A method for detecting the shape of a slanted skirt

Abstract

The application discloses a kind of oblique skirt modeling detection methods;The method is as follows: 1, the measured oblique skirt is worn on the mannequin.2, the measured oblique skirt worn on the mannequin is scanned three-dimensionally, and the point cloud model of the measured oblique skirt is obtained.3, the point cloud model of the measured oblique skirt is pretreated by reverse engineering software.4, the comprehensive exhibition angle of the measured oblique skirt is extracted.5, the overall fullness of the measured oblique skirt is extracted.6, the average straightness of the profile line of the outer spread pleat on the measured oblique skirt and the average straightness of the profile line of the inner recessed pleat are extracted.7, the naturalness index, uniformity, stereoscopic degree, drape and smoothness of the measured oblique skirt wave are calculated.8, the comprehensive modeling excellence of the measured oblique skirt is calculated.The application obtains the modeling information of the three-dimensional space of the oblique skirt with the aid of three-dimensional scanning technology and reverse engineering software, extracts the spatial modeling index of multiple dimensions of the oblique skirt, realizes the accurate and objective description of the appearance modeling of the oblique skirt, and realizes the quantitative and objective evaluation of the clothing modeling.

Description

Technical Field

[0001] This invention belongs to the field of textile and apparel performance testing technology, specifically relating to a method for testing the shape of a slanted skirt. Background Technology

[0002] The excellence of clothing design is assessed using multiple indicators, and comprehensive judgment often relies on expert experience, resulting in subjective qualitative evaluations with poor consistency. Utilizing instrumental testing and image processing can help determine objective quantitative evaluation indicators for clothing design, thus improving the evaluation system. For asymmetrical skirts, the characteristics are the spatial layers of curved surfaces and the variations in the concavity and convexity of pleats, mainly including the outer contour and local pleat design. The overall outer contour and local design are inextricably linked; local design enriches and strengthens the overall style of the asymmetrical skirt, while the overall design also influences local design. The asymmetrical skirt's design exists in three-dimensional space, possessing horizontal, vertical, and extended characteristics. To more comprehensively examine the design characteristics of asymmetrical skirts, it is necessary to evaluate both the overall and local design from a spatial perspective. Summary of the Invention

[0003] The purpose of this invention is to provide a method for detecting the shape of a slanted skirt.

[0004] This invention discloses a method for detecting the shape of a slanted skirt, comprising the following steps:

[0005] Step 1: Put the skirt to be measured on the mannequin.

[0006] Step 2: Perform a 3D scan of the skirt being tested, which is worn on a mannequin, to obtain a point cloud model of the skirt.

[0007] Step 3: Use reverse engineering software to preprocess the point cloud model of the sloped skirt being measured.

[0008] Step 4: Extract the front development angle θ of the measured inclined skirt. F Rear expansion angle θ B Left side expansion angle θ C right-side expansion angle θ D The combined development angle θ of the measured sloping skirt is then calculated based on the four development angles.

[0009] Step 5: Extract the fullness δ of the waist circumference section L1, abdomen circumference section L2, hip circumference section L3, and hem section L4 of the measured oblique skirt. k Based on the fullness δ corresponding to the four cross sections k Calculate the overall fullness δ of the skirt being measured.

[0010] Step 6: Extract all pleat contour lines on the measured sloping skirt; the pleat contour lines include outward pleat contour lines and inward pleat contour lines; calculate the average deviation of each outward pleat contour line. and the average deviation of each concave fold contour line

[0011] Step 7: Calculate the naturalness F1, uniformity F2, three-dimensionality F3, sag F4, and smoothness F5 of the measured oblique skirt wave as follows:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017] Step 8: Calculate the overall shape excellence F of the tested slanted skirt.

[0018] F=0.225*F1+0.212*F2+0.213*F3+0.220*F4+0.208*F5

[0019] The larger the overall design quality (F), the better the design of the skirt being tested.

[0020] Preferably, in step one, the lower edge of the waistline of the skirt being measured is aligned with the waistline of the mannequin.

[0021] Preferably, in step two, a handheld multi-functional 3D scanner is used for 3D scanning.

[0022] As a preferred option, the point cloud model is denoised and simplified in step three.

[0023] As a preferred option, in step three, the point cloud model is sequentially reconstructed into a coordinate system, the point cloud models of the dressed mannequin and the nude mannequin are aligned, and the area between the lower edge of the waistband and the edge of the hem is cropped and preserved.

[0024] As a preferred option, the point cloud model uses the width, thickness, and vertical direction of the mannequin as the X-axis, Y-axis, and Z-axis of the spatial rectangular coordinate system, respectively.

[0025] Preferably, in step four, the front expansion angle θ F Rear expansion angle θ B Left side expansion angle θ C right-side expansion angle θ D The angle between the line connecting corresponding points on the circumscribed rectangles of the waist and hem contours of the skirt being measured and the vertical axis is taken. The combined development angle θ of the skirt being measured is 0.2θ. F +0.2θ B +0.3θ C+0.3θ D .

[0026] Preferably, in step five, the fullness δ of the cross-section... k Take the ratio of the area enclosed by the profile of the cross section to the area of ​​the smallest circumscribed rectangle of the cross section. The overall fullness of the measured inclined skirt is δ = 0.2δ1 + 0.3δ2 + 0.3δ3 + 0.2δ4.

[0027] As a preferred method, the extraction process for the pleat contour line is as follows: extract the crest or trough point corresponding to the same pleat on the skirt being measured on the lower edge of the waistband and the skirt hem contour, respectively; and use a plane that passes through both the crest and trough point to cut out the pleat contour line. The deviation of the pleat contour line is the maximum distance that the pleat contour line deviates from the central axis.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] This invention utilizes 3D scanning technology and reverse engineering software to obtain the 3D spatial shape information of a slanted skirt, extracts spatial shape indicators of the slanted skirt in multiple dimensions, and accurately describes the appearance of the slanted skirt, thereby achieving quantitative and objective detection of clothing shape. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the reconstructed spatial coordinate system of the nude mannequin in this invention;

[0031] Figure 2 This is a schematic diagram of the scanner spatial coordinate system obtained by scanning the oblique skirt under test according to the present invention;

[0032] Figure 3 This is a schematic diagram of the aligned point cloud model of the oblique skirt in this invention;

[0033] Figure 4 This is a schematic diagram of the measured oblique skirt point cloud model before region clipping in this invention;

[0034] Figure 5 This is a schematic diagram of the measured oblique skirt point cloud model after region clipping in this invention;

[0035] Figure 6 This is a schematic diagram of the minimum bounding rectangle of the lower contour of the skirt and the hem of the skirt in this invention;

[0036] Figure 7 This is a schematic diagram illustrating the extraction of the wavy contour line deviation in this invention. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] A method for detecting the shape of a slanted skirt includes the following steps:

[0039] Step 1: After ironing the skirt to be measured flat, select a suitable mannequin and put the skirt on the mannequin so that the waistband of the skirt is completely above the waistline of the mannequin, the lower edge of the waistband is flush with the waistline of the mannequin, the left and right side seams of the skirt are symmetrical about the center line of the mannequin, and the skirt is stable when worn.

[0040] Step 2: Using a handheld multi-functional 3D scanner, spatial information of the skirt shape is obtained through light reflection calibration, resulting in a point cloud model of the skirt being measured. The handheld multi-functional 3D scanner used in this embodiment is an EinScanPro 2XPlus.

[0041] Step 3: Preprocess the point cloud model of the sloped skirt under test using reverse engineering software: reduce the amount of point cloud data through point cloud denoising and simplification. The reverse engineering software used in this embodiment is IMAGEWARE 13.0.

[0042] 3-1. Coordinate System Reconstruction: Because the scanner's self-positioning technology differs from reverse engineering software, this embodiment reconstructs the coordinate system of the mannequin not wearing the skirt being measured (i.e., the nude mannequin). For example... Figure 1 As shown, a waist circumference feature section is created for the mannequin. The center point O of this feature section is used as the origin, and the width, thickness, and vertical direction of the mannequin are used as the X, Y, and Z axes, respectively, to establish a spatial rectangular coordinate system. The old and new coordinate systems are then overlapped using the feature section to achieve the best fit, resulting in the reconstructed spatial coordinate system of the mannequin. Figure 1 As shown.

[0043] 3-2. Point cloud model alignment processing: The scanner spatial coordinate system of the measured inclined skirt is as follows: Figure 2 As shown, it serves as the unified spatial coordinate system for the point cloud of the measured oblique skirt, facilitating subsequent processing. The point cloud models of the dressed and nude mannequins are aligned. Specifically, the scanned model of the measured oblique skirt is completely superimposed onto the reconstructed mannequin's spatial coordinate system. The aligned result is shown below. Figure 3 As shown.

[0044] 3-3. Trimming Process: The "Plane Division Triangular Mesh" tool in reverse engineering software is used to trim the pre-processed test skirt model, removing the area above the waistline and the uneven parts of the skirt hem caused by manufacturing processes and fabric deformation. In this embodiment, the point cloud model of the test skirt is trimmed using planes with Z=0cm (i.e., the lower edge of the skirt waist) and Z=-54cm (i.e., the skirt hem, taking a skirt length of 54cm as an example). All models are confined to bounded regions in XYZ space. The results before and after the trimming are as follows: Figure 4 and Figure 5 As shown.

[0045] Step 4: Extraction of the profile index of the oblique skirt being measured:

[0046] 4-1. For example Figure 6 As shown, the waist and skirt outlines of the point cloud model are cut off respectively, and the minimum bounding rectangle of the curve outline is fitted to obtain the waist bounding rectangle and the skirt bounding rectangle. The width W1 and thickness T1 of the waist bounding rectangle, and the width W4 and thickness T4 of the skirt bounding rectangle are obtained.

[0047] 4-2. In the spatial coordinate system, lock the coordinates of the four critical points of the waist circumference rectangle and the skirt hem circumference rectangle. The four critical points are the points where the waistline or skirt hemline is tangent to the four sides of the corresponding circumscribed rectangle.

[0048] 4-3. For example Figure 6 As shown, the angle between the line connecting the critical points along the -X-axis of the waistline and the skirtline circumcircle rectangles from the side view and the vertical direction is denoted as the front development angle θ. F The angle between the line connecting the critical points along the +X axis and the vertical direction is denoted as the rear development angle θ. B .

[0049] The angle between the line connecting the outermost points of the waistline and skirt hem bounded rectangles along the +Y-axis and -Y-axis directions, respectively, from a front or back view, and the vertical axis is defined as the left-side unfolding angle θ. C right-side expansion angle θ D .

[0050] 4-4. Calculate the composite angle θ based on the four angles of development as shown in equation (1).

[0051] θ = 0.2θ F +0.2θ B +0.3θ C +0.3θ D Equation (1)

[0052] Step 5: Extract the fullness of the measured slant skirt as a lateral indicator:

[0053] 5-1. Taking the waist, abdominal, hip, and skirt cross-sections of the measured oblique skirt point cloud model as the research object, the "parallel section cutting point cloud tool" is used in reverse engineering software to sequentially cut the waist section L1, abdominal section L2, hip section L3, and skirt cross-section L4 along the -Z axis direction in the XOY plane on the point cloud model, and the four obtained sections L1, L2, L3, and L4 are extracted. k The bounded area S of the outline k The width W of its largest bounding rectangle k Thickness T k k = 1, 2, 3, 4.

[0054] 5-2. Extract the fullness δ of each cross section kThe fullness δ is the ratio of the cross-sectional area to the area of ​​the smallest bounding rectangle, used to characterize the cross-sectional shape, with a value ranging from 0 to 1. A smaller fullness δ value indicates a more pronounced unevenness in the cross-section; a larger value indicates a fuller cross-section. The calculation formula is as follows:

[0055]

[0056] Among them, S k W represents the area enclosed by the outline. k T k Section L k The width and thickness of the minimum bounding rectangle.

[0057] 5-3. Based on the overall fullness δ of the waist, abdomen, hip, and hem sections. k The overall fullness δ is calculated as shown in equation (3).

[0058] δ=0.2δ1+0.3δ2+0.3δ3+0.2δ4 Formula (3)

[0059] Step 6: Extraction of radial shaping parameters of the pleats on the oblique skirt being measured

[0060] 6-1. Longitudinal acquisition of the outward and inward fold point clouds of the oblique skirt under test: from the skirt hem crest point P t (x i ,y i (-54) and trough point P a (x j ,y j (-54) Perform a straight upward sectioning cut to obtain the radial point cloud of the folds, and define the point cloud at the waist section as the fold initiation point, correspondingly denoted as the outward fold initiation point P. t '(x i ',y i ',0) and the inward fold initiation point P a '(x j ',y j ',0).

[0061] 6-2. Extract the mean deviation of the outward folds Mean deviation of concave folds

[0062] The process for determining the deviation of a pleat (outward or inward pleat) is as follows:

[0063] First, find the central axis of the entire curve. The curve is composed of many point clouds. Then, calculate the distances between these point clouds and the central axis, starting from the smallest distance and continuing to the largest distance, thus obtaining the maximum radius. This process is equivalent to using a box, continuously expanding outwards from the center point until it completely encloses the curve, i.e., starting from the smallest radius and continuously expanding outwards until it perfectly encompasses the curve without redundancy. This method finds the maximum radius deviating from the central axis, that is, the maximum position of the curve from the central axis.

[0064] In this embodiment, the deviation of each fold point cloud is estimated using R(u). A larger value indicates a greater deviation and a less straight line-like appearance. The average of R(u) is used as the mean fold deviation. Figure 7 As shown, the formula is as shown in (4):

[0065]

[0066] In the formula: R(u)=max{R(v); v∈V}=max{R1,R2,...,R i ,...,R m} represents the maximum radius function of the cylinder surrounding the radially folded point cloud, where n is the wave number. Here, v represents the point cloud coordinates; V is the set of coordinates of the radially folded point cloud v; i∈1,2,...,m; m represents the number of point clouds. u is (x0,y0,α,β) representing the position and direction of the ideal axis, (x0,y0) is the intersection of the cylinder axis in the Z=0 plane, α is the angle between the projection of the cylinder axis onto the XOZ plane and the Z-axis, and β is the angle between the projection of the axis onto the YOZ plane and the Z-axis.

[0067] The value of u is determined by detecting the fold point cloud, and then R(v) is calculated, as shown in formula (5):

[0068]

[0069] Extract the mean deviation of the outward folds using the methods described above. Mean deviation of concave folds

[0070] Step 7: Calculate the naturalness F1, uniformity F2, three-dimensionality F3, sag F4, and smoothness F5 of the measured oblique skirt wave. Their meanings are shown in Table 1, and the calculation formulas are as follows:

[0071] Naturalness

[0072] Uniformity

[0073] Three-dimensionality

[0074] sag

[0075] Smoothness

[0076] Where: θ is the composite expansion angle. The mean straightness of the outward folds, δ represents the average straightness of the concave folds, and δ represents the overall fullness.

[0077] Table 1 Evaluation Indicators and Meanings of the Appearance Design of the Tested Skirt

[0078]

[0079] Step 8: Calculate the overall shape excellence F of the tested slanted skirt.

[0080] F=0.225*F1+0.212*F2+0.213*F3+0.220*F4+0.208*F5 (11)

[0081] The higher the F-value, the better the overall design of the asymmetrical skirt.

[0082] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for detecting the shape of a slanted skirt, characterized in that: The method comprises the following steps: Step one, wearing the measured skirt on a mannequin; Step two, three-dimensionally scanning the measured skirt worn on the mannequin to obtain a point cloud model of the measured skirt; Step three, pre-processing the point cloud model of the measured skirt by using reverse engineering software; Step four, extract the front side spread angle θ of the measured skirt F , the back side spread angle θ B , the left side spread angle θ C , and the right side spread angle θ D of the measured skirt, and calculate the comprehensive spread angle θ of the measured skirt according to the four spread angles; the front side spread angle θ F , the back side spread angle θ B , the left side spread angle θ C , and the right side spread angle θ D of the measured skirt Take the included angle between the connecting line of the corresponding points on the outer rectangle of the waistline contour and the outer rectangle of the skirt hem contour of the measured skirt and the vertical axis; the comprehensive spread angle θ of the measured skirt = 0.2θ F + 0.2θ B + 0.3θ C + 0.3θ D ; Step five, extract the fullness δ of the measured skirt waist cross section, abdominal cross section, hip cross section and skirt cross section respectively k , according to the fullness δ of the four cross sections corresponding to the overall fullness δ of the measured skirt k ; Cross section fullness δ k Take the ratio of the cross section contour area and the area of the minimum circumscribed rectangle of the cross section; The overall fullness δ of the measured skirt = 0.2δ1+0.3δ2+0.3δ3+0.2δ4; Step six, extract all wave crease profile lines on the measured slanted skirt respectively; the wave crease profile lines include the wave crease profile lines of flared and the wave crease profile lines of concave; calculate the average deviation of each wave crease profile line of flared and the average deviation of each wave crease profile line of concave ; The extraction process of the wave fold contour line is as follows: extracting the wave crest points or wave trough points corresponding to the same wave fold on the skirt waist lower edge line and the skirt hem contour line respectively, and cutting the wave fold contour line by using a plane passing through the wave crest points or wave trough points at the same time; the deviation degree of the wave fold contour line is the maximum distance of the wave fold contour line deviating from the central axis; Step seven, calculating the naturalness F1, uniformity F2, stereoscopicness F3, drapability F4 and smoothness F5 of the wave of the measured skirt as follows: F1 = 0.178 x + 0.641 x - 0.771 x - 5.575 x δ F2 = -0.048 x + 2.186 x + 8.339 x - 2.502 x δ F3 = 0.294 x + 0.803 x - 4.013 x - 5.999 x δ F4 = 0.002 x + 0.009 x + 1.134 x - 4.889 x δ F5 = -0.124 x -0.806 x +3.794 x -2.822 x δ Step eight, calculating the comprehensive modeling excellence F of the measured skirt as follows: F=0.225×F1+0.212×F2+0.213×F3+0.220×F4+0.208×F5 The greater the comprehensive modeling excellence F is, the better the modeling of the measured skirt is.

2. The method of claim 1, wherein: In step one, the skirt waist lower edge line of the measured skirt is flush with the waistline of the mannequin.

3. The method of claim 1, wherein: In step two, a handheld multifunctional 3D scanner is used for three-dimensional scanning.

4. The method of claim 1, wherein: In step three, the point cloud model is subjected to denoising and simplification processing.

5. The method of claim 1, wherein: In step three, the point cloud model is subjected to coordinate system reconstruction, point cloud model alignment processing of the dressed mannequin and the naked mannequin, and cutting to reserve the region between the skirt waist lower edge line and the skirt hem edge in sequence.

6. The method of claim 1, wherein: The point cloud model takes the width, thickness and vertical direction of the mannequin as the X-axis, Y-axis and Z-axis of the spatial rectangular coordinate system respectively.

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