the breast contour line is differentiated on the breast boundary, and the large deformation is converted into a number of dangerous change curvatures, and closed units are formed one by one to obtain a breast boundary that conforms to the human body surface. The closed area of ​​the breast bottom is filled in sequence by the boundary blending method while ensuring that the breast bottom can smoothly transition along the boundary, so that the breast bottom boundary can conform to the human body space form;

[0009] S4. Breast volume calculation: The three-dimensional breast model obtained in S3 is cut longitudinally into very thin units, and the volume of the three-dimensional breast model is calculated using calculus.

[0010] According to a method for quantitatively calculating female breast volume based on boundary mixing features provided by the present invention, the scanning accuracy of the three-dimensional human body scanner in S1 is 0.1 mm, the scanning speed is 550,000 points / second, and the spatial spacing is 0.2-3 mm.

[0011] According to a method for quantitatively calculating female breast volume based on boundary mixing features provided by the present invention, the specific steps of the point cloud stage in S1 are: preprocessing the three-dimensional point cloud data using Cloud Compare reverse engineering software, and converting the discrete three-dimensional human body point cloud data into a polygonal model with smooth boundaries through point cloud deletion, rounding, and unified sampling methods.

[0012] According to a method for quantitatively calculating female breast volume based on boundary hybrid features provided by the present invention, the specific steps of the polygon stage in S1 are: editing and refining the human body model by triangles, first creating a manifold, detecting and repairing intersecting triangular facets, filling holes on the human body surface by using curvature or a surface method, and at the same time relaxing polygons, removing features and refining the mesh to refine the human body model so that the surface of the human body model is smoother, and finally performing a mesh defect check to lay a foundation for surface fitting.

[0013] According to a method for quantitatively calculating female breast volume based on boundary hybrid features provided by the present invention, the specific steps of the surface stage in S1 are: dividing the human body model into characteristic areas by detecting curvature and manually dividing the surface grid, dividing the human upper body model into multiple low curvature areas by placing contour lines by detecting curvature; constructing a surface to generate a NURBS surface boundary structure, further completing surface fitting, and generating a human body entity model.

[0014] According to a method for quantitatively calculating female breast volume based on boundary mixed features provided by the present invention, the specific steps of determining the breast boundary in S2 are: based on a three-dimensional human body solidification model, determining seven feature points required for the breast boundary, namely, the nipple point, the anterior axillary point, the upper breast point, the lower breast point, the inner breast point, the shoulder midpoint, and the side waist point; drawing seven auxiliary lines based on the determination of the seven feature points to determine the breast boundary through the distribution of human body curvature.

[0015] According to a method for quantitatively calculating female breast volume based on boundary hybrid features provided by the present invention, after the breast boundary is determined in S2, a three-dimensional solid model of the breast is constructed, and a three-dimensional model based on the breast boundary is constructed through curvature detection, surface patch construction, grid construction, and surface fitting.

[0016] Beneficial Effects

[0017] The present invention can fill the three-dimensional breast model under the premise of ensuring that the bottom of the breast can smoothly transition along the boundary, so that the bottom of the breast can conform to the spatial form of the human body, and calculate the volume of the three-dimensional breast model through calculus, thereby solving the problem of accurately calculating the three-dimensional breast volume when the bottom of the breast inside the human body cannot be clearly known. Compared with the breast volume actually measured by the white latex method, the calculation error is smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0019] Figure 1 It is a schematic flow chart of a method for quantitatively calculating female breast volume based on boundary mixing features of the present invention;

[0020] Figure 2 A schematic diagram of breast boundaries of a method for quantitatively calculating female breast volume based on boundary mixed features of the present invention;

[0021] Figure 3 A three-dimensional solid model diagram of a breast according to a method for quantitatively calculating the volume of a female breast based on boundary mixing features of the present invention;

[0022] Figure 4 It is a schematic diagram of arc differentiation of the method for quantitatively calculating the volume of female breasts based on boundary mixing features of the present invention. DETAILED DESCRIPTION

[0023] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0024] Reference Figure 1-4 The present invention provides a method for quantitatively calculating the volume of female breasts based on boundary mixing features, which comprises the following steps:

[0025] S1. Concrete human 3D model: The 3D point cloud data of the whole body is obtained through a 3D human body scanner. The scanning accuracy of the 3D human body scanner is 0.1 mm, the scanning speed is 550,000 points / second, and the spatial spacing is 0.2-3 mm. In order to make the whole scanning process more stable and achieve uniform sampling, the breast point cloud data is then reversely engineered through the point cloud stage, polygon stage and surface stage to construct a human 3D model based on NURBS surface fitting;

[0026] The specific steps of the point cloud stage are: pre-processing the 3D point cloud data using Cloud Compare reverse engineering software, and converting the discrete 3D human body point cloud data into a polygonal model with ideal boundaries and relatively smooth surfaces through methods such as point cloud deletion, rounding, and unified sampling;

[0027] The specific steps of the polygon stage are: edit the triangles to refine the human body model. First, create a manifold, detect and repair intersecting triangles, fill the holes on the human body surface by using curvature or surface, and relax polygons, remove features, and refine the mesh to make the human body model surface smoother. Finally, check for mesh defects to lay the foundation for surface fitting;

[0028] The specific steps of the surface stage are: divide the human body model into characteristic areas by detecting curvature and manually dividing the surface mesh. Divide the upper body model into multiple low curvature areas by detecting curvature and placing contour lines; construct the surface to generate the NURBS surface boundary structure, further complete the surface fitting, and generate the human body solid model.

[0029] S2. Establishing the human breast boundary: Based on the human body three-dimensional model obtained in S1, the breast boundary is determined by combining curvature distribution with feature point positioning method;

[0030] The specific steps for determining the breast boundary are as follows: Based on the three-dimensional human body solidification model, determine the nipple point (BP), front axillary point (FNP), upper breast point (UBP), lower breast point (BBP), inner breast point (I BP), shoulder midpoint (CSP), and side waist point (SWP) required for the breast boundary. Draw 7 auxiliary lines (auxiliary line selection is based on definition) based on the determination of the 7 characteristic points, and determine the breast boundary through the distribution of human body curvature. The method for determining the auxiliary points of the human body is shown in the following table:

[0031]

[0032]

[0033] After the breast boundary is determined, the female breast 3D model is constructed. In the surface stage of the human body 3D model, a 3D model based on the breast boundary is constructed through curvature detection, surface patch construction, grid construction, and surface fitting.

[0034] S3. Breast boundary closed filling: The curvature of the breast contour line is differentiated on the breast boundary, and the large deformation is converted into a number of dangerous change curvatures, and closed units are formed one by one to obtain a breast boundary that conforms to the human body surface. The closed area of ​​the breast bottom is filled in sequence by the boundary blending method while ensuring that the breast bottom can smoothly transition along the boundary, so that the breast bottom boundary can conform to the human body space form;

[0035] Since the breast 3D solid model has been completely constructed on the outer surface, the breast base is the bottom of the breast 3D model, and its shape and size directly affect the accuracy of the breast volume. Since the breast base is inside the breast, it cannot be directly detected. Considering the close relationship between the breast base and the breast boundary, the breast bottom surface is a smooth surface that conforms to the curvature of the human breast boundary, and the upper side of the breast to the lower side of the breast needs to conform to the human body shape, so the breast base is a flat transition based on the curvature of the human breast boundary.

[0036] On the basis of the above concept of conforming to human body morphology, in order to achieve a smooth transition and conform to the curvature change of human body, the curvature differentiation of the breast bottom contour line is performed on the breast boundary, and the large deformation is converted into several small curvature changes, and each of them constitutes a closed unit to obtain the breast bottom boundary that conforms to the human body surface morphology (i.e. ).

[0037] The present invention is based on arc Take UBP and IBP as the two endpoints of the arc, insert feature points P0, P1, P2, ..., Pn, Pn+1, ..., and connect two adjacent points with chords to obtain an inscribed broken line for calculation. That is, take the integral variable x, and within the interval [Pn, Pn+1], randomly select a small interval [x, x+dx], and replace the arc area with the straight line area. As the accuracy requirements increase, the number of feature points increases successively, and the length of the collar arc is:

[0038] (ds) 2 =(dx) 2 +(dy) 2

[0039] Arc length elements: Arc Length:

[0040] Its arc differential is Figure 4 As shown; Similarly, we can use the differential method to obtain The length of the arc, the length of the overall breast boundary arc is obtained by the sum of the four segmented arcs.

[0041] Based on the arc differential, the breast bottom edge line is combined with the differential point to form a closed figure, and the bottom surface of the breast bottom is filled through boundary blending, so that the bottom of the breast can have a smooth transition while meeting the boundary curvature of the human body.

[0042] The present invention uses 6 differential points as an example to introduce and explain breast bottom closure. Six points are selected on the breast boundary and connected with straight lines so that the breast bottom surface can smoothly transition along the curvature of the breast boundary. Three horizontal straight lines differentiate the entire breast bottom (i.e., the vertical distance from UBP to BBP) into four parts, and the four parts of breast bottom closure are filled in sequence through boundary blending.

[0043] S4. Breast volume calculation: The three-dimensional breast model obtained in S3 is cut longitudinally into very thin units, and the volume of the three-dimensional breast model is calculated using calculus.

[0044] The volume of the three-dimensional breast model to be tested is obtained by calculus calculation using the Polyworks reverse engineering software IMEd it module. The breast model is cut longitudinally into very thin layers, called units. The larger the number of slices, the finer the division, and the smaller the error of the obtained volume. The number of slices for each model is preferably 10,000. Since each unit is already very small, using the principle of calculus calculation, each unit can be regarded as a straight column with a bottom area of ​​Amm2. Each unit Volum = ΣAmm2×Hn, where Hn is the difference between the point on the vertical curve of the nth unit and the Z coordinate data of the back surface of the breast area. The breast volume is obtained by superimposing each unit, so the breast volume Breast Volume = ΣSlice×Volumn.

[0045] Through the above method, the present invention can ensure that the breast bottom can be filled with the breast three-dimensional model under the premise of smooth transition along the boundary, so that the breast bottom can conform to the spatial form of the human body, and calculate the volume of the breast three-dimensional model through calculus. Compared with the breast volume actually measured by the white latex method, the calculation error is less than 18mL, and the error percentage is less than 4%, which proves that the present invention is accurate and effective in calculating the breast volume.

[0046] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A method for quantitatively calculating female breast volume based on boundary mixing features, characterized in that: The following steps are involved: S1. Concrete human body 3D model: obtain the 3D point cloud data of the whole body through the 3D human body scanner, and then use reverse engineering to transform the breast point cloud data through the point cloud stage, polygon stage and surface stage to construct a human body 3D model based on NURBS surface fitting; S2. Establishing the human breast boundary: Based on the human body three-dimensional model obtained in S1, the breast boundary is determined by combining curvature distribution with feature point positioning method; S3. Breast boundary closed filling: The curvature of the breast contour line is differentiated on the breast boundary, and the large deformation is converted into a number of dangerous change curvatures, and closed units are formed one by one to obtain a breast boundary that conforms to the human body surface. The closed area of ​​the breast bottom is filled in sequence by the boundary blending method while ensuring that the breast bottom can smoothly transition along the boundary, so that the breast bottom boundary can conform to the human body space form; S4. Breast volume calculation: The three-dimensional breast model obtained in S3 is cut longitudinally into very thin units, and the volume of the three-dimensional breast model is calculated using calculus.

2. The method for quantitatively calculating female breast volume based on boundary mixing features according to claim 1, characterized in that: The scanning accuracy of the three-dimensional human body scanner in S1 is 0.1 mm, the scanning speed is 550,000 points / second, and the spatial spacing is 0.2-3 mm.

3. The method for quantitatively calculating female breast volume based on boundary mixing features according to claim 1, characterized in that: The specific steps of the point cloud stage in S1 are: pre-processing the three-dimensional point cloud data using Cloud Compare reverse engineering software, and converting the discrete three-dimensional human body point cloud data into a polygonal model with smooth boundaries through point cloud deletion, rounding, and unified sampling methods.

4. The method for quantitatively calculating female breast volume based on boundary mixing features according to claim 1, characterized in that: The specific steps of the polygon stage in S1 are: editing the triangles to refine the human body model, first creating a manifold, detecting and repairing intersecting triangles, filling the holes on the human body surface using curvature or surface methods, and at the same time relaxing polygons, removing features and refining the mesh to refine the human body model, making the surface of the human body model smoother, and finally performing mesh defect inspection to lay the foundation for surface fitting.

5. The method for quantitatively calculating female breast volume based on boundary mixing features according to claim 1, characterized in that: The specific steps of the surface stage in S1 are: dividing the human body model into feature areas by detecting curvature and manually dividing the surface mesh, dividing the upper body model into multiple low curvature areas by detecting curvature and placing contour lines; constructing the surface to generate a NURBS surface boundary structure, further completing the surface fitting, and generating a human body solid model.

6. The method for quantitatively calculating female breast volume based on boundary mixing features according to claim 1, characterized in that: The specific steps of determining the breast boundary in S2 are: based on the three-dimensional human body entity model, determine the nipple point, anterior axillary point, upper breast point, lower breast point, inner breast point, shoulder midpoint, and side waist point required for the breast boundary; draw seven auxiliary lines based on the determination of the seven feature points; and determine the breast boundary through the distribution of human body curvature.

7. The method for quantitatively calculating female breast volume based on boundary mixing features according to claim 1, characterized in that: After the breast boundary is determined in S2, a three-dimensional solid model of the breast is constructed, and a three-dimensional model based on the breast boundary is constructed by curvature detection, surface patch construction, grid construction, and surface fitting.

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