Scanner-Assisted Selection of Fitting Footwear with Individualized Footbed

Abstract

A method is described for selecting, in a cost-effective and largely automated manner, best fit footwear with an optimally selected or individualized footbed. With the aid of a preferably multisensory foot scanner, the geometric three-dimensional shape of the foot and the plantar pressure image registered with it are determined at the same time. A database of digitized shoe interiors is used for determining, by means of a best fit selection, the series-produced shoe that best matches the 3D foot model. Using a conventional system for producing individualized insoles and/or footbeds, an insole that matches the sole of the foot is selected or prepared and, in a further, novel method step according to the invention, by means of numerical determination of the three-dimensional surfaces of the footbed, the foot sole and the peripheral zone of the sole in the inner shoe, the so-called insole space, the required insole constituting the footbed is selected, or further processed numerically, such that it fits in an optimum manner into the selected best fit item of footwear in the put-on condition.

Description

Supplying customers with well-fitting footwear in a cost-effective manner has been a problem that has, to date, been only insufficiently solved by the shoe trade which still is not very optimized in terms of metrology, whether in the area of dress shoes or casual shoes, sports shoes, orthopedic shoes or special shoes such as, e.g., safety shoes.

Selecting an item of footwear which fits best from a catalog of available products is often referred to as “best fit” selection. The production of individually made shoes, on the other hand, is referred to as “customization”. It goes without saying that a “best fit” solution is, as a rule, considerably more reasonably priced than an individual customization.

The subject matter of the present application relates to methods and arrangements for putting to practice a cost-effective supply of the customer with best-fit footwear which also comprises an individually customized or best-fit type selected footbed.

The efforts that have been made so far to produce customized footwear or best-fit footwear at low cost have, in most cases, failed to take the role of a fitting footbed into consideration. With regard to the correct fit and the functionality of a shoe, the footbed or an insole, however, plays at least as significant a role as the fit of the shoe upper and constitutes a commonly used option for an individual optimization of footwear.

To this end, either series-produced or customized insoles are used which are selected for an individual foot (best fit insoles) or are specially made (customized insoles).

Known methods for this include, among others,

for the selection of a series-produced insole:

by an expert or by the wearer of the shoe himself/herself

by an analysis and proposal system, e.g., a 2D flatbed scanner for determining the contour of the foot sole and a corresponding expert system which generates a proposal (http://www.boot-doc.com/),

for the production of individual insoles:

the customer's foot sole is molded with the aid of a foot impression foam, a plaster cast or a vacuum cushion and, on this basis, an insole is produced manually or in a partly automated manner (http://www.conform-able.com, http://www.fussgesundheit.info/abdruck.htm),

the customer's foot sole is determined as a 2D contour using a flatbed scanner

and, based thereon, a CAD/CAM milling machine is controlled by means of an interactive computing program,

the milling machine producing an individual pair of insoles from a blank (see, e.g., www.josamerica.com, System Ortho Scan Organizer),

the 3D shape of the foot inclusive of the foot sole is determined using a 3D scanner (see, e.g., www.vorum.com; System Can Fit-Plus Yeti or http://www.pedcad.de),

the pressure image, i.e. the local distribution of the load on the foot sole is recorded using a pressure image sensor with a high local resolution (see, e.g., www.bauerfeind.com; MediLogic® foot pressure measuring system).

On the basis of this data, manual or semi-automated processes are used for selecting or producing an individual insole that matches each foot.

The insoles selected or prepared based on the foot sole information (e.g., 2D image of the foot sole or 2D pressure distribution) are, however, not yet adjusted to a selected item of footwear since the space coordinates of the inner shoe that are required for the definition of the outer peripheral zone of the footbed are not determined by these insole production technologies and are not made use of, either. Due to the lack of spatial information between the foot, the insole and the inner shoe, it is not possible on the basis of the known methods to automatically produce or suitably select an insole not only with respect to the surface thereof that is in contact with the foot sole of the customer, but also with respect to its extent and its surfaces in contact with the customer's shoe.

The company of corpus.e AG, Stuttgart, Germany (www.corpus-e.com) has developed a particularly cost-effective photogrammetric 3D foot scanner under the designation “Lightbeam®”, which simultaneously and fully automatically digitizes those areas of the human foot which are visible from above and from the side (see Rutschmann, U.S. Pat. No. 7,433,502 B2, “Three-dimensional digitized capturing of the shape bodies and body parts using mechanically positioned imaging sensors”) and, at the same time, measures the pressure image of the foot sole by means of a locally resolving pressure sensor installed in the foot scanner (see Rutschmann et al., U.S. Pat. No. 7,489,813 B2, “Method and System for Detecting the Three-Dimensional Shape of an Object”.

Since both measuring methods are mechanically rigidly combined in the photogrammetrically marked platform on which the customer stands during the scanning process, this “Lightbeam®” scanner provides a combined data record: the geometric 3D model of the foot and, at the same time, the pressure image of the foot sole. Due to this installation, both data records are compulsorily registered (aligned with each other) and generate a so-called “multisensory” data record. As is shown in FIG. 2 for a better illustration of the prior art, the geometric 3D shape -11- and the physical plantar pressure image -21- are blended into one single numerical model. Using this scanner technology, the position of the foot sole (based on the pressure image) in relation to the spatial foot model (as determined by the photogrammetric 3D foot scanner) is therefore known individually for each customer and separately for each foot.

corpus.e AG has furthermore developed a cost-effective technology for digitizing the interior space of series-produced shoes (see Pfeiffer and Rutschmann, DE 2007 032 609 A2, “Kostengünstige Erfassung der inneren Raumform von Fuβbekleidung and Körpern” [Cost-effective detection of the three-dimensional inside shape of footwear and bodies]; Massen, U.S. Pat. No. 7,446,884 B2, “Method for optically detecting the spatial form of inside spaces and a device for carrying out said method”. Based thereon, a numerical 3D model of the interior of a fabricated shoe can be established, i.e. of an interior the shape of which matches the anatomical shape of the foot considerably better than a last that is manufactured from the aspects of production engineering and is required for the production of the footwear.

Moreover, corpus.e AG has developed a novel strategy of the so-called “best fit” selection, which is based on the comparison of the numerical 3D model of the foot of a customer as determined by the 3D foot scanner with the 3D models of the interior spaces of available, series-manufactured footwear as stored in a database (see: Robert Massen, “Kostengünstige und kalibrierungsfreie 3D Digitalisierung von Beinen, Füssen und Schuh-Innenräumen für orthopädische und normale Fuβbekleidung” [cost-effective and calibration-free 3D digitization of legs, feet and shoe interiors for orthopedic and standard footwear], satellite symposium on the occasion of the Orthopädie+Reha-Technik trade fair, Leipzig, Germany 2008, Kongress 28 Fortbildung Technische Orthopädie und Biomechanik: 3D-Vermessung und Analyse in der Technischen Orthopädie, Vortragsgruppe “Stumpf und Schaft, CAD/CAM” [congress 28, advanced training in technical orthopedics and biomechanics: 3D measurement and analysis in technical orthopedics, “stump and shaft, CAD/CAM” lecture group].

Owing to this novel approach of adapting the numerical 3D model of the customer's foot to the numerical three-dimensional interiors of the series-produced shoes that come into question, the previous, problematical, adaptation of the digitized 3D shape of the customer' foot to the shape of the last from a database of lasts, which, for principle-related reasons, does not sufficiently represent the inner shoe, is no longer required.

According to the prior art, the last which, for physical and production engineering reasons, is shaped differently from the shoe interior as a matter of principle, leads to the fact that an automatic best fit selection of footwear by an adaptation of the scanned foot to a library of lasts will, in principle, remain unsatisfactory. On account of the production requirements, a last has a shape that distinctly differs from that of the anatomical foot:

in comparison with a foot, it has a markedly narrower shape because automatic machines are used for sewing the leather in a tensioned and stretched condition when pulled over the last;

the last has a folding mechanism and an especially narrow shape where the leg starts because the last needs to be removed from the shoe after sewing thereof has been completed.

The adaptation as commonly used today of a scanned foot to a last shape is therefore considerably more unfavorable than the adaptation of a scanned foot to a shoe interior. A foot and a shoe interior constitute congruent 3D shapes, whereas the three-dimensional shapes of a foot and a last are, in principle, considerably less consistent with each other.

In spite of this progress based on the adaptation of a foot to a shoe interior for a best fit selection of a series-produced shoe for a customer's foot, the problems related to the non-adapted footbed continue to exist in connection with this novel concept as well. Unlike in the current prior art, a satisfactory and cost-effective best fit of footwear should not be limited to the three-dimensional shape of the upper part of the shoe, but should also comprise an individual, cost-effective, i.e. largely automated individual customization or best fit selection of the footbed, for example in the form of an insole which is adapted to both the anatomy of the individual foot sole of the customer and the load zones of the foot sole and also to the geometric interior of the selected best fit footwear.

There is, therefore, a great economic and technical interest in a cost-effective best-fit solution for footwear, in which, with the aid of the combined numerical model made up of the three-dimensional shape of the foot and the plantar pressure image, a best-fit selection of the footwear matching the foot of the customer is performed from a database of shoe interior models and in which, at the same time, with the aid of the digitized interior shape of the selected item of footwear and the plantar pressure image as measured and registered with the foot model, an insole or footbed adapted to both the individual anatomy of the foot and the specific interior of the selected series-produced footwear can be generated largely automatically or selected from a database of digitized insoles.

This is carried out according to the invention by the teachings of the method and arrangement claims of the present application for property rights. The following figures are used herein for illustrating the concept of the invention more clearly:

FIG. 1 shows, in a black-and-white diagram to illustrate the prior art and the geometric conditions, the 3D foot model -11-, obtained with the aid of a photogrammetric multisensory scanner, of a customer in an item of footwear -13-, the foot sole -12- resting on an insole -14- constituting the footbed.

FIG. 2 shows, in a plantar view from obliquely below, the 3D wire frame model of a foot -11- scanned using a multisensory foot scanner and, superimposed in this identical model, the local plantar pressure image -21- which has been prepared using a plantar pressure image sensor incorporated in the scanner. For reasons relating to the printing process, the plantar pressures -21-, which are color-coded in the original, are shown as black zones here.

This simplified drawing therefore only reproduces the places of the greatest foot pressures, but not the pressure amplitudes that were also measured.

FIG. 3 shows, in a graphical representation, a view of a heel from which the position of the foot sole -12- of the customer's foot -11- within the shoe interior -13- is visible, and the insole -14- which is drawn using a vertical hatching and which has to adapt to the non-flat foot sole -12- both on the sides and from below and also to the non-flat footbed -31- in the lower part of the inner shoe. The shoe sole -32- with its tread is shown in black.

FIG. 4 shows the production of the desired insole -14- which adjusts to the foot sole, to the two inner side walls of the footwear, and also to the footbed, which oftentimes is not flat, of the best-fit series-produced shoe and which is therefore produced from a prefabricated block using, for example, two numerical XYZ milling cutters -41- and -42-.

FIG. 5 shows the step-by-step sequence in the implementation of the concept of the invention, from scanning the foot of the customer inclusive of obtaining a registered plantar pressure image, the best fit selection of a fitting shoe by a comparison with a database of 3D inner shoe models, the classical derivation of the insole from the pressure image, with the adjustment or fitting into the shoe having not yet been realized, the numerical milling-out, from a blank, of the insole fitted into the shoe interior, the milling data record being calculated as a differential 3D surface model of the 3D foot model fitted into the best fit inner shoe model in relation to the inner shoe model.

The concept of the invention will now be explained, by way of example, based on the best fit selection of a shoe with an individualized footbed, this explanation being confined to one individual shoe for reasons of clarity. In any case, the concept of the invention inherently allows the selection of two different shoes and different fitted-in insoles for a customer and in this way takes into account the anatomical asymmetries which are often encountered between the left foot and the right foot of a customer.

As shown in FIG. 1, the purpose of the concept of the invention resides in the cost-effective, largely automated, best fit selection of an item of footwear -13- from an existing series production, this item of footwear optimally enclosing the foot -11- from an anatomical, aesthetic and functional point of view, and the footbed -14- being individually adjusted to the foot sole anatomy -12- of the customer and adjusted to and fitted into the selected item of footwear.

To this end, according to the invention, in a first step the customer's foot is scanned as shown in FIG. 2, using a preferably multisensory 3D scanner having an integrated pressure measuring plate, and a numerical 3D model of the foot shape -11- of the customer is established, in which the plantar pressure image -21- determined by means of the pressure measuring plate integrated in the scanner is correctly aligned and integrated so as to be registered. We refer to this integrated numerical model as a “multisensory” 3D model, which numerically describes the two connected information contents, “geometric three-dimensional foot shape” and “plantar pressure image”.

As a result, according to the invention, one single integrated numerical model is available, rather than, as is usually the case today, two separate models: one geometric 3D model determined using a 3D scanner and a second, two-dimensional plantar pressure image determined using an external pressure measuring plate. This separate determination according to the current prior art has the big disadvantage that the two items of information, “three-dimensional foot shape” and “plantar pressure image”, are not registered, i.e. are not put into a spatial relation to each other.

But the concept of the invention is not limited to this advantageous multisensory foot digitization, but also comprises a separate recording of the 3D model of the foot using a scanner and of the plantar pressure image using a separate plantar sensor. A person skilled in the art knows a variety of manual methods for registering these two data records. For example, the foot sole contour from the 3D model of the foot can be printed out on a film or sheet and placed onto the pressure sensor such that the XY coordinate axes of the 3D scanner and those of the plantar pressure sensor coincide.

FIG. 3 shows, from a view of the heel, the spatial relationships of the shoe interior -13-, the foot -11- of the customer, the foot sole -12- resting on an insole -14- which is drawn hatched, and the critical left and right peripheral zones, in which the insole has to adjust or fit snugly to the foot interior. It is furthermore apparent from this diagram that the footbed of a series-produced shoe, which is located above the shoe sole, features a standard sole as produced by the manufacturer, which is not necessarily planar and to which the individual insole -14- to be produced likewise has to snugly adjust.

The selection or production of an individualized insole in a series-produced shoe selected according to a best-fit process therefore requires a procedure which is automated, if possible, for a cost-effective production of an insole which, as clearly shown in FIG. 4, is usually given a complex shape:

the upper surface of the insole needs to assume a shape which is derived from the plantar pressure image in accordance with the rules which are known to a person skilled in orthopedics or incorporated in insole manufacturing programs;

the lower surface of the insole needs to adapt to the existing footbed of the series-produced shoe selected;

the lateral edges of the insole need to fit into the free space between the foot and the inner wall of the shoe in the lower portion of the shoe;

the insole needs to adapt to the shoe interior and the foot such that it does not curtail the free space needed for the foot.

It is common practice today to manually select insoles from a large number of different series-manufactured insoles or else to mill insoles from the top on one side in a numerically controlled manner with the aid of prefabricated blanks; according to the current prior art, the data of the shoe interior is not made use of here since, to date, shoe interior scanners have not been available. Therefore, it is currently necessary to fit the selected or, respectively, milled insole into the customer's shoe in a purely manual fashion, by an orthopedic specialist, shoe technician, salesperson etc. using a knife, grinder or similar tools for trimming the peripheral zone such as to make it fit into the shoe. Aside from the fact that this process is time-consuming, inaccurate, and undocumented, the insole produced in this way is still not yet anatomically defined in terms of its height, i.e. it is not made sure that once the insole is inserted, the free space in the shoe interior is suitable for good wearing comfort.

It is therefore an essential element of the concept of the invention that by the best-fit selection according to the invention of a fitting series-produced shoe, on the basis of the adaptation of the 3D foot model and the 3D shoe interior (which has been digitized using, for example, the above-mentioned scanner according to the teaching of DE 2007 032 609 A2), at the same time the space coordinates can be determined which describe the space, taken up by the insole, between the inner wall of the shoe, the foot sole and the footbed of the shoe, as shown in FIG. 4, and that these space coordinates are used for producing an individualized insole that matches both the foot and the shoe.

According to the invention, the individualized insole is produced by means of numerically controlled, chip-removing, applying or thermally deforming automatic insole production machines by controlling the traveling axes of these automatic machines using the space coordinates of the three-dimensional surface of the space to be occupied by the insole -14-. In the following, we will refer to this complexly shaped space as the “insole space”, i.e. that portion of the space in the interior of a shoe in the put-on condition which is to be filled by the insole or the footbed.

For the simpler and more cost-effective process of identifying a best-fit item of footwear and a best-fit insole, making use of the space coordinates of the three-dimensional surface of the space that is to be taken up by the insole, the “insole space”, according to the invention that insole which best fits into this insole space is determined from a database of digitized insoles.

According to the invention, the best-fit selection of an insole from a database of series-produced lasts is carried out on the basis of dimension specifications which describe the insole space.

The method according to the invention for a cost-effective production of a best-fit item of footwear with a customized footbed/insole is summed up in FIG. 5 in the form of a flow chart:

Step 1: the foot of the customer is scanned and digitized by means of a preferably multisensory foot scanner which establishes a numerical model of the three-dimensional shape of the foot and, at the same time, a plantar pressure image registered therewith;

Step 2: the best-fitting shoe is determined by comparing the geometric 3D model of the foot with a database of the digitized interior spaces of shoes to choose from;

Step 3: using known methods of insole production, the surface model of the insole is computed from the plantar pressure image fully automatically or in a computer-assisted manner for the region of the contact surface foot sole < > insole. This so-called “classical” insole model is neither defined on the lower side nor in its height nor in the peripheral zone.

Step 4: the space coordinates for the peripheral zone and the lower side of an insole fitting into the inner shoe are determined from the intersection of the space coordinates of the 3D model of the best-fit inner shoe, of the 3D model of the customer's foot, and of the “classical” 3D model, defined on one side, of the insole, the 3D model of the “classical” insole is supplemented by these coordinates to form the “insole space” and is finished in a customized manner by a numerically controlled automatic processing machine, or a fitting insole is selected accordingly by a best-fit comparison of the insole space with a database of the three-dimensional shapes of prefabricated series-produces lasts;

Step 5: the insole is fixed in place in the best-fit shoe and the best-fit shoe with the insole is handed over to the customer.

The concept of the invention is not limited to a particular type of footwear, but comprises dress shoes and casual shoes, sports shoes, safety shoes and orthopedic footwear of any kind.

The concept of the invention describes a method and an arrangement which allow a best fit method that is as highly automated as possible, for the selection of footwear with an individualized footbed at low cost. But the concept of the invention permits various degrees of automation or non-automation, such as, for example:

the decision by the sales staff or the customer himself/herself in favor of a particular best fit footwear from the n>1 potentially best-fitting items of footwear indicated by the database;

the production of the “classical” 3D model of the insole can be interactively influenced by a specialist on the basis of his/her experience and with the aid of additional information such as the body weight, age, purpose of the footwear (casual shoe, sports shoe, orthopedic shoe, etc.), the materials used (leather, textile, synthetic material, etc.).

What is decisive for the concept of the invention is the multi-step method which proceeds from the digitized foot, the plantar pressure image, and a database of digitized shoe interiors and delivers to the customer a best fit footwear with an individualized insole that is fitted into the available shoe interior and defined by way of the “insole space” with the aid of the numerically available data and, where desired, interactively influenced parameters and criteria.

In addition to the reduction in cost by the automation, to a large extent, of the process of supplying well-fitting footwear separately for each customer in spite of shoes that are mass-produced at low cost, the method according to the invention also allows the ever increasing lack of technical knowledge of the sales staff to be counteracted.

According to the invention, the numerical 3D models of the foot, of the shoe interior, and of the insole space are visualized on a data display unit in the salesroom and display to the customer and to the sales staff the position and fit of the foot and the insole in relation to the selected shoe, as in a complicated CAT scan.

This considerably facilitates the decision that, in the final analysis, remains to be taken by the customer in favor of a particular shoe model and a particular insole on the basis of the anatomical, easily comprehensible 3D visualization of the foot fitted into the shoe with the insole.

According to the invention, the best fit selection of the footwear as well as the individual preparation of the insole or the best fit selection thereof are performed separately for each foot, so that any asymmetries and anatomical differences between the feet of a customer are taken into account.

According to the invention, the visualized data is collected by the shoe trade and transmitted to the shoe manufacturers, for the latter to supply the trade with a range of series-produced shoes and insoles that are specially optimized with a view to its customers, and for storage costs to be optimized in this way.

According to the invention, the feet of the customer are re-digitized at greater time intervals (three-dimensional shape and plantar pressure image), and the customer is informed of whether the footwear, based on its 3D shape, is still anatomically fitting.

The concept of the invention also comprises the situation in which a well-fitting insole is customized or selected as a best fit insole subsequently for a shoe that has already been worn. In this case, step 2 (access to a database of available footwear interiors) is replaced by the digitization of the interior of the already worn footwear for which an insole is desired. The other steps remain unchanged.

According to the invention, steps 3 and 4 may be combined in that, following the determination of the 3D insole space and taking into consideration the compressibility and flexibility of the insole blank, the 3D shape of the insole to be produced or to be selected in a best fit process is individualized (customized insole) or is selected from a database as a best fit insole.

A further concept of the invention is to transact the entire business process via the Internet in that the feet of the customer are digitized once only with the aid of a preferably multisensory foot scanner, and this person-related data is stored in a central database or is handed over to the customer on a digital storage medium, and that the process for ordering a new item of best fit footwear with an individualized customized or best fit insole is carried out via a computer terminal.

By way of summary and in simplified terms, the concept of the invention describes novel methods and arrangements which proceed in a largely automated manner and which, with the aid of the combination of the “3D foot scanner”, “3D shoe interior scanner” and “foot sole scanner” technologies (optical image of the sole and/or plantar pressure image), calculate from the 3D and 2D data provided by these scanners the complexly shaped insole space to be taken up by a fitting insole in the interior of the footwear which is put on, and which by means of numerical processing methods, produce the insole or footbed that matches both the foot and the footwear either individually from a blank or select it as a best fit insole from a collection of prefabricated insoles.

Claims

1. A method of equipping footwear with a footbed customized to a foot of a person, comprising the following steps:

a) acquiring a numerical model of the three-dimensional shape of the foot by means of a foot scanner;

b) preparing a plantar pressure image of the foot by means of a pressure sensor plate on which the person stands;

c) registering the plantar pressure image with the numerical model of the three-dimensional shape of the foot;

d) obtaining, or acquiring by means of an interior scanner, a numerical model of the interior shape of the footwear;

e) calculating, from the plantar pressure image, a surface model of an insole for the surface contacting the foot sole;

f) establishing, from the intersection of the three-dimensional surfaces of the interior shape of the footwear and the surface model of the insole, the space coordinates for the peripheral zone and the lower side of the insole, taking into consideration the three-dimensional shape of the foot, and determining therefrom the three-dimensional shape of an insole fitting into the footwear;

g) obtaining or customizing the insole defined by the three-dimensional shape determined, and inserting it into the footwear.

2. The method according to claim 1, wherein a fitting footwear is selected on the basis of the numerical model of the three-dimensional shape of the foot and numerical models of the interior shapes of available items of footwear.

3. The method according to claim 1, wherein a selected or existing item of footwear is used.

4. The method according to any of the preceding claims, wherein the insole is selected by comparing its three-dimensional shape with data records of a database of available prefabricated insoles.

5. The method according to any of the preceding claims, which is carried out separately for each foot of the person.

6. The method according to any of the preceding claims, wherein the numerical model acquired of the three-dimensional shape of the foot and/or the plantar pressure image prepared of the foot are documented.

7. The method according to claims 2 and 6, wherein the selection of the fitting footwear is effected online over the Internet based on the documented numerical model of the three-dimensional shape of the foot.

8. The method according to claims 4 and 6, wherein the selection of the prefabricated insole is effected online over the Internet based on the documented numerical model of the three-dimensional shape of the foot and based on the documented plantar pressure image.

9. The method according to any of the preceding claims, wherein the numerical model acquired of the three-dimensional shape of the foot is superimposed on models of the interior shape of potentially fitting items of footwear and is visually displayed.

10. An arrangement for carrying out the method according to any of the preceding claims, comprising

an optically operating 3D foot scanner;

a pressure sensor plate which includes a surface for a person to stand on during operation of the 3D foot scanner;

a computing unit for processing the data supplied by the two scanners with a program that calculates a surface model of an insole from the data and calculates the three-dimensional shape of a customized insole from the surface model of the insole, from the numerical model supplied by the foot scanner of the three-dimensional shape of a scanned foot, and from numerical models of the interior shape of potentially fitting items of footwear.