SYSTEM FOR CHOOSING A FOOTWEAR

Abstract

A system for choosing an article of footwear provides for capturing an image of a foot in order to obtain a reference sole or morphology, measuring a length of the foot for the application of equalization and calculation constant values, constructing a grid on the image including twelve squares, calculating full/empty ratios of the twelve squares of the grid and storing them in a user table, using the length of the foot and the user table in a lookup table of a database to find a size and a fit of an article of footwear that is most suitable for the foot of the user.

Claims

1. System for choosing an article of footwear, comprising: image capture means suitably configured to capture an image of a sole of the foot of the user; length measurement means suitably configured to measure a length of the foot of the user from a rear end of the heel to a front end of the hallux; grid construction means suitably configured to construct a grid on the image of the foot captured by the image capture means; said grid has a rectangular shape and comprises twelve identical squares disposed in two lines and six columns; six squares are disposed above a longitudinal axis of the image of the sole of the foot and the other six squares are disposed under the longitudinal axis; the grid begins from the rear end of the heel of the image of the sole of the foot and has a total length equal to the length of the foot plus a constant value; each square has a side with a length equal to the total length of the grid divided by six; full/empty ratio calculation means suitably configured to calculate a full/empty ratio of each square of the grid; said full/empty ratio is the ratio between an area of a full surface of the square occupied by the image of the sole of the foot and an area of an empty surface of the square not occupied by the image of the sole of the foot; table creation means suitably configured to create a user table that contains twelve full/empty ratio values of the twelve squares of the grid; a database that contains a lookup table comprising: a size vector comprising a plurality of footwear sizes; a fit vector comprising a plurality of fits for each footwear size; and a table matrix containing a plurality of reference tables that correspond to each size and to each fit; wherein each reference table of the table matrix has been created in an experimental way and comprises twelve full/empty ratios that correspond to a given footwear size and to a given footwear fit; conversion means suitably configured to convert the length of the foot of the user measured by said length measurement means into a footwear size that corresponds to said length of the foot of the user, wherein the conversion means and the table creation means communicate with said lookup table of the database in order to identify the size of the user in the size vector the lookup table and to identify the reference table in the table matrix in closest position with respect to the user table created by the table creation means, said lookup table being configured in such a way to output said footwear size that corresponds to said length of the foot of the user, and a fit that corresponds to the size and to the reference table identified in the lookup table.

2. The system of claim 1, wherein said database comprises a plurality of lookup tables wherein each lookup table refers to a fit model and foot morphology that can be associated with a footwear model and said system comprises model choice means suitably configured in such a way that the user can choose the footwear model; said model choice means being connected to the database in order to choose the lookup table according to the footwear model chosen by the user.

3. Method for choosing an article of footwear, comprising the following steps: capture of an image of a sole of the foot of the user; measurement of a length of the foot of the user from a rear end of the heel to a front end of the hallux; construction of a grid on the image of the foot; said grid has a rectangular shape and comprises twelve identical squares disposed in two lines and six columns; six squares are disposed above a longitudinal axis of the image of the sole of the foot and the other six squares are disposed under the longitudinal axis; the grid begins from the rear end of the heel of the image of the sole of the foot and has a total length equal to the length of the foot plus a constant value; each square has a side with a length equal to the total length of the grid divided by six; calculation of a full/empty ratio of each square of the grid; said full/empty ratio is the ratio between an area of a full surface 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 of the sole of the foot; creation of a user table that contains twelve full/empty ratio values of the twelve squares of the grid; creation of a database that contains a lookup table comprising: a size vector comprising a plurality of footwear sizes; a fit vector comprising a plurality of fits for each footwear size; and a table matrix containing a plurality of reference tables that correspond to each size and to each fit; wherein each reference table of the table matrix has been created in an experimental way and comprises twelve full/empty ratios that correspond to a given footwear size and to a given footwear fit; conversion of the length of the foot of the user into a footwear size that corresponds to said length of the foot of the user, use of said length of the foot of the user and of said user table in said lookup table to output said footwear size that corresponds to said length of the foot of the user and a fit that corresponds to the size and to the reference table identified in the lookup table.

4. The method of claim 3, wherein said database comprises a plurality of lookup tables wherein each lookup table refers to a footwear model; a step of model choice being provided, wherein the user can choose the footwear model in such a way to choose the lookup table of the database according to the footwear model chosen by the user.

Description

[0034] 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:

[0035] FIG. 1 is a block diagram of the system for choosing an article of footwear according to the invention;

[0036] 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;

[0037] FIG. 3 is a view of a grid constructed on the image of the sole of the foot of FIG. 2;

[0038] 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;

[0039] FIG. 5 is a schematic view illustrating a lookup table of the system according to the invention;

[0040] 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;

[0041] FIG. 7 is a view illustrating the construction of the grid onto the image of FIG. 6.

[0042] 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.

[0043] 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.

[0044] With reference to FIG. 1, the system (100) comprises: [0045] image capture means (1) suitably configured to capture an image (Im) of a sole of the foot of the user; and [0046] 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.

[0047] The image capture means (1) may be a camera, a scanner or another type of optical detector.

[0048] 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).

[0049] 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.

[0050] 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.

[0051] 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).

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Full/empty ratio calculation means (4) calculate a full/empty ratio (R) of each square (Q) of the grid (Gr).

[0057] 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

[0058] The area of the full surface (Sp) can be calculated with BLOB (Binary Large Object) techniques.

[0059] 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.

[0060] 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.

[0061] 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).

[0062] The system (100) comprises a database (DB) that contains a lookup table (7).

[0063] With reference to FIG. 5, the lookup table (7) comprises: [0064] a size vector (Vs) comprising a plurality of footwear sizes (S1, . . . Sm); [0065] a fit vector (Vc) comprising a plurality of fits (C1, . . . Cn) for each footwear size; and [0066] a table matrix (M) containing a plurality of reference tables (T11, . . . , Tnm) that correspond to each size and to each fit.

[0067] 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.

[0068] 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.

[0069] With the system according to the invention, many reference tables can be implemented based on the sizes and the fits of a footwear model.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] Following is a description of the studies that were performed by the inventor to construct the grid (Gr).

[0075] 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.

[0076] Such a standard foot comprises: [0077] a longitudinal axis (X), [0078] 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 [0079] a Lisfranc joint identified by a second straight line (r2) inclined with respect to the longitudinal axis (X) by an angle (3) lower than 90?.

[0080] In this way, starting from the calcaneus, the foot can be divided into three macro-regions: hindfoot (R1), midfoot (R2), and forefoot (R3).

[0081] The hindfoot (R1) goes from an initial straight line (r0) tangent to the rear end of the heel to the first straight line (r1) corresponding to the Chopard joint. The initial line (r0) is orthogonal to the longitudinal axis (X).

[0082] 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.

[0083] 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).

[0084] 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).

[0085] The hindfoot (R1) comprises the following detail areas: inner heel (A), outer heel (B), inner arch beginning (C), and outer arch beginning (D).

[0086] 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).

[0087] 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).

[0088] 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.

[0089] 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

[0090] 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.

[0091] 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)).

[0092] 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)).

[0093] A constant value k=7.8 mm was added to the length L3 of the forefoot.

[0094] Thus, the three macro-regions of the foot have an equal length, i.e., a length of 80 mm.

[0095] 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).

[0096] 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, H I, L, M, N) of the foot.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.