Non-destructive determination of scalp hair thickness

Abstract

A device (10) for determining hair thickness is described. The device comprises a computing unit (100) and a user interface (110). The computing unit (100) includes a processor (102) and local memory (104), the processor being connected to the local memory in such a way that the processor can read data from and / or write data to the local memory. The user interface (110) serves as an input and / or output unit for user interaction. The computing unit (100) further comprises an image data input interface (106) for receiving image data of a hair ensemble consisting of at least one single hair, the image data input interface being connected to the processor, and a user interface (107) being connected to the user interface (110) and to the processor.The computing unit (100) is designed to process the image data of the hair ensemble, creating a histogram of the hair thickness values ​​occurring in the hair ensemble and outputting the histogram to the user interface.

Description

[0001] The invention relates to a device for determining the thickness of hair, a method for determining the thickness of hair and a computer program product designed to be executed on a computing unit.

[0002] The thickness of the hair being treated can be relevant for some cosmetic and non-therapeutic treatments of human hair, particularly scalp hair. In the context of this description, hair thickness refers specifically to the diameter of a single hair, assuming that a single hair has a round or circular cross-section, which is essentially true. Examples are disclosed in: QUISPE, MD [et al.]: Development and preliminary validation of an automatic digital analysis system for animal fibre analysis, South African Journal of Animal Science, Vol. 47, October 2017, pp. 822-833; HOFFMAN, R.: TrichoScan: A Novel Tool for The Analysis of Hair Growth In Vivo. Journal of Investigative Dermatology, Vol. 8, 2003, pp. 109-115; LIM, H.-W. [et al.]: Development of a Novel Automated Hair Counting System for the Quantitative Evaluation of Laser Hair Removal. Photomedicine and Laser Surgery, Vol.35, published online on 3.11.2016, pp. 116-121; US ​​2007 / 0 040 907 A1; and WO 2017 / 072 009 A1.

[0003] To determine hair thickness, a tuft of hair can be cut from a person and submitted for analysis. This allows the thickness of individual hairs to be determined, and statistical methods can be used to establish a distribution of hair thickness values ​​across a range. However, this procedure requires taking a specific amount of hair, i.e., a sample, and submitting it for analysis. The analysis may be performed at a different location, and the transport of the hair sample and the subsequent reporting of the results can take a considerable amount of time before the results are available and further treatment decisions can be made.

[0004] Accordingly, it is desirable to provide user-friendly and effective approaches for determining hair thickness that deliver the result in a short time and without invasive intervention in a person's head hair.

[0005] It can be considered an object of the invention to provide a device and an associated method which make it possible to determine the thickness of hair in a short time without damaging the hair or having to cut it off at least partially.

[0006] This problem is solved by the features of the independent claims. Further developments of the invention result from the dependent claims and from the following description.

[0007] According to one aspect, a device for determining hair thickness is specified. The device comprises a computing unit and a user interface. The computing unit includes a processor and local memory, the processor being connected to the local memory in such a way that the processor can read data from and / or write data to the local memory. The user interface serves as an input and / or output unit for user interaction. The computing unit further comprises an image data input interface for receiving image data of a hair ensemble consisting of at least one single hair, the image data input interface being connected to the processor, and a user interface being connected to the user interface and to the processor.The processing unit is designed to process the image data of the hair ensemble, creating a histogram of the hair thickness values ​​occurring in the hair ensemble and outputting the histogram to the user interface.

[0008] The device described here enables non-destructive measurement of hair thickness, particularly human scalp hair. This means that the hair does not need to be cut to determine its thickness. The device and the associated method are suitable, for example, for demonstrating the effectiveness of hair thickening processes or for mechanistic investigations. Hair thickening can be achieved, for instance, using a swelling process that increases the hair's cross-section or with coatings, such as polymer coatings. Mechanistic investigations can be used, for example, during hair coloring and especially permanent waves to observe the swelling and shrinking processes that occur in hair.With the aid of the described device and the associated method, it is possible to observe such swelling and shrinking processes non-invasively during their occurrence and without significant time delay. Conclusions about the mode of action of products can be drawn from such observations. These conclusions can be collected in the device and evaluated for product modification and adaptation.

[0009] Knowing the thickness of a person's hair can be important for various hair-related treatments. These treatments can be particularly cosmetic and non-therapeutic in nature. For example, the thickness of the hair can determine which treatments should be applied and how, in order to avoid damaging the hair. The device described here allows for a simple method of determining hair thickness.

[0010] The processor can contain a logic circuit which can perform a variety of functions and be configured as needed to execute a series of instructions.

[0011] This set of instructions is typically referred to as a program or software. The processor can be a hard-wired logic circuit or a programmable logic circuit, such as a programmable processor, e.g., a microprocessor or an FPGA (field programmable gate array). The processor can execute any type of computer program, such as a computer program written in programming code for a virtual machine (a self-contained runtime environment), like a Java computer program.

[0012] Local storage can be volatile or persistent, and in particular, rewritable and / or readable. Image data can be stored in local storage and read for processing. The processed image data can be stored in local storage in a modified form, for example, for further processing steps.

[0013] The user interface is an arrangement for interacting with a human user using at least one input device (keyboard, mouse, microphone, touchscreen) and / or at least one output device (display unit, screen, speaker). For example, the user interface can be a touch-sensitive display, and the human user can interact directly with the displayed content by touching a specific area of ​​the display.

[0014] Image data can be read via the image data input interface, for example, from an image data storage device or directly from an image acquisition unit. It is conceivable that an image data storage device containing a large number of image data (individual images of hair ensembles from one or more people) could be provided and connected to the image data input interface. The image data would then be read in, and a histogram of the hair thickness values ​​would be created for each individual image. Furthermore, it is conceivable that the processing unit could read metadata (identification data of an image to identify the person depicted, date of capture, etc.) from the individual images and display at least some of this metadata in the corresponding histogram. Using this metadata, it is possible to assign several individual images to the same person and summarize the values ​​from these images in a single histogram.For example, there may be several images of different regions of a person's head hair, and it may be desirable to display the information from all these images in a single histogram to get an overview of the overall condition of the person's head hair.

[0015] A hair ensemble, as mentioned in this description, refers to an image of one or more individual hairs. The position and orientation of the hairs are not necessarily relevant. For example, the hairs can be photographed against a light background or, more generally, against a background with a color that contrasts with the hair color. Blonde hairs can be photographed against a dark background, while dark hairs can be photographed against a light background. The hairs can be arranged on or around a two-dimensional element and lie against its surface. Preferably, the individual hairs are distributed across this surface in such a way that individual hairs can be identified in the image data.

[0016] It is conceivable that the hairs lying on the surface are pressed against it by a transparent, flat element to ensure that the distance between each hair and an optical group of an image acquisition unit, which generates the image data, is uniform. This can reduce or eliminate distortions in the image acquisition, ultimately increasing the accuracy of the determined hair thickness values.

[0017] Hair thickness can be specified in pixels or in any unit of length (e.g., metric units), provided the image scale is known. The image scale can be defined by assigning a pixel to the desired unit of length. In this context, hair thickness corresponds to the diameter of a single hair, i.e., the dimension of a hair perpendicular to its longitudinal direction in a two-dimensional image of a group of hairs.

[0018] Individual human head hairs typically have a diameter of 50 to 100 µm. The image of the hair ensemble can, for example, have a scale or resolution of 5 µm per pixel. Within the diameter range specified above, this resolution corresponds to an accuracy of 5% to 10% relative to the hair diameter.

[0019] The user interface sends signals to the processor, which then converts these signals into information usable by a human operator, such as audio or video signals, particularly static image signals. The user interface also receives input from a human operator and forwards this input to the processor.

[0020] The user interface can, for example, display the image data underlying the analysis and simultaneously or subsequently the histogram of the hair thickness values.

[0021] The histogram of the hair thickness values ​​occurring in the hair sample shows how frequently each value occurs. The frequency can be a relative frequency, which refers to the total number of hair thickness values ​​determined.

[0022] In other words, the device described here enables the use of image analysis methods to determine hair thickness. The device requires only a sufficiently magnified or high-resolution image of a person's scalp hair as input data. Such an image can be created, for example, with a digital microscope.

[0023] For example, the DiameterJ method (https: / / imagej.net / DiameterJ) can be used as an image analysis method.

[0024] According to one embodiment, the computing unit is configured to receive a grayscale image via the image data input interface and to convert the grayscale image into a binary image before creating the histogram of the hair thickness values ​​occurring in the hair ensemble.

[0025] In a binary image, each pixel has exactly one of two possible states. For example, each pixel can be either white or black. This has the advantage that the state of each pixel can be easily identified and the pixels can be clearly distinguished from one another.

[0026] According to another embodiment, the computing unit is designed to display the hair thickness values ​​in the histogram in pixels.

[0027] Multiple thickness values ​​can be determined for a single hair. For example, it is conceivable that a single hair could be divided into several longitudinal segments, and a thickness value determined and reported for each segment. Even assuming that a single hair has a substantially uniform thickness along its length (the hair tip or end segment might be thinner than the other longitudinal segments), this approach can increase the number of measurements to reduce the influence of measurement errors or image distortions.

[0028] When the diameter of a single hair is specified in pixels, this specification refers to the number of pixels between the first edge of the hair and the opposite edge. For this purpose, the processing unit can draw a perpendicular line to a point on the hair's edge and determine the number of pixels traversed by this perpendicular line before it crosses the opposite edge.

[0029] To increase measurement accuracy, this approach can exclude diagonally growing hairs or longitudinal sections of hair from the analysis, because in these cases the vertical line, due to its also diagonal orientation, may intersect a significantly higher number of pixels before reaching the opposite edge. This consideration applies to a matrix-like image structure with horizontally oriented rows and vertically oriented columns of pixels.

[0030] In the histogram, the number of measurements corresponding to each measured hair thickness value (for example, on a scale with 5 µm increments, i.e., 50 µm, 55 µm, 60 µm ... 100 µm) is plotted. This then yields the relative frequency of each hair thickness value.

[0031] According to another embodiment, the computing unit is designed to determine a scale of the hair ensemble in a predefinable unit of length and to convert the values ​​of the hair thickness into the predefinable unit of length and to indicate them in the histogram.

[0032] The scale can be determined, for example, by inserting an element (which can also be called a reference element) with known dimensions (length and / or width) into the hair ensemble before the image of the hair ensemble is taken. The element could, for example, be rod-shaped.

[0033] For example, the hair ensemble can be placed on a flat element with a light surface for image capture. A dark bar of known width can be displayed on this surface. This bar can serve as a reference element.

[0034] To identify the reference element, a user can mark it in the image of the hair ensemble via the user interface. Alternatively or additionally, the reference element can have a visually recognizable and evaluable pattern to be automatically recognized by the processing unit. This pattern could, for example, consist of numerous bright areas at regular intervals along a longitudinal axis of the reference element. The bright areas can also have the same shape to facilitate automated recognition of the reference element. The bright areas can have an asymmetrical shape to indicate the position or orientation of the reference element. The reference element can have longitudinal segments of varying widths. It is also conceivable that the width of the reference element can be derived from the spacing of the bright areas along the reference element.For example, the distance between the bright areas can be an integer multiple of the width of the reference element.

[0035] It should be noted that the light areas of the reference element mentioned above are examples and that the width of the reference element can generally be derived from a light-dark pattern of the reference element.

[0036] The reference element can also be used to determine whether the image of the hair ensemble is optically distorted. Such distortion can then be corrected using the known dimensions of the reference element.

[0037] It is conceivable that two reference elements could be used for a recording of a hair ensemble, one of which runs horizontally and the other vertically, in order to detect and compensate for distortions in both directions.

[0038] According to a further embodiment, the computing unit is configured to output the image data of the hair ensemble on the user interface, wherein the user interface is configured to receive an input that identifies an area of ​​the hair ensemble and to transmit this input to the computing unit, wherein the computing unit is further configured to limit the histogram of the hair thickness values ​​occurring in the hair ensemble to the area identified in the input.

[0039] This makes it possible to analyze hair thickness in different areas of the hair stalk. For example, the image of the hair stalk can cover a specific length segment of individual hairs or even the entire length of individual hairs. In this embodiment, it is possible to analyze different areas of the image separately. For example, the ends of the hairs can be analyzed separately from a middle segment and also separately from a segment of the hairs located near the scalp.

[0040] It is of course also conceivable that different images of different regions of the hair are taken and analyzed to obtain information about the thickness of the hair in different areas.

[0041] According to another embodiment, the computing unit is designed to determine treatment agents and / or application instructions for hair treatment agents based on the histogram of hair thickness and to output them to the user interface.

[0042] Based on the measured hair thickness, treatment products and / or application instructions for these treatment products, or general application instructions for hair treatment products, can be determined and displayed to the user via the user interface, for example, shown or announced. Some treatment products may be less suitable for certain hair thickness values. Similarly, the application of the treatment products may depend on the hair thickness value.

[0043] If hair thickness falls below a certain threshold, it may be advantageous to provide the user with treatment products and / or application instructions for increasing hair thickness. Treatment products for increasing hair thickness may advantageously include ingredients selected from the group consisting of xanthine compounds, vitamin B3 compounds, panthenol compounds, and mixtures thereof. The xanthine compound is advantageously selected from caffeine xanthine, 1-methyl xanthine, theophylline, theobromine, and mixtures thereof. The vitamin B3 compound is preferably selected from niacinamide and its salts, nicotinic acid and its salts, nicotinyl alcohol and its salts, nicotinic acid esters, nicotinyl amino acids, nicotinyl esters of carboxylic acids, nicotinic acid N-oxide, niacinamide N-oxide, and mixtures thereof. The panthenol compound is advantageously selected from D-panthenol, DL-panthenol, panthenyl triacetate, panthetin, pantothein, panthenyl ethyl ether and mixtures thereof.

[0044] It is conceivable that the user will be presented with a questionnaire via the user interface to request further relevant information from the user in addition to the visually captured information about the hair. This additional information could relate to previous hair care and treatments, but also to age, gender, ethnicity, and lifestyle and dietary habits. This additional information, along with the histogram of hair thickness, could also be incorporated into the determination of a suitable treatment product and / or application instructions.

[0045] The device described here makes it possible to easily determine and display to a user treatment products and / or application instructions tailored to a person's hair.

[0046] Information about treatments and / or application instructions can be stored in local memory and determined by the processing unit based on hair thickness or a histogram of a person's hair thickness. For this purpose, the processor uses the hair thickness information to read treatments and / or application instructions from local memory that are associated with or suitable for the determined hair thickness.

[0047] It is also possible, of course, for information about treatments and / or their application instructions to be made available, at least in part, in remote storage. This remote storage can be part of a server or a group of servers accessible via a public or private communication network. This server or group of servers can also be referred to as an external computing unit and is described below.

[0048] In one embodiment, the user interface is designed to receive input from a user after the characteristics of a treatment agent have been output, and to initiate an action concerning the output treatment agent based on this input.

[0049] The action could, for example, involve offering the user a treatment product for purchase and enabling the user to initiate the purchase via an input field. In addition to purchasing treatment products, the user can also be offered further information about the purchase. This further information could include more detailed treatment and application instructions. The user interface receives, for example, the input that the user wishes to purchase the treatment product, saves the request, and / or forwards the request to a retailer that distributes the treatment product. The computer program prompts the user to enter their personal data (address, bank information, shipping preference, etc.) via the input device. Alternatively, the user can be shown where, for example, a drugstore, pharmacy, etc., the product is available.in his vicinity, so that he can purchase the prescribed treatment locally.

[0050] According to another embodiment, the computing unit and the user interface are arranged in a common housing.

[0051] The processing unit and the user interface can, for example, be part of a computer. The computer can be a portable user device, such as a smartphone, phablet, tablet computer, or laptop.

[0052] According to another embodiment, the computing unit has a data transmission interface, wherein the data transmission interface is designed to exchange data with an external computing unit via a transmission link or, more generally, a data network.

[0053] This can be used to allow the processing unit to transfer image data of the hair ensemble, either completely or partially, to the external processing unit so that the image data can be analyzed by the external unit. This can be advantageous if the analysis of the image data requires high computing power that the (local) processing unit cannot provide.

[0054] For example, the image data of the hair ensemble can be transferred to the external processing unit immediately after being received by the (local) processing unit. However, it is also conceivable that only the image data relevant for analysis is transferred to the external processing unit, for example, after a user has selected or specified a region of the image data for analysis on the user interface.

[0055] The external processing unit can be located remotely from the device used to determine hair thickness (also called the local processing unit). The local processing unit can be connected to the external processing unit via a data network, i.e., it can be in a communication link. The external processing unit can be a single computer or processor, or a cluster of computers or processors. In a cluster of computers or processors, the processing load can be distributed among the individual components of the cluster according to various criteria.

[0056] This computer network can provide not only computing power but also storage capacity for users, and can hold data shared or marked by users. This reduces the storage space required in the local computing unit. It also makes it easier for users to replace a local computing unit because little or no data is stored locally. The computer network can be configured as a group of interconnected servers.

[0057] According to a further embodiment, the device as described herein also includes an image acquisition unit. The image acquisition unit is configured to create an image of a hair ensemble. Furthermore, the image acquisition unit is coupled to the image data input interface in order to transmit the image of the hair ensemble to the processor.

[0058] The image data input interface can enable wireless or wired communication between the processing unit and the image acquisition unit. For example, the image acquisition unit can be connected to the processing unit via a USB (universal serial bus) interface or via a wireless communication protocol from the IEEE 802.11 (WiFi, wireless LAN) or IEEE 802.15 (wireless personal area network) family.

[0059] Similarly, in another example, protocols that operate according to the principles of mesh networks can be used to connect the image acquisition unit to the processing unit. For example, the Thread protocol, which is based on IPv6, can be used for data transmission and for connecting the image acquisition unit to the processing unit. The Thread protocol is used in particular to connect automated or semi-automated devices.

[0060] In one example, the image acquisition unit can be structurally mounted onto the processing unit, or conversely, the processing unit can be mounted onto or connected to the image acquisition unit. This means that the image acquisition unit is mechanically attached to the processing unit or a housing of the processing unit, or vice versa. For example, this can be achieved through tool-free assembly via a reversible connection. In the mounted position, the image acquisition unit can be held relative to the processing unit by a releasable frictional or positive locking connection. The interfaces between the image acquisition unit and the processing unit can be arranged such that an electrical connection between the image acquisition unit and the processing unit is automatically established or created in the mounted position.Alternatively, the processing unit and image acquisition unit can be structurally separate, with a data connection between them as described above. The image acquisition unit could, for example, comprise a microscope attachment for smartphones, such as the Scrona µPeek.

[0061] The processing unit can execute an application (or program) that receives or queries data from the image acquisition unit. The received or queried data is used in the application to determine one or more output values, i.e., to display image data of a hair ensemble and / or to determine and display an associated histogram. The data is processed and / or evaluated by the application according to the approaches described herein.

[0062] To run the application, the processors (and one or more memory modules) of the processing unit can be used. However, the processing unit can also be configured to outsource computational steps for running the application. For example, the application can transfer data received from or queried by the image acquisition unit to an external processing unit. Before the data is transferred to the external processing unit, it can undergo preprocessing.

[0063] According to a further embodiment, the device also has a reference surface, wherein the reference surface is coupled to the image acquisition unit via a retaining element and wherein the reference surface is designed for placing a hair ensemble.

[0064] Preferably, the reference surface is movable relative to the image acquisition unit in order to adjust the distance between the reference surface and the image acquisition unit. For this purpose, the holding element can have a joint or other adjustment element.

[0065] The reference surface represents the reference area described above. A reference element can be depicted on the reference surface to establish a scale in the captured image. It is conceivable that a vertical bar and / or a horizontal bar with a predefined width and / or length is depicted on the reference surface. When taking an image of a group of hair, it can be helpful if the reference elements are not covered by hair.

[0066] According to another aspect, the use of a device described herein for determining the thickness of hair is indicated.

[0067] According to another aspect, a method for determining hair thickness using a processing unit is described. The method comprises the following steps: reading an image of a hair ensemble; feeding the image to the processing unit; converting the image into a binary image; determining hair thickness values ​​within the binary image; generating a histogram of the hair thickness values; and outputting the histogram to a user interface.

[0068] The method essentially corresponds to the functions of the device described herein. Therefore, the explanations given above and below relating to the device apply equally to the method.

[0069] According to a further embodiment, the method further includes the step of transferring the image capture to an external computing unit, wherein the steps of converting the image capture into a binary image and determining values ​​of the hair thickness in the binary image are at least partially performed by the external computing unit and the results of these steps are transferred back to the computing unit.

[0070] According to another embodiment, the method further includes the step of: determining a treatment agent and / or application instructions for treatment agents based on the histogram of the hair thickness values, and outputting the treatment agent and / or the application instructions.

[0071] According to another embodiment, the values ​​of the hair thickness in the binary image are determined in pixels and / or in a predefinable unit of length.

[0072] According to another aspect, a computer program product is specified which is executed to instruct a processor of a computing unit to perform the steps of the procedure described herein when the computer program product is executed on the processor.

[0073] Exemplary embodiments of the invention are shown in the figures and are explained in more detail below. These show: Fig. 1 a schematic representation of a device for determining the thickness of hair according to an exemplary embodiment; Fig. 2 a greyscale image of a hair ensemble; Fig. 3 a binary image of the grayscale image from Fig. 2; Fig. 4. An example of a histogram of hair thickness; Fig. 5 a schematic representation of a computer program product according to an exemplary embodiment; Fig. 6 a schematic representation of a method according to a further embodiment; Fig. 7 An exemplary image of a hair in a pixel field of a device according to an embodiment.

[0074] The following detailed description refers to the accompanying drawings, which form part of this application and illustrate specific embodiments in which the invention can be implemented. It is understood that other embodiments may be used and structural, functional, or logical modifications may be made without deviating from the scope of protection of the present invention. In this respect, directional terminology such as "top," "bottom," "front," "back," "anterior," "rear," etc., is used with reference to the orientation of the described figure(s). Since components of embodiments can be positioned in a number of different orientations, the directional terminology serves only for illustration and is in no way restrictive.It is understood that the features of the various exemplary embodiments described herein can be combined with one another, unless specifically stated otherwise. The following detailed description is therefore not to be interpreted in a restrictive sense, and the scope of protection of the present invention is defined by the attached claims and their equivalents.

[0075] Fig. Figure 1 shows a device 10 for determining hair thickness. The device 10 has a computing unit 101 and a user interface 110. The computing unit 101 and the user interface 110 can be arranged in a common housing 90. The device 10 can optionally include an image acquisition unit 120 and a reference surface 125, which is coupled to the image acquisition unit 120 by means of a retaining element 123.

[0076] The processing unit 100 is designed to determine the hair thickness of the depicted hairs from image data of a hair ensemble. The image data is provided by the image acquisition unit 120. Alternatively, the image data can also be read from an image data storage device.

[0077] The retaining element 123 can be designed to adjust a distance between the image capture unit 120 and the reference surface 125 so that a hair ensemble adjacent to the reference surface 125 can be optically captured.

[0078] The computing unit 100 comprises: a processor 102, a local memory 104, an image data input interface 106, a user interface 107, and a data transmission interface 108. The image data input interface 106 is used to establish a connection between the computing unit 100 and the image acquisition unit 120, so that image data can be transferred from the image acquisition unit 120 to the computing unit 100. In particular, the image data is transferred to the processor 102, and the processor 102 is configured to perform image analysis procedures to extract the required information from the image data.

[0079] The processor 102 can access the local memory 104 to store the results of the image analysis procedures and / or to read information from the local memory.

[0080] The processor 102 can output the image data via the user interface 107 to the user interface 110 and present it visually to a human operator of the device 10. The user interface 110 has output and input units to enable interaction with the operator. The operator can make selections in the presented image data or enter other inputs to control or influence the image analysis procedures performed by the processor 102.

[0081] The processor 102 can be connected to an external computing unit 130 via the data transmission interface 108 and a corresponding transmission link 135. The external computing unit 130 can be part of a network 140 or be accessible via the network 140. The network 140 can be a private or public wide area network. The transmission link 135 can be used to exchange data between the computing unit 100 and the external computing unit 130. For example, it is possible to have the aforementioned image analysis procedures executed, at least partially, by the external computing unit 130 and to transmit the results to the computing unit 100.

[0082] The data connections 109, 119, 135 originating from the computing unit 100 to the user interface 110, the image acquisition unit 120 and the external computing unit 130 can be wireless or wired or as a combination of wireless or wired sections.

[0083] Data connections 109, 119, and 135 can enable unidirectional or bidirectional data transmission between the connected units. For example, image acquisition unit 120 transmits image data relating to the captured hair ensemble to processing unit 100, while processing unit 100 can transmit control commands to image acquisition unit 120, specifying how image acquisition unit 120 operates. In the case of a unidirectional data connection 119, which only allows data transmission from image acquisition unit 120 to processing unit 100, control parameters can be specified via input elements (buttons, switches, rotary controls, etc., not shown) on image acquisition unit 120. Image acquisition unit 120 may also have display elements (not shown) that indicate the status of the image acquisition unit or the set control parameters.Alternatively, the image acquisition unit 120 can also transmit the set control parameters to the computing unit 100, where they can optionally be displayed.

[0084] The computing unit 100 comprises a processor 102 and local memory 104. The computing unit 100 receives signals relating to features of the examined hair ensemble and, based on these features, determines a recommendation for non-therapeutic treatment of the hair ensemble. The non-therapeutic treatment may include recommendations for treatment agents and / or treatment instructions or application guidelines for the respective surface area examined. Treatment instructions and application guidelines are used synonymously in this description and refer to instructions for the non-therapeutic treatment of the hair ensemble displayed in the image data, using selected treatment agents or without the use of treatment agents. Treatment instructions may, in particular, include the application of a treatment agent or measures to be taken or omitted by the user.For example, treatment instructions may include information on desired or undesired behavior after the application of a treatment agent. To determine a recommended non-therapeutic treatment, the recorded characteristics of the examined hair ensemble can be compared with the areas of application, effects, and instructions for use of treatment agents and / or treatment instructions. Information about the treatment agents and / or treatment instructions may be stored in local memory 104.

[0085] Local memory 104 can exist outside of and be spatially separated from the processing unit 100. The processing unit 100 can access local memory 104 via a data connection and retrieve information about the treatment agents and / or treatment instructions stored there. This retrieved information is compared by the processing unit 100 with the recorded characteristics of the examined hair stalk to determine appropriate recommendations for the non-therapeutic treatment of the examined hair stalk. In other words, local memory 104 is queried using the determined characteristics of the hair stalk. A large amount of stored information can first be retrieved from local memory and then filtered, using the determined characteristics of the hair stalk and, if applicable, treatment goals, to determine which treatment agents and / or treatment instructions are relevant.For this purpose, the data can be loaded from local memory into the volatile working memory of processing unit 100. Alternatively, the determined characteristics of the hair ensemble can be used when retrieving the information from local memory, in order to retrieve only the relevant information from local memory. For the purposes of this description, these two variants can be considered equivalent in their effect. The term "characteristics of the hair ensemble" refers in particular to the histogram of the hair thickness values.

[0086] The user interface 110 can have an input unit and an output unit (not shown). The input unit allows a user to specify parameters for the operation and configuration of the computing unit 100, the image acquisition unit 120, and / or the user interface 110. The input unit can receive information via various interfaces: a keyboard, a mouse, a touch-sensitive display, or a microphone (so-called voice control). It is conceivable that any interface through which a human user can communicate with a computing unit and input or transfer data can be used. The output unit can be a display or other display unit that provides visual information to a user. The output unit can also have a speaker through which acoustic information can be emitted.Visual information can be displayed on a touch-sensitive output unit, allowing the user to input data via the output unit.

[0087] In one example, the computing unit 100 is executed to query information from a user and to additionally consider this information when querying the local memory 104 in order to obtain from the local memory 104 characteristics of treatment agents for the non-therapeutic treatment of the hair ensemble according to the queried information.

[0088] The requested information can be collected using a predefined questionnaire, in which the user assigns more or less weight to a statement or selects from several possible answers. The questionnaire may focus on the user's age, gender, ethnicity, lifestyle habits, and any unusual stresses, such as dietary habits, sleep duration and quality, fluid intake, type of beverages consumed, use of stimulants (e.g., nicotine, alcohol), occupational activities, and leisure activities (e.g., spending a lot of time outdoors in all weather conditions, spending time in the mountains, using a tanning bed). The information requested may also relate to a desired or achievable characteristic of the user's hair or hair itself.

[0089] Fig. Figure 2 shows a highly magnified grayscale image 200 of a hair assemblage from a person's scalp. A multitude of individual hairs 205 are depicted here. The scale 210 of this image is also indicated. The thickness of the individual hairs can be determined from this image. It is conceivable that several thickness values ​​could be determined for a single hair, with these values ​​relating to different longitudinal sections of the individual hair.

[0090] In addition to the individual hairs 205, a reference element 215 is shown. The reference element 215 has known dimensions, so the scale of the image can be determined from it. The use of the reference element 215 is optional. The scale can also be determined in another way.

[0091] From the greyscale image of Fig. 2. A binary image is generated in which each individual image is assigned one of two possible states. Such a binary image is in Fig. 3 shown.

[0092] The binary image consists of a multitude of pixels (described in detail with reference to Fig. (7 shown and explained). From the value of the individual pixels and the number of adjacent pixels with the same value, the thickness of a hair at a specific point can be determined. For this, it may be necessary to apply further image analysis approaches to determine the longitudinal direction of a hair and to determine the thickness perpendicular or transverse to the longitudinal direction of the hair.

[0093] Fig. Figure 4 shows a histogram of 400. This histogram displays the frequency or occurrence of a specific value for hair thickness. In the example of the Fig. In section 4, the number of pixels is used as the value for hair thickness. If the resolution of the image (pixels / unit of length) is known, the thickness can be deduced from the number of pixels.

[0094] For example, the resolution of such an image can be 5 µm per pixel. From the histogram of the Fig. 4. This results in a strong concentration of values ​​for hair thickness in the lower fifth of the value scale between 0 and 255 pixels and a strong decrease in the occurrence of the values ​​up to slightly over half of the value scale.

[0095] Fig. Figure 5 shows a computer program product 500. The computer program product 500 is designed to instruct the processor 102 of the arithmetic unit 100 to execute the functions or procedures described herein.

[0096] Fig. Figure 6 shows a schematic representation of a method 600 for determining hair thickness using a computing unit. The method comprises the following steps: reading (610) an image of a hair ensemble; feeding (620) the image to the computing unit; converting (630) the image into a binary image; determining (640) hair thickness values ​​in the binary image; generating (650) a histogram of the hair thickness values; and outputting (660) the histogram to a user interface.

[0097] Essentially, the method 600 and its steps correspond to the functions described with reference to the device 10. Reference is made here to the description of the device.

[0098] The procedure may also include further steps, which are designed analogously to the functions of device 10.

[0099] Fig. Figure 7 shows a schematic representation of an image 700 with a greatly enlarged depiction of hair 710. The image 700 consists of a pixel array 720 with individual pixels 725. The pixels 725 are of the same size and arranged in rows and columns.

[0100] The hair 710 initially runs from the upper left to the lower right, then bends so that it runs almost vertically downwards from about half the height of the pixel field 720. A central axis 712 of the hair 710 is shown with a dashed line.

[0101] To determine the thickness of hair 710, the number of pixels between its left and right edges can be calculated. For example, a line can be placed in the image at various positions, with this line perpendicularly intersecting the central axis 712. The number of pixels through which this line passes from the left to the right edge can then be determined. Fig. Figure 7 shows an example of this at two positions, with lines 714 and 716 drawn and the pixels traversed by these lines marked by hatching.

[0102] Line 714 intersects six pixels and runs obliquely to the rows of the pixel array 720. Line 716, on the other hand, intersects five pixels and runs approximately horizontally, i.e., parallel to the rows of the pixel array 720. It is evident from this representation that the path of a single hair 710 through the pixel array can influence the measurement accuracy. This can also be described as quantization inaccuracy and is due to the fact that in a binary image, a pixel can only assume exactly one state. Because of these effects, it may be advisable to use longitudinal segments of a single hair for determining hair thickness that run essentially perpendicular or horizontally in the pixel array 720 or that do not exceed a predefinable angle between the central axis 712 and a row or column of the pixel array 720, for example, 10° to 15°.The thickness of a hair is understood to be the extent perpendicular to the central axis 712 or longitudinal direction of a hair. LIST OF REFERENCE MARKS 10 Device for determining hair thickness 90 cases 100 computing units 102 processor 104 local storage 106 Image data input interface 107 User interface 108 Data transmission interface 109 Data connection 110 User interface, input and output unit 119 Data connection 120 image capture units 123 Holding element 125 Reference area 130 external computing units 135 transmission line 140 network 200 grayscale image 205 individual hairs 210 scale 215 Reference element 220 Binary image 400 Histogram 500 computer program product 600 procedures 610-650 process steps 700 images 710 hair 712 Center axis 714, 716 diameter 720 pixel field 725 pixels

Claims

[1] Device (10) for determining the thickness of hair, comprising the device: a computing unit (100) comprising a processor (102) and a local memory (104), wherein the processor is connected to the local memory in such a way that the processor can read data from the local memory and / or write data to the local memory; a user interface (110) which serves as an input unit and / or output unit for interaction with a user; where the computing unit has (100): an image data input interface (106) for receiving image data of a hair ensemble consisting of at least one single hair, wherein the image data input interface is connected to the processor; a user interface (107) which is connected to the user interface (110) and to the processor; where the computing unit (100) is executed: to process the image data of the hair ensemble and thereby create a histogram of the hair thickness values ​​occurring in the hair ensemble and output the histogram to the user interface; an image acquisition unit (120) which is designed to create an image recording of a hair ensemble; wherein the image acquisition unit (120) is coupled to the image data input interface (106) to transmit the image acquisition of the hair ensemble to the processor (102); a reference area (125); wherein the reference surface (125) is coupled to the image acquisition unit (120) via a retaining element (123) which is designed as a joint, wherein the joint is designed such that the reference surface is movable relative to the image acquisition unit, so that a distance between the reference surface and the image acquisition unit can be adjusted; wherein the reference surface (125) is designed to hold a hair ensemble and the reference surface further comprises a reference element that is configured so that the computing unit determines a scale in the image data. [2] Device (10) according to claim 1, wherein the computing unit (100) is configured to receive a grayscale image via the image data input interface (106) and to convert the grayscale image into a binary image before creating the histogram of the hair thickness values ​​occurring in the hair ensemble. [3] Device (10) according to claim 1 or 2, wherein the computing unit (100) is configured to indicate the values ​​of the hair thickness in the histogram in pixels. [4] Device (10) according to claim 3, wherein the computing unit (100) is configured to determine a scale of the hair ensemble in a predefinable unit of length and to convert the values ​​of the hair thickness into the predefinable unit of length and to indicate them in the histogram. [5] Device (10) according to any of the preceding claims, wherein the computing unit is designed to output the image data of the hair ensemble on the user interface (110); wherein the user interface (110) is executed to receive an input which designates an area of ​​the hair ensemble and to transmit this input to the computing unit; the computing unit is designed to limit the histogram to the area specified in the input based on the hair thickness values ​​occurring in the hair ensemble. [6] Device (10) according to one of the preceding claims, wherein the computing unit (100) is designed to determine treatment agents and / or application instructions for treatment agents for the hair based on the histogram of the hair thickness and to output them to the user interface (110). [7] Device (10) according to one of the preceding claims, wherein the computing unit (100) and the user interface (110) are arranged in a common housing (90). [8] Device (10) according to any of the preceding claims, wherein the computing unit (100) has a data transmission interface (108); wherein the data transmission interface (108) is designed to exchange data with an external computing unit (130) via a transmission link (135). [9] Method for determining the thickness of hair using a device according to any one of claims 1 to 8, the method comprising the steps: Reading (610) an image of a hair ensemble; Feeding (620) the image capture to the processing unit; Converting (630) the image capture into a binary image; Determining (640) values ​​of hair thickness in the binary image; Determine, using the reference element, a scale in the binary image; Converting the determined hair thickness values ​​into a predetermined unit of length using the calculated scale; Create (650) a histogram of the hair thickness values ​​in the specified length unit; Output (660) of the histogram to a user interface. [10] The method of claim 9, further comprising the step of: Transferring the image capture to an external computing unit; wherein the steps of converting the image capture into a binary image and determining values ​​of hair thickness in the binary image are at least partially performed by the external computing unit and the results of these steps are transmitted back to the computing unit. [11] Method according to claim 9 or 10, further comprising the step: Determining a treatment agent and / or application instructions for treatment agents based on the histogram of hair thickness values; and Dispensing the treatment product and / or the instructions for use. [12] Method according to any one of claims 9 to 11, wherein the values ​​of the hair thickness in the binary image are determined in pixels and / or in a predefinable unit of length. [13] Computer program product (500) which is configured to instruct a processor of a computing unit to execute the steps of the method according to any one of claims 9 to 12 when the computer program product is executed on the processor.

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