TITLE

SYSTEM AND METHODS OF MAKING CUSTOM FOOTWEAR

FIELD OF THE INVENTION

[0001] This invention relates to a system and the methods of making custom footwear. More particularly, this invention relates to a system and the methods applying in an efficient, integrated, front-to-end process in the making of cost- effective footwear with multi-level customization.

RELEATED ART

[0002] Mass production industries have been successful for almost a century due to the efficiency and cost-effectiveness associated with its concept. However, the consumers usually have to struggle to balance their personalized needs with the limitations of the off-the-shelf products. If the mass-produced products could not meet consumers' individualized requirements, either the consumers had to sacrifice their requirements or the providers of the off-the-shelf products would suffer from high inventory cost.

[0003] Custom-tailored products can address consumers' personalized needs in great details. During the past decades, the rapid progress of computer technologies and Internet has provided powerful tools for various industries in efficiently and economically marking custom products. Especially, the healthcare and consumer industries have to switch from traditional mass production to computerized custom production since their clients are humans with diversified biometric characteristics. As to the footwear industry, the footwear mass- producers are experiencing more and more problems developing and fitting the

right footwear as the consumers becoming increasingly selective of what they wear.

[0004] The foot of an individual contains many unique biometric features, which are the fingerprints of the person. Mass-produced footwear is not adequate to address the biological diversity of human feet. The off-the-shelf footwear usually causes pain, fatigue, and sometimes serious foot problems due to lacking of proper fitting to the foot. For normal people, the conditions and shape of their feet continuously change with age and biological conditions. One of such cases is that the shape and conditions of feet become very different when a female is pregnant. In addition to that normal human foot having large diversity in biometric characteristics, there also exists large population who have already developed certain foot disorders. Common foot disorders include arthritis, bunion, claw toe, hammer toe, diabetic foot, excessive pronation/supination, flat foot, metatarsalgia, hallux rigidus, heel spur, and plantar fasciitis, just to name a few. Foot disorders usually induce deformities in the foot. The patients with foot disorders suffer the most from ill-fitted footwear, and their foot condition might worsen if they continue to wear improperly fitted footwear. [0005] Custom- tailored footwear can increase the fitting level; hence reduce potential health hazards. Various systems and methods related to the making of custom footwear have emerged over the past decades. In United States patent 5,632,104, customized shoes built to reduce the stress in feet are described. In patent 5,632,104, an improved shoe structure is developed to reduce the tibial strains on walking subjects. According to the invention, the shoe comprises an upper and a sole portion that define a foot support surface. The foot support surface is curved to fit the natural shape of a heel of the wearer's foot. The foot support surface further gradually slopes under toes of wearer's foot such that when wearer is standing erect, articulate extremities of toes do not nominally touch said foot support surface, thereby allowing toes to plantarflex and dorsiflex. The footwear in the invention is generally related to orthopedic shoes. Compared to the customized footwear in the present invention, the customization process in US patent 5,632,104 does not involve the production of customized last and insole components, and the wearer's special needs and tastes of the

footwear were not addressed. In United States patent 4,868,945, a bio- mechanically adapted custom shoe sole is introduced. The sole of such custom shoe is made to exactly conform to the foot surface of the wearer. More specifically, the custom shoe in United States patent 4,868,945 is made by taking a negative impression of the foot. Compared to the custom footwear of the present invention, no method was described in United States patent 4,868,945 for the custom-making of the upper and insole of the footwear. Furthermore, the style customization was not addressed therein. In United States patent 4,662,079, a method of producing custom footwear is described. According to this method, an impression of the whole foot is first used to make a positive mold. The positive mold is then used directly as the custom last for the making of the custom shoe. Compared to the custom footwear of the invention herein, the custom last of United States patent 4,662,079 is not optimized and cannot be adjusted. Besides, the shape and style of the custom shoe in the United States patent 4,662,079 can not be customized according to wearer's preference since it has the exact shape of the foot. In United States patent 6,823,550, methods of making custom orthotics are described. First, the wearer selects orthotics with certain style and appearance according to their needs and taste. Custom inserts are then added into the selected orthotics. The custom orthotics in the United States patent 6,823,550 is related to the customization of a medical device rather than the general footwear. The regarding customization methods don't include the custom making of shoe upper and shoe sole. Similar methods of making custom-tailored medical devices are also described in United States patent 6,463,351. In United State patent 6,463,351, the customization process starts from making a model of customer's body part for which a medical structure is to be manufactured, followed by a reverse-engineering process in which the model of the body part is digitized into data points. The data points are then processed for the design and manufacture of the medical device. Compared to the customization process of the present invention, the customization process in United State patent 6,463,351 is not towards the custom-making of footwear components, as well as the integration of these custom components into final custom footwear. In United States patent application US2001/0020222 Al,

system and method of using Internet for custom footwear manufacturing are described. The shoe last in United State patent application US2001/0020222 Al is generated by a shoe last design unit, which makes the shoe last to match the 3- D shape of the individual foot. Therefore, the last is not re-usable. Not like the system and methods of this invention, in United State patent application US2001/0020222 Al only the system and method of custom-making of shoe upper were described while the custom-making of other footwear components such as insole and sole were not included. Similarly, an integrated system for foot measurement and footwear manufacture was described in United State patent 5,339,252. In this invention, only the customization process of shoe last was introduced. There also exist some inventions relating the fitting of shoes through sizing the foot, such as United State patents 5,879,725, 5,979,725, 6,550,149, 6,741,728, 7,114,260, 7,086,168, and United State patent application US2004/0168329 Al. These inventions generally involve the systems and methods for the reverse-engineering process of foot as well as the fitting of noncustom shoes according to the 2-D or 3-D shape of the foot. [0006] There also exist publications related to systems and methods for the design and manufacture of custom footwear. For example, see T. J. Hwang, K. Lee, H. Y. Oh and J. H. Jeong, Derivation of template shoe-lasts for efficient fabrication of custom-ordered shoe-lasts, Computer- Aided Design, V 37, No. 12, October 2005, pp 1241-1250. In this paper, the authors concern the inefficiency involved in the production of custom footwear. The authors address that the design and manufacturing processes of customized footwear are time consuming and labor intensive, since the shoe lasts have to be individually designed and custom-made. The authors further propose a new manufacturing method for making custom shoe-lasts, which is as the follows: A series of templates for shoe lasts are cast in advance. These last templates are not actual shoe lasts so that they can not be used in making custom footwear without further machining. The most similar template is identified later according to the footwear order containing a customer's information such as foot geometry. Then the selected last template is further machined into the customized last for the customer. According to this method, the manufacturing process of custom shoe last is

divided into two consecutive steps: the manufacturing of pre-finished last templates, and the further machining on the last templates into final custom lasts. In this case, special precision equipment and additional time are still required to machine every last template into individualized custom last. According to the methods in the present invention, an electronic database containing custom lasts is constructed first. In the electronic last database, all the lasts have been fine- tuned in multiple biometric dimensions of human foot, and these lasts are fully functional. As to the foot without abnormalities in shape, generally no further modification is required on the custom lasts before they are used in making custom footwear. The custom last in the database can also be further modified to accommodate foot abnormalities or disorders, such as hammer toe, bunion, etc. Therefore, the custom-making of shoe upper using custom lasts is a more efficient process in the present invention. As to another publication, see A. Luximon, R. S. Goonetilleke and K. L. Tsui, Foot landmarking for footwear customization, Ergonomics, 2003, V 46, No. 4, pp 364-383. In this paper, the authors address that a shoe with a shape more similar to the foot could achieve higher comfortable level. This is because that the shoe was more able to maintain the foot in its neutral posture. The authors also address that customized footwear is expensive to produce due to a variety of complex constraints that have to be imposed in the footwear customization process, such as the design and fabrication of custom shoe-lasts, the manufacturing of customer moulds for outsoles, and the design and manufacturing of custom dies for the cutting of the upper patterns. Finally, the authors propose a method of land-marking the 2-D projected contour of consumers' foot so that the best match of the mass-produced shoes could be identified. Compared to the footwear customization methods in the present invention, the authors of the publication did not come up with an effective method of making custom footwear in an effective and efficient way. In the present invention, furthermore, the custom fit between the footwear and the foot is achieved by matching the 3-D features of the custom lasts and the 3-D biometric features of the foot. The fitting level is calculated and adjusted in multiple 3-D dimensions. Hence the customization process of this invention is

more comprehensive than the 2-D land-marking method proposed in the above publication.

[0007] In spite of the recognized advantages of the existing methods in the design and manufacturing of custom footwear, generally these methods did not provide an efficient, integrated, front-to-end process in the making of cost- effective custom footwear.

SUMMARY OF THE INVENTION

[0008] This invention relates to a system and the methods of making custom footwear. A multi-level customization process is employed in the system of the invention. First, shoe last is customized according to the biometric features of the foot. Secondly, the components of the footwear are fine-tuned through a set of interactive measurements for the wearer' needs, while the appearance of the footwear is custom-designed according to the taste of the wearer. Major components of the custom footwear include: a custom upper that best-fits the shape of wearer's foot; a multi-layered custom insole with its surface conforming to the plantar surface of the foot; and a custom sole that sandwiching a heel pad with custom height. The methods for custom-making of the footwear include: custom last database construction, reverse-engineering for the 3-D foot model, measurement and analysis for foot features, expert system-guided automatic last look-up for the best- fit last, modification and tune-up on the best- fit last, custom- making of shoe upper using the custom last, custom-making of multi-layered insole according to the plantar surface geometry of the foot, making of custom sole, and the integration of custom upper, insole and sole into final custom footwear. In the preferred embodiment, the custom footwear is made through the following process. First, a custom last database is constructed, which stores the geometric features of custom-designed lasts along multiple dimensions. In the last database, one last table corresponds to a footwear style. A reverse- engineering process is used to acquire a 3-D computer model of the foot. The 3- D model of the foot is further measured and analyzed to extract the 3- dimensional features of the foot. In the foot measurement process, not only the foot geometries along last dimensions are measured, but also the 3-D shape and

locations of any foot abnormalities are recorded. Automatic last look-up is then carried out according to the extracted foot features, which iterate the last table of the desired style. In this process, fitting indices of all lasts are computed by fitting algorithms derived from a set of rules from an expert system. The fitting indices show the fitting levels between the last features and those of the foot. A best-fit last is chosen from the last database after sorting all the fitting indices of the lasts. The 3-D shape of the best-fit last may further be tuned up and optimized to accommodate any deformities or irregularities of the wearer's foot. In certain cases, fully customized last would be manufactured if the look-up process is not able to select a best-fit last. Custom upper of the footwear is then made using the finalized custom last. For the insole, a thermal-plastic forming mould is made by Computer Numerical Controlled (CNC) machining process referring to the 3-D shape of the plantar surface of the foot. A multi-layered plate, comprising a layer of shell material, a layer of cushioning material, and a layer of lining material, is then thermal-plastically-formed and trimmed into the custom insole. A custom sole is made by trimming the outlines of the midsole and outsole according to the contour of the bottom of the custom last, and by sandwiching a custom-made heel-pad between the midsole and outsole. Finally, the custom upper, insole, and sole are integrated into the custom footwear, with the colors, materials and other accessories of the footwear customized according to the wearer's preferences.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGURE 1 shows the overall workflow for the making of the custom footwear of the invention;

[0010] FIGURE 2 shows an example of the reverse-engineering process for acquiring a 3-D computer model of a foot. An optical scanning method is employed where a handheld optical scanner is used to scan the foot. A rigid and transparent plate is used to support the foot at its plantar surface so that the plantar surface of the foot can be scanned;

[0011] FIGURE 3 is an example of the 3-D computer model of a foot in Surface Triangulation List (STL) format. The CAD model is converted from the 3-D point clouds that are reconstructed from the optical scanning process; [0012] FIGURE 4 shows the Cartesian coordinate system used to define the position of the foot. The coordinate system is used as the reference for the measurement and extraction of the foot features;

[0013] FIGURE 5 shows examples of the key features of a foot, as well as the method of extracting these features from the 3-D computer model of the foot. Here the features displayed include: foot length, forefoot width, rear-foot width, ball girth, waist girth, instep girth, and heel girth;

[0014] FIGURE 6 is a computer model of the plantar surface of the foot, which is generated from the 3-D model of the foot. The plantar surface model of the foot includes the whole arch of the foot. This computer model is used to make a plantar surface mold by CNC machining. The mold is later used to in the thermal-plastic forming process for the custom insole. [0015] FIGURE 7 shows an example of a multi-layered custom insole (in exploded view). The insole is composed of a top layer made of breathable lining material and cushioning material, and a middle shell layer made from thermal cork, and a bottom heel pad layer (optional) made of cushioning material. The custom insole is made through a thermal forming process. A heel pad with customized height and cushioning effect may be attached at the bottom of the custom insole. The insole can be further customized according to any special needs (such as certain foot disorders). In this example, a hole is cut off from the insole where the wearer has a corn.

[0016] FIGURE 8 shows an example of multi-layered custom sole (in exploded view). The sole is composed of a midsole (top), a rigid heel pad with customized height (middle), and an outsole with bottom texture customized according to the gait pattern of the wearer (bottom). The midsole and outsole sandwiches the heel pad. The contour of the sole is trimmed according to the outline of the bottom of the custom last.

DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

Integrated Process and Overall Workflow for the Making of Custom Footwear [0017] Figure 1 shows the integrated process and overall workflow for the making of the custom footwear of the invention. A custom last database is constructed beforehand as the reference of the footwear-making process. In the database for custom lasts, the lasts with the same style form a data table (last table). The custom lasts are featured with more geometric dimensions than the conventional lasts for off-the-shelf footwear, while in each dimension the last size are divided into finer scales. The footwear-making process starts with a reverse-engineering process for obtaining the 3-D geometric model of the wearer's foot. The 3-D foot model is further processed to provide information for making the custom upper as well as the custom insole. In the upper manufacturing process, the major task is to determine the custom last that best- fits the biometric features of the wearer' s foot, so that any occurrence of localized pressure concentration between the upper and the foot can be prevented (See, A. Luximon, R. S. Goonetilleke and K. L. Tsui, Foot landmarking for footwear customization, Ergonomics, 2003, V 46, No. 4, pp 364-383). The custom upper made from the best-fit last should also be able to constrain the foot in a proper space so that the foot would not slide in the shoe while the wearer walks. To select the best-fit last, the 3-D foot model is measured and analyzed in multiple dimensions for a multi-dimensional foot feature vector. The number of the foot features that are measured may vary according to the foot condition. For example, the 3-D shape and location of any foot abnormalities (such as hammer toe, bunion, etc.) have to be measured in addition to the foot features used to describe a normal foot. In the preferred embodiments, the measurement and analysis of the 3-D foot model is carried out using professional Computer- Aided Design (CAD) software. The 3-D foot model from the reverse-engineering process is also processed to generate a 3-D geometric model containing the plantar surface of the foot (with foot arch) (See Figure 7). This 3-D model of the plantar surface is used to manufacture the mold for the custom insole through a CNC machining process. A multi-layered plate is thermal -plastically formed

into the shape of the foot plantar surface using the insole mold. The deformed plate is trimmed into the custom insole.

[0018] Once the foot features are obtained from the 3-D foot model, they may be adjusted according to the wearer's wearing need, such as sock thickness and the wearer's preference for shoe tightness. Given the wearer's preference for the style of the footwear, the foot features are then used as the inputs of a last lookup process for the best-fit last in the custom last database. The last look-up process is fully automatic and is guided by a set of fitting algorithms derived from the rules of an expert system. The expert system contains knowledge bases and rules used to judge the fitting between a last of the desired style and the foot. As the searching result, the best- fit last is fetched from physical last storage for later use. In some cases, the best-fit last may need further tune -up or optimization if a small portion of the fitting indices of the last are beyond a set tolerance, or any foot deformities have to be accommodated. If the last look-up process was not able to find a best- fit last after searching the last table, a fully customized last would be made. The finalized custom last is used for making the custom shoe upper.

[0019] Once proper last has been identified and customized shell component has been fabricated, the manufacturing process goes through a set of secondary processes as another level of customization. The secondary process starts from a set of interactive measurements for the wearer' s special needs and tastes for the custom footwear. The parameters measured include, but not limited to: softness of the insole cushioning layer, height of the heel pad in the sole, preferences of colors and materials, preferences for monograms and logos, and any special requirements on the upper, insole, and/or sole. With these parameters, the secondary manufacturing processes are carried out. They are: The manufacturing of shoe upper using the finalized custom last, the custom-making of shoe sole, the making of custom-insole, the integration of the custom upper, custom sole, and custom insole into final custom footwear.

Method of Construction of Custom Last Database

[0020] Last is one of the key components in footwear manufacturing. The size of foot differs from person to person. Correspondingly, shoe lasts are divided

into groups and categorized according to age, gender, foot length, girth, and other distinguishable parameters. Conventionally, the index system for a last set comprises the discrete information including customer group (e.g., boys, girls, men, ladies, etc.), foot size (foot length, forefoot width, and rear foot width), and foot girth (ball, waist, and instep). For instance, a last record with key field as LadiesSB would have the following data, which correspond to their fields:

220 foot length

76 forefoot width

50 rearfoot width

198 ball girth

198 waist girth

210 instep girth

[0021] Therefore, each last is uniquely labeled and contains a unique feature vector. Note some fully customized lasts are exact copies of the surface shape of the feet; hence no indexing system is available for this type of fully customized lasts.

[0022] There are major drawbacks associated with both mass-produced lasts and fully customized ones. The problems associated with the mass-produced lasts are as follows: First, the scaling system is rigid and oftentimes the scaling is too rough. The geometric features of the lasts are stipulated according to rough and fixed scaling rules. Wearers with foot shape not quite correlated to the set last shape, or with foot size in the middle of two scaled last sizes, would have to sacrifice the fitting between the foot and the shoe upper along one or more feature dimensions. Secondly, the fitting between the last and a foot cannot be determined before the wearer tries on the shoes since the feature vector of the last is usually not accessible to the wearer. Therefore, the wearer would have to physically test-wear a large number of shoes in order to determine the "best-fit" between his/her foot and the shoe last. Oftentimes such "best-fit" is not optimized but the customer has no control on it.

[0023] Making a fully customized last for every foot inevitably involves inefficiency, high manufacturing cost and high inventory cost (see T. J. Hwang, K. Lee, H. Y. Oh and J. H. Jeong, Derivation of template shoe-lasts for efficient fabrication of custom-ordered shoe-lasts, Computer- Aided Design, V 37, No. 12,

October 2005, pp 1241-1250). Individually-made last is often of necessity in making custom footwear for people with foot disorders; however, fine-scaled custom lasts are proven to be able to fit most of the people with normal foot condition.

[0024] In the preferred embodiments of the invention, therefore, custom last database is constructed to store the key geometric features of custom-designed lasts. The database is composed of multiple data tables. Each table corresponds to a footwear style, and is composed of a set of electronic lasts of the style. In the custom last database, more dimensions are used to define the geometry of the custom last than those used to define conventional non-custom lasts. Furthermore, finer scales are used in all these dimensions. The dimensions used to describe the last geometry, as well as the scaling of these dimensions, are collected according to the gathered foot statistics from a test population. [0025] In the preferred embodiments of the present invention, the custom last database is constructed referring to the US standard foot-last reference tables for mass production footwear industries, as the follows.

[0026] Scanning and measurements were performed on a test population. From the reverse-engineered 3-D models of the feet, foot features were extracted for every test subject, including the length and girth information. The foot features were then categorized according to gender, then the length, and then the girth. Afterwards, the adjustments of last features are carried out. Referring to the last tables for mass production footwear, the following errors are calculated on all the last (or foot) dimensions:

E ₁ = (L ₁ - F ₁ ) I L ₁

Here i is the /th dimension in foot (or last) dimensions; "L" stands for the feature vector a last in a last table for off-the-shelf footwear, and "F" stands for the feature vector a foot in the test population. The averages of the errors were calculated in every dimension. Shifts are corrected first by modifying the last dimensions so that the errors have zero means. Afterwards, another set of errors is calculated by comparing the modified last feature vector and the foot feature vector. The standard deviations of the new errors are calculated. Any dimension with error standard deviation larger than a threshold is further divided into finer-

scales, or added as a new dimension for the custom last. For example, a finer- scaled last with higher dimensions can be derived from a original last with label Ladies-5B, as Ladies-(5.2)(5.0)(5.3)(B.l)(B.3)(B.2), which corresponds to lady' last with main length index 5, and length sub-scale 2, forefoot width sub-scale 0, rear foot width subscale 3; main girth index B, and ball girth sub-scale 1, waist girth sub-scale 3, and instep girth sub-scale 2. In this way, the custom last database is constructed by combining the fine-tuned foot-last reference tables. [0027] Any last table of the database can be targeted after the wearer picked a specific style, and searched automatically to find the last that best- fits the biometric features of the wearer's foot. A tolerance value is set in this last lookup process to constrain the allowed geometric difference between a last and the foot. In most cases, the tolerance can be met provided the wearer's foot is in normal condition. There are two solutions available if this tolerance is not met after searching through the whole last table. The first solution is to tune up or modify the last (usually local modifications are used to accommodate foot disorders such as hammer toe, bunion, etc.) until the fitting indices in all dimensions are within the tolerance. Such local modifications on the last are reversible in the sense that the last is restored to the original shape after it is used in the making of custom upper. The second solution is to manufacture a fully customized last if numbers of fitting indices are way beyond tolerance. Usually this case occurs when the foot has significant abnormalities over a large volume or area. The geometric features of the fully customized last can be added into the last table for future reference. The 3-D foot model is the reference for the fully custom last. There are many ways to manufacture the fully customized last, such as CNC milling. In the preferred embodiments of the invention, the fully custom last is manufactured using a technique similar to Rapid Prototyping & Manufacturing (RPM). The 3-D foot model is sliced into multiple layers. The outline of each layer is used to guide the cutting of a layer of sheet material with the same height. The cut layers are combined together as a physical replica of the foot. Finally, the foot replica is patched and smoothed into the fully custom last.

Reverse Engineering Process for the 3-D Computer Model of a Foot [0028] Human foot has complicated 3-D geometric shape. The conformity between the inner shape of a shoe and the shape of the foot plays significant role in the fitting of footwear. Therefore, the 3-D geometry of a foot should be acquired and further quantified into representative foot features. With the foot features, the fitting level between the foot and a custom last can be quantitatively measured.

[0029] In certain footwear customization methods, the shoe is custom-made to exactly match the 3-D shape of a foot. In these cases, usually the shoe upper is made through a series of foot molding process. The foot mold used as the shoe last has the exact 3-D shape of the foot. According to this method, the reverse engineering process for acquiring the 3-D foot shape is not necessary. However, there are drawbacks associated with the method. First, the clearance between the footwear and the foot cannot be adjusted or optimized since the foot mold is of the exact shape of the foot. In most cases, such exact matching between the shoe upper and the foot does not yield the highest fitting. Secondly, the shape and style of this kind of custom footwear cannot be adjusted since the last is set to foot shape. Finally, usually the molding process is labor-intensive, costly and time-consuming.

[0030] In the preferred embodiments of the invention, optical scanning method is used in the reverse-engineering process for acquiring the 3-D computer model of the foot. In the optical scanning process, a laser strip travels through the foot surface. A camera captures the curved laser strip as it travels along the foot surface so that the images can be processed to reconstruct the shape of the foot as discrete 3-D points. The scanner reconstructs the 3-D point clouds according to optical triangulation method. The acquired 3-D point-clouds on foot surface can be converted into a 3-D digital model in certain computer file format, so that the 3-D digital model can be imported into proper CAD software for further process. [0031] Any optical scanner can be employed in the reverse-engineering process. In the preferred embodiments of the invention, a portable, hand-held scanner is used. The scanning covers the whole surface of the foot, including the upper surface of the foot and the plantar surface of the foot containing foot arch. For

certain type of footwear such as boots, the scanning covers a part of the lower leg.

[0032] In order to scan the plantar surface of foot effectively and accurately, an apparatus is designed to elevate the foot from ground, and support the foot at its plantar surface. In the scanning of foot plantar surface, the foot is pressed against a rigid and transparent plate made of glass or plasti-glass. The thickness of the plate is small so that laser beam can pass through the plate with negligible refraction. The reverse-engineering process is as the follows. The wearer places his/her foot on the transparent plate of the foot-support apparatus, and adjusts the posture and position of the body and the foot until no stress is felt in the foot and the leg. As shown in Figures 1, an operator holds the hand-held laser scanner and makes multiple sweeps. The sweeps are made along different directions until the laser strip travels through the whole foot surface. As a sweep is being made, the reconstructed point clouds corresponding to the foot surface are displayed in real time on a computer screen. The whole scanning process would comprise of N sweeps, with N determined by the completeness and quality of the reconstructed 3-D points of the foot surface. Once the scanning process is completed, a series of operations are performed on the reconstructed point clouds. These operations may include de-noising, removal of redundant points, check for completeness, interpolation to raw surface, and gap filling. The raw surfaces generated from the point clouds are then converted into a 3-D computer model, which can be in any 3-D surface format such as STL, DXF, VRML, and IGES, etc. Figure 3 shows an exported foot geometric model in Surface Triangulation List (STL) format. In the preferred embodiments of the invention, the obtained 3-D computer model of the foot is used in both extracting key foot features for the searching and optimization of custom last, , and CνC machining of the plantar surface mold for the thermal-plastic forming of the custom insole.

Method of Extracting Representative Features from the 3-D Foot Model [0033] A foot of a person has fingerprinting biometric features which uniquely representing the person. In order to calculate the fitting indices between a custom last and the foot, both the 3-D surfaces of the last and the surface of the foot has to be abstracted into a set of quantitative features. The dimensions along which

the features are extracted should be adequate in representing the geometric characteristics of the foot and the last. The dimensions that play important roles in determining the fitting between a foot and a shoe should also be included for feature extraction.

[0034] The 3-D foot model acquired by the reverse-engineering process is measured and analyzed to extract the key features of the foot. First, the foot features are extracted along the dimensions that are used to describe a custom last of the wearer-picked style. Afterwards, special foot features are extracted from the 3-D foot model in representing any local deformations of the foot, such as hammer toe, bunion, heel spur, etc.

[0035] According to Frank Kao {Handbook of practical shoe-making technologies, February 2004, Harbor footwear group, Ltd), there exist several key dimensions on a normal foot, along which the fitting between a last and a foot can be quantified and evaluated. These dimensions may include (but not limited to): foot length, forefoot width, rear foot width, height of the toes, ball girth, foot waist girth, foot instep girth, and heel girth, etc. These dimensions have been scaled into a set of lasts in the targeted last table. Figure 5 shows an example of the measurement procedure for the foot features along these dimensions. The measurement process is as the follows. [0036] After the reverse-engineering process, the 3-D foot model is loaded into proper CAD software, such as Pro/Engineer. The CAD software should have the capability of handling complex 3-D surfaces. The 3-D surface model of the foot can be further converted into any other CAD model format to facilitate the measurement process. As the first step, a 3-D Cartesian coordinate system is bound onto of the foot model, as shown in Figure 4. Therefore, a set of cross- sections can be constructed with the reference of this coordinate system. In these cross-sections, the following geometric information of the foot is contained: the line on which the foot length is measured; the lines along which the fore-foot width and rear-foot width are measured; the planes on which the ball girth, the waist girth, and the instep girth are measured, and more. The measurements of length and width are performed on the corresponding cross-sections by measuring the distance between two end-planes which containing the fore-most

and rear-most points of the cross-section. For the measurements of the girth features, feature curves containing the girth information are constructed first on the corresponding cross-sections. The length of a feature curve is then measured or calculated as the girth feature.

[0037] Once the foot features are measured, a feature vector comprising of all the foot features is formed. The foot features are placed into the feature vector with certain order that corresponds to the data fields in the targeted last table.

Methods of Expert-System-Guided Automatic Last Look-up, and Last Optimization and Shoe Upper Customization

[0038] The feature vector extracted from the 3-D foot model is applied as the input in the search process for a best-fit last in the custom last database. In the preferred embodiments of the invention, the automatic last look-up process is to compare the feature vector of the foot and that of a custom last with the desired style. It is guided by the rules from an software-based expert system. The expert system contains expert knowledge for the optimum fitting between a foot and a last of the exact style. For all the styles derived from a base style, an expert system is and configured to guide the corresponding last look-up process. [0039] For each footwear style, the rules of the expert system are derived from the statistical analysis on a test population. The expert system suggests a range for the difference between any foot feature and the corresponding last feature. In the last look-up process, an optimum difference between a foot feature and the corresponding last feature is automatically determined within the range imposed by the expert system. This optimum difference is controlled by a set of rules in the expert system, such as the preferred sock thickness and the preferred shoe tightness of the wearer, etc.

[0040] Taking into account the optimum difference in all feature dimensions, a last- foot difference vector is formed by the expert system. A desired last feature vector is then formed by adding the difference vector onto the foot feature vector. The last look-up process is carried out to automatically search for a custom last with feature vector closest to the desired last feature vector. In the preferred embodiments of the invention, the look-up process is performed as the follows.

[0041] A computer software first picks a last table from the custom last database, which corresponds to the chosen style. A set of fitting indices are calculated for any last in this last table, as the following:

[0042] S _{1 1} = ^[DL ₁ - L _{1 1} )IDL ₁ ] ²

[0044] Where i is the z ^' th last in the targeted last table, j is thejth dimension in the feature vector of a last, S stands for the fitting index, with S ₁₁ being the fitting index of last i along feature dimension j, and S ₁ being the overall fitting index of last i over all feature dimensions; w stands for the weight associated with the jth dimension of the feature vector of the last, DL stands for the feature vector of the desired last, and L stands for the feature vector of a last in the targeted last table. An upper threshold is set as the minimum requirement for any fitting index S ₁₁ . Once the software finishes searching the targeted last table, the last with the highest fitting index S ₁ is selected as the custom last providing all the fitting indices S ₁₁ are below the threshold.

[0045] If a small portion of fitting indices S _l} were beyond the threshold, a last would be selected by the software for further modification into the custom last: The primary feature dimensions of the last satisfies the primary requirements imposed by the desired last feature vector. The secondary feature dimensions of the last are modified physically to meet the secondary requirements imposed by the desired last. In the preferred embodiments of the invention, the primary feature dimension is the length of the last. The secondary feature dimensions may include one or more of the following: forefoot width, rear-foot width, toe part height, ball girth, instep girth, waist girth, and heel girth, etc. Such modification on the selected last is reversible. The last is restored into its original shape after the custom footwear is made.

[0046] If a large portion of fitting indices S _l} were beyond the threshold (the foot heavily deforms from a normal shape over large area), the last- lookup software would not select any last from the targeted last table. Instead, a fully customized last would be made for the foot. The fully customized last is first manufactured

as a replica of the 3-D model of the foot. Then it is patched, smoothed, and finished into its final shape. A variety of methods are available in making a replica of the 3-D foot model, such as 3-D CNC machining. In the preferred embodiments of the invention, a method similar to Rapid Prototyping & Manufacturing (RPM) is employed in replicate the 3-D foot model into a physical template for the fully customized last.

[0047] The finalized custom last is used for the making of custom shoe upper. The upper style is determined by the last style. In the preferred embodiments of the invention, a set of constraints is further imposed in the upper-making process. These constraints are imposed by certain geometric characteristics of the wearer' s foot that are involved in the motion of the foot but are not involved in defining the 3-D shape of the foot. These geometric characteristics are measured directly from the 3-D foot model. These constraints need to be met in the upper making process to ensure that the custom upper would not interfere with any motion of the foot. For example, one of such constraints is that the upper should not interfere with the foot movement about the ankle joint.

Methods of Making Multi-layered Custom Insoles

[0048] Multi-layered custom insole is a key component of the custom footwear in the preferred embodiments of the invention. The custom insole is to provide elastic support to the foot arch to prevent arch fatigue from long-term expansion (standing) or cyclic expansion and contraction (walking), and to re-distribute the body load from the high pressure areas (especially the heel and metatarsal areas) onto the whole plantar surface. The custom insole is also to provide custom cushioning and shock-absorption to the plantar surface of the foot. In the preferred embodiments of the invention. The custom insole can be customized to accommodate any health problems associated with the foot plantar surface. [0049] In the custom insole, the arch support is achieved by integrating an elastic shell layer (the middle layer in Figure 7). The shell layer sets the surface shape of the custom insole to conform to the plantar surface of the foot. It acts as non-linear distributed springs that support the arch of the foot. Therefore, body load can be distributed by the insole shell over the whole plantar surface. The pressure concentration on the heel and metatarsal area can be reduced, and the

arch can be protected from long-term or cyclic deformation. The shell layer is made of any thermal-plastic material that is elastic in room temperature and deforms plastically after being heated . In the preferred embodiments, the shell layer is made of thermal cork. The thermal plastic forming process of the shell layer is as the following: A thermal-plastic forming mold is manufactured by CNC machining according to the generated plantar surface model of the foot (as shown in Figure 6). The mold can be made from easy-to-machine and cheap materials such as wood or plaster. A plate of shell material is heated until it can deform freely . The heated shell plate is put against the mould surface and pressed by a vacuum pump until it deforms to match the exact surface of the mold. Then the shell plate is cooled down to room temperature, and trimmed to remove unnecessary materials according to the 2-D contour of the plantar surface model of the foot.

[0050] In the preferred embodiments of the invention, a layer of cushioning material and a layer of lining material are glued on top of the shell material before the thermal-plastic forming process. After the thermal-plastic forming process, these layers have the same surface shape and are trimmed together with the shell layer. The cushioning layer is used for shock absorption. It also helps to distribute the high pressure at the heel and metatarsal areas onto the plantar surface of the foot by increasing the contact area between the foot and the insole. The thickness and the softness (Duro value) of the cushioning layer are customized according to the preferences of the wearer. In the preferred embodiments of the invention, the lining layer is made of soft porous material, such as calfskin or lamp skin. The lining material is used to further increase the contact area between the foot and the insole, as well as make the custom insole breathable

[0051] After the thermal-plastic forming process for the custom insole, a cushioning heel pad can be attached onto the insole bottom at the heel area (see Figure 7). The insole heel pad is integrated into the custom insole to provide additional cushioning and shock absorption for the heel since the heel takes the most of the body load while standing or walking. The insole heel pad also helps to adjust the position of the foot to let the foot set in a stress-free position along

the foot length direction. The insole heel pad is also made with custom softness and thickness according to the wearer's preferences.

[0052] The custom insole of the inventions further adjusted to accommodate any foot problem of the wearer, especially the foot disorders associated with the plantar surface. Figure 7 shows an example of the multi-layered custom insole of the invention. In Figure 7, a hole in cut off from the custom insole if the wearer has a corn at the metatarsal area. Hence, the corn would not be touched or pressed by the insole.

Methods of Making Custom Sole

[0053] In the preferred embodiments of the invention, a custom sole comprises of a midsole, a rigid heel pad, and an outsole. The midsole and outsole sandwiches the heel pad, as shown in Figure 8. The 2-D outlines of these sole components are trimmed according to the 2-D contour of the bottom of the custom last. The rigid heel pad elevates the heel of the wearer, so that the clearance between the foot plantar surface and the top of the outsole tapes down from the heel to the toe. The height of the sole heel pad is customized according to the wearer's preference. Interactive measurements are carried out for the optimum height of the sole heel pad, as the following: The wearer is requested to step on two 5 mm-thick pads, with the pads beneath the heels. If he/she feels that the pad is not of the right height in the sense that that lower leg and/or the feet are not stress-free in the foot length direction, another 5 mm-thick pad is added beneath each foot heel, or an existing pad is removed from the stack. This process repeats until the wearer feels that the lower legs and the feet are stress- free in the foot length direction. For each foot, the height of the pad stack is recorded as the custom height of the sole heel pad of this foot. The height of left heel pad is not necessarily the same as that of the right heel pad. Therefore, adjusting the height of sole heel pads can compensate any length discrepancy in the wearer's legs. The texture pattern of the ground-contact surface of the outsole is customized according to the wearing habit and gait pattern of the wearer. For example, the rear part of the outsole would be made of wear-resistant material and has a rough and zigzagged texture if the wearer tends to make heavy impact at the heel-landing phase in the gait cycle.

Methods of Integrating Individualized Needs and Tastes into Custom Footwear [0054] In the preferred embodiments, the custom footwear of the invention is made by a bi-level customization process. The first level of customization relates to the customization of the footwear according to the wearer's biometric characteristics, as described in the previous sections. The second level of customization relates to further customization of the footwear based on the subjective needs and tastes of the wearer. These personal needs and tastes may include the health-care requirements, the colors and materials of the footwear, and any footwear accessories such as personal monograms and logos, etc. [0055] The wearer has selected his/her preferred style from diversified shoe styles before the last look-up process. In the second level customization process, the wearer may design the appearance of the footwear with the selected style, or make further modifications on any footwear component of the selected style. Collections of colors, materials, shapes or types of footwear components of the style, are provided to the wearer so that he/she can build his/her own footwear with his/her preferred appearance. For example, a color template of 36 colors are provided to the wearer so that the wearer can select his/her preferred color for any patch of the custom footwear. A material template composed of different upper material (leather or non-animal materials), insole materials (cushioning and lining materials), and outsole materials (leather, rubber, etc.), are also provided to the wearer so that the wearer can select the preferred materials for the custom footwear. Footwear accessories for cosmetic or personal use can be integrated into the custom footwear, such as monograms and logos. Personalized marks such as characters or favorite drawings, can also be integrated into the custom footwear according to the wearer's opinion.

[0056] In the second level customization process, special modifications can further be made on upper component, insole component, or sole component, or the combination thereof to accommodate any special need. For example, a local cushioning pad or a local cut-off can be added on a specific area on the footwear, according to wearer's foot condition.