Determining the location of a device

Abstract

The present invention discloses a computer-implemented method (1600) for determining the position of a personal care device configured to perform a personal care treatment on the skin when in contact with a skin surface of a subject. The method includes receiving (1602) data representing a measured curvature of the skin surface within a first region of the skin surface of the subject in contact with the personal care device, determining (1604) an indication of the position of the first region of the subject's skin surface by comparing the measured curvature with curvature information for multiple regions of the subject's skin surface contained in a database, and performing (1606) an action related to the personal care device based on the determined indication of the position of the first region. Processing devices, systems, personal care devices, and computer program products are also disclosed.

Description

[Technical field]

[0001] The present invention relates to methods, apparatus and systems for determining device position, and in particular for determining the position of a personal care device relative to the surface of a subject's skin. [Background technology]

[0002] The personal care device is used to perform personal care treatments on the skin of a user. Such personal care treatments include, but are not limited to, hair removal, hair care treatments such as shaving and trimming, or massage. Although the user knows which part of the body is being treated by the personal care device and can adjust the application of personal care accordingly, the device itself may perform in a suboptimal manner for some body parts compared to others.

[0003] EP 3 528 091 A1 discloses an apparatus for determining a position of a personal care device relative to a user, the apparatus comprising a processor configured to detect the position of one or more body parts of a user, to detect a movement of at least one of the user's body parts induced by the personal care device during use of the personal care device, and to determine a position of the personal care device relative to the user based on the detected movement of the at least one user's body part and in relation to the detected position of the at least one user's body part. Summary of the Invention [Problem to be solved by the invention]

[0004] In order for a personal care device to operate in an improved or optimal manner, it may be beneficial to identify its approximate location relative to the user / subject's body, for example by identifying the portion of the subject's skin where a personal care treatment is being performed. Existing means for determining the location of the device are ineffective. Thus, more effective means for determining an indication of the device's location relative to the subject's skin surface are desired. [Means for solving the problem]

[0005] It has been appreciated by the inventors of the present disclosure that the position of a personal care device can be determined based on the measured curvature of the surface on which the device is used. For example, the position of the personal care device relative to the subject's body can be determined by measuring the curvature of a body part in contact with the device and determining the portion of the area of ​​the body that has a corresponding curvature based on the measured curvature.

[0006] Knowledge of the part or area of ​​the body on which the device is being used can be used to take appropriate action to improve the performance of the device, for example, by adjusting operating parameters of the device to operate more appropriately for the part of the body on which the device is being used, analyzing personal care routines, tracking skin parameters over time, or providing feedback on personal care treatments.

[0007] According to a first aspect, a computer-implemented method for determining a position of a personal care device relative to a skin surface of a subject is provided, the method comprising the steps of receiving data representative of a measured curvature of the skin surface in a first region of the skin surface of the subject in contact with the personal care device, determining an indication of a position of the first region of the skin surface of the subject by comparing the measured curvature with curvature information of a plurality of regions of the skin surface of the subject contained in a database, and performing an action related to the personal care device based on the determined indication of the position of the first region.

[0008] Based on the previously acquired curvature measured during use of the personal care device, the position of the device is determined using data regarding the curvature of various parts of the subject's skin surface. In this way, the position of the device can be easily determined to adopt an appropriate treatment based on the determined position.

[0009] In some embodiments, the method further comprises receiving data representative of a measured displacement of the personal care device between a first region and a second region of the skin surface previously contacted by the personal care device, wherein determining an indication of a location of the first region is further based on comparing the data representative of the measured displacement to location information of a plurality of regions of the skin surface of the subject contained in a database.

[0010] In some embodiments, the method further comprises, prior to receiving data representing the measured curvature of the skin surface in the first region of the skin surface, receiving calibration displacement data representing the measured displacement between a plurality of regions of the skin surface of the subject of the personal care device, fitting a computer model of the skin surface of the subject to the received calibration displacement data, determining curvature information of each of the plurality of regions from the calibration displacement data and the fitted computer model, and storing the determined curvature information in a database in association with a corresponding region on the skin surface of the subject. This is considered as a calibration process.

[0011] According to a second aspect, a processing device is provided that is configured to determine a position of a personal care device relative to a skin surface of a subject, the processing device being configured to receive data representing a measured curvature of the skin surface in a first region of the subject's skin surface in contact with the personal care device, retrieve curvature information of a plurality of regions of the subject's skin surface from a storage medium, determine a position of the first region of the subject's skin surface by comparing the measured curvature with the curvature information of the plurality of regions of the skin surface, and generate instructions for a treatment to be performed with respect to the personal care device based on the determined position of the first region.

[0012] According to a third aspect, there is provided a system configured to determine a position of a personal care device relative to a skin surface of a subject, the system comprising a housing for receiving a communication unit, a skin surface curvature measurement mechanism configured to measure a curvature of the skin surface in a first region of the skin surface of the subject and coupled to the housing, and a processing device as discussed herein. The skin surface curvature measurement mechanism is configured to generate data representative of a measured curvature of the skin surface in the first region of the skin surface. The communication unit is configured to communicate the data representative of the measured curvature of the skin surface in the first region of the skin surface to the processing device.

[0013] In some embodiments, the skin surface curvature measurement mechanism comprises an imaging device configured to acquire image data relating to a first region of the skin surface, and the processing device is further configured to use the acquired image data to determine a curvature of the skin surface within the first region of the skin surface.

[0014] The skin surface curvature measurement mechanism, in some embodiments, comprises a first surface engaging element and a second surface engaging element movable relative to one another. The data representative of the measured curvature of the skin surface within the first region of the skin surface is determined by a relative displacement of the first surface engaging element and the second surface engaging element. Direction Includes measurements of.

[0015] In some embodiments, the system includes a first surface engaging element relative to the housing. Direction and a second surface-engaging element Direction The data representative of a measured curvature of the skin surface within the first region of the skin surface is based on a relationship between the first surface engaging element and the housing. Direction and the measurement of the second surface-engaging element relative to the housing. Direction Includes measurements of.

[0016] The first surface engaging element and the second surface engaging element are each pivotally mounted relative to the housing and the other engaging element. The data representative of the measured curvature includes an average curvature of the skin surface within the first region.

[0017] A fourth aspect provides a personal care device comprising a body, a skin surface curvature measuring mechanism configured to measure a curvature of the skin surface within a first region of the skin surface of a subject in contact with the personal care device, and a processing device as disclosed herein, the processing device configured to receive data representative of the measured curvature of the skin surface from the skin surface curvature measuring mechanism.

[0018] The personal care device in some embodiments further comprises an attachment detachable from the body for housing a communication unit, the skin surface curvature measuring mechanism being coupled to the attachment, the body housing a processing device, the communication unit configured to communicate data representative of the measured curvature of the skin surface to the processing device.

[0019] In some embodiments, the personal care device further comprises a sensor for acquiring motion data of the personal care device. The processing device is configured to determine a position of the first region of the subject's skin surface further based on the motion data acquired using the sensor. The motion data includes, for example, data representing a measured displacement.

[0020] The personal care device further comprises a housing supporting at least a first treatment element and a second treatment element, the first treatment element comprising a first surface engaging element and the second treatment element comprising a second surface engaging element, each of the first surface engaging element and the second surface engaging element pivotally mounted relative to the housing and the other engaging element. The skin surface curvature measuring mechanism is adapted to measure the position of the first surface engaging element relative to the housing. Direction a first sensor configured to measure a second surface-engaging element relative to the housing; Direction and a second sensor configured to measure

[0021] In some embodiments, the personal care device is an electric shaver, and both the first treatment element and the second treatment element comprise a shaving unit having an external cutting member, an internal cutting member configured to be movable relative to the external cutting member, and a skin-supporting rim surrounding the external cutting member and pivotally attached to the housing, and the first surface-engaging element comprises the skin-supporting rim of the shaving unit of the first treatment element, and the second surface-engaging element comprises the skin-supporting rim of the shaving unit of the second treatment element.

[0022] According to a fifth aspect, there is provided a computer program product comprising a non-transitory computer readable medium embodied with computer readable code configured, when executed by a suitable computer or processor, to cause the computer or processor to perform the steps of the methods disclosed herein.

[0023] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0024] For a better understanding of the present invention and to show more clearly how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which: [Brief description of the drawings]

[0025] [Figure 1] 1 is a schematic diagram of an example of a personal care device according to various embodiments. [Diagram 2] 1 is a schematic diagram of a further example of a personal care device according to various embodiments. [Diagram 3] 1 is a schematic diagram of a further example of a personal care device according to various embodiments. [Figure 4] 1 is an illustration of a portion of a personal care device according to various embodiments. [Diagram 5] 5 is a top view of an example of an attachment for the personal care device of FIG. 4, according to various embodiments. [Figure 6] 1A-1D are side views of attachments for personal care devices according to various embodiments. [Figure 7] 11A-11C are side views of further examples of attachments for personal care devices according to various embodiments. [Figure 8] FIG. 2 is a plan view of an example of an attachment according to various embodiments. [Figure 9] 11A-11C are plan views of further examples of attachments according to various embodiments. [Figure 10] 11A-11C are plan views of further examples of attachments according to various embodiments. [Figure 11] 1A-1C are side views of further examples of personal care devices according to various embodiments. [Figure 12] 1 is a schematic diagram of an example of a processing device according to various embodiments. [Figure 13] FIG. 1 is a schematic diagram of an example of a system in accordance with various embodiments. [Figure 14A] FIG. 1 illustrates an example of how curvature may be measured according to various embodiments. [Figure 14B] FIG. 1 illustrates an example of how curvature may be measured according to various embodiments. [Figure 15] 11A-11C show further examples of how curvature may be measured according to various embodiments. [Figure 16] 1 is a flow diagram of an example of a computer-implemented method for determining a position of a personal care device relative to a subject's skin surface in accordance with various embodiments. [Figure 17] 4 is a flow diagram of a further example of a computer-implemented method for determining a position of a personal care device relative to a skin surface of a subject according to various embodiments. [Figure 18] 1 is a schematic diagram of a computer-readable medium in communication with a processor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The disclosed embodiments provide a mechanism for determining the position of the apparatus relative to the subject's skin surface in contact with the device. Some embodiments are described in the context of a handheld shaver, where the position of the handheld shaver is determined relative to the subject's body or facial area where the shaver is being used to trim or shave. However, it is understood that the present invention is not limited to shaving devices, and the embodiments described herein may be implemented with a wide range of personal care devices configured to perform a personal care treatment on the skin when in contact with the skin surface. Thus, the personal care devices described herein include, for example, hair removal devices such as epilators or intense pulsed light (IPL) devices, hair care devices such as shavers, clippers, or hair trimmers, skin health analysis devices, electric massagers, phototherapy devices, or pain relief devices. Other personal care devices configured to perform a personal care treatment on the skin when in contact with the skin surface are also envisioned.

[0027] Referring now to the drawings, Figure 1 is a schematic diagram of an example of a personal care device 100. The personal care device 100 is intended to be held in a user's hand during use, and is therefore referred to as a handheld personal care device. The personal care device 100 comprises a body 102, a skin surface curvature measuring mechanism 104, and a processing unit 106. In some embodiments, the personal care device 100 is formed as a unitary device, with the components inseparably connected or coupled. However, in other embodiments, various components of the personal care device 100 are detachable from other components of the personal care device, such that the personal care device is considered modular.

[0028] The body 102 houses one or more components of the device. In some examples, the body is intended to be held in a user's hand during use.

[0029] The skin surface curvature measuring mechanism 104 (also referred to herein as the measuring mechanism 104) is configured to measure the curvature of the skin surface in a first region of the subject's skin surface in contact with the personal care device. As described in more detail below, the measuring mechanism 104 measures the skin surface curvature in a number of ways. The processing device 106 is configured to receive data from the skin surface curvature measuring mechanism 104 representative of the measured curvature of the skin surface. The received data is then processed by the processing mechanism 104 to determine the position of the personal care device 100.

[0030] In some embodiments, the skin surface curvature measuring mechanism 104 includes a number of elements that are pivotally attached to the personal care device 100 and other elements. These elements are considered to be surface-engaging elements that contact the subject's skin surface during use. The measured surface-engaging elements of the skin surface curvature measuring mechanism 104 Direction By using the surface curvature sensor 100, the curvature of the skin surface can be determined. Thus, the skin surface curvature is determined for the portion of the skin surface that is in contact with the surface engaging element. As the personal care device 100 is moved over the subject's skin surface, the skin surface curvature is determined at more positions and data representative of the skin surface curvature is communicated (e.g., via a wired or wireless connection) to the processing unit 106 so that the position of the personal care device can be determined.

[0031] When data obtained using the skin surface curvature measurement mechanism 104 is transmitted to the processing device 106, the processing device compares the data with existing curvature information for multiple regions of the subject's skin surface. For example, the processing device 106 obtains such curvature information from a database or other data structure stored in a storage medium, such as a memory associated with the personal care device 100. The curvature information was obtained and stored in the storage medium as part of a previously performed calibration process such that the curvature information of multiple regions or locations is known for a particular subject. The processing device 106 can determine the location of the first region of the skin surface by comparing the measured curvature data of the first region of the subject's skin surface with the stored curvature information. For example, if the processing device receives data from the skin surface curvature measurement mechanism 104 indicating that the first region has a particular curvature c, it determines from the comparison with the stored curvature information that the curvature c corresponds to the subject's chin. Thus, it is determined that the personal care device 100 is in contact with the subject's chin. Such a determination can be useful for adjusting the settings or operating parameters of the personal care device 100 to improve the personal care treatment. For example, the hair on a person's chin is generally coarser than the hair on his / her cheeks. Therefore, when it is determined that the cutting element of the shaver is located on the subject's chin rather than on the cheek, it is beneficial to increase the speed of the cutting element of the shaver.

[0032] The embodiment shown in Fig. 1 is formed from a single unit. In other embodiments, the skin surface curvature measurement mechanism 104 is housed in or forms part of a separate attachment that is removably attachable or connectable to the body 102 of the personal care device 100. Fig. 2 is a schematic diagram of an example of a personal care device 200 in which the skin surface curvature measurement mechanism is part of a unit that is separable from the body 102. The personal care device 200 includes the body 102 and the processing unit 106 as shown in the example of Fig. 1. However, the personal care device 200 further comprises an attachment 202 for housing a communication unit 204 that is detachable from the body 102. The attachment 202 is attached to the body 102 of the personal care device 200 using attachment mechanisms well known to those skilled in the art. The detachability of the attachment 202 from the body 102 is beneficial for cleaning or easily replacing the attachment or its components. For example, an attachment for one type of treatment (eg, shaving) can be removed and replaced with an attachment for another type of treatment (eg, peeling).

[0033] 2, the attachment 202 has a skin surface curvature measurement mechanism 104 coupled thereto. In some examples, the measurement mechanism 104 forms part of the attachment 202. In this example, the body 102 houses the processing device 106. However, in other examples, the processing device 106 is located on the attachment 202 itself.

[0034] The communication unit 204 is configured to communicate data representative of the measured curvature of the skin surface to the processing device 106. Thus, in some examples, data obtained using the skin surface curvature measurement mechanism 104 is communicated directly from the measurement mechanism to the processing device 106 (as shown by the dashed line in FIG. 1), while in other examples, it is communicated to the processing device via the communication unit 204 (as shown by the dashed line in FIG. 2).

[0035] Supplemental electrical connections (not shown) are provided for the attachment 202 and the body 102, and the attachment is mounted to facilitate the transfer of power and / or data between components of the attachment 202 (e.g., the skin surface curvature measurement mechanism 104) and components of the body 102 (e.g., the processing unit 106).

[0036] The skin surface curvature measuring mechanism 104 may acquire sufficient curvature data so that the position of the personal care device 100, 200 may be determined. However, according to some embodiments of the present invention, additional data is acquired and used to more accurately determine the position of the personal care device 100, 200. In some embodiments, the personal care device 100, 200 further comprises a sensor 206 for acquiring motion data of the personal care device. The motion data may include, for example, data representative of the motion or displacement of the personal care device for a defined measurement period. The processing device 106 is configured to determine the position of the first area of ​​the subject's skin surface further based on the motion data acquired using the sensor 206, as described in more detail below. The sensor 206 is any sensor capable of measuring, among other things, the displacement of the personal care device 100, 200 and / or, more specifically, the displacement of the skin surface curvature measuring mechanism 104 of the personal care device. In one example, the sensor 206 comprises an inertial measurement unit (IMU). IMUs are well known to those skilled in the art and use accelerometers, gyroscopes, and / or magnetometers to measure various parameters of the device to which the IMU is attached, such as specific forces, angular rates, and / or Direction ) as measured by the sensor 206. As shown in FIG. 2 using dashed lines to represent the sensor, the sensor 206 is located within the body 102 or attachment 202. Data acquired using the sensor 206 is communicated by a wired or wireless connection to the processing unit 106 for use in determining device position. In some embodiments, data is communicated from the sensor 206 to the processing unit 106 by the aforementioned electrical connections.

[0037] In some examples, a gravity vector along three special axes is estimated using a Kalman filter from data acquired using an IMU (e.g., from data acquired using an accelerometer in the IMU). The gravity vector is the ratio of the skin surface curvature measurement mechanism 104 to the gravitational field (with or without data from the IMU's gyroscope). Direction , which can help improve the accuracy of the position determination by the processing unit 106. In some examples, the body part of the subject on which the personal care device is being used may be positioned in a particular way, such as during a shaving procedure, with the user's head held upright or slightly tilted. Orientation It is sometimes assumed that

[0038] 3 is a schematic diagram of a further example of a personal care device 300 according to various embodiments of the present invention. The personal care device 300 includes a body 102, a processing device 106, and a skin surface curvature measurement mechanism 104. The personal care device 300 further includes a housing 302 supporting at least a first treatment element 304 and a second treatment element 306. The first treatment element 304 includes a first surface engaging element 305, and the second treatment element 306 includes a second surface engaging element 307. Each surface engaging element 305, 307 is pivotally mounted to the housing 302 so as to be pivotable relative to each other. Thus, when the surface engaging elements 305, 307 engage the skin surface of the subject, each surface engaging element pivots independently depending on the curvature of the surface with which it is in contact. The skin surface curvature measurement mechanism 104 determines the position of the first surface engaging element 305 relative to the housing 302. Direction and a first sensor 308 configured to measure a second surface engagement element 307 relative to the housing. Direction and a second sensor 310 configured to measure the relative position of the first surface-engaging element 305 and the second surface-engaging element 307. Direction is used to determine the location of a first area of ​​the subject's skin surface that is in contact with the personal care device 300.

[0039] An example of a personal care device embodying the present invention will now be discussed with reference to Figures 4-11. Figure 4 illustrates a portion of a personal care device 400, which in this example comprises an electric shaver. In Figure 4, a portion of the main body 102 is shown with an attachment 202 attached thereto. Figure 5 is a plan view of the attachment 202 of Figure 4. The attachment 202 is pivotally attached to the main body 102 about a pivot point 402. The personal care device 400 also includes a housing 302. In the example shown in Figures 4 and 5, the housing 302 supports three treatment elements 404, 406, 408, each of which comprises a shaving unit. In other examples, more or fewer treatment elements are provided on the attachment 202. The shaving unit of each treatment element 404, 406, 408 has an external cutting member 410 and an internal cutting member 412 configured to be movable relative to the external cutting member. The internal cutting member 412 is located below the external cutting member 410 and therefore can only be seen through the slits in the external cutting member. For this reason, the internal cutting member 412 is shown in dashed lines. In some examples, the internal cutting member 412 rotates (e.g., in the opposite direction) relative to the corresponding external cutting member 410 to shave the subject's skin. Each treatment element 404, 406, 408 also includes a skin support rim 414 that surrounds the external cutting member 410 and is pivotally mounted (about the axis indicated by the crosshairs) relative to the housing 302. In this example, the skin support rim 414 of each treatment element 404, 406, 408 includes a surface engaging element (e.g., surface engaging element 305, 307). Thus, in use, the treatment elements 404, 406, 408 of the personal care device 400 are placed against the skin surface of the subject to be shaved and the skin support rim 414 pivots relative to the housing 302 relying on the curvature of the skin surface with which it is in contact.

[0040] The above example described with reference to Figures 4 and 5 relates to an electric shaver with three shaving units. More generally, the personal care device (e.g., personal care device 300) is an electric shaver, and the first treatment element 304 and the second treatment element 306 both comprise a shaving unit having an external cutting member 410, an internal cutting member 412 configured to be movable relative to the external cutting member, and a skin-supporting rim 414 surrounding the external cutting member and pivotally attached to the housing 302, the first surface-engaging element 305 comprises the skin-supporting rim 414 of the shaving unit of the first treatment element 304, and the second surface-engaging element 307 comprises the skin-supporting rim 414 of the shaving unit of the second treatment element 306.

[0041] As previously mentioned, the respective surface engaging elements 305, 307, 414 relative to the housing 302 Direction One or more sensors (e.g., sensors 308, 310) are used to measure the relative position of each skin support rim 414 relative to the housing 302, and various techniques are used to accomplish this. FIG. 5 shows a pair of fulcrums 416 or pivots located on opposite sides of each shaving unit, and thus on each skin support rim 414. Each skin support rim 414 is mounted so that it can pivot about an axis defined by its respective pair of fulcrums 416. The relative position of each skin support rim 414 relative to the housing 302 is determined by a number of different techniques. Direction is measured by sensing contact (or the degree of contact) with an underlying engagement surface 418 on one side of the skin support rim. Various embodiments of the engagement surface 418 and the interaction of each skin support rim 414 with a corresponding engagement surface are described below with reference to Figures 6, 7, 8, 9 and 10.

[0042] 6 and 7 are side views of attachments 600, 700, respectively, each with a cutaway view showing the pivoting of the surface-engaging elements. In both Figs. 6 and 7, the cutaway views show treatment element 404, which includes a shaving unit formed from inner cutting member 412 and outer cutting member 410, and a skin-supporting rim 414. Skin-supporting rim 414 is pivotally attached to fulcrum 416 via base 602 (or an extension thereof) in the direction of arrow A. In the embodiment shown in Figs. 6 and 7, the position of skin-supporting rim 414 relative to housing 302 is Direction A separate sensor is used to measure

[0043] The attachment 600 of FIG. 6 includes a skin support rim 414 to a housing 302. Direction A multi-point resistive force sensor 604 is provided to measure the force of the skin support rim 414. In this embodiment, when a force is applied to the surface (e.g., by pressing against the subject's skin surface), the skin support rim 414 pivots towards the force sensor 604, compressing the spring 606, thereby exerting a force on the force sensor. When the spring 606 exerts a force on the force sensor 604, a resistance change occurs in the force sensor, which is measured by electronics (not shown) within the attachment 600 and / or the body 102 (not shown in FIG. 6). The force exerted on the force sensor 604 is proportional to the amount that the spring 606 is compressed by the skin support rim 414. Each skin support rim 414 is provided with a corresponding spring 606, which in the illustrated example comprises a three-point thin film resistive force sensor. In other examples, a separate force sensor 604 is provided for each spring 606.

[0044] The attachment 700 of FIG. 7 includes a skin support rim 414 to a housing 302. DirectionA switch-type sensor is provided to measure the skin support rim 414's position. The sensor in this embodiment includes a first switch 702 disposed under the skin support rim 414 on one side of the pivot, and a second switch 704 disposed under the skin support rim on the opposite side of the pivot. When a force is applied to the side of the skin support rim 414 closest to the first switch 702 (e.g., the skin support rim engages the subject's skin surface), the skin support rim 414 pivots toward the first switch, thereby engaging and activating the first switch. When a force is applied to the side of the skin support rim 414 closest to the second switch 704, the skin support rim 414 pivots toward the second switch, thereby engaging and activating the second switch. Each skin support rim 414 of the attachment includes a switch 702 for each skin support rim. Direction A corresponding pair of switches are provided to measure the skin support rim 414's first and second switches 702, 704. One or both of the first and second switches 702, 704 comprise capacitive switches configured to respond (i.e., be activated) to the presence of (e.g., engagement with) the skin support rim 414. The use of the first and second switches 702, 704 for each skin support rim 414 allows for the determination of the first switch position for each skin support rim when the skin support rim is tilted towards the first switch. Direction , the second when the skin support rim is tilted toward the second switch. Direction and a third when the skin support rim is not tilted in a direction that activates the first switch or the second switch. Direction , and three Direction is measured.

[0045] In the embodiment shown in Figures 6 and 7, the skin support rim 414 of each treatment element 404, 406, 408 is adapted to rotate relative to the housing 302 to determine the curvature of the skin surface. DirectionIn other embodiments, however, a surface-engaging element that is not part of the treatment element of the personal care device is provided for curvature measurement. Figures 8 and 9 are plan views of examples of attachments 800, 900, in which a separate surface-engaging element is provided for measuring the curvature of the skin surface in addition to the treatment element for performing the personal care treatment. In Figure 8, a surface-engaging element 802 is provided between the pair of treatment elements 404 and 406, a surface-engaging element 804 is provided between the pair of treatment elements 406 and 408, and a surface-engaging element 806 is provided between the pair of treatment elements 404 and 408. In this embodiment, each surface-engaging element 802, 804, 806 is configured to pivot about a respective fulcrum 808, 810, 812 to compress a respective spring 814, 816, 818 when a force is applied to the surface-engaging element. Each spring 814, 816, 818 is in contact with a resistive force sensor 820, and when each spring is compressed, the internal resistance of the force sensor changes an amount proportional to the applied force, which is measured by the electronics (not shown) of the attachment 800 or personal care device to which the force sensor is attached. The mechanism of FIG. 8 functions similarly to the mechanism shown in FIG.

[0046] In some embodiments, the treatment elements 404, 406, 408 of FIG. 8 may be configured such that a resistive force sensor 820 senses the force of each of the surface engaging elements 802, 804, 806, as shown in the mechanisms of FIGS. Direction In addition, each treatment element Direction In such an arrangement, as the personal care device moves over the subject's skin surface, additional curvature information (i.e., curvature information from the surface engaging elements 802, 804, 806 and curvature information from the treatment elements 404, 406, 408) is obtained. In another example, the surface engaging elements 802, 804, 806 are provided on a device with only one treatment element. Thus, curvature information is measured even on a device containing only one treatment element.

[0047] In an alternative embodiment, the skin surface curvature measuring mechanism comprises one or more flexible sensors comprising multiple capacitive sensors. FIG. 9 shows an attachment 900 having three treatment elements 404, 406, 408, which in this example are treatment elements such as brushes other than shaving units. The skin surface curvature measuring mechanism in this embodiment comprises three flexible sensors 902, 904, 906. A grid of capacitive sensors is attached on each flexible sensor 902, 904, 906. In one example, electrodes (e.g., silver nanowires) are stacked in a multi-layer stack on an insulating substrate with an intermediate layer of polydimethylsiloxane (PDMS). When the skin engaging element of each of the treatment elements 404, 406, 408 engages with the skin surface, causing it to bend (e.g., exert a force on the sensor). Thus, the surface of the electrodes changes to measure the skin curvature. In other embodiments, fewer ring-shaped sensors of this type, for example one, are provided, which are capable of measuring the curvature of the skin surface that they are in contact with.

[0048] 10 is a plan view of an attachment 1000 according to a further embodiment. In this embodiment, each treatment element 404, 406, 408 comprises a rotatable brush 1004, 1006, 1008, respectively, for example, massaging or exfoliating the subject's skin. Each brush 1004, 1006, 1008 is rigidly mounted within a respective limb 1010, 1012, 1014, which is pivotally mounted to the housing 302 in a manner similar to the skin support limb 414 of the attachments 600, 700 shown in FIGS. 6 and 7, respectively. Under one side of each limb 1010, 1012, 1014 is a spring 1016, 1018, 1020, which pivots to compress the spring when a force is applied to that side of the brush. The force compressing each spring is measured by a resistive force sensor 1022 in a manner similar to that discussed with reference to FIGS.

[0049] 11 is a side view of an example of a personal care device 1100, which in this example is a beard trimmer or clipper. The personal care device 1100 comprises a body 1102 that can be held by a user during a personal care treatment (e.g., beard trimming or shaving). The treatment element 1104 provided comprises, in this example, a blade or a pair of reciprocating blades configured to cut the beard that encounters the treatment element. The personal care device 1100 further comprises a skin surface curvature measurement mechanism 1106 comprising a first surface engaging element 1108 and a second surface engaging element 1110 that is rotatable about a fulcrum 1112 relative to the first surface engaging element. In this embodiment, the first surface engaging element 1108 is in a fixed position relative to the body 1102, while the second surface engaging element 1108 can pivot about the fulcrum 1112 in response to engagement with the changing curvature of the subject's skin surface with which the personal care device 1100 is in contact. Thus, during use, as the personal care device 1100 moves over the skin surface, the treatment element 1104 and the first surface engaging element 1108 engage the skin surface of the subject. Data representative of the curvature measured by the skin surface curvature measuring mechanism 1106 is processed using a processing unit 106 associated with the personal care device 1100 to determine the position of the personal care device relative to the skin surface of the subject. In some embodiments, a sensor 1114 is provided and forms part of the skin surface curvature measuring mechanism 1106. The sensor 1114 detects the position of the first surface engaging element 1108 relative to the second surface engaging element 1110. Direction 11, the sensor comprises a spring 1116 and a force sensor 1118 (e.g., a resistive force sensor). The spring 1116 is configured to bend or twist when the second surface engaging element 1110 pivots about a fulcrum 1112. The spring 1116 engages the force sensor 1118 to measure the relative force between the first surface engaging element 1108 and the second surface engaging element 1110 when the second surface engaging element 1110 pivots to twist the spring. DirectionFor a change in the force, the force exerted by the spring on the force sensor changes. An indication of the force measured by the force sensor 1118 is received by the processing unit 106, which determines the position of the personal care device 1100 in the manner described herein.

[0050] In the embodiments described herein, the data from the skin surface curvature measuring mechanism is processed by a processing device or processor (e.g., processing device 106). According to a further aspect, the present invention provides such a processing device. FIG. 12 is a schematic diagram of an example of a processing device 1200 configured to determine a position of a personal care device relative to a skin surface of a subject. The processing device 1200 is configured to receive data 1202 representing a measured curvature of the skin surface in a first region of the skin surface of the subject in contact with the personal care device. The data 1202 is obtained, for example, using the skin surface curvature measuring mechanism 104, 1106 discussed above. The processing device 1200 is further configured to retrieve curvature information for a plurality of regions of the skin surface of the subject from the storage medium 1204. The storage medium 1204 comprises, for example, a memory storing a database or look-up table of curvature information for a plurality of regions of the skin surface of the subject. The processing device 1200 is further configured to determine a position of a first region of the subject's skin surface in contact with the personal care device by comparing the measured curvature with curvature information of multiple regions of the skin surface. For example, if the measured curvature in the first region corresponds to the curvature information obtained from the chin region in the storage medium, the data representing the measured curvature is also determined to be obtained from the chin region of the subject. In some embodiments, the processing device 1200 also receives motion data of the personal care device from a motion sensor, such as the sensor 206. The motion data includes, for example, data representing a motion or displacement of the personal care device during a defined measurement period. The processing device 1200 is configured to determine a position of the first region of the subject's skin surface further based on the motion data. The sensor used to capture the motion data is any sensor capable of measuring, among other things, the displacement of the personal care device and / or, more specifically, the displacement of the skin surface curvature measuring mechanism 104 of the personal care device. For example, the motion data is acquired by an inertial measurement unit (IMU). The processing device 1200 is further configured to generate instructions 1206 for an action to be taken with respect to the personal care device based on the determined location of the first region.For example, the processing unit 1200 generates instructions (e.g., command signals) to increase power (e.g., cutting power) when the personal care device is in the jaw region. In another example, the instructions to perform a treatment include instructions to provide feedback to the subject (e.g., through a user interface of the personal care device) regarding the personal care treatment. In yet a further example, the instructions to perform a treatment include instructions to track parameters (e.g., skin parameters) over a period of time to provide health and / or beauty advice.

[0051] As mentioned above, the attachments 202, 600, 700, 800, 900 are removable from the body 102 of the personal care device. The attachments discussed herein are considered as systems in themselves. Thus, according to a further aspect, the present invention provides such a system. FIG. 13 is a schematic diagram of an example of a system 1300 for determining a position of a personal care device relative to a skin surface of a subject. The system 1300 comprises a housing 1302 for receiving a communication unit 204. The system 1300 further comprises a skin surface curvature measurement mechanism 104 coupled to the housing 1302 configured to measure a curvature of the skin surface in a first region of the skin surface of the subject. The system 1300 further comprises a processing device 106, 1200 described herein. As discussed with reference to FIG. 12, the processing device 106, 1200 is configured to receive data representing a measured curvature of the skin surface in a first region of the subject's skin surface in contact with the personal care device, and to determine a position of the first region based on this data and other derived curvature information.

[0052] The skin surface curvature measurement mechanism 104 is configured to generate data representative of a measured curvature of the skin surface in a first region of the skin surface. For example, the skin surface curvature measurement mechanism 104 generates the data using techniques described herein. The communication unit 204 is configured to communicate the data representative of the measured curvature of the skin surface in the first region of the skin surface to the processing device 106, 1200. In some examples, communication of data between the communication unit 204 and the processing device 106, 1200 is accomplished using known data transmission methods. For example, the communication unit 204 transmits the data to a receiver connected / associated with the processing device 106, 1200.

[0053] The curvature of the skin surface is measured in a variety of ways using the skin surface curvature measurement mechanism 104. In some embodiments, as previously described, the skin surface curvature measurement mechanism 104 comprises a first surface engaging element 305 and a second surface engaging element 307 (see FIG. 3 ), where the first surface engaging element and the second surface engaging element are movable relative to one another. In such an example, data representative of the measured curvature of the skin surface within a first region of the skin surface is determined by measuring the relative position of the first surface engaging element 305 and the second surface engaging element 307. Direction Includes measurements of.

[0054] In other embodiments, the curvature data is measured in other ways. For example, in some embodiments, the skin surface curvature measurement mechanism 104 comprises an imaging device configured to acquire image data relating to a first region of the skin surface. For example, the imaging device comprises a camera configured to capture an image or a series of images (e.g., a video stream) of the skin surface from which the curvature of the skin surface can be measured or determined. In some embodiments, the processing device 106, 1200 is further configured to use the acquired image data to determine the curvature of the skin surface in the first region of the skin surface.

[0055] The curvature data is obtained from the relative position of the surface-engaging elements, not from the imaging device. DirectionIn an embodiment where the measurement is taken using the distance between the first surface engaging element 305 and the housing 1302, the system 1300 may measure the distance between the first surface engaging element 305 and the housing 1302. Direction and the second surface engaging element 307 Direction The at least one orientation sensor 308, 310 may, in some embodiments, comprise a force sensor or a switch as described in embodiments herein. The data representative of the measured curvature of the skin surface in the first region of the skin surface may include a position of the first surface engaging element 305 relative to the housing 1302. Direction and the measurement of the second surface engaging element 307 relative to the housing. Direction Includes measurements of.

[0056] In some embodiments of the system 1300, the first surface engaging element 305 and the second surface engaging element 307 are each pivotally mounted relative to the housing 1302 and the other engaging element. For example, the first surface engaging element 305 and the second surface engaging element 307 are mounted in a manner similar to that shown in the embodiment of Figures 4-7.

[0057] The data representing the measured curvature includes an average curvature of the skin surface within the first region. The average curvature is calculated from the curvatures measured in a number of different "directions" or normal planes as described below. The curvature of a surface at a particular point is a measure of how curved the surface is at that point. For example, consider a plane that contains a normal (outward) vector at a point on the skin surface. Such a normal plane cuts the skin surface in a planar curve. This curve will generally have different curvatures for different normal planes. The principal curvatures k p1 and k p2 are the maximum and minimum values ​​of these curvatures.

[0058] An example of how the curvature at a point (in one of the normal planes) is determined is discussed with reference to Figures 14 and 15. Figures 14A and 14B are diagrams illustrating how the curvature is measured using a skin surface curvature measurement mechanism according to an embodiment disclosed herein. The example shown in Figures 14A and 14B is based on a skin surface curvature measurement mechanism having a surface engaging element 1400 similar to that shown in the embodiment of Figures 4-7. An axis perpendicular to the three treatment elements 404, 406, 408 (e.g., at the center of the housing 302 in Figure 5) when these treatment elements are in a neutral position without pivoting (e.g., extending outward from the page in Figure 5) is assumed to be an approximation of the normal to the skin surface at the center of the personal care device during use of the personal care device. Such a perpendicular axis 1402 is shown in Figures 14A and 14B. Now consider a normal plane perpendicular to the pivot axis 1404 of the surface engaging element 1400 (e.g., one of the treatment elements 404, 406, 408) that passes through this assumed surface normal. Figures 14A and 14B show such a normal plane 1406, where the normal plane is the plane of the page. The surface normal of the skin at the center of the treatment element 1400 relative to the surface normal 1402 of the skin at the center of the device Direction The angle α can be considered to represent i 14A and 14B, the curve k i (the inverse of the radius of curvature) can be calculated. The curvature can be positive (as in FIG. 14A) or negative (as in FIG. 14B). In an embodiment having three surface engaging elements (e.g., three treatment elements 404, 406, 408), three curvature values ​​k1, k2, k3 can be determined. The average curvature (k αv =Σ i k i / N, where N is the number of surface-engaging elements) and curvature range

number

[0059] If the number of surface-engaging elements N is greater than 3, then k αv and Δ k The value of is calculated using the above relationship. As measurements are taken from more surface-engaging elements, k αv and Δ k The relationship between the principal curvatures becomes more accurate.

[0060] In embodiments with only two surface-engaging elements (i.e., N=2), the two pivot axes are generally aligned parallel to one another and the curvature is recorded only in a single plane perpendicular to the pivot axes. In this case, k αv is calculated.

[0061] In another embodiment where N=2, a single pivot axis connects the two surface engaging elements as shown in the example of Figure 15. In this example based on the embodiment of Figure 11, a first surface engaging element 1500 and a second surface engaging element 1502 are pivotally connected about a fulcrum 1504. In this example, the bisector 1506 that bisects the opening angle is interpreted as an assumed normal axis to the skin surface as indicated in Figure 15.

[0062] According to a further aspect, a computer-implemented method is provided. FIG. 16 is a flow diagram of an example of a computer-implemented method 1600 for determining a position of a personal care device relative to a skin surface of a subject. The method 1600 includes receiving 1602 data representing a measured curvature of a skin surface in a first region of the skin surface of the subject in contact with the personal care device. The received data is obtained or measured, for example, using a skin surface curvature measurement mechanism 104, 1106 and / or a technique described herein. For example, the data is measured and received by a processor or processing device performing the method 1600 as a user moves the personal care device over the skin surface. The method 1600 includes determining 1604 an indication of a position of the first region of the skin surface of the subject by comparing the measured curvature with curvature information of a plurality of regions of the skin surface of the subject contained in a database. The method 1600 includes performing 1606 an action on the personal care device based on the determined indication of the position of the first region. The treatment taken will depend on the nature of the personal care device, in some instances the treatment taken will include adjusting an operating parameter of the personal care device, such as the motor speed or the cutting length of the blades.

[0063] As mentioned above, the position of the personal care device relative to the skin surface (i.e., the position of the first region) is determined more accurately when data representative of the motion of the personal care device is also taken into account. Therefore, the personal care device is provided with a motion sensor, such as an IMU, and used to measure the motion of the device. FIG. 17 is a flow diagram of a further example of a method 1700 for determining the position of a personal care device relative to a skin surface of a subject. The method 1700 comprises steps 1602, 1604, and 1606 of FIG. 16. In some embodiments, the method 1700 further comprises step 1702 of receiving data representative of a measured displacement of the personal care device between a first region and a second region of the skin surface where the personal care device was previously in contact. Thus, the displacement is measured using a motion sensor, such as an IMU, and provides information indicative of the previous position of the device. In one example, the data indicates that the personal care device, such as a shaver, has moved from the second region to the first region in a movement representative of a movement from the top of the subject's chin to the upper right portion of the subject's chin. In such instances where data representative of the measured displacements is available, determining the indication of the location of the first region is further based on comparing the data representative of the measured displacements to position information of a plurality of regions of the subject's skin surface contained in a database. Thus, if it is determined that the data representative of the measured displacements corresponds to position information (e.g., data indicative of two previously acquired positions, or movement between two positions), this determination helps to enhance determining the location of the first region using curvature data from the skin surface curvature measurement mechanism.

[0064] In step 1604, the curvature information to be compared with the data received in step 1602 is obtained during a calibration process performed by the subject before using the personal care device or during its first use. In some embodiments, the method 1700 further comprises a series of steps before receiving data representing the measured curvature of the skin surface in a first region of the skin surface (step 1602). The method 1700 comprises receiving calibration displacement data representing the displacement of the personal care device between a plurality of regions of the skin surface of the subject in a manner disclosed herein, for example, during a calibration process as discussed above, using a motion sensor of the personal care device (or calculated from data obtained using the motion sensor). The user is prompted to perform a calibration when using the personal care device for the first time. Each user of the personal care device performs a personalized calibration of the personal care device when using the device for the first time, for example by moving the device over the skin (or a part thereof) to measure the calibration displacement data representing the displacement. The measured calibration displacement data of the subject is stored in association with the subject, for example as part of a user profile. In some embodiments, the user is prompted to begin the calibration process with the personal care device at a specific position, such as on the chin, to provide a defined reference for the position of the personal care device during calibration. In some examples, curvature data is also obtained during the calibration process (e.g., using a skin surface curvature measurement mechanism), and in such examples, the curvature data is also stored in association with the data representing the displacement.

[0065] During calibration, as the personal care device is moved, data representative of the measured displacements (e.g., from an IMU) are recorded in terms of three-dimensional displacements (e.g., Δx, Δy, Δz) of the personal care device. As the personal care device moves over the skin surface, a skin surface curvature measurement mechanism measures data representative of the curvature of the skin surface. DirectionFrom the data representing the measured displacements, the processing unit can calculate the current position of the device relative to the position of the device at the start of data collection. As discussed above, Direction From the data, a value representative of the curvature of the skin surface can be calculated. The relative position data is stored in a storage medium (e.g., memory) along with the simultaneously acquired curvature values. Data sampling and processing continues in this manner until a defined amount of data has been acquired or the calibration process is terminated. In other embodiments, no data representative of measured displacements (e.g., from an IMU) are acquired and calibration of the personal care device relies on the measurement of the skin surface curvature from a skin surface curvature measurement mechanism. Direction It is based solely on data.

[0066] In some embodiments, the processing device is configured to determine whether a sufficient amount of data has been acquired at the end of the calibration process (e.g., indicated by a user pressing a button on the personal care device or by the expiration of a predetermined time). For example, the processing device is configured to determine whether the spatial extent of the subject's skin surface included in the study fits within expected minimum and maximum bounds. If the data is determined to be incomplete (e.g., more data is required from the calibration), the user is requested to repeat or supplement the calibration process immediately or at a later time.

[0067] On the other hand, if the amount and / or quality of the acquired data is determined to be sufficient and / or appropriate, the method 1700 starts the step of fitting the model. Thus, the method 1700 further comprises a step 1706 of fitting a computer model of the subject's skin surface to the received calibration displacement data representing the displacement of the personal care device. The processing device is configured, for example, to fit a model (e.g., a facial model) to the stored relative position data. The facial model is, for example, a generic CAD-like model of a human face controlled by a set of model parameters that determine the distances between facial landmarks (e.g., chin, corners of the mouth, ears, jaw angle, etc.) and the shape of the facial elements (e.g., flat or round cheeks, neck, etc.). In another example, the model comprises a model of another part of the subject's body.

[0068] At the start of the model fitting process, the frontal plane (i.e. the plane that divides the subject's face between the left and right sides) and chin are identified in the "point cloud" formed by the relative position data. In some embodiments, machine learning techniques are applied to assist in the identification. A face model (with model parameters based on average or arbitrary values) is aligned to the frontal plane and chin identified in the relative position data. In some embodiments, the alignment process comprises applying a least squares fitting process. In such a process, for each point in the relative position data, the distance to the surface of the face model is calculated. The sum of the squares of these distances gives the degree of fit of the model to the measured position data with respect to the current model parameters. The model parameters are then adapted until the sum of squares is reduced or minimized by an optimization algorithm. A good optimization algorithm will converge to a global minimum, which represents the best fit of the model to the measured data. For embodiments in which the personal care device comprises a beard trimmer or shaver, only the lower part of the face model (below the nose-ear line) and the relevant model parameters are used. Thus, the method 1700 further comprises determining 1708 curvature information for each region of the plurality of regions from the calibration displacement data and the fitted computer model.

[0069] In some examples, the curvature information is estimated from a fitted model, for example, the point cloud of displacement data reveals which portions of the data correspond to certain parts of the subject's body or face, and for those regions the curvature information is known or pre-determined, in other examples, the curvature information is obtained together with the calibration displacement data and stored in association with the corresponding calibration displacement data.

[0070] For a selected number of points on the fitted face model, a set of corresponding curvature values ​​is calculated (e.g., by interpolation and averaging of the curvature values ​​associated with the closest relative position data). The fitted model and the corresponding curvature values ​​are then stored in memory. Thus, method 1700 further comprises a step 1710 of storing the determined curvature information in a database in association with corresponding regions on the subject's skin surface.

[0071] The steps of the methods 1600, 1700 are performed using the processing devices 106, 1200 described herein.

[0072] According to a further aspect, the present invention provides a computer program product. Figure 18 is a schematic diagram of an example of a computer readable medium 1804 in communication with a processor 1802. According to some embodiments, the computer program product comprises a non-transitory computer readable medium 1804 having computer readable code embodied therein, which, when executed by a suitable computer or processor 1804, is configured to cause the computer or processor to perform steps of the methods 1600, 1700 disclosed herein. The processor 1802 may comprise or function in a similar manner to the processing unit 106, 1200.

[0073] The processor or processing unit 106, 1200, 1802 may comprise one or more processors, processing units, multi-core processors or modules configured or programmed to control the system 1300 in the manner described herein. In certain implementations, the processor or processing unit 106, 1200, 1802 may comprise multiple software and / or hardware modules, each configured to perform an individual step or steps of the methods described herein.

[0074] The term "module" as used herein is intended to include a hardware component, such as a processor or a component of a processor configured to perform a particular function, or a software component, such as a set of instructions that, when executed by a processor, results in a particular function.

[0075] It will be understood that the embodiments of the present invention also apply to a computer program adapted to carry out the invention, in particular a computer program on or in a carrier. The program may be in the form of object code, such as source code, object code, intermediate source and partially compiled forms of code, or in any other form suitable for use in carrying out the method according to the embodiments of the present invention. It will also be understood that such a program may have various architectural designs. For example, the program code implementing the functionality of the method or system according to the present invention is subdivided into one or more subroutines. Various ways of distributing functionality among these subroutines will be clear to a person skilled in the art. The subroutines are stored together in one executable file to form a self-contained program. Such an executable file comprises computer executable instructions, for example processor instructions and / or interpreter instructions (for example Java interpreter instructions). Alternatively, one or more or all of the subroutines are stored in at least one external library file and associated statically to the main program or, for example, dynamically at run-time. The main program contains at least one call to at least one of the subroutines. The subroutines also comprise function calls to each other. One embodiment of a computer program product includes computer-executable instructions corresponding to each processing stage of at least one of the methods described herein, the instructions being subdivided into subroutines and / or stored in one or more statically or dynamically linked files. Another embodiment of a computer program product includes computer-executable instructions corresponding to each means of at least one of the systems and / or products described, the instructions being subdivided into subroutines and / or stored in one or more statically or dynamically linked files.

[0076] A carrier of a computer program is any entity or device capable of carrying the program. For example, the carrier includes a data storage mechanism such as a ROM, for example a CD ROM, a semiconductor ROM, or a magnetic recording medium, for example a hard disk. Moreover, the carrier is a transmissible carrier, such as an electric or optical signal, conveyed by electric or optical cable or by radio or other means. When the program is embodied in such a signal, the carrier is constituted by such a cable or other device or means. Alternatively, the carrier is an integrated circuit in which the program is embedded, the integrated circuit being adapted to perform, or for use in the performance of, the relevant method.

[0077] Variations to the disclosed embodiments can be understood and achieved by those skilled in the art from studying the drawings, the disclosure, and the appended claims in practicing the claimed invention. In the claims, the word "comprises" does not exclude other elements or steps, and the singular does not exclude a plurality. A single processor or other unit performs the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program is stored and / or distributed on a suitable medium, such as an optical storage medium or a solid-state medium, provided together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless communication systems. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. 1. A computer-implemented method for determining a position of a personal care device for performing a personal care treatment on a skin surface of a subject when in contact with the skin surface of the subject, the computer-implemented method comprising: receiving data representative of a measured curvature of the skin surface within a first area of ​​the skin surface of the subject in contact with the personal care device; determining an indication of the position of the first area of ​​the skin surface of the subject by comparing the measured curvature with curvature information of the areas of the skin surface of the subject contained in a database and by referring to position information of the areas of the skin surface of the subject contained in the database; performing an action related to the personal care device based on the determined indication of the location of the first area.

23. A computer-implemented method comprising:

2. 11. A computer-implemented method, further comprising receiving data representing a measured displacement of the personal care device between the first area and a second area of ​​the skin surface previously contacted by the personal care device, determining the indication of the location of the first region is further based on comparing the data representative of the measured displacements with location information of a plurality of regions of the skin surface of the subject contained in the database.

2. The computer-implemented method of claim 1.

3. Prior to the step of receiving data representative of the measured curvature of the skin surface within the first region of the skin surface, receiving calibration displacement data representing measured displacements between a plurality of regions of the skin surface of the subject of the personal care device; fitting a computer model of the subject's skin surface to the received calibration displacement data; determining curvature information for each region of the plurality of regions from the calibration displacement data and the fitted computer model; storing the determined curvature information in the database in association with corresponding regions on the skin surface of the subject; 3. The computer-implemented method of claim 1 or 2, further comprising:

4. 1. A processing device for determining a position of a personal care device relative to a skin surface of a subject, the personal care device performing a personal care treatment of the skin when in contact with the skin surface, the processing device comprising: receiving data representative of a measured curvature of the skin surface within a first area of ​​the skin surface of the subject in contact with the personal care device; retrieving curvature information and position information of a plurality of regions of the skin surface of the subject from a storage medium; determining a position of the first region of the skin surface of the subject by comparing curvature information of the plurality of regions of the skin surface with the measured curvature and by referring to position information of the plurality of regions of the skin surface; generating instructions for an action to be taken with respect to the personal care device based on the determined location of the first region; Processing unit.

5. 1. A system for determining a position of a personal care device relative to a skin surface of a subject, the personal care device performing a personal care treatment of the skin when in contact with the skin surface, the system comprising: a housing for accommodating a communication unit; a skin surface curvature measurement mechanism coupled to the housing for measuring a curvature of the skin surface of the subject within a first region of the skin surface; The processing device according to claim 4, the skin surface curvature measurement mechanism generating data representative of the measured curvature of the skin surface within the first region of the skin surface; the communication unit communicates to the processing device the data representative of the measured curvature of the skin surface within the first region of the skin surface. system.

6. the skin surface curvature measurement mechanism comprises an imaging device that acquires image data relating to the first region of the skin surface; the processing device using the acquired image data to determine the curvature of the skin surface within the first region of the skin surface. The system of claim 5.

7. the skin surface curvature measurement mechanism comprises a first surface engaging element and a second surface engaging element movable relative to one another; the data representative of the measured curvature of the skin surface within the first region of the skin surface includes a measurement of a relative orientation of the first surface engaging element and the second surface engaging element. The system of claim 5.

8. 11. A system further comprising at least one orientation sensor configured to measure an orientation of the first surface engaging element relative to the housing and an orientation of the second surface engaging element relative to the housing, the data representative of the measured curvature of the skin surface within the first region of the skin surface includes a measurement of the orientation of the first surface engaging element relative to the housing and a measurement of the orientation of the second surface engaging element relative to the housing. The system of claim 7.

9. each of the first surface engaging element and the second surface engaging element is pivotally mounted relative to the housing and the other engaging element; the data representative of the measured curvature comprises an average curvature of the skin surface within the first region; 9. A system according to claim 7 or 8.

10. 1. A personal care device for providing a personal care treatment to a skin surface when in contact with the skin, the personal care device comprising: The main body, a skin surface curvature measurement mechanism for measuring a curvature of the skin surface within a first area of ​​the skin surface of a subject in contact with the personal care device; 5. A processing device as claimed in claim 4, receiving data representative of the measured curvature of the skin surface from the skin surface curvature measuring mechanism. A personal care device comprising:

11. A personal care device further comprising an attachment for accommodating a communication unit, the attachment being detachable from the main body, the skin surface curvature measuring mechanism is coupled to the attachment; the body houses the processing device; the communication unit communicates data representative of the measured curvature of the skin surface to the processing device.

11. The personal care device of claim 10.

12. the personal care device further comprising a sensor for acquiring movement data of the personal care device; the processing unit determining a location of the first area of ​​the skin surface of the subject further based on movement data acquired using the sensor.

12. A personal care device according to claim 10 or 11.

13. A personal care device further comprising a housing supporting at least a first treatment element and a second treatment element, the first treatment element comprises a first surface engaging element, the second treatment element comprises a second surface engaging element, the first surface engaging element and the second surface engaging element each being pivotally mounted relative to the housing and the other engaging element; the skin surface curvature measurement mechanism comprising a first sensor for measuring an orientation of the first surface engaging element relative to the housing, and a second sensor for measuring an orientation of the second surface engaging element relative to the housing.

13. A personal care device according to any one of claims 10 to 12.

14. 14. The personal care device of claim 13, wherein the personal care device is an electric shaver, and the first treatment element and the second treatment element both comprise a shaving unit having an external cutting member, an internal cutting member configured to be movable relative to the external cutting member, and a skin-supporting rim surrounding the external cutting member and pivotally mounted to the housing, and the first surface engaging element comprises the skin-supporting rim of the shaving unit of the first treatment element, and the second surface engaging element comprises the skin-supporting rim of the shaving unit of the second treatment element.

15. A non-transitory computer readable medium having computer readable code embodied therein, the computer readable code being configured, when executed by a suitable computer or processor, to cause the computer or processor to perform the computer-implemented method of any one of claims 1 to 3.

Images