GB2602097A

GB2602097A - Method of designing a bespoke compression garment

Info

Publication number: GB2602097A
Application number: GB2020050.7A
Authority: GB
Inventors: Harwood Adam; Gunther Clive; Hassan Chaudhury Najmal; Sopper James
Original assignee: Advanced Therapeutic Materials Ltd
Current assignee: Advanced Therapeutic Materials Ltd
Priority date: 2020-12-17
Filing date: 2020-12-17
Publication date: 2022-06-22
Also published as: GB202020050D0; WO2022129924A1

Abstract

A computer-implemented method of designing a bespoke compression garment by obtaining a representation of a body part being a foot and part of a leg, obtaining a pressure configuration for the body part and determining respective circumferences at a series of fabric course positions along the body part, determining a first reference position along the body part where the leg has a small first circumference and determining a second reference position having a relatively large circumference, and determining using characteristic data of one or more materials for knitting the garment, a respective strain value at which a fabric course knitted from the material would provide the specified pressure on the leg at the first reference position, determining from the strain value and the first circumference of the leg a first unstretched circumference of the fabric course at the first reference position and determining a peak force required to stretch the respective course of fabric in the first region at the second reference position and assessing suitability of the material by verifying peak force doesn’t exceed a threshold, thus ensuring the garment isn’t damaged by the narrowest circumference being stretched to the largest circumference of the leg.

Description

METHOD OF DESIGNING A BESPOKE COMPRESSION GARMENT

Field of the Invention

This invention relates to a computer-implemented method of designing a bespoke compression garment. The invention further relates to a method of manufacturing such a compression garment, to a compression garment manufactured by such a method, and to a computer program for carrying out the design method.

Background to the Invention

Compression garments are worn on a person's or patient's body part and apply pressure to the body part, typically to improve blood circulation (in particular venous return) therein. This can help to improve or cure a number of different health conditions or may address other medical needs. Compression garments are commonly worn on limbs, for example on the leg and/or foot.

The present disclosure relates to such compression garments, that are designed to envelop at least part of a foot and at least part of the corresponding leg of the wearer. Such compression garments may be termed compression stockings or compression socks. It should be noted, though, that although the exemplary compression garments in the present disclosure are generally illustrated and described as completely covering the wearer's foot, this need not necessarily be the case. For instance, when worn in use, the compression garment need not necessarily extend to cover the wearer's toes, and instead may take the form of a sleeve that is open at both ends.

Compression garments are conventionally knitted. Knitting, rather than weaving, may be used for compression garments since knitting is suited to cylindrical garments and compression garments are typically cylindrical. As such, knitted compression garments are quicker and more cost effective to manufacture than woven garments and may provide greater comfort than woven garments.

A knitted compression garment may typically comprise a plurality of courses or bands of fabric (which may also be referred to herein as "material courses" or "fabric courses"). These have a circumference which, when at rest (i.e. unstretched), is smaller than a circumference of the associated body part. As such, the courses are required to be strained to be worn over the body part, which causes a pressure to be applied on the body part.

Since people's legs vary in shape and size from person to person, it is desirable for a compression garment to be customised for a specific wearer, to provide the wearer with a specified pressure configuration along the length of the garment in use, along the wearer's foot and the part of their leg. Such a compression garment may be referred to as a bespoke compression garment. In such a case, the pressure configuration may for example be prescribed by a clinician or healthcare professional, to suit the wearer's particular health condition or other medical needs.

It is important that the compression garment provided to the wearer is configured to accurately apply the prescribed pressure configuration. If the pressure which is applied is too great, then this can cause pain or discomfort. If the pressure is too little, then the patient's blood circulation may not be improved.

To impart the desired pressure configuration along the wearer's foot and part of their leg requires the compression garment to be tight-fitting along its length.

However, conventionally, such compression garments are notoriously difficult for the wearer to put on -especially in the case of garments that deliver higher levels of pressure. All compression garments require the patient to stretch the garment circumferentially to get it on; the amount of force required to achieve this varies depending on the fabric, construction and amount of circumference increase required. While these compression garments are designed with the good clinical outcomes in mind, the difficulty of application can be too high, to the extent that many manufacturers find it necessary to offer application aids to help the wearer put the garment on. However, such application aids can still be awkward to use, and add cost and additional manufacturing requirements to the overall process of supplying the compression garment.

It will be appreciated that simply increasing the circumferential size of the compression garment by a couple of centimetres, say, with a view to aiding application, is usually not feasible. For instance, in a traditional compression garment, a 1 cm increase in a circumference can equate to a decrease in pressure of 10mmHg (corresponding to a 25% decrease in pressure in a typical 40mmHg garment). The stiff fabrics used within traditional compression garments therefore leave manufacturers with having to choose between the correct level of pressure or ease of application (thus the choice of application aids).

There is therefore a desire to address the above problems to produce a method of designing a bespoke compression garment -in particular optimising the choice of fabric -in order to achieve both ease of application and the correct level of pressure.

In more detail, it will be appreciated that, for any given wearer, different positions along the foot and leg have considerably different circumferences. This can make it difficult to design a bespoke compression garment that is sufficiently tight-fitting along its length in order to provide the required level of pressure, that is comfortable when worn, and that is not unduly difficult for the wearer to put on or take off.

More particularly, the region of the leg above the ankle, at the bottom of the calf, typically has a relatively small circumference compared with other parts of the leg, and consequently a bespoke compression garment should also have a relatively small circumference in a corresponding position, to apply a desired level of pressure to that part of the leg. This part of the compression garment may be termed the "waist" of the compression garment.

However, the circumference of the foot around the heel and ankle (over the bridge of the foot) is typically much greater than the small circumference around the leg mentioned above. Consequently, in practice, it can be very difficult for the wearer to pull the waist of the compression garment around their heel and ankle. This is particularly the case with elderly people who may suffer from poor grip or need the assistance of a carer or partner to help them put the compression garment on or take it off. Such difficulties risk the wearer becoming discouraged from using the compression garment. As a consequence, they may stop using the compression garment and thus not obtain the health benefits the compression garment was designed to provide.

There is therefore a desire to design a bespoke compression garment that is not unduly difficult to put on or take off, that is comfortable to wear, and consequently that the wearer ought not become disheartened to wear -whilst providing the desired pressure configuration (by being sufficiently tight-fitting) along the length of the garment.

Summary of the Invention

According to a first aspect of the present invention there is provided a computer-implemented method as defined in Claim 1 of the appended claims. Thus there is provided a computer-implemented method of designing a bespoke compression garment, the method comprising: obtaining a representation of a body part on which the compression garment is to be worn, the body part comprising a foot and at least part of a leg, the foot having an ankle and a heel; obtaining a specified pressure configuration to be applied by the compression 20 garment on the body part; determining, from the representation of the body part, a respective circumference measurement at each of a series of fabric course positions along the body part; determining, from the representation of the body part, a first reference position along the leg, at which position the leg has a relatively small circumference compared with other positions along the leg, and determining a respective first circumference of the leg at the first reference position; determining, from the representation of the body part, a second reference position around the ankle and heel, having a relatively large circumference compared with other positions along the foot, and determining a respective second circumference, around the ankle and heel, at the second reference position; determining, using characteristic data in respect of one or more candidate materials for knitting at least part of the compression garment, a respective reference strain value at which a respective fabric course knitted from the or each candidate material would provide the specified pressure on the leg at the first reference position; determining, for the respective fabric knitted from the or each candidate material, from the determined respective reference strain value and the first circumference of the leg at the first reference position, a first unstretched circumference of the respective fabric course in a corresponding first region of the compression garment that, when stretched to the first circumference of the leg at the first reference position, would adopt the respective reference strain value and thus impart the specified pressure on the leg; determining, for the respective fabric knitted from the or each candidate material, a peak force required to stretch the respective course of fabric in the first region of the compression garment around the ankle and heel at the second reference position, and/or a peak strain that the respective course of fabric would adopt when stretched from the first unstretched circumference to the second circumference; assessing the suitability of the or each candidate material, by verifying that, for the or each candidate material, the determined peak force does not exceed a respective threshold force, and/or the determined peak strain does not exceed a respective threshold strain, and rejecting, at least in respect of use in the first region of the compression garment, candidate materials for which one or both of these thresholds are exceeded; selecting, from the candidate material(s) that have not been rejected, a material from which to manufacture at least the first region of the compression garment; and generating a set of knitting instructions for producing at least the first region of the compression garment from the selected material in accordance with the representation of the body part and the specified pressure configuration.

Such a method ensures that the material from which at least the relatively-narrow first region of the compression garment is to be made is able to be pulled around the relatively-broad ankle-and-heel region (the second reference position) of the body part, without requiring an unacceptably high level of force and/or without undergoing an unacceptably high level of strain.

In certain embodiments the representation of the body part comprises scan data (for 5 example 3D scan data) of the body part At the first reference position, the leg may have its smallest circumference (typically just above the ankle and below the calf).

At the second reference position, the circumference around the ankle and heel may have a maximum value.

The method may further comprise determining, from the representation of the body part, one or more respective radius measurements at each of the series of fabric course positions along the body part.

For example, at one or more of the series of fabric course positions along the body part, a single average radius measurement may be determined.

Alternatively, at one or more of the series of fabric course positions along the body part, a plurality of radius measurements may be determined. For instance, this may be done by fitting an arc to a respective portion of the circumference of the body part and determining the radius of said arc.

Advantageously the threshold force may be determined according to the physical strength of the intended wearer of the compression garment.

Moreover, for the or each candidate material, the threshold strain may be determined according to the elastic limit of the respective fabric.

The step of selecting a material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, may comprise selecting the stiffest non-rejected candidate material.

The step of selecting a material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, may further comprise: verifying that the stiffest non-rejected candidate material, if used, would not have any courses of stitches that would exceed a threshold strain; and if any courses of stitches would exceed the threshold strain, reverting to another of the non-rejected candidate materials.

Optionally the step of selecting a material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, may comprise selecting a material for which the manufacturing time is less than a threshold value.

According to a further embodiment, the selected material from which to manufacture at least the first region of the compression garment is a first material; and the method further comprises selecting a second material from which to manufacture one or more regions of the compression garment other than said first region.

The second material may for example be a previously-rejected material.

Advantageously, to enable a smooth transition between the first and second materials, the method may further comprise incorporating a transition zone between a first fabric course to be manufactured from the first material, and a second fabric course to be manufactured from the second material.

For example, a third material may be selected from which to manufacture the transition zone. The third material may have a level of stiffness between that of the first material and that of the second material.

Alternatively, or in addition, the transition zone may differ from the first fabric course and the second fabric course in respect of one or more of: the course width; the course height; the number of needles across the course; the number of needles per centimetre; the loop size or knit size.

According to a second aspect of the invention there is provided a method according to the first aspect of the invention; and manufacturing the compression garment by knitting the selected material(s) in accordance with the generated set of knitting instructions.

According to a third aspect of the invention there is provided a compression garment made by the method according to the second aspect of the invention. The garment as produced by the method is different to garments not formed by the method. The garment as produced by the method more accurately conforms to the body part as compared to garments not produced by the method.

According to a fourth aspect of the invention there is provided a computer program comprising instructions which, when the program is executed by a computer processor, cause the computer processor to carry out the method according to the first or second aspect of the invention.

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example only, and with reference to the drawings in which: Figure 1 illustrates an example of a bespoke compression garment; Figure 2 illustrates typical characteristic data in respect of three candidate materials 25 from which the fabric of a bespoke compression garment may be made, showing the relationship between exerted pressure and strain; Figure 3 is a procedural flow diagram to provide an overview of a first embodiment of a method of designing a bespoke compression garment, based around a single candidate material being selected to knit the compressive part of the compression garment (at least); Figure 4 is a more detailed procedural flow diagram in respect of the first embodiment of the method; Figure 5 illustrates a body part comprising a foot and at least part of a leg, and showing a series of exemplary corresponding fabric course positions along the body part; Figure 6 illustrates (a) the cross-sectional circumference of the body part in one such fabric course position; and (b) the fitting of a curve to a respective portion of the cross-sectional circumference of the body part to determine the local radius of that portion of the circumference; Figure 7 illustrates a series of steps for determining, from scan data, a point along the front of the leg where the foot transitions to the leg; Figure 8 illustrates a series of steps for determining, from scan data, a point along the back of the leg where the foot transitions from the floor to the heel; Figure 9 illustrates steps for determining, from the determined points in Figures 7 and 8, a circumference around the heel and ankle; Figure 10 illustrates an example of a set of knitting instructions (i.e. a knitting file) for a bespoke compression garment, as produced by the design method; and Figure 11 is a procedural flow diagram to provide an overview of a second embodiment of a method of designing a bespoke compression garment, based around multiple candidate materials being selected to knit the compressive part of the compression garment (at least).

In the figures, like elements are indicated by like reference numerals throughout.

Detailed Description of Preferred Embodiments

The present embodiments represent the best ways known to the Applicant of putting the invention into practice. However, they are not the only ways in which this can be achieved.

Overview of a compression garment Figure 1 illustrates an example of a bespoke knitted compression garment 10 as may be designed and manufactured using embodiments of the present invention. The knitted compression garment is tubular or substantially tubular in form, and comprises a plurality of fabric courses. For flat knitted garments in weft knitting, each fabric course may be considered to be a band, ring or circle of yarn. Adjacent courses or bands of yarn have interconnected or interknitted loops or bights. Preferably, the fabric courses are flat knitted.

The compression garment 10 comprises a toe region 11, a foot region 12, a heel region 13, a leg region 16 and an open top 17 through which the wearer inserts their foot and leg when putting on the garment. Whilst the toe region 11 and heel region 13 are shown in the illustration as distinct areas, this need not necessarily be the case, and they may instead be a smooth continuation of the foot region 12 and leg region 16.

Of particular note with the compression garment 10 are the regions 14 and 15. Region 15 may be termed the "waist" of the compression garment, and is a region of relatively small circumference that corresponds to the region of the wearer's leg, above the ankle, at the bottom of the calf, that typically has a relatively small circumference compared with other parts of the leg.

Conversely, region 14 is a region of relatively large circumference, that corresponds to the circumference of the wearer's foot, around the heel and ankle (over the bridge of the foot), which is typically much greater than the small circumference around the 20 leg mentioned above.

An objective of the present work is to enable the relatively small waist 15 of the compression garment 10 to be pulled over and around the relatively large circumference of the heel and ankle region of the wearer without undue difficulty, but without unduly relinquishing the tight fit of the waist 15 of the compression garment 10 around the corresponding part of the wearer's leg at the bottom of the calf, above the ankle.

Relationship between pressure and strain for elastic fabrics To introduce a concept that will be used significantly later, Figure 2 illustrates typical characteristic data in respect of three candidate elastic fabric materials (A, B and C) from which the fabric of a compression garment may be made, showing the relationship between exerted pressure (in mmHg) and strain, for a given radius of curvature of the compression garment.

We have identified an upper limit on the stress/strain gradient of knitting fabrics that can support both ease of application and the correct level of pressure. This constraint was discovered because we did not limit ourselves to existing compression garment knitting constructions.

Typical compression garments are constructed from both a body yarn (for the purpose of delivering stiffness) and an inlay yarn (for the purpose of delivering pressure). While this is not limited, we have found that using a typical inlay yarn as the body yarn produces suitable stress/strain gradients in the resulting garment. Conventionally, manufacturers have not used inlay yarns as body yarns as they are unable to produce consistent results due to their typical elasticities. However, we have found that, by using a suitable tension control device (e.g. as described in WO 01/77427 Al and WO 2005/014903 A2), we are able to use inlay yarns as a body yarn and knit with consistent results When designing a compression garment, it is preferable to have a database of suitable fabrics with gradients below the upper limit to deliver different amounts of pressure for a given radius of curvature. For instance, for a given radius of curvature, one fabric may deliver 30mm Hg of pressure at 50% strain, while another may deliver 10m mHg of pressure at the same 50% strain.

First embodiment-method of designing a bespoke compression garment in which the compressive part is to be made from a single selected candidate material A first embodiment of the present invention will now be described, primarily with reference to Figures 3 and 4, and also with reference to Figures 5 to 10. This embodiment provides a computer-implemented method (algorithm) of designing a bespoke compression garment in which the compressive part (at least) is to be made from a single material, selected from one or more candidate materials that are in contention for use in the garment, and which may be identified in a database of such candidate materials Figure 3 is a procedural flow diagram 20 which provides an overview of the first embodiment, having principal steps 1-8 (boxes 21-28 of the flow diagram), whereas Figure 4 provides a more detailed procedural flow diagram 30 in relation to the same embodiment. The steps, which will now be described in detail, may in practice be implemented by a suitably-programmed microprocessor (e.g. forming part of a computer or part of a processing system). A program which, when executed by the microprocessor or computer, causes the microprocessor, computer or system to carry out the method, is also provided by the present disclosure.

Step 1 -obtaining representation of body part and specified pressure configuration In step 1 (box 21 of Figure 3; boxes 31 and 32 of Figure 4) the system obtains a representation (e.g. 3D scan data) of the body part of the intended wearer of the compression garment, onto which body part the compression garment is to be applied; and also obtains a specified pressure configuration (e.g. as prescribed by a healthcare professional) that is to be applied by the compression garment on the body part when worn.

The obtaining of such scan data may be performed by scanning the body part of the intended wearer. Alternatively, data generated by a previously-carried-out scan (potentially by a different entity, in potentially a different geographical location) may be obtained. From the scan data, a representation of the body part may be obtained.

The scanning may be undertaken by any appropriate scanning means or scanning setup. For example, the scanning may be carried out by a healthcare professional using a camera, such as that on a portable electronic device such as a tablet, to take images or record video of the body part from multiple angles or perspectives.

Scanning software may then transform such images or video into a representation, in other words a model or three-dimensional model, of the body part which comprises a plurality of datapoints or vertices. The representation or model is an electronic or computer implemented representation. The representation comprises the plurality of datapoints.

In the present work, given that the body part on which the compression garment is to be worn is a leg and foot, the representation is such that it includes at least part of both the leg and the foot, for example including at least a majority of the foot and at least a majority of the lower leg.

For convenience, the scanning may be done with the patient or user having their legs spaced apart and therefore at an angle to a vertical direction. The representation may be provided by the scanning software with respect to a conventional Cartesian coordinate system. As such, the representation, or a longitudinal extent thereof, which is produced via such scanning may be offset relative to an axis which indicates the vertical direction, typically the z-axis, compared to an in-use arrangement. The rotation of said representation may therefore be necessary and will be better understood hereinbelow.

Whilst a scanning process has been described, it will be appreciated that this may not be necessary to the invention and a representation of the body part may instead be provided from an alternative source.

Moreover, whilst a three-dimensional (3D) scanning process has been described, and is generally preferable, the use of 3D data is not essential to the present invention. For instance, individual body part measurements (e.g. made by the healthcare professional using a measuring device) may be used instead.

The scan or representation may then be provided to a processor or system by the healthcare professional, along with other information such as a desired pressure configuration to be applied by the garment, the colour of the compression garment, 30 and the number of garments.

The representation, having been produced by scanning a leg and/or foot, may be misoriented and therefore may be a misoriented representation. In other words, the representation is in an orientation or at angle relative to the z-axis of the coordinate system which is not representative of the body part when the patient or user is in a typical standing condition. As such, said misoriented representation should be transformed or rotated to a correctly oriented condition, having an orientation relative to said z-axis which is representative of the body part when the patient or user is in a typical standing condition.

If the body part has areas or portions which are at an angle to each other, the representation should be appropriately, and preferably automatically, analysed to determine the location of these areas. This is for the purpose of modelling the likely geometry and orientation of material courses of the garment, when worn on the body part, as representation courses on the representation. This will be understood with reference to the leg and the foot, where it will be appreciated that an axial direction of the material courses of the foot area of the tubular compression stocking will be parallel or substantially parallel or aligned or substantially aligned with a horizontal axis when worn on the body. Contrastingly, an axial direction of the material courses of the leg area of the tubular compression stocking will be parallel or substantially parallel or aligned or substantially aligned with a vertical axis when worn on the body. Therefore, the foot and leg areas of the body should be identified so that representation courses can be appropriately modelled around the relevant body part area. This may be achieved by determining at least one transition point which characterises a transition between leg and foot.

The orientation and geometry of the representation courses are preferably set to accurately reflect the material courses of the garment. For example, the axial direction of each of the representation courses of the foot portion should be oriented so as to be horizontal or substantially horizontal. Similarly, the axial direction of each of the representation courses of the leg portion is orientated so as to be vertical or substantially vertical.

Those representation courses of the leg and foot which are proximate to the heel may be modelled to be non-planar, for example being curved. Thus, the geometry of the representation courses should reflect this to accurately model the material courses. Thus is since, if the non-planar or curvate character of the courses is not modelled, an accurate value of circumference of the non-planar or curvate course cannot be calculated given that a non-planar course typically has a greater circumference than a planar course.

The method preferably comprises a step of the system dividing the representation into the plurality of representation courses, based on a length of the desired garment and the height or spacing of each course. In other words, bands are defined around the representation, the bands having a given height. For example, the garment or representation may be 300 mm in length, and an average or typical course height may be 0.75 mm, resulting in 400 representation courses defined around the representation. The course height may be selected based on the type of material for the yarn, and/or the desired properties of the garment Other garment lengths and course heights may be considered.

Non-planar material courses of a garment when worn on a body part are typically more stretched (longitudinally) at the back, and less stretched or looser at the front. As such the system or processor preferably adjusts the curved or non-planar representation courses to have a greater course height at or adjacent to the front and a lesser course height at or adjacent to the rear. As such, the course height of the non-planar representation courses may not be uniform.

In a similar way, material courses having a greater circumference value may have a lower course height due to manufacturing techniques. So different representation courses may have different course heights depending on the circumference.

Although it is preferable that material courses having a greater circumference value may have a lower course height, it will be appreciated that this may not be the case. For example, a uniform course height may be used providing a given number of courses for a given height of garment. The value of the course height may then be refined and adjusted using an algorithm which predicts the variance of course height due to the manufacturing technique.

A set of datapoints for each representation course may be selected by the processor, each set of datapoints being located within the corresponding representation course. In other words, the datapoints which have coordinates within the boundaries defined the representation courses are grouped into sets associated with the relevant representation courses.

Those sets which are associated with representation courses which are planar or substantially planar may be modelled as flat. The difference in height or z-axis position between datapoints of such a set which may arise due to the non-zero value 10 of the course height may be disregarded.

A spline, and in particular a basis spline or B-spline, function of best fit may be calculated by the system based on the datapoints of each planar set. Although a spline is presently preferred, it will be appreciated that other curve fitting or curve approximation techniques or functions may be considered. Since the spline is calculated based on the raw datapoints, rather than based on an approximation of the datapoints or based on boundary curves, contours or surfaces which are in turn based on the datapoints, the spline is more representative of the body part.

Before calculating the spline, the datapoints may be required to be centred around x and y axes. This can be done via calculating the average of the x-axis position value of the datapoints and subtracting it from the x-axis position of each datapoint. The same process is done relative to the y-axis. The datapoints can then be converted to polar coordinates to obtain an angular, or azimuth, value of each datapoint around a centre or origin of the datapoints. The datapoints are then sorted by the angular, or azimuth, value. This is to prevent or limit the datapoints being assigned an incorrect order around the origin when calculating the spline. The B-spline can then be calculated.

For sets of datapoints associated with non-planar courses, at least some of the datapoints may have differences in height or z-axis position which require consideration to provide a spline which is representative of the associated material course. As such, if the non-planar representation is modelled as two planar portions at an angle to each other, one planar portion may be rotated relative to the other planar portion so as to be coplanar. For example, the portion which is at an angle to the x-y plane is rotated so as to be parallel with the x-y plane. This rotation may be done in a similar or identical way as the rotation of the representation relative to the z-axis as previously described Having rotated or transformed the datapoint set of the or each non-planar representation course, a B-spline may be calculated as previously described.

Step 1 also includes obtaining a pressure profile or pressure configuration that is to be applied by the compression garment on the wearer's body part when worn. The pressure configuration may be prescribed by a healthcare professional, based on a patient's requirement. The pressure configuration may be a uniform pressure arrangement, such that the garment is intended to provide a uniform pressure across the garment, or a graduated pressure configuration, such that the garment is intended to apply a higher pressure at one portion of the garment and a decreasing pressure away from this portion; or some other different pressure arrangement. The pressure configuration may be input to the processor or system at the same time as the representation or datapoints are provided to the processor or system. Values of pressure which a garment may apply may be provided in millimetres of mercury (mmHg). Typical clinical values of pressure clinically desirable to apply may be between 10 mmHg and 50 mmHg (1333 Pa and 6666 Pa).

Step 2 -determining respective circumference measurement at each of a series of fabric course positions along the body part In step 2 (box 22 of Figure 3; box 33 of Figure 4) the system determines, from the representation of the body part, a respective circumference measurement at each of a series of fabric course positions along the body part.

Figure 5 shows some examples of fabric course positions P1-P8 in relation to a foot 50 and a leg 52. In practice, there would typically be many tens or hundreds of individual fabric courses along the length of the compression garment. Only eight fabric course positions are shown in Figure 5, for the sake of illustration.

In the presently-preferred embodiment determining the circumference measurement of each fabric course is carried out using the fitted splines as discussed above.

More particularly, the method further comprises a circumference or perimeter value for each spline circumference being calculated by the system This may be done via the formula: C = (x'2 + y'2)" Where C is the circumference of the spline, x' is a first derivative of x for example the first derivative of x with respect to y, and y' is a first derivative of y for example the first derivative of y with respect to x. It will be appreciated that the x-y plane is transverse across the body part, orthogonal to the longitudinal z-axis.

The method may further comprise the step of the system defining a plurality of reference points on or around the circumference of the spline. For example, each spline may have 500 reference points defined thereon. Alternatively, or additionally, the circumference value of the spline may be used to determine the number of reference points, for example if the circumference value was 100 mm, 100 reference points could be used per 1 mm, or 200 reference points per 0.5 mm.

A radius of curvature may be defined at each reference point using the formula: )1") - X")I r,. (X 2 y 2)3 / 2 where rr is the radius of curvature at a reference point, x" is a second derivative of 30 x for example the second derivative of x with respect to y, and y' is a second derivative of y with respect to x.

Additionally, the splines may be analysed to identify concave and convex areas.

Step 2.1 -optional determination of multiple radii at each fabric course position A single circumference measurement for each fabric course position may be determined, and from this, a corresponding single average radius value for each fabric course (or for each of a subset of the fabric courses) may be readily derived by assuming that the foot or leg has a circular cross section shape and dividing the circumference measurement by 27c.

However, a higher level of precision in the design of the compression garment, enabling us to deliver different specific pressure values at different circumferential positions around any given fabric course, may be achieved by determining (box 34 in Figure 3) a plurality of local radius measurements around any given fabric course.

This is illustrated in Figure 6, which shows (a) the cross-sectional circumference of the body part in one such fabric course position (position P3 of Figure 5); and (b) the fitting of a curve A2 to a respective portion X2 of the cross-sectional circumference of the body part to determine the local radius R2 of that portion of the circumference.

More particularly, Figure 6(a) shows the cross-sectional circumference of the foot in position P3 of Figure 5. A plurality of positions X1-X5 have been allotted by the system around the circumference, in this case in positions where the local radius undergoes a pronounced change.

Figure 6(b) is an enlargement around a portion of the circumference, in position X2 of Figure 6(a). In this position, to determine the local radius R2 of that portion of the circumference, the system has fitted an arc A2 (in this case an arc of a circle) to that portion of the circumference. Having done that, the radius R2 of the arc is evaluated, thereby giving the local radius of the circumference in that position.

A similar approach may be taken to determine the local radius in the other positions X1, X3 and X4 around the circumference.

Step 2.2 -determining a first reference position of relatively small circumference along the leg; and determining a respective first circumference of the leg at the first reference position In this step (box 35 in Figure 4) the system determines a first reference position of relatively small circumference along the leg, as denoted by RP1 in Figure 5. The first reference position RP1 is preferably the position where the leg has the smallest circumference, just above the ankle and below the calf, corresponding to the previously-identified position P5. In variants of the method a different position for the first reference position may be chosen, but it should nevertheless be a position at which the leg has a relatively small circumference compared with other positions along the leg.

A respective first circumference CRpi of the leg in the first reference position RP1 is then determined from the representation (e.g. 3D scan data) of the leg in that position, e.g. using the spline fitting technique as described above.

Step 3 -determining a second reference position of relatively large circumference around the ankle and heel; and determining a respective second circumference, around the ankle and heel, at the second reference position In step 3 (box 3 in Figure 3, box 36 in Figure 4) the system determines a second reference position of relatively large circumference around the ankle and heel, as denoted by RP2 in Figure 5. The second reference position RP2 is preferably the position at which the circumference around the ankle and heel has a maximum value, corresponding to the previously-identified position P4. In variants of the method a different position for the second reference position may be chosen, but it should nevertheless be a position having a relatively large circumference compared with other positions along the foot.

A respective second circumference CRp2 of the leg in the second reference position RP2 is then determined from the representation (e.g. 3D scan data) of the leg in that position, e.g. using the spline fitting technique as described above.

In more detail, in step 3, the calculation of substantially the largest circumference around the foot is achieved by following method, made up of three sub-steps, which will be described with reference to Figures 7, 8 and 9.

The first sub-step, with reference to Figure 7, is to find a reference point RP3 along the front of the leg where the foot transitions to the leg. In practice, selection of this reference point RP3 can be difficult as not all legs have the stereotypical gradual slope. (This is especially the case with unhealthy legs.) Instead we need to refine the data points to a smaller subset before looking for a slope. While we could use a variety of rules to refine the data points, the following stages have been most successful for us.

(a) Select all the data points that have the largest x value on a range of z values.

(b) The desired point is very close to the minimum x value of the slope. Thus, the point must be within 3cm of that point so data is refined by this requirement.

(c) Stage (b) has removed many of the points on top of the foot. The desired point is then very close to the height of the top of foot points. Thus, the point must be within 3cm of the z minimum value of the slope so a second refinement is performed.

(d) The remaining of points should have an x value and a z value that is very close to the desired point. The slope of the remaining points can be used to find the desired reference point RP3. Typically, the average value of the remaining points is most suitable to do this.

The second sub-step, with reference to Figure 8, is to find a reference point RP4 at the back of the foot. The stages to locate this reference point RP4 are similar to those of the of the first sub-step as outlined above, and are as follows: (a) Select all the data points that have a similar y value to the minimum x value.

We can refine this initial selection by only selecting an x value that is less than 0 and has a z value less than 5cm.

(b) The desired point is very close to the x minimum value. Thus, the point must be within 1cm of that point so data is refined by this requirement.

(c) The desired point would also be very close to the floor. A further refinement is done to select only points that are lcm from the floor.

(d) With the remaining points, the slope can be used to find the desired point RP4 when the foot starts to transition from the floor to the heel.

Finally, with reference to Figure 9, now that we have the two reference points, RP3 and RP4, we can (a) create a diagonal line between them and select any points that lie on that line. Then (b) the circumference of this can be calculated by using the circumference determination method as described above.

Step 4 -determining reference strain value (minimum strain) for candidate material(s) to provide specified pressure at first reference position (small circumference) The method further comprises selecting a candidate material for knitting at least part of the compression garment. The method may also include determining a number of needles for each representation course based on the course pressure of the associated material course, a strain characteristic of the material, and the circumference value of the associated spline. The selection of the candidate material may be from a selection of suitable materials known to the system (e.g. held in a database). Alternatively, there may only be one possible material that is in contention within the system.

In step 4 (box 24 of Figure 3; box 37 of Figure 4), for the or each candidate material 30 the system determines a reference strain value at which a respective fabric course knitted from the respective candidate material would provide the specified pressure on the leg at the first reference position RP1.

In this regard, we have determined that different fabric constructions require a different amount of strain to deliver the same amount of pressure. In this step the system determines the amount of strain necessary to deliver the required amount of pressure for each candidate material in the database.

A candidate material may be selected based on values or characteristics of a stress-strain curve, or a curve similar to a stress-strain curve, of the material, as illustrated in Figure 2 (these being examples of characteristic data of the respective materials). Whilst described as a stress-strain curve, it will be appreciated that this may in fact be a force-extension curve, or a force-strain curve. One characteristic is the y-intercept of material coefficient, which may be the y-intercept of a tangent to the curve divided by the thickness or cross-sectional area of the material being tested, or twice the thickness of the material being tested if two thicknesses of material are being tested. This may be considered an equipment normalisation stress. The tangent to the curve may be drawn at a linear portion of the curve. An initial portion of the curve is non-linear, after which there is the linear portion to which a tangent is to be drawn. Although described as a linear portion, the portion may be nonlinear, and therefore the tangent or tangent equivalent may be a polynomial function. Another characteristic is the gradient material coefficient, which may be equivalent to, similar to or dependent upon the Young's modulus. The gradient material coefficient may be the gradient of the aforementioned tangent divided by the thickness or cross-sectional area of the material, or twice the thickness of the material being tested if required.

A number of needles or wales for each representation course which would achieve the desired course pressure may be calculated based on the material characteristics, the circumference of the associated spline and the radius of curvature values at the reference points of the associated spline.

For each fabric, based on the circumference of the leg CRpi in the first reference position RP1, the following approach is used to calculate a reference strain value E required to deliver the specified amount of pressure on the leg in that position RP1.

Firstly, in this regard, the pressure applied by a course is generally calculated according to the following equation: )1771C ± Vnic E 72= where p is the pressure applied by the course, ym, is the y-intercept of material coefficient (from a plot as in Figure 2), V",, is the gradient of material coefficient (likewise from a plot as in Figure 2), c is strain of the course, and r is the radius of curvature of the course.

The radius of curvature r may be either a single (average) radius for the course, or a local radius of a portion of the circumference of the course, as outlined above.

For a single (average) radius for the course, rearranging the above equation gives the strain e of the course necessary to apply the desired pressure p as Pr -Yrnc E = On the other hand, to use individual local radius of curvature values around the circumference of the course in this calculation, the y-intercept of material coefficient is divided by a first individual radius of curvature value. This is added to the y-intercept of material coefficient divided by a second individual radius of curvature value, and so on until a sum of all of the y-intercept of material coefficient divided by the radius of curvature values of the reference points of a spline is calculated. This sum may be represented by yr.

Similarly, the gradient material coefficient is divided by a first individual radius of curvature value. This is added to the gradient material coefficient divided by a second individual radius of curvature value, and so on until a sum of all of the gradient material coefficient divided individually by the radius of curvature values of the reference points of a spline is calculated. This sum may be represented by V,.

The initial equation may then be rearranged to calculate the required strain to achieve the desired pressure of the course as P Tit Yr E =Vr where it,. is the number of reference points.

In box 38 of Figure 4, the calculated strain for each fabric E is then converted into an unstretched garment circumference Co_Rpi for the course of the garment that corresponds to the first reference position RP1 using the following equation: CO-RP1 = 1 + E Accordingly, the output of this step is an unstretched garment circumference Co_Rpi for each fabric at the smallest leg circumference (reference position RP1). In other words, for each material, the unstretched garment circumference Co_Rpi is the unstretched circumference of the respective fabric course in a corresponding first region in the waist of the compression garment that, when stretched to the first circumference CRpi of the leg at the first reference position RP1 as when worn, would adopt the respective reference strain value and thus impart the specified pressure on that part of the leg.

Step 5 -determine peak force and/or peak strain to stretch fabric course in first region of compression garment around the ankle and heel (the second reference position) In step 5 (box 25 of Figure 3; box 39 of Figure 4), for the or each candidate material the system determines a peak force Fp required to stretch the respective course of fabric in the first region in the waist of the compression garment (i.e. corresponding to the first reference position RP1 when worn) around the ankle and heel at the second reference position RP2, and/or a peak strain ep that the respective course CRP1 of fabric would adopt when stretched from the first unstretched circumference Co_ Rpi to the second circumference CRP2.

In effect, this step models the act of pulling what is essentially the narrowest part of the compression garment over what is essentially the widest part of the foot. More This step evaluates the force required to increase the circumference of the garment to do this, and also the strain that the garment would undergo when doing this.

To calculate the peak force Fp required, the system may use the following equation: Pp = t * n (Vnic (,,C"2)+ ymc) \uo-Rpi where t is the fabric thickness, n is number of courses in the first region of the compression garment (corresponding to the first reference position, RP1, of the body part), Co_ppi is the unstretched garment circumference in that position, Cpp2 is the second circumference (in the second reference position, RP2, of the body part), V," is the gradient of material coefficient, and ynt, is the y-intercept of material coefficient (from a plot as in Figure 2).

Lastly, the strain increase experienced by the courses in the first region of the compression garment, when stretched from the first unstretched circumference Co_ Rpi to the second circumference CRp2 is also evaluated, to obtain the peak strain Ep experienced by the fabric To calculate this, the system may use the following equation: Ep CRP2 CO-RP1 CO -RP1 Step 6 -assess the suitability of the or each candidate material with reference to the determined peak force and/or the determined peak strain In step 6 (box 26 of Figure 3; box 40 of Figure 4), for the or each candidate material the system assesses the suitability of the or each candidate material, by verifying that, for the or each candidate material, the determined peak force FP does not exceed a respective threshold force FT (box 41 of Figure 4), and/or the determined peak strain Ep does not exceed a respective threshold strain Er (box 42 of Figure 4), and rejecting candidate materials for which either one, or both, of these thresholds are exceeded.

The threshold force FT may be determined by the system according to the physical strength of the intended wearer of the compression garment. For example, the system may select an appropriate value of the threshold force FT from a database or lookup table, based on input factors such as the age, manual dexterity and/or general health of the intended wearer.

The threshold strain Er may be determined by the system according to the elastic limit of the respective fabric, which may be stored in a database or lookup table. By operating below the threshold strain, we can be sure that the fabric of the compression garment (in the position of smallest circumference) will not be irreversibly damaged when the compression garment is stretched around the widest part of the ankle and heel.

Appropriate values of the threshold force FT, as stored in a database or lookup table, may initially be determined based on user trials and/or anthropomorphic data. From the outset, the database should only contain fabrics with a stress/strain gradient below a certain amount (as any fabric above this amount would almost never pass the upper force limit test).

The present method inherently takes into account the desired pressure profile and leg shape of the intended wearer, and also the stress/strain gradient of the fabric.

Accordingly, from this step, fabrics may be rejected -either entirely, or just in respect of use in the aforementioned first region in the waist of the compression garment -that would be above the threshold force or threshold strain when putting the garment on.

Step 7 -select a non-rejected candidate material from which to manufacture compression garment In step 7 (box 27 of Figure 3; box 43 of Figure 4) the system selects, from the candidate material(s) that have not been rejected in step 6, a material from which to manufacture at least the aforementioned first region of the waist of the compression garment, and potentially the entire of the compression garment.

Preferably this step involves the system selecting the stiffest non-rejected fabric with a suitable strain map that, if used, would not have any courses of stitches that would exceed a threshold strain (that corresponds to the fabric's elastic limit, or comes within a certain margin of it). Consequently, this may include the system verifying that the stiffest non-rejected candidate material, if used, would not have any courses of stitches that would exceed a threshold strain; and if any courses of stitches would exceed the threshold strain, reverting to another of the non-rejected candidate materials.

The fabric material with the steepest stress/strain gradient is preferably selected first, as the optimal fabric choice, because any changes to the leg size while moving 20 will increase the pressure the most. This technique has been found to have good clinical outcomes.

The step of selecting the material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, may also, or alternatively, comprise the system selecting a material for which the manufacturing time is less than a threshold value. In this regard, as fabrics decrease in stress/strain steepness, the shorter the manufacturing time would be. The system may penalise certain fabrics in the material selection process for any given individual if the garment would take too long to manufacture.

Rejected materials may be used elsewhere in the compression garment, in positions other than the aforementioned first region in the waist of the compression garment.

Step 8 -generate a set of knitting instructions In step 8 (box 28 of Figure 3; box 44 of Figure 4) the system generates a set of knitting instructions for producing the compression garment (or at least part of it) from the selected material(s) in accordance with the representation of the body part and the specified pressure configuration.

More particularly, a knitting pattern may be produced based on the number of needles for each representation course. An example of such a knitting pattern is represented in Figure 10. The knitting pattern 70 comprises a series of lines adjacent to each other arranged in a top-to-bottom direction. Each line represents a material course which will be knitted, and may be described as a knitting course. The length of each line indicates the number of needles of the respective course. The left-to-right position of each line relative to adjacent lines indicates an offset of the courses. For example, as shown in Figure 10, all of the lines of the knitting are aligned along one side, to the left, and as such a garment knitted to according to the knitting pattern would have all courses aligned along one side. It will be appreciated that such a garment would not have shaping along this side. This may be advantageous for typical patients who have a flat portion on a lower leg, formed by the shin bone.

As initially generated, the knitting pattern may have too much variability in the number of needles, which may increase a risk of dropping stiches. In other words, the knitting pattern may be too rough. Consequently, the knitting pattern may be smoothed to reduce or prevent the dropping of stiches. The knitting pattern may be smoothed via the use of a further algorithm, which may, for example, adjust the number of needles of the lines so that each line of the smoothed knitting pattern has at least four adjacent lines having an equal or substantially equal value of needles. At least a portion of the knitting pattern consists of groups of lines of equal or substantially equal value of needles, each group having at least five lines or knitting courses. However, other group numbers may be considered, for example at least two.

Alternatively, the knitting pattern may be shaped at both sides of the pattern. A garment produced by such a shaped knitting pattern may be more suited to patients who do not have a flat portion on a lower leg (for example, patients having oedema, obesity or lipoedema). Additionally, for stockings worn on an upper leg, shaping may be required. As such, a stocking may have a lower portion which is not shaped at one side, and an upper portion which is shaped at both sides.

Shaping at both sides may be conveniently provided by centre aligning the lines of the knitting profile. This provides symmetrically shaping for the garment.

However, for more accurate shaping, a plane may be defined across the associated representation. The plane extends through the interior of the representation, and is preferably normal to a front-to-back direction of the representation. The proportion of each representation course on one side of the plane may be recorded. The lines of the knitting profile may then be correspondingly aligned about a reference line.

In other words, each line or knitting course of the knitting profile may have a proportion of the line or knitting course on one side of the reference line which corresponds to the proportion of the associated representation course which was on said side of the plane. As such, the knitting profile is shaped to correspond to the representation. The reference line may be considered to be internal to the knitting profile, rather than at an edge of the knitting profile.

Second embodiment -method of designing a bespoke compression garment in which the compressive part is to be made from multiple selected candidate 25 material A second embodiment of the present invention (a variant of the first embodiment) will now be described with reference to Figure 11 and the procedural flow diagram 80 therein. More particularly, this embodiment provides a computer-implemented method (algorithm) of designing a bespoke compression garment in which the compressive part is to be made from multiple materials, selected from a plurality of candidate materials that are in contention for use in the garment, and which may be identified in a database of such candidate materials.

In this embodiment, principal steps 1-7 (boxes 21-27 of Figure 11) are substantially the same as those described above in relation to the first embodiment, and as shown in Figure 3 (hence the use of the like reference numerals in Figure 11).

However, in this embodiment, step 6 (box 16 of Figure 11) involves rejecting candidate materials only in respect of use in the aforementioned first region in the waist of the compression garment, and fully anticipates the possibility of using other fabrics (including materials rejected above) in positions of the compression garment other than the aforementioned first region.

Further, in this embodiment, step 7 (box 17 of Figure 11) involves selecting, from the non-rejected materials in step 6, a material from which to manufacture the aforementioned first region of the waist of the compression garment, and fully anticipates the possibility of using other fabrics (including materials rejected above) in positions of the compression garment other than the aforementioned first region.

Thus, as a result of steps 6 and 7, the system can incorporate other suitable fabrics (including materials rejected above) from which to make regions of the compression garment other than the aforementioned first region.

In step 8 (box 88 of Figure 11) the system takes the material identified in step 7, from which to manufacture the aforementioned first region of the waist of the compression garment, and one or more other suitable fabrics from which to make other regions of the compression garment, and calculates how to maintain the required pressure gradient(s) when going between two or more different fabrics.

For example, one of the reasons why two (or more) fabrics may be desirable is that the fabric on the leg may desirably have a higher stiffness than the fabric used in the ankle region. Typically, the stiffer fabric will deliver higher levels of pressure on a larger garment size.

The two (or more) fabrics could be of significantly different circumferential size. It will be appreciated that connecting two (or more) fabric courses having significantly different circumferential sizes can potentially be problematic in manufacture, or can leave the resulting garment looking disformed. Thus, in step 8 (box 88 of Figure 11) the system calculates how to transition between two (or more) adjoining fabric courses.

It will also be appreciated that, if pressure control were not an issue, it would be relatively simple to increase or decrease the size of one (or both) of the adjoining fabrics to join them together. However, in a compression garment comprising multiple fabrics, it is necessary to maintain a pressure gradient across the adjoining fabrics. Consequently, it is generally not feasible to simply change the size of a fabric course without creating a tourniquet effect or having a sudden drop in pressure.

To address this, we have developed a method to transition between a first fabric course and a second fabric course having different levels of stiffness. This involves forming a transition zone between the first and second fabric courses, the transition zone using further (intermediate) fabric courses that ease the transition of pressure/stiffness and allow for the garment to be both manufacturable and not ill formed.

An example of a transition between two fabric courses would be that a first fabric, "Fabric A", requires 50 needles to deliver the correct pressure for a respective first course, whereas a second fabric, "Fabric B", requires 60 needles to deliver the correct pressure for the respective second course. In one solution, a third fabric, "Fabric C", could be introduced, between the first and second courses, that requires e.g. 55 needles to deliver the correct pressure for a respective third (intermediate) fabric course. Thus, starting from the first fabric (Fabric A), after one or more courses of the third fabric (Fabric C), the design can then transition to the second fabric (Fabric B), as the jump in needles would be more manufacturable.

Moreover, to achieve this transitioning method using an intermediate fabric course, fine control is desirable over the variables that influence pressure delivery. While it would be possible to build a database of different fabrics from which the system could choose, storing and accessing details of how scalar aspects of each fabric can be adjusted can also be useful (potentially more so than using different fabrics).

For example, in one implementation, details may be stored as to how the pressure of a fabric changes with loop size. From this, the system can calculate the desired loop size of an intermediate fabric course (which may be a modification of either the first fabric or the second fabric), to transition smoothly between the first and second fabrics.

Whilst the above example uses a single fabric in the transition zone between the first fabric and the second fabric, variants of this embodiment may beneficially use multiple fabrics in the transition between the first fabric and the second fabric.

The above examples relate to the transition zone needing to connect first and second fabrics having different number of needles. However, alternatively, the first and second fabrics could be manufactured using the same number of needles but having different circumferential sizes. This could be due to the first and second fabrics each having a unique "needles per centimetre" quality. For example, the first fabric could have one needle corresponding to 0.125 cm (i.e. 8 needles per centimetre), whereas the second fabric could have one needle corresponding to 0.145 cm (i.e. -7 needles per centimetre). An implemented may be envisaged where the objective is not to match the number of needles but to have a similar course width, i.e. a smooth shape change rather than a garment that has a jagged edge. Again, either a single intermediate fabric or multiple intermediate fabrics could be used to provide a smooth transition between the first and second fabrics of different sizes or different numbers of needles per centimetre, whilst maintaining a desired pressure gradient.

A further implementation could be to prioritise both the number of needles (or number of needles per centimetre) and the course width by selecting one or more transition fabric(s) that represent a middle ground between the two.

More generally, parameters that may be varied in the transition zone include: * selection of fabric material/yarn * course width * course height * number of needles across the course (i.e. absolute number of needles across the course) * number of needles per centimetre (also known as "wales per centimetre") * loop size or knit size Whilst many outcomes from steps 6 and 7 can require a transition zone, in some cases the natural leg shape, pressure profile and fabric choices may be such that no transition zone is required. However, if the variables of the first and second fabrics do not align, a transition zone may be required to ensure the compression garment has a suitable pressure gradient.

Finally, the method of the second embodiment continues with step 9 (box 89 of Figure 11) whereby the system generates a set of knitting instructions for producing the compression garment from the selected materials in accordance with the representation of the body part, the specified pressure configuration, and incorporating the above-determined transition zone between first and second constituent materials. This step is similar to step 8 (box 28 of Figure 3; box 44 of Figure 4) of the first embodiment, but with a notable difference being that the knitting instructions will include a reference to the location of the transition zone and a fabric specification for manufacturing the transition zone.

Knitting the compression garment The above methods, and the present disclosure more generally, are primarily directed to designing a bespoke compression garment, and therefore the methods 30 may end once the product has been designed. The above methods may however continue to include the manufacture of the compression garment itself.

Thus, the above methods may further comprise a step of knitting the compression garment based on the or each knitting pattern using the selected material The bespoke compression garment may be knitted with a knitting machine.

The system may export quality information about the processing and quality checks for post-manufacture. Examples of this could include pressure maps, strain maps, transition markers, datapoints or coordinates, or measurements. The system may export key quality checks as a text file or spreadsheet for a knitting facility, with the knitting machine, to check against. The system may also generate the production documents with all the order information and the quality checks.

The system may be required to save or store all files, data, maps or other information generated. This could work in a variety of ways. For example, the system could store the files to a cloud location that is accessible by the knitting facility. A more advanced system could include a Graphical User Interface that has a process flow that integrates with an enterprise resource planning system. For example, the system could record the approval of quality checks by the operator and directly instruct the knitting machine. Other version of the system could integrate with an email system to notify the patient or healthcare professional of the order progress.

Although a bespoke knitted compression garment may be manufactured, it will be appreciated that this may not be necessary in all situations. For example, an offthe-shelf garment may be able to provide a sufficient pressure configuration to the patient. This may be the case if a geometry of the body part of the patient and a pressure therefor corresponds closely to that for which an off-the-shelf garment is designed. As such, once the scan or representation and order information is provided to the system, the system may use a database of pre-existing compression garments having different size data and for applying different pressure configurations to determine whether an off-the-shelf garment may be suitable. A pre-existing compression garment from the database is selected based on matching or substantially matching size data and pressure configuration of the representation to the size data and pressure configuration of the pre-existing compression garment. The pre-existing compression garment may then be ordered and provided to the patient. The healthcare professional may utilise this option if a wait-time for a bespoke manufactured garment is unacceptable.

Although the compression garment is described as knitted, it will be appreciated that similar modelling methods and processes may be applied for non-knitted garments, for example woven garments or other garment construction.

Although the method describes generating a knitting profile and knitting the garment, it will be appreciated that these steps may be excluded if only a garment modelling process is required.

Although flat knit courses are described above, it will be appreciated that helically knitted courses may be designed and manufactured using a variant of the present principles. Sections of the helical course may be modelled in a similar or identical 15 way as the representation courses described above.

A system may be provided for manufacturing a bespoke knitted compression garment. The system comprises a body part scanner for scanning the body part of the patient and producing the representation, and pressure configuration data, in other words the pressure configuration prescribed by the healthcare professional to be applied to the patient. The system further comprises material data, such as a database of characteristics of at least one material type. A processor or computer may carry out the analysis steps on the representation and produce the knitting pattern. A knitting machine may be required to knit the garment.

The words 'comprises/comprising' and the words 'having/including' when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

CLAIMS1. A computer-implemented method of designing a bespoke compression garment, the method comprising: obtaining a representation of a body part on which the compression garment is to be worn, the body part comprising a foot and at least part of a leg, the foot having an ankle and a heel; obtaining a specified pressure configuration to be applied by the compression garment on the body part; determining, from the representation of the body part, a respective circumference measurement at each of a series of fabric course positions along the body part; determining, from the representation of the body part, a first reference position along the leg, at which position the leg has a relatively small circumference compared with other positions along the leg, and determining a respective first circumference of the leg at the first reference position; determining, from the representation of the body part, a second reference position around the ankle and heel, having a relatively large circumference compared with other positions along the foot, and determining a respective second circumference, around the ankle and heel, at the second reference position; determining, using characteristic data in respect of one or more candidate materials for knitting at least part of the compression garment, a respective reference strain value at which a respective fabric course knitted from the or each candidate material would provide the specified pressure on the leg at the first reference position; determining, for the respective fabric knitted from the or each candidate material, from the determined respective reference strain value and the first circumference of the leg at the first reference position, a first unstretched circumference of the respective fabric course in a corresponding first region of the compression garment that, when stretched to the first circumference of the leg at the first reference position, would adopt the respective reference strain value and thus impart the specified pressure on the leg; determining, for the respective fabric knitted from the or each candidate material, a peak force required to stretch the respective course of fabric in the first region of the compression garment around the ankle and heel at the second reference position, and/or a peak strain that the respective course of fabric would adopt when stretched from the first unstretched circumference to the second circumference; assessing the suitability of the or each candidate material, by verifying that, for the or each candidate material, the determined peak force does not exceed a respective threshold force, and/or the determined peak strain does not exceed a respective threshold strain, and rejecting, at least in respect of use in the first region of the compression garment, candidate materials for which one or both of these thresholds are exceeded; selecting, from the candidate material(s) that have not been rejected, a material from which to manufacture at least the first region of the compression garment; and generating a set of knitting instructions for producing at least the first region of the compression garment from the selected material in accordance with the representation of the body part and the specified pressure configuration.
2. The method according to claim 1, wherein the representation of the body part comprises scan data of the body part.
3. The method according to claim 2, wherein the representation of the body part comprises 3D scan data
4. The method according to any preceding claim, wherein, at the first reference position, the leg has its smallest circumference.
5. The method according to any preceding claim, wherein, at the second reference position, the circumference around the ankle and heel is a maximum value.
6. The method according to any preceding claim, further comprising determining, from the representation of the body part, one or more respective radius measurements at each of the series of fabric course positions along the body part.
7. The method according to claim 6 wherein, at one or more of the series of fabric course positions along the body part, a single average radius measurement is determined.
8. The method according to claim 6 wherein, at one or more of the series of fabric course positions along the body part, a plurality of radius measurements are determined.
9. The method according to claim 8 wherein, at each of the series of fabric course positions along the body part, each of the plurality of radius measurements is determined by fitting an arc to a respective portion of the circumference of the body part and determining the radius of said arc.
10. The method according to any preceding claim, wherein the threshold force is determined according to the physical strength of the intended wearer of the 20 compression garment.
11. The method according to any preceding claim wherein, for the or each candidate material, the threshold strain is determined according to the elastic limit of the respective fabric.
12. The method according to any preceding claim, wherein the step of selecting a material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, comprises selecting the stiffest non-rejected candidate material.
13. The method according to claim 12, wherein the step of selecting a material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, further comprises: verifying that the stiffest non-rejected candidate material, if used, would not have any courses of stitches that would exceed a threshold strain; and if any courses of stitches would exceed the threshold strain, reverting to another of the non-rejected candidate materials.
14. The method according to any preceding claim, wherein the step of selecting a material from which to manufacture at least the first region of the compression garment, from the non-rejected candidate materials, comprises selecting a material for which the manufacturing time is less than a threshold value.
15. The method according to any preceding claim, wherein the selected material from which to manufacture at least the first region of the compression garment is a first material; and wherein the method further comprises: selecting a second material from which to manufacture one or more regions of the compression garment other than said first region.
16. The method according to claim 15, wherein the second material is a previously-rejected material.
17. The method according to claim 15 or claim 16, further comprising incorporating a transition zone between a first fabric course to be manufactured from the first material, and a second fabric course to be manufactured from the second material.
18. The method according to claim 17, further comprising selecting a third material from which to manufacture the transition zone.
19. The method according to claim 18, wherein the third material has a level of stiffness between that of the first material and that of the second material.
20. The method according to any of claims 17 to 19, wherein the transition zone differs from the first fabric course and the second fabric course in respect of one or more of: the course width; the course height; the number of needles across the course; the number of needles per centimetre; the loop size or knit size.
21. The method according to any preceding claim; and manufacturing the compression garment by knitting the selected material(s) in accordance with the generated set of knitting instructions.
22. A compression garment manufactured by the method of claim 21.
23. A computer program comprising instructions which, when the program is executed by a computer processor, cause the computer processor to carry out the method of any of claims 1 to 20