DESCRIPTION

The present invention relates to a system for choosing an article of footwear.

Currently, the knowledge of the foot anatomy is not related with the measurement of the fit of a footwear. In fact, although there are scientific studies on foot dynamics (morphological changes of the foot under load with respect to different foot inclinations), these studies have not been used to relate a foot with a footwear.

Currently, the market offers articles of footwear with different sizes based on the foot length. For each size there can be different fits, depending on the way in which designers, or developers of shoe lasts, interpret the fashion trends. In fact, if for a specific season the trend is to have square and wide toes, the shoes that will derive from such a shape will have a more comfortable fit than a shoes with a pointed toe. Therefore, the end user will find himself/herself in an uncomfortable position because there could be a discrepancy between the size of his/her purchase history and the size due to the fashion of the moment. The confusion is exacerbated by the fact that, in lack of a shared standard, each region or country where footwear is produced adopts local extemporaneous solutions, creating a series of dysfunctional consequences.

With the advent of world drop shipping, on-line orders are often inadequate and the number of shoes that are returned and sent back at the expense of the sender is growing exponentially. Such returns of shoes, which are poorly packaged and visibly no longer new, will have to be packaged again in boxes and discounted significantly, generating a vicious circle of excessive production. The confusion about which size to buy is aggravated by the fact that there is little information and often wrong information about the conversion of the fits between different countries, and by the fact that there is no clear information between the various fits (footwear morphology) and the offers of fits that are available on the market.

The large majority of footwear manufacturers offer only one type of fit. Manufacturers that offer multiple options have a letter added to each numerical size in order to distinguish the specific fit. Many of these variations are due to differences that arise from different interpretations at manufacturing level and not to real requirements in terms of fits.

Moreover, footwear sizes are different in the various countries. In view of the above, users must find a size conversion table in order to understand which size they need. These tables are often wrong and the error can also be seen in the relation between measurement in cm and size or even in the fact that some conversions cannot be made because some sizes are completely missing.

The fit is influenced by countless variables (duration, environment and surfaces of the footwear bottoms, relation between the inclination of the sole and the contact of the forefoot with the ground, temperature, humidity, circulation, swelling, sweating, friction, frictional overheating, breathability, morphology, training, habits, and nutrition). Such a situation is aggravated by the technological progress in the field of components. In fact, in the old times, after measuring the customer's foot, a shoemaker would make a custom-made shoe. Today shoes are made in series by numerical control machines. Consequently the practical test made by the user in the store or at home (in case of an online purchase) is the only way to know whether that model of footwear fits comfortably. Nevertheless, problems often occur only subsequently, after using the footwear for a prolonged time; in fact, with the passing of time, an article of footwear that is apparently comfortable will turn out not to be so with the passing of time.

W02008070537A2 discloses a system and a method of making a custom footwear for a customer. The custom footwear comprises a custom upper, a custom insole and a custom sole.

The system comprises a preconstructed database wherein a series of tables is stored, each table corresponding to a style of the footwear that is to be chosen by the customer. Each table contains a plurality of vectors with indices that indicate the morphological features of a given foot (length, front foot width, rear foot width, instep height, instep circumference etc....). The system comprises 3D scanning means of the customer's foot in order to generate a 3D model of the foot. The system comprises feature extraction means to extract features from the 3D model and further comprises automatic processing and search means configured in such a way to search the footwear style table chosen by the customer in order to find the foot vector with indices similar to the features extracted from the 3D model of the foot. Therefore, in order to realize the custom footwear, such a method provides for:

- constructing the database comprising a plurality of footwear style tables, each one comprising a plurality of foot vectors with indices that indicate morphological features of a given foot;

- scanning the foot in 3D in order to obtain a 3D model of the foot;

- extracting features from the foot model that indicate the foot morphology;

- processing the features and selecting the foot vector with the indices that are the most similar to the features from the footwear style table chosen by the user;

- making the upper, the sole and the insole according to the selected foot vector and according to images of the 3D foot model. The system and method described in W02008070537A2 are somewhat complex and expensive because they require 3D scanning systems and a software program for making 3D models. Moreover, they require the use of processors with an extremely high computational level. In addition, since the system is designed to scan the user's foot completely, the customer must physically go to the store or to the factory equipped with said 3D scanning system. Therefore, the customer cannot receive information on the footwear that is most suitable for his or her foot while comfortably remaining at home because the scanning systems are extremely expensive and therefore they are not accessible to all users. So, the system described in W02008070537A2 is rather inconvenient and complicated for a user to use. Moreover, such a system is rather inconvenient for shopkeepers or shoe manufacturers because they will have to buy the entire scanning system, with a purchase cost as well as maintenance and management costs.

US2007043582A1 describes a method of providing a custom shoe for a customer that is composed of a plurality of assemblage elements. Each element of the shoe is selected from a group of elements that have the same function, but different conformation and different physical attributes based on the type of foot and/or on the type of user wearing the shoe.

The method provides for identifying measurable features (foot length, foot width, foot conformation, customer's weight, customer's height, etc...) and/or non-measurable features (user's age, user's sex, activity usually performed by the user) of the foot and/or of the user. The measurable features can be manually taken by a shopkeeper in a store or with special measuring devices (scanners, load cells, and the like). After obtaining such features, the shopkeeper can rely on his/her experience to choose the most appropriate components for the custom footwear, or he can rely on a special software installed in a device that processes the features and outputs a list of components to be assembled in order to produce the footwear.

The method described in US2007043582A1 requires the customer to go to the store in order to find a suitable footwear. Therefore such a method is rather inconvenient for the customer. Moreover, the method provides for obtaining a multitude of information and features that make the selection of the elements of the footwear extremely complex. Moreover, due to the amount of information and features of the foot and/or the user, the method is neither reliable nor precise.

W02008036398A2 describes an apparatus and a method for determining at least one property of the foot, the primary purpose being to select or recommend foot care products (such as insoles, pads, etc.). The apparatus comprises an analysis device comprising a support surface on which the foot is to be placed and a plurality of pressure sensors under the surface to detect pressure data relative to the pressure exerted by the foot. The apparatus further comprises a software program capable of processing said data to classify the foot into a foot type stored in a database and to select a suitable product for treating the foot. The product suitable for treating the foot is selected based on software programs that associate different foot care products with the foot type. Also in this case, in order to analyze his/her own foot, a user must necessarily go to a hospital or a podiatry office equipped with the system and in particular with the analysis device provided with pressure sensors. Moreover, the purpose of the system is to recommend foot care products or orthotics, and not to recommend a suitable footwear for the foot.

The purpose of the present invention is to eliminate the drawbacks of the prior art by providing a system for choosing an article of footwear that is reliable and easy to understand both for those who buy the footwear and for the whole chain of those who instead produce and sell the footwear. Another purpose is to provide a system for choosing an article of footwear that is simple and easy to use even for a user who does not have special skills.

Another purpose is to provide a system for choosing an article of footwear that is able to reduce the errors made in orders, and ensure a uniformity of choice, avoiding the discrepancies that exist in the current market.

These purposes are achieved in accordance with the invention with the features of the appended independent claims.

Advantageous embodiments of the invention appear from the dependent claims.

The system for choosing an article of footwear according to the invention is defined by the independent claim 1 .

The method for choosing an article of footwear according to the invention is defined by the independent claim 3.

The advantages of the system and of the method according to the invention, which are respectively described in the independent claims 1 and 3, are evident.

The system and method devised by the applicant only need a 2D image of the foot and the length of the foot as input data. The 2D image can be obtained by simply taking a photograph of the sole of the foot, whereas the length of the foot can be measured with a ruler or graduated paper. Thus, the user can easily obtain such information while comfortably remaining at home and send such information online to an operations center which in turn will process such information (image and length) in order to obtain fit and size information that is sent to the customer and/or to footwear vendors in order to identify the type of footwear that is most suitable for the customer.

In addition, the system and method according to the invention allow for obtaining the fit and size information in a much simpler and faster manner than the systems described in the documents of the prior art. In fact, the system according to the present invention only provides for: constructing a grid with twelve squares on the foot image, calculating the full-empty ratio of each square, creating a user table with the twelve full-empty ratio values, converting the foot length into a size, and finally using the foot length and the user table in the experimentally preconstructed lookup table to obtain the fit and the size.

The use of the twelve squares and of the full/empty variations of the squares to define the fit of a footwear is the result of numerous complex experimental studies that were performed to obtain a choice system that on one side was efficient and precise and on the other side was implementable in a simpler way than the current systems of the prior art.

Therefore, the invention completely satisfies both the needs of a customer and those of shoe retailers or suppliers without having to use complex 3D scanning systems and sensors. In fact, the customer can obtain information on the footwear that is most suitable for his/her foot without having to undergo slow and complex measurements made in a store or in a dedicated center. The shopkeeper or footwear producer instead receives precise information that is simple to understand for supplying or producing a suitable footwear for a customer, without the necessity of using a complex and expensive system to measure and analyze the foot.

Additional features of the invention will appear clearer from the following detailed description, which refers to a merely illustrative and therefore non-limiting embodiment thereof, illustrated in the appended drawings, wherein:

Fig. 1 is a block diagram of the system for choosing an article of footwear according to the invention; Fig. 2 is a view of an image of a sole of a foot captured by the image capture means of the system according to the invention;

Fig. 3 is a view of a grid constructed on the image of the sole of the foot of Fig. 2; Fig. 4 is a detail of Fig. 3 illustrating a square of the grid, wherein a full and an empty of the square is shown;

Fig. 5 is a schematic view illustrating a lookup table of the system according to the invention;

Fig. 6 is a view of an image of a sole of an ideal standard foot, divided into three macro-regions and twelve detail areas;

Fig. 7 is a view illustrating the construction of the grid onto the image of Fig. 6.

With the aid of the Figures, the system for choosing an article of footwear according to the invention is described, which is generally indicated by the reference numeral 100. hereinafter, the term “foot” indicates the right foot of the user, it being understood that the system can also work with the left foot of the user.

With reference to Fig. 1 , the system (100) comprises: - image capture means (1 ) suitably configured to capture an image

(Im) of a sole of the foot of the user; and

- length measurement means (2) suitably configured to measure a length (Lp) of the foot of the user, measured from a rear end of the heel to a front end of the hallux. The image capture means (1) may be a camera, a scanner or another type of optical detector.

The length measurement means (2) may be a meter or a measuring sensor or a software program that detects the length (Lp) of the foot from the image (Im)., By way of example, the user can take a photograph of his/her foot on graduated paper, thus obtaining the image (Im) of the sole of the foot and the length (Lp) of the foot at the same time.

Fig. 2 shows the image (Im) of the sole of the foot and the length (Lp) of the foot, measured from a rear end of the heel to a front end of the hallux..

The system (100) comprises grid construction means (3) suitably configured to construct a grid (Gr) onto the image (Im) of the foot captured by the image capture means (1 ).

With reference to Fig. 3, the grid (Gr) has a rectangular shape and comprises twelve identical squares (Q) disposed in two lines and six columns. Considering a longitudinal axis (X) of the image (Im) of the sole of the foot, six squares are disposed above the longitudinal axis and the other six squares are disposed under the longitudinal axis.

The grid (Gr) begins from the rear end of the heel of the image (Im) of the sole of the foot and has a total length equal to the length of the foot (Lp) plus a constant value (k) that takes into account the tolerance between a size and the next one.

Therefore each square has a side with a length (La) equal to the total length (Lt) of the grid divided by six; i.e.

La = (Lp + k)/6.

By way of example, the constant value (k) is chosen in the range of 5-10 mm, for instance k = 7,8 mm, in the case in which the length of the foot Lp corresponds to a European size 38.5.

Full/empty ratio calculation means (4) calculate a full/empty ratio (R) of each square (Q) of the grid (Gr).

With reference to Fig. 4, the full/empty ratio is the ratio (R) between an area of a full surface (Sp) of the square occupied by the image of the sole of the foot and an area of an empty surface (Sv) of the square not occupied by the image, i.e. R = Sp/Sv

The area of the full surface (Sp) can be calculated with BLOB (Binary Large Object) techniques.

The image (Im) of the sole of the foot is dark against a light background. Each square (Q) in the grid is converted into a two-color binary image, e.g., black and white. Then the full surface (Sp) that is darker than the empty surface (Sv) is identified. The full surface (Sp) is approximated to a regular surface, whose area can be computed using bounding box techniques of known type. Alternatively, the boundary profile between the full surface (Sp) and the empty surface (Sv) is approximated to a curve and the area of the full surface (Sp) is calculated using the integral of the curve.

Once the area of the full surface (Sp) is calculated, the area of the empty surface (Sv) is calculated by subtraction from the area of the square.

Table creation means (5) create a user table (T) that contains twelve full/empty ratio values (R) of the twelve squares of the grid (Gr).

The system (100) comprises a database (DB) that contains a lookup table (7). With reference to Fig. 5, the lookup table (7) comprises:

- a size vector (Vs) comprising a plurality of footwear sizes (S1 , ....

Sm);

- a fit vector (Vc) comprising a plurality of fits (C1 , ...Cn) for each footwear size; and - a table matrix (M) containing a plurality of reference tables (T11 ,

..., Tnm) that correspond to each size and to each fit.

Each reference table of the table matrix (M) has been created experimentally and comprises twelve full/empty ratios that correspond to a given size and to a given fit of the footwear. By way of example, if there are 30 footwear sizes and 10 fits for each size, the table matrix (M) will contain 300 reference tables.

With the system according to the invention, many reference tables can be implemented based on the sizes and the fits of a footwear model.

The database (DB) may comprise a plurality of lookup tables (7) based on a plurality of footwear models. In such a case, the system comprises model choice means (9) that select the footwear model chosen by the user to access the lookup table relative to the requested model.

Conversion means (6) convert the length (Lp) of the foot of the user into a footwear size (S ^* ) that corresponds to said length. The conversion means (6) communicate with the lookup table (7) of the database (DB) to identify the size of the user in the size vector (Vs) of the lookup table.

The table creation means (5) communicate with the lookup table (7) of the database (DB) to identify the reference table in the table matrix (M) closest to the user table (T) created by the table creation means (5). Based on the size and reference table, the lookup table (7) outputs the fit (C ^* ) that corresponds to the size and to the reference table.

Footwear choice means (8) receive the size (S ^* ) and the fit (C ^* ) from the database (DB) in such a way that the most suitable footwear for the user's foot can be identified.

Following is a description of the studies that were performed by the inventor to construct the grid (Gr).

For the sake of convenience, with reference to Fig. 6, the inventor considered an ideal standard foot of European size 38.5 (intermediate size between size 34 and size 43), having a length Lp= 24 cm measured from a rear end of the heel to a front end of the hallux.

Such a standard foot comprises:

- a longitudinal axis (X), - a Chopard joint identified by a first straight line (r1) inclined with respect to the longitudinal axis (X) by an angle (a) greater than 90°, and

- a Lisfranc joint identified by a second straight line (r2) inclined with respect to the longitudinal axis (X) by an angle (b) lower than 90°. In this way, starting from the calcaneus, the foot can be divided into three macro-regions: hindfoot (R1), midfoot (R2), and forefoot (R3).

The hindfoot (R1) goes from an initial straight line (rO) tangent to the rear end of the heel to the first straight line (r1) corresponding to the Chopard joint. The initial line (rO) is orthogonal to the longitudinal axis (X). The midfoot (R2) goes from the first straight line (r1 ) corresponding to the Chopard joint to the second straight line (r2) corresponding to the Lisfranc joint.

The forefoot (R3) goes from the second straight line (r2) corresponding to the Lisfranc joint to a third straight line (r3) passing through the front end of the hallux. The third straight line (r3) is orthogonal to the longitudinal axis (X).

Each macro-region (R1 , R2, R3) can be divided into four detail areas with respect to the longitudinal axis (X) and with respect to respective transverse axes (t1 , t2, t3). The hindfoot (R1) comprises the following detail areas: inner heel

(A), outer heel (B), inner arch beginning (C), and outer arch beginning (D).

The midfoot (R2) comprises the following detail areas: inner central arch (E), outer central arch (F), inner arch end (G), and outer arch end (H).

The forefoot (R3) comprises the following detail areas: internal transverse arch (I), external transverse arch (L), first metatarsal end (M), second and third metatarsal end (N). The detail areas vary from foot to foot and greatly influence the type of fit. Therefore, the purpose of the invention was to find a system for measuring such detail areas of the foot.

In the case of an ideal standard foot with size 38.5 (intermediate size from 34 to 43), the hindfoot (R1) has a length L1 = 8.19 cm, the midfoot (R2) has a length L2 = 8.59 cm, and the forefoot (R3) has a length L3 = 7.22 cm. These lengths are measured on the longitudinal axis (X). The result is Lp = L1 + L2 + L3 = 24 cm

Starting from these measurements of an ideal standard foot, for the construction of the grid (Gr), the inventor made some adjustments in order to obtain a grid with 12 equal squares, which mathematically can determine the change in size in a regular and constant mode (change of half a size every increase or decrease of 0.55 mm on the length La of the side of the square). In each case the 12 equal squares can cover the 12 detail areas of the foot.

A constant value d1 = 2 mm was added to the L1 length of the hindfoot (i.e., the first straight line (r1) of the Chopard joint was shifted forward from the longitudinal axis (X)).

A constant value d2 = 2 mm was subtracted from the L2 length of the midfoot (i.e., the second straight line (r2) of the Lisfranc joint was shifted backward relative to the longitudinal axis (X)).

A constant value k = 7.8 mm was added to the length L3 of the forefoot.

Thus, the three macro-regions of the foot have an equal length, i.e., a length of 80 mm.

In the construction of the grid, the first line r1 that separates the forefoot from the midfoot and the second line r2 that separates the midfoot from the forefoot were considered orthogonal to the longitudinal axis (X). In view of the above, with reference to Fig. 7, the grid (Gr) comprising twelve identical squares (Qa, Qb, Qc, Qd, Qe, Qf, Qg, Qh, Qi, Ql, Qm, Qn) was constructed, wherein each square contains a respective detail area (A, B, C, D, E, F, G, FI I, L, M, N) of the foot. As a result of experimental studies performed on different types of feet, the inventor ascertained that the variation of the full/empty ratio of the twelve areas of the foot affects the fit of a footwear.

Therefore, the inventor created a database with a plurality of tables containing twelve full/empty ratios correlated with the model, the size and the fit of the footwear.

Thus, after choosing the footwear model, all the user has to do is provide an image of the sole of the foot and the length of the foot. From this information, the system (100) builds a table of twelve full/empty ratios to be compared with the tables of the database and indicates the size and the fit of the shoe that are most suitable for the user's foot.

To the present embodiment of the invention, equivalent variations and modifications may be made, within the scope of a person skilled in the art, but still within the scope of the invention as expressed by the appended claims.