Projection and measurement system

Abstract

A projection and measurement system (100) comprises a projection unit (110), a tracking unit (120) and a control unit (130). The control unit (130) is configured for controlling the projection unit to determine a feature of a body part of a user, to generate a light guide to be projected to the body part in dependence on the determined feature, and to control the projection unit to project the light guide. The control unit (130) is further configured for controlling the projection unit (110) to project the light guide to the body part in an asynchronous manner with respect to a detection of an image of the body part, and / or to produce a modulated form of the light guide and / or an illumination light projected to the body part.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a projection and measurement system capable of supporting a user in performing a personal care activity, and a method of performing light projection and feature determination associated with a body part of a user at a position and measurement system. BACKGROUND

[0002] Users performing personal care activities can generally benefit from getting assistance during the personal care activities. This is useful as people often perform various personal care activities in front of a mirror. For example, personal care activities performed in front of a mirror can include personal health care activities (which can be monitored to study the health of a user performing the personal health care activities), personal hygiene activities (e.g. dental care activities such as cleaning, brushing or flossing teeth, or skin care activities such as treating or cleaning the skin), and personal grooming activities (e.g. removing hair, such as cutting or shaving hair on any part of the body, or styling or straightening hair). Thus, a smart mirror can be used in combination with many different personal care devices, such as a weighing scale, an electric shaving razor, a skin moisture sensor, an electric toothbrush or a skin cleansing brush. SUMMARY

[0003] Some currently available systems provide an opportunity to add extra visual information to the user experience by displaying a processed image of the user’s face on a mirror portion. This visual information can directly enhance and support the personal care activity performed by the user. In particular, these systems can provide a user interface that allows for an enhanced experience of using a respective personal care device, such as an electric toothbrush or an electric shaving razor, and this in turn leads to an improved user friendliness of the personal care device. However, using this type of arrangement, it can be difficult for the user to associate the processed image with the processed image as the processed image can be perceived as unnatural and unintuitive compared to viewing the reflected image in the mirror of one’s own.

[0004] Thus, in some other currently available systems, an optical light projection associated with guidance information or diagnostic information can be projected onto a body part of a user, such as a face, so that when the user observes themselves in the mirror, they are provided with useful information about their skin condition or state or instructions for using a personal care device. These systems typically involve tracking the position and orientation of the body part, such as by imaging means, so that the position and orientation of the projection corresponds to the position and orientation of the body part in question. Furthermore, these systems can also include functionality to detect features of the body part of the user. For example, in the context of a user’s face, the relative positions of the eyes, nose, lips, ears can be detected based on a detected image of the user’s face. However, as the detection of the facial features and the performance of the diagnosis are based on an image of the user’s face, these operations can be affected by the guidance information that is simultaneously projected onto the face optically.

[0005] As mentioned above, there are many associated drawbacks with the currently available systems for the personal care field. Therefore, it would be advantageous to provide a system and method that addresses these drawbacks by differentiating the operation of projecting a light guide onto a body part of a user and the detection of the image(s) of the body part. Therefore, additionally or alternatively, these drawbacks can be addressed by projecting a light guide in the form of a modulation and / or an illumination light that can be subsequently processed to differentiate the projected light guide from the detected image.

[0006] To better address one or more of the issues mentioned above, in a first aspect, there is provided a position and measurement system. The projection measurement system comprises: a projection unit configured for projecting a light onto a body part of a user; a tracking unit configured for detecting an image of the body part of the user; a control unit configured for controlling the projection unit to project an illumination light onto the body part of the user during the detection of the image of the body part of the user; determining a position and an orientation of the body part of the user from the image of the body part of the user; determining a feature of the body part of the user from the image of the body part of the user; generating a light guide to be projected onto the body part of the user based on the determined feature; and controlling the projection unit to project the light guide such that the position and the orientation of the light guide correspond to a current position and orientation of the body part of the user, wherein the control unit is further configured for performing at least one of: controlling the projection unit to project the light guide onto the body part of the user in an asynchronous manner with respect to the detection of the image of the body part, and producing a modulation form of at least one of the light guide and the illumination light by including an identification pattern and controlling the projection unit to project the modulation form onto the body part of the user.

[0007] In some embodiments, the control unit is at least configured for producing the modulation form of at least one of the light guide and the illumination light by including an identification pattern and controlling the projection unit to project the modulation form onto the body part of the user, the determination of the feature of the body part of the user can be based on demodulating the detected image by differentiating the identification pattern. In these embodiments, the discrimination of the identification pattern can be based on a comparison between an original flicker rate frequency of at least one of the light guide and the illumination light and a flicker rate frequency of the modulation form.

[0008] In some embodiments, the modulation form can be generated by performing at least one of: a spatial modulation, a temporal modulation, and a spectral modulation.

[0009] In some embodiments, the determined feature of the body part of the user can be associated with at least one of: a composition of the body part, a skin anomaly at the body part, a skin attribute of the body part, a hair on the body part, and a makeup applied at the body part.

[0010] In some embodiments, the control unit can be further configured for determining a relative position of the determined feature of the body part of the user. In these embodiments, the generation of the light guide to be projected can be further based on the determined relative position of the feature.

[0011] In some embodiments, the body part onto which the light guide is to be projected can be a face of the user. In these embodiments, the light guide can be associated with at least one of a simulated makeup style and a simulated beard style.

[0012] In some embodiments, the light guide can be associated with instructions for using the personal care device.

[0013] In some embodiments, the tracking unit can be further configured for detecting information associated with a skin diagnosis of the body part of the user. In these embodiments, the determination of the feature of the body part of the user by the control unit can be further based on the detected information associated with the skin diagnosis of the body part of the user.

[0014] In some embodiments, the tracking unit can comprise at least one of a multi-spectral imaging unit configured to capture image data of the body part of the user in one or more predetermined wavelength ranges and a photoplethysmogram sensing unit configured for capturing data associated with blood volume changes of the body part of the user.

[0015] In some embodiments, the generation of the light guide to be projected onto the body part of the user by the control unit can be further based on a user input.

[0016] In some embodiments, the projection and measurement system can further comprise a reflective portion configured for reflecting incident light.

[0017] In a second aspect, a method of performing light projection and feature determination of a body part of a user at a position and measurement system is provided. The method comprises detecting an image of the body part of the user; projecting illumination light onto the body part of the user during the detection of the image of the body part of the user; determining a position and an orientation of the body part of the user based on the image of the body part of the user; determining a feature of the body part of the user from the image of the body part of the user; generating a light guide to be projected onto the body part of the user based on the determined feature; and projecting the light guide such that a position and an orientation of the light guide correspond to a current position and orientation of the body part of the user, wherein the method further comprises at least one of the following steps: projecting the light guide to detect the body part of the user in an asynchronous manner with respect to the detection of the image of the body part; and generating at least one of a modulated form of the light guide and the illumination light projected onto the body part of the user by at least one of comprising an identification pattern and projecting at least one of a modulated form of the light guide and the illumination light.

[0018] According to the above aspects and embodiments, the limitations of the prior art are addressed. In particular, the above aspects and embodiments provide a projection and measurement system which is capable of projecting information in optical form onto a body part of a user and determining a feature of the body part of the user in such a way that the projected light does not affect the operation of the feature determination. Thus, the above aspects and embodiments enable a more reliable and accurate way of feature determination based on imaging of the body part. An improved projection and measurement system and a method of performing light projection and feature determination associated with a body part of a user at a position and measurement system are thus provided. These and other aspects of the present disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0019] For a better understanding of the embodiments and to show how they can be implemented, reference will now be made, purely by way of example, to the accompanying drawings, in which:

[0020] Figure 1A is a block diagram of a position and measurement system according to an embodiment.

[0021] Figure 1B is Figure 1A a view of the position measurement system of

[0022] Figure 2 performing light projection and feature determination associated with a body part of a user in Figure 1A and Figure 1B the position and measurement system of DETAILED DESCRIPTION

[0023] As mentioned above, an improved position and measurement system and a method of performing light projection and feature determination associated with a body part of a user at a position and measurement system addressing the prior problems are provided.

[0024] Figure 1A is a block diagram of a projection and measurement system 100 according to an embodiment, Figure 1B is a view showing Figure 1A the position and measurement system 100 of Figure 1A during use by a user. With reference to

[0025] The projection unit 110 is configured to project light onto the body part of the user. In some embodiments, the projection unit 110 can be configured to project light associated with a predetermined wavelength range. Further, in some embodiments, the direction of the projection unit 110 can be configured to be adjustable with respect to the surface of the reflection portion 140, such that the light projected by the projection unit 110 can correspond to the current direction and / or position of the body part of the user.

[0026] The tracking unit 120 is configured to detect an image of the body part of the user. The detected image can be a two-dimensional, 2D, or three-dimensional, 3D, image. In some embodiments, the tracking unit 120 can include a 2D / 3D camera (e.g., a laser projection based camera) capable of 2D / 3D imaging. Further, in some embodiments, the tracking unit 120 can include at least one of a multi-spectral imaging unit and a photoplethysmogram (PPG) sensing unit. The operation of the multi-spectral imaging unit and the PPG sensing unit will be explained in more detail below.

[0027] The control unit 130 is configured to control the projection unit 110 to project an illumination light onto the body part of the user during the detection of the image of the body part of the user by the tracking unit 120. The illumination light can be a uniform white light for illuminating the body part of the user to ensure the quality of the detected image. The control unit 130 is further configured to determine the position and orientation of the body part of the user based on the image of the body part of the user detected by the tracking unit 120.

[0028] Further, the control unit 130 is configured to determine a feature of the body part of the user based on the image of the body part of the user to generate a light guide to be projected onto the body part of the user based on the image. The feature is determined and the projection unit 110 is controlled to project the light guide such that the position and orientation of the light guide correspond to the current position and orientation of the body part of the user.

[0029] In some embodiments, the control unit 130 can be configured to generate the light guide associated with at least one of a simulated makeup style and a simulated beard style. The simulated makeup style or the simulated beard style can be retrieved from a simulated makeup style database and a simulated beard database, respectively. These databases can be stored in a memory (e.g., a memory of the system 100).

[0030] In some embodiments, the control unit 130 can be configured to generate the light guide associated with instructions for using a personal care device (e.g., an electric shaving razor or an electric skin cleansing brush). Further, in some embodiments, the control unit 130 can be configured to generate the light guide based on a user input (e.g., a selection of a light guide type).

[0031] The features of the user's body part can be associated with at least one of: a composition of the body part, a skin abnormality of the body part, a skin attribute of the body part, a hair of the body part, and a makeup applied on the body part. For example, in the case that the user's body part is the user's face, the composition of the body part can be the user's eyes, nose, lips, mouth, teeth, gums, tongue, etc.; the skin abnormality can be a pimple (e.g., a bump) on the user's face or an inflamed area on the user's face; the skin attribute can be the user's skin color, a skin moisture level of the user's face, a blood perfusion rate of the user's face (or a region of the face), a mole on the user's face, a pore on the user's face, or a wrinkle on the user's face; the hair can be a beard on the user's face; and the makeup applied can be a shade of lipstick applied on the user's lips. Other examples of skin abnormalities that can be determined by the control unit 130 of the system 100 include: hives, warts, blisters, rashes, psoriasis, etc.

[0032] In some embodiments, the control unit 130 can also be configured to determine a relative location of the determined features of the user's body part. In these embodiments, the control unit 130 can be configured to generate a light guide to be projected onto the user's body part based on the relative location of the determined features. For example, the control unit 130 can determine that there is a pimple on a cheek region of the user's face. In this example, the light guide 130 can be generated by the control unit such that the light guide indicates and / or highlights the cheek region where the pimple is located. Furthermore, in some embodiments, the projection unit 110, the tracking unit 120, and the control unit 130 can implement a feedback loop such that the projection of the light guide corresponds to the intended region of the user's body part for indication or emphasis. For example, the control unit 130 can be configured to continuously determine whether the light guide projected onto the user's body part corresponds to the determined relative location of the determined features based on the images detected by the tracking unit 120. If it is determined that the projected light guide does not correspond to the determined relative location of the determined features (e.g., because the user has moved the body part simultaneously), the control unit 130 can be configured to control the projection unit 110 to adjust at least one of its position, orientation, and projection such that the light guide is projected to correspond to the determined relative location of the determined features (e.g., to highlight one pimple on the user's cheek). In this way, the control unit 130 can ensure that the projected light guide accurately conveys important information to the user.

[0033] As another example, the control unit 130 can determine an area of the user's face with facial hair. In this example, the light guide is generated by the control unit 130 such that the light guide indicates the facial region with facial hair that is to be shaved off by an electric shaver.

[0034] Further, the control unit 130 is configured to perform at least one of two functions. The first function is to control the projection unit 110 to project the light guide onto the body part of the user in an asynchronous manner with respect to the detection of the image of the body part by the tracking unit 120. The second function is to generate a modulated form of at least one of the light guide and the illumination light by including an identification pattern, and to control the projection unit 110 to project the modulated form of at least one of the light guide and the illumination light onto the body part of the user.

[0035] In embodiments where the control unit 130 is configured to generate a modulated form of at least one of the light guide and the illumination light by including an identification pattern and to control the projection unit 110 to project the modulated form onto the body part of the user, the control unit 130 can be configured to determine a feature of the body part of the user based on a demodulation of the detected image. In particular, the demodulation of the detected image can include distinguishing the identification pattern from the detected image, such that the determination of the feature of the body part of the user can be performed based on a processed image that does not contain the identification pattern.

[0036] As one example, the body part of the user can be tracked by the tracking unit 120 at a frame rate of 300 frames per second, and the light guide can be projected at a flickering frequency of 80 Hz. Further, the signal strength of the light guide detected by the tracking unit 120 will vary from frame to frame. Knowing the original flickering frequency of the projected light, the identification pattern can be distinguished based on a comparison between the original flickering frequency and the flickering frequency of the modulated light. In some embodiments, the demodulation of the detected image can be based on a Fourier transform of each pixel over time. In particular, in some embodiments, a specific frequency of the projected light can be filtered by the control unit 130 during the demodulation process.

[0037] In some embodiments, the modulated form of the light guide or the illumination light can be produced by performing at least one of: spatial modulation, temporal modulation, and spectral modulation. For example, spatial modulation can include producing a 2D or 3D pattern of the light guide or the illumination light; temporal modulation can include modulating at least one of the amplitude, frequency, and phase of the light, similar to AM / FM of radio; spectral modulation can include modulation of the wavelength (or color) of the light.

[0038] The control unit 130 can include one or more processors, processing units, multi-core processors, or modules configured or programmed to control the system 100 in the manner described herein. In particular implementations, the control unit 130 can include a plurality of software and / or hardware modules (e.g., image analysis software), each module configured to perform or for performing a single or multiple steps of the methods described herein.

[0039] The control unit 130 can be implemented in numerous ways, with software and / or hardware, to perform the various functions described herein. The control unit 130 can include one or more microprocessors or digital signal processors (DSPs) that can be programmed using software or computer program code to perform the required functions and / or control the components of the control unit 130 to perform the required functions. The control unit 130 can be implemented as a combination of dedicated hardware (such as amplifiers, pre-amps, analog-to-digital converters (ADCs), and / or digital-to-analog converters (DACs) to perform some functions and a processor (e.g., one or more programmed microprocessors, controllers, DSPs, and associated circuitry) to perform other functions. Examples of components that can be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, DSPs, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0040] In some embodiments, the tracking unit 120 can also be configured to detect information associated with a skin diagnosis of the body part of the user. As described above, in some embodiments, the tracking unit 120 can include at least one of a multispectral imaging unit and a PPG sensing unit. The multispectral imaging unit can be configured to capture image data of the body part of the user at one or more predetermined wavelength ranges, and the photoplethysmogram sensing unit can be configured to capture data associated with a change in blood volume of the body part of the user. Thus, the detected information associated with the skin diagnosis of the body part of the user can be the image data of the body part of the user at the one or more predetermined wavelength ranges (in the case of the multispectral imaging unit) and / or the data associated with the change in blood volume of the body part of the user (in the case of the PPG sensing unit). Further, in these embodiments, the control unit 130 can be configured to determine a feature of the body part of the user based on the detected information associated with the skin diagnosis of the body part of the user. For example, the data captured by the photoplethysmogram sensing unit can indicate at least one of a skin color of the body part of the user, a blood perfusion of the body part of the user, and a change in a region of the body part of the user that is flushed. In this example, the control unit 130 can be configured to perform a skin diagnosis (e.g., determine a blood oxygen level of the body part of the user) and determine a feature of the body part (e.g., a region of the body part that has a low blood oxygen content).

[0041] The reflective portion 140 is configured to reflect incident light. In some embodiments, the reflective portion 140 can be provided as a component of a mirror assembly. Further, in some embodiments, such as in the case of a mirror assembly that includes a mirror and a light source, the reflective portion 140 can be provided as a component of the light source. Figure 1BIn the illustrated embodiment, the projection unit 110 and the tracking unit 120 can be positioned such that they are both aligned with the surface of the reflective portion 140. Thus, during use of the system 100, the user 15 can position himself in front of the reflective portion 140 (e.g. for performing a personal care activity) such that when a light guide is projected by the projection unit 110 onto the face of the user 15, the user 15 can see the light guide through the reflection at the reflective portion 140.

[0042] In some embodiments, the system 100 can further comprise at least one user interface. Alternatively or additionally, the at least one user interface can be external to (i.e. separate or remote from) the system 100. The user interface can be configured for receiving user input. For example, the user interface can allow a user of the system 100 to manually input instructions, data or information. In these embodiments, the control unit 130 can be configured for obtaining user input from the one or more user interfaces.

[0043] The user interface can be any user interface capable of presenting (or outputting or displaying) information to a user of the system 100. Alternatively or additionally, the user interface can be any user interface capable of enabling a user of the system 100 to provide user input, interact with and / or control the system 100. For example, the user interface can comprise one or more switches, one or more buttons, a keypad, a keyboard, a touchscreen or an application (e.g. on a tablet or smartphone), a display screen, a graphical user interface (GUI) or other visual presentation component, one or more speakers, one or more microphones or any other audio component, one or more lights, a component for providing haptic feedback (e.g. a vibration function), or any other user interface, or a combination of user interfaces. In some embodiments, the reflective portion 140 of the system 100 can be implemented as part of the user interface, e.g. a touch input interface.

[0044] In some embodiments, the system 100 can comprise one or more memories. Alternatively or additionally, the one or more memories can be external to (i.e. separate or remote from) the system 100. For example, the one or more memories can be part of another system or device. The memory can be configured for storing program code executable by the control unit 130 to perform the methods described herein. The memory can be used to store information, data, signals and measurements obtained or made by the control unit 130.

[0045] It will be appreciated that, Figure 1A and Figure 1BOnly the components necessary to illustrate one aspect of the system 100 are shown, and in actual implementations, the system 100 can include alternatives or additional components to those shown. For example, the system 100 can include means for connecting to a power source or battery in order to power the system 100. As another example, in some embodiments, the system 100 can not include the reflective portion.

[0046] Figure 2 A method of performing light projection and feature determination of a body part of a user at a position and measurement system 100 is illustrated. The method can generally be performed or controlled under the control of the control unit 130 of the system 100. Figure 1A Figure 1B With reference to

[0047] At block 202, an image of the body part of the user is detected, and at block 204, illumination light is projected onto the body part of the user. In this embodiment, blocks 202 and 204 are performed simultaneously, such that the illumination light is projected onto the body part of the user while the image of the body part of the user is detected. More specifically, the illumination light is projected by the projection unit 110, while the image of the body part of the user is detected by the tracking unit 120 of the system 100. As indicated above with reference to Figure 2 , the tracking unit 120 of the system 100 can include a 2D / 3D camera capable of 2D / 3D imaging. Thus, in these embodiments, the detected image can be a 2D or 3D image. Further, in some embodiments, multiple images of the body part of the user can be detected at block 202. Figure 1A

[0048] Returning to Figure 2 , at block 206, a position and orientation of the body part of the user is determined based on the image of the body part of the user detected at block 204, and at block 208, a feature of the body part of the user is determined based on the image of the body part of the user detected at block 204. As indicated above with reference to Figure 1A and Figure 1B , the feature of the body part of the user can be associated with at least one of: a composition of the body part, a skin anomaly of the body part, a skin attribute of the body part, a hair of the body part, a makeup of the body part. For example, the feature that can be determined at block 208 can be a mole on the face of the user.

[0049] Returning to Figure 2 ​​At block 210, a light guide to be projected to the body part of the user based on the feature determined at block 208 is generated. The generation of the light guide can be performed by the control unit 130 of the system 100. If the body part of the user is the face, the generated light guide can be associated with at least one of the simulated makeup style and the simulated beard style. In some embodiments, the light guide can be associated with instructions for using the personal care device. Furthermore, in some embodiments, the generation of the light guide at block 210 can be based on user input. For example, a user input indicating a light guide type can be received from the user via the user interface. The user can be provided with a plurality of types of light guides to be selected, e.g., "simulated makeup style", "simulated beard style", "personal care device instructions", and "skin diagnosis", through the user interface. In this example, if the user selects "simulated makeup style", the control unit 130 can generate a light guide associated with the simulated makeup style. Additionally, in this example, once the user has selected the type of light guide to be generated, the user can also be provided with a plurality of light guide templates to be selected (e.g., for "simulated makeup style", a plurality of different makeup style templates can be provided through the user interface for the user to select). Thus, the light guide can be generated based on the makeup style template selected by the user.

[0050] Returning to block 212, Figure 2 At block 212, the light guide generated at block 210 is projected onto the body part of the user such that the position and orientation of the projected light guide correspond to the current position and orientation of the body part of the user. The projection of the light guide can be performed by the projection unit 110 of the system 100 under the control of the control unit 130.

[0051] Proceeding to block 212, the method proceeds to either block 214 or block 216, at block 214, the detection of the image of the body part of the user relative to the light guide generated at block 210 is projected to the body part of the user in an asynchronous manner. Thus, while the light guide is being projected by the projection unit 110, the tracking unit 120 does not perform any image detection operations. In other words, in embodiments where the method proceeds to block 214, the steps of block 202 are performed at different times than blocks 212 and 214.

[0052] In some embodiments, blocks 212 and 214 can be performed simultaneously. In other words, in these embodiments, the generated light guide can be projected to the body part of the user such that the position and orientation of the light guide correspond to the current position and orientation of the body part, while performing the detection of the image of the body part of the user relative to the projection, the projection being performed in an asynchronous manner. Furthermore, in some embodiments, at block 214, the projection of the light guide to the body part of the user and the detection of the image of the body part can be performed in an alternating manner. For example, the projection of the light guide can be performed between instances of the detection of the image of the body part of the user by the tracking unit 120.

[0053] At block 216, a modulated version of at least one of the light guide and the illumination light comprising the identification pattern is generated and projected onto the body part of the user. The modulation of the light guide can be performed by the control unit 130 of the system 100. In some embodiments, block 212 and block 216 can be performed simultaneously. In other words, in these embodiments, the modulated version of at least one of the light guide and the illumination light can be projected onto the body part of the user such that the position and orientation of the light guide correspond to the current position and orientation of the body part. The generation of the modulated version of the light guide or the illumination light at block 216 can comprise performing at least one of: spatial modulation, temporal modulation and spectral modulation.

[0054] Although not explicitly indicated in the method of Figure 2 Fig. 1, the method shown can be performed in a repetitive manner. For example, following block 216, in which the modulated version of at least one of the light guide and the illumination light is generated and projected, the method can return to block 202, in which a new image of the body part of the user is detected, block 204, in which the illumination light (or the modulated version of the illumination light) is projected onto the body part of the user, block 206, in which the position and orientation of the body part of the user are determined, and block 208, in which the features of the body part of the user are determined. In these embodiments, at least block 216 and block 202 can be performed simultaneously such that a new image of the body part of the user is detected at block 202 (following the generation of the modulated version at block 216), which can be considered equivalent to the superposition of the original image of the body part of the user with the modulated version of at least one of the light guide and the illumination light. Thus, in these embodiments, the determination of the features of the body part at block 208 (following block 216, in which the modulated version of at least one of the light guide and the illumination light is generated and projected), can be based on the demodulation of the newly detected image by identifying the identification pattern. In some embodiments, the identified identification pattern can be based on a comparison between the original flickering frequency of at least one of the light guide and the illumination light and the flickering frequency of the modulated version. In part of these embodiments, the projection of the modulated version of the light guide at block 216 and the projection of the illumination light (or the modulated version of the illumination light) at block 204 can be performed simultaneously.

[0055] Although Figure 2In some embodiments, the method can further include detecting information associated with a skin diagnosis of the body part of the user, although not shown in FIG. 2. This step can be performed by the control unit 130 of the system 100. In these embodiments, determining the characteristic of the body part of the user at block 208 can be based on the detected information associated with the skin diagnosis of the body part of the user. For example, the detected information associated with the skin diagnosis of the body part of the user can be image data of the body part of the user in one or more predetermined wavelength ranges and / or data associated with blood volume changes of the body part of the user. In this example, at block 208, the control unit 130 can be configured to determine a skin abnormality of the body part of the user based on the image data of the body part of the user in one or more predetermined wavelength ranges and / or the data associated with blood volume changes of the body part of the user. For example, a higher blood volume in a particular area of the user's skin can indicate acne.

[0056] Although the method is described above as proceeding from block 212 to either block 214 or block 216, in some embodiments, the method can proceed to both block 214 and block 216 simultaneously. In these embodiments, blocks 212, 214, 216 can be performed simultaneously such that the modulated form of at least one of the light guide and the illumination light can be projected onto the body part of the user such that the position and orientation of the light guide correspond to the current position and orientation of the body part, while the projection is performed in an asynchronous manner relative to the detection of the image of the body part of the user. Figure 2 In some embodiments, the method can further include, after determining the characteristic of the body part of the user at block 208, then determining a relative position of the determined characteristic of the body part of the user, although not shown in FIG. 2. In these embodiments, the generation of the light guide at block 210 can be based on the determined relative position of the characteristic. For example, the characteristic determined at block 208 can be a bump on the face of the user and it can then be determined that the bump is located on the chin of the user. In this example, at block 210, the control unit 130 can be configured to generate the light guide to indicate the location of the bump (e.g., the light guide involves a green light projection onto the chin of the user while the projected white light or no light is used for the rest of the user's face).

[0057] Furthermore, in some embodiments, the method can further include continuously determining whether the light guide projected onto the body part of the user corresponds to the determined relative position of the determined characteristic based on the image detected at block 202 (or a new image). If it is determined that the projected light guide does not correspond to the determined relative position of the determined characteristic (e.g., because the user moved the body part during this time), the method can further include controlling the projection unit 110 such that the light guide is projected to correspond to the determined relative position of the determined characteristic (e.g., highlighting a bump on the cheek of the user).

[0058] Although the method is described above as proceeding from block 212 to either block 214 or block 216, in some embodiments, the method can proceed to both block 214 and block 216 simultaneously. In these embodiments, blocks 212, 214, 216 can be performed simultaneously such that the modulated form of at least one of the light guide and the illumination light can be projected onto the body part of the user such that the position and orientation of the light guide correspond to the current position and orientation of the body part, while the projection is performed in an asynchronous manner relative to the detection of the image of the body part of the user.

[0059] Thus, there is provided an improved position and measurement system and a method of performing light projection and feature determination associated with a body part of a user at a position and measurement system, which overcomes the problems of the prior art.

[0060] There is also provided a computer program product comprising a computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform the method or methods described herein. Accordingly, it should be understood that the present disclosure also applies to computer programs, particularly computer programs on or in a carrier, adapted to put embodiments into practice. The program can be in the form of a script, a set of instructions, or code portability, for example partially compiled, or in any other suitable form of computer program.

[0061] It should also be understood that such a program can have many different architectural designs. For example, a program code implementing the functionality of the method or system can be subdivided into one or more subroutines or procedures, and can be structured in accordance with a sequential, iterative, or alternate design within, for example, an object-oriented programming environment. A

[0062] Embodiments relating to a computer program product include computer-executable instructions corresponding to each processing stage of at least one of the methods set forth herein. These instructions can be subdivided into subroutines and / or stored in one or more files that can be linked statically or dynamically. Another embodiment relating to a computer program product includes computer-executable instructions corresponding to each means of at least one of the systems and / or products set forth herein. These instructions can be subdivided into subroutines and / or stored in one or more files that can be linked statically or dynamically.

[0063] The carrier of a computer program can be any entity or device capable of carrying the program. For instance, the carrier can include a data storage, such as a ROM, a CD ROM, or a semiconductor ROM, or a magnetic recording means, such as a hard disk. Furthermore, the carrier can be a transmissible carrier, such as an electrical or optical signal, which can be conveyed by electrical or optical cable or by radio or other means. When the program is embodied in such a signal, the carrier can be constituted by such electrical or optical cable or other device or means of conveyance of the signal. Alternatively, the carrier can be a integrated circuit in which the program is embedded, the integrated circuit being suitable for performing, or for use in performing, the relevant method.

[0064] Variations to the disclosed embodiments can become apparent to those of ordinary skill in the art from the foregoing description and disclosure of the application. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit can fulfil 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 can be stored / distributed on a suitable medium, such as an optical storage medium or a solid state storage medium supplied together with or as part of other hardware, but can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A projection and measurement system (100), comprising: a projection unit (110) configured for projecting an illumination light and a light guide onto a body part of a user; a tracking unit (120) configured for detecting an image of the body part of the user; and a control unit (130) configured for: controlling, by the tracking unit, the projection unit (110) to project the illumination light onto the body part of the user during detection of the image of the body part of the user; determining a position and an orientation of the body part of the user based on the image of the body part of the user; determining a feature of the body part of the user based on the image of the body part of the user; generating the light guide based on the determined feature; and controlling the projection unit (110) to project the light guide such that a position and an orientation of the light guide correspond to the position and the orientation of the body part of the user, wherein the control unit (130) is further configured for at least one of: controlling the projection unit (110) to project the light guide onto the body part of the user in an asynchronous manner with respect to detection of the image of the body part such that the projection unit projects the light guide at a different time than the illumination light, which enables the tracking unit to detect the image of the body part, or generating a modulated form of at least one of the light guide or the illumination light by including an identification pattern and controlling the projection unit (110) to project the modulated form onto the body part of the user.

2. The projection and measurement system (100) according to claim 1, wherein the control unit (130) is configured to generate the modulated form of at least one of the light guide or the illumination light by including the identification pattern and controlling the projection unit (110) to project the modulated form onto the body part of the user, and wherein the determination of the feature of the body part of the user is based on a demodulation of a detected image by distinguishing the identification pattern.

3. The projection and measurement system according to claim 2, wherein the distinguishing of the identification pattern is based on a comparison between an original flickering frequency of at least one of the light guide or the illumination light and a flickering frequency of the modulated form.

4. The projection and measurement system according to any one of the preceding claims, wherein the modulated form is generated by performing at least one of: a spatial modulation, a temporal modulation, and a spectral modulation.

5. The projection and measurement system according to any one of the preceding claims, wherein the determined feature of the body part of the user is associated with at least one of: a composition of the body part, a skin anomaly at the body part, a skin property of the body part, a hair on the body part, and a makeup on the body part. ​ ​ 6. The projection and measurement system according to any one of the preceding claims, wherein the control unit (130) is further configured to determine a relative position of the determined feature of the body part of the user, and wherein the generation of the light guide is further based on the relative position of the determined feature.

7. The projection and measurement system according to any one of the preceding claims, wherein the body part onto which the light guide is to be projected is a face of the user, and the light guide is associated with at least one of a simulated makeup style and a simulated beard style.

8. The projection and measurement system according to any one of the preceding claims, wherein the light guide is associated with instructions for use of a personal care device.

9. The projection and measurement system according to any one of the preceding claims, wherein the tracking unit (120) is further configured for detecting information associated with a skin diagnosis of the body part of the user, and wherein the determination of a feature of the body part of the user by the control unit (130) is further based on the detected information associated with a skin diagnosis of the body part of the user.

10. The projection and measurement system according to claim 9, wherein the tracking unit (120) comprises a multispectral imaging unit configured to capture image data of the body part of the user in one or more predetermined wavelength ranges.

11. The projection and measurement system according to any one of the preceding claims, wherein the generation of a light guide projected onto the body part of the user by the control unit (130) is further based on a user input.

12. The projection and measurement system according to any one of the preceding claims, further comprising a reflective portion configured to reflect incident light towards the user located in front of the reflective portion.

13. A method of performing light projection and feature determination of a body part of a user at a position and measurement system (100), the method comprising: detecting (202) an image of the body part of the user; projecting (204) illumination light from a projection unit onto the body part of the user during detection of the image of the body part of the user; determining (206) a position and orientation of the body part of the user based on the image of the body part of the user; determining (208) a feature of the body part of the user based on the image of the body part of the user; generating (210) a light guide based on the determined feature; and projecting (212) the light guide from the projection unit onto the body part of the user such that a position and orientation of the light guide corresponds to a current position and orientation of the body part of the user, wherein the method further comprises at least one of: projecting (214) the light guide onto the body part of the user in an asynchronous manner with respect to detection of the image of the body part such that the light guide is projected at a different time than the illumination light, which enables detection of the image of the body part, or ​ A modulation pattern is generated (216) that includes an identification pattern, and the modulation pattern of at least one of the light guide or the illumination light is projected onto the body part of the user.

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