SI22848A - Procedure for measurement of inner dimensions of footwear - Google Patents

Abstract

The subject of the invention is a procedure for measurement of inner dimensions of footwear, which enables a precise determination of inner footwear dimensions by means of a three-dimensional cloud of points of the inner footwear surface. According to the procedure for measurement of inner dimensions of footwear in accordance with the invention, only a ground plan and a side view footwear snapshots (X-ray or other kind, based on penetration of radiation through matter) are used for calibration of the 3D model of footwear, in which case a contrasting agent is put into footwear, by which a contrast is achieved between the footwear interior and the remaining part of the footwear, considering the greyness level of the X-ray snapshot.

Description

PROCEDURE FOR MEASURING INTERNAL DIMENSIONS OF SHOES

The object of the invention is a method for measuring the internal dimensions of a shoe, which enables accurate determination of the internal dimensions of the shoe by means of a three-dimensional cloud of points of the inner surface of the measured shoe. The invention belongs to Class A43D1 / 06 of the International Patent Classification.

A technical problem solved by the present invention is how to measure the three-dimensional shape of the inside of the shoe and the internal dimensions of the shoe, such as length, width in the ankle, circumference in the ankle, height in the toe, height in the heel, width in the heel and other internal dimensions without damaging the footwear during measurement.

The development of foot gauges to accurately measure three-dimensional foot geometry has opened up the possibility of using foot gauges in the classic footwear store, where footwear is stocked on shelves and in a store warehouse. The customer first measures the feet using a foot gauge, and then compares the foot gauge computer to the geometry of the feet measured with the geometry of all the shoes available in the store and suggests the shoes that would best fit the measured feet. In order to compare the measured feet with shoes, a computer program requires accurate information on the geometry of the inside of the shoe, which can be measured by the measuring method of the present invention.

A partial solution to a technical problem is described in patent document EP 1 791 448 A1, which describes a device that can measure only the length of a shoe, which is not sufficient to compare the geometry of the foot and the shoe.

The technical problem is also solved by the method described in patent document US2008004833A1, where a large amount of X-ray images are required to measure the inside of the shoe. Because of this, the method described is very time consuming and unsuitable for measuring a large amount of shoes.

io In accordance with the method for measuring the internal dimensions of a shoe according to the invention, only a floor plan and a side view of the shoe (x-ray or other type based on penetration of rays through the substance) are used, with a contrast medium inserted into the footwear to contrast the inside of the shoe and other parts of the shoe and considering the gray level of the X-ray.

The process for measuring the internal dimensions of a shoe according to the invention will be explained on the basis of an embodiment and the accompanying figures, of which:

Figure 1 is a schematic view of the production of the clip;

Figure 2 is a plan view and a side X-ray image of a contrast medium containing shoe;

Figure 3 is a section of the inside of an X-ray shoe;

Figure 4 is a schematic view of the different shape of the shoe, with the same outlines in plan view and lateral view;

Figure 5 X-ray of an empty shoe; Figure 6 3D model of the lower part of the shoe interior; Figure 7 compares footage of the shoe facing and away from the X-ray source;

Figure 8: placement of the shoe while capturing the side clip;

Figure 9 3D model of shoe interior.

The method for measuring the internal dimensions of a shoe according to the invention enables to determine the three-dimensional shape of the inside of the shoe, and thus the internal dimensions, by using a plan view and a side view of the shoe (X-ray or other type based on penetration of rays through the substance). obuvala.

Two X-ray or other types of imagery are required to determine the 3D model of the shoe interior, based on the penetration of rays through the substance, namely the floor plan of the shoe and the shoe image from the side (Figure 1,2). Just the information about the outline of the interior from these two views is not enough to determine the unique shape of the inside of the shoe in a completely unique way. Such an example of differently shaped shoes is shown in Figure 4, where both cases share the same floor plan and lateral outline, but still differ greatly in shape. This also makes the size of the left and right shoes differ greatly, which cannot be deduced from the contours of the floor plan and the side view. The error in this would be too large to be neglected when fitting or. matching shoes and feet. Due to this problem, it is necessary to add new information when constructing a 3D model of the footwear interior, which is the level of gray in the X-ray image of the floor plan.

When X-rays or other rays pass through a substance, a portion of the rays are absorbed into the substance and a part of it is passed through the substance and detected by detectors. The amount of rays passing through a substance depends on the absorption coefficient of the substance and the thickness of the material through which the rays pass. The relationship between the thickness of the material and the amount of particles passing through the substance is exponential. According to the above, depending on the amount of rays passing through the substance, the thickness of the material can be inferred.

X-rays or other rays absorb both footwear and contrast agent. Comparing Figures 2a and 2b, we find that the absorption of the shoe itself is very small compared to the absorbance of the contrast medium. Above all, this ratio is small in the front of the shoe, which is the most important in terms of shape and fit of the foot / shoe. If necessary, the contribution of the blank shoe to the measurement can be deducted. However, for this purpose an additional measurement of the blank shoe is required.

Liquid, gel or solid particles may be used as a contrast agent in the shoe. When used as a contrast medium, the liquid should be placed in an elastic wrap to prevent the shoe from getting wet. In the case of particulate matter, keep the particles as small as possible in order to achieve better resolution of the measurement. However, the particles should not be too small, since it is difficult to remove them from the shoe in this case.

The absorbance of the contrast medium should be such that the maximum contrast between the shoe and the interior is reached. On the other hand, the absorption should not be too large, since it must be achieved that the use of grayscale can also be used to infer the thickness of the contrast agent, as will be shown below.

Due to the high contrast between the inside and the outside of the shoe, 10 the part of the clip that relates to the inside of the shoe is eliminated. In this case, it is necessary to binarize the image with a certain threshold and eliminate all disturbed objects. Figure 5 also clearly shows the different grayness of the object, which is proportional to the thickness of the material.

To determine the relationship between the grayscale of the X-ray image and the thickness of the contrast medium 15, an X-ray image of the contrast medium with variable thickness is made. For this purpose, use a slightly inclined prism filled with contrast medium. This results in a continuously varying level from 0 mm to a level where the passage of X-rays or other beams can no longer be detected. The form of the function is exponential.

The 3D model of the shoe's interior is built from the bottom of the shoe's interior. In doing so, it is assumed that the lower part of the interior of the shoe is straight in the y direction. In fact, the lower part is not completely flat, but this assumption does not significantly affect the determination of the shoe and foot matching parameters. From the floor plan, the shape of the bottom of the shoe is determined, and the curvature of the shoe in the x direction is determined from the lateral view, as shown in Figure 8. On this basis, the upper part of the shoe's interior is built. The points of the upper part are determined from the blueprint of the grayscale according to the intensity of the particular point. This does not achieve the perfect result. The highest point in the cross section of the shoe should match the side view of the shoe. This does not happen completely for the following reasons: due to the influence of the outside of the shoe on the grayness of the image, the non-ideality of the X-ray or other image which is noisy, and the fact that we cannot detect X-rays or other rays on the part of the shoe where it is thicker. Because of these problems, the height of the shoe is adjusted to fit the lateral view.

Using a metal calibration grid whose X-ray or another type is taken at multiple heights, the relationship between the image units (pixels) and the length units (eg mm) is determined. This relation must be made for both x and y directions at different heights.

The position of the shoe in the X-ray machine has a very large influence on the measurement.

Keep the floor plan completely perpendicular to the plane of the sole. To reduce projection errors, it is preferable that the shoe is turned away from the sensor during the floor plan (Figure 7). This gives a better picture of the lower part of the shoe, which is usually the widest part of the shoe.

The side track should be rotated exactly 90 ° with respect to the floor plan. It should be positioned in such a way that the X-rays or other rays go as precisely as possible between the sole and the inside of the shoe (Figure 8).

The final complete calibrated 3D model of the shoe performed according to the method of the 5 invention is shown in Figure 9.

Claims (4)

PATENT APPLICATIONS 1. A method for measuring the internal dimensions of a shoe using an X-ray or other type of shoe image based on the penetration of rays through the substance, 5, characterized in that the complete calibrated 3D model of the shoe is obtained by means of a ground plan image and an image by the measured shoe and by the insertion of a contrast medium into the shoe by considering the grayscale of the image according to the intensity of a particular point. Method for measuring the internal dimensions of the shoe according to claim 1, characterized in that the floor plan must be completely perpendicular to the plane of the sole of the shoe. A method for measuring the internal dimensions of a shoe according to claims 1,2, characterized in that the lateral image must be rotated exactly 90 ° with respect to the floor plan in such a way that X-rays or other rays go as precisely as possible between 20 soles and insole. A method for measuring the internal dimensions of a shoe according to claims 1 to 1, characterized in that the resulting image is binarized with a certain threshold for eliminating interfering objects.