FR2872405A1 - METHOD FOR PARAMETERSING A SKIN TREATMENT DEVICE USING LIGHT SOURCES - Google Patents

Abstract

A skin treatment device uses a light source (26) consisting of a low pressure discharge tube with xenon or other gas allowing the generation of light discharge. A method of setting up this device comprises the steps consisting in: - acquiring image data of an area of the skin (50) by means of a color CCD camera (4), - extracting luminance and luminance data. chrominance, - weighting these data with information specific to a person treated, and - calculating light source parameters from the weighted data obtained.

Description

METHOD FOR CONFIGURING A SKIN TREATMENT DEVICE USING

LIGHT SOURCES.

  The present invention relates generally to the field of the treatment of human skin, in particular for aesthetic purposes. More particularly, it relates to the field of treatments using light sources, continuous or pulsed, such as, for example, pulsed light sources or laser sources.

  The use of light sources for the treatment of human skin, in particular for aesthetic purposes, is well known. This is particularly the case in the field of hair removal, rejuvenation, treatment of skin spots, etc. Dermatological treatments using light specifically target melanin, hemoglobin and skin water. For hair removal, for example, we target the melanin contained in the hair. The light energy is absorbed by the melanin and the corresponding temperature rise is used selectively to raise the temperature of the hair to destroy it. By taking advantage of the differences between the thermal relaxation time of the hair and the skin, a suitable combination of emission time and extinction of the light beam allows the heat to be removed from the skin as it accumulates in the skin. the hair where it spreads to destroy the follicle.

  The distribution and respective densities of melanin, hemoglobin and water result in optical characteristics, including skin phototype, redness and pigmentation of the hair. The setting of the light sources can be done with precision and safety taking into account all of these characteristics.

  In current practice, an operator evaluates these characteristics by eye in order to adapt the settings of the light source that he plans to use. This subjective evaluation depends both on the operator's practice and the lighting under which the examination is performed. Uncertainties generated by this method may reduce the effect of the treatment performed or even, in the worst cases, lead to skin burns.

  The present invention provides a method for simply reliably setting a skin treatment device using light emission.

  To do this, the present invention relates to a method of parameterizing a skin treatment device using at least one light source, characterized in that it comprises the steps of: acquiring image data of an area of the skin by means of an acquisition device; - extracting luminance and chrominance data from said image data, and - calculating light source parameters from said luminance and chrominance data.

  According to another aspect of the present invention, the luminance and chrominance data comprises an L component (luminance), a component a (chrominance range extending from yellow to blue) and a component b (chrominance range extending from from green to red), compliant with Lab mode. The Lab mode is a known color model in which one color is represented by three values: L, luminance, and a and b, two color ranges. It covers the entire spectrum visible by the human eye and is independent of any color reproduction technology, so any device.

  According to another aspect of the present invention, said light source parameters are calculated based on said luminance and chrominance data supplemented by information entered by a user.

  According to another aspect of the present invention, said light source is controlled by a pulse generator which provides current-regulated pulses whose independently adjustable parameters form said light source parameters.

  According to another aspect of the present invention, said light source comprises a low pressure discharge tube containing a gas for generating discharge.

  According to another aspect of the present invention, said light source comprises an optical filter for selecting the wavelength of the light and a reflector and a light guide for bringing the luminous flux into contact with said skin area.

  According to another aspect of the present invention, said light source and said acquisition device are associated with respective movable members that can be handled by a user and applied alternately to said skin area.

  According to another aspect of the present invention, said method further comprises a refrigeration step of said zone of the skin by means of a refrigeration device associated with a movable member that can be taken in hand by an operator and applied to said zone skin alternating with said light source.

  Advantageously, said refrigeration device is controlled according to a set temperature.

  According to another aspect of the present invention, a light source, an image acquisition device and a refrigeration device are controlled by the same control means.

  According to another aspect of the present invention, said light source comprises an optical sensor adapted to transmit to a control means light source characteristics corresponding to light source control parameters in order to control said command.

  According to another aspect of the present invention, said image acquisition device 4 comprises a charge coupled device (CCD) camera module.

  According to another aspect of the present invention, said treatment of the skin is a hair removal treatment, treatment of pigment spots, treatment of certain dermatological conditions such as acne or psoriasis, or treatment of superficial vascular disorders.

  According to another aspect of the present invention, said information stored on a processed individual is stored in a database associated with a control means.

  Advantageously, said stored information is obtained by means of a multiple-choice questionnaire managed by said control means.

  Alternatively, said stored information is extracted from images obtained by said image acquisition means.

  The invention will be better understood from the following description, given purely for explanatory purposes, of one embodiment of the invention, with reference to the appended FIG. 1 schematically illustrating a light treatment system for the skin. pulsed parameterizable according to a method according to the invention.

  A skin treatment system illustrated in FIG. 1 uses a pulsed light generator based on a high-power flash tube, for example xenon, to carry out skin treatment operations such as hair removal, the treatment of pigment spots. treatment of certain dermatological conditions such as acne, psoriasis or others, treatment of superficial vascular disorders such as telangiectasia or others and, more generally, for any treatment in which the application of pulsed light may play a role.

  As seen in FIG. 1, such a system comprises a control means enclosed in a housing 17, a pulsed light generating device 26, an image pickup device 4 and a refrigeration device 34, all three connected to the control means. The three devices are handpieces intervening outside the casing 17 and connected to the latter by respective cords enclosing electrical connection cables and, where appropriate, fluid conduits. The housing contains cards and generators constituting the control unit in association with ancillary means such as refrigeration fluid pumping device. The handpieces can be manipulated by an operator for application to a skin to be treated.

  The control means comprises an electronic assembly structured around a computing unit 12 based, for example, on a microcontroller MPC823 (Motorola). The calculation unit is provided with its own operating system and is associated with specific software for performing the various functions provided by the control means. This calculation unit is also associated with RAM and flash memory means making it possible in particular to constitute a database 15.

  The control means is particularly adapted to perform the following functions: rapid acquisition of images captured by the input device 4, extraction of luminance and chrominance components from the images acquired, weighting of these data by information previously stored in the database 15.

  To do this, a specific program 10 is adapted to extract in real time an image of the luminance and chrominance components. A second specific program 11 is adapted to calculate a global phototype.

  In addition, the control means is adapted to perform the following functions: - calculation of optimal pulse train parameters from the weighted data obtained previously, and - generation of pulses according to the calculated parameters.

  To do this, the computing unit 12 is associated with a pulse generator 14 which supplies current-regulated pulses. Each shot is composed of a burst of pulses whose following parameters are independently adjustable by the computing unit 12: - amplitude of each pulse, - duration of each pulse, - rest time between pulses, - number of pulses by salvo, - repetition period of each salvo.

  The calculation unit 12 is also associated with a refrigeration device supply generator 16.

  A human-machine interface uses a color touch-screen LCD 13 and a specific application to allow communication with an operator. In addition, a control pedal 60 makes it possible to actuate the pulse generator according to the parameters set by the calculation unit 12.

  The power supply (not shown) can be made from batteries, internal or external to the housing, or from the single-phase home network.

  Each pressing of the control pedal 60 triggers a burst of current pulses to be applied to a xenon tube. In order to ensure repetitive emission, each of these pulses has its current regulated amplitude in order to guarantee an identical spectral emission curve from one pulse to another. In addition, it is possible to generate pulses of variable duration while maintaining the rectangular template.

  For safety, the pulse bursts can be emitted by the generator 14 only after validation of a first authorization command via the touch screen, then pressing the control pedal 60. Each time the pedal is pressed, only one burst is issued, with the parameters defined by the calculation unit. Pressing the pedal again can only trigger a new salvo after a predetermined delay.

  For safety, any modification of a parameter via the touch screen requires the validation of the authorization command again.

  The pulsed light generating device 26 comprises a low pressure discharge tube 20 containing a gas allowing the generation of discharge such as for example xenon. This flash tube is excited by the generator 14.

  An output window is composed of an optical filter 22 making it possible to select the wavelengths that are useful for the treatment envisaged. A reflector 21 makes it possible to concentrate most of the emitted beam towards the exit window. A light guide 25 broadband glass (for example the BK7 / Schott) or sapphire has the role of bringing the luminous flux in contact with the skin.

  In the context of an embodiment described below in which a refrigeration element is associated with the light guide, a sapphire guide is used, the thermal conduction of which is much better than that of a glass.

  A cooling device uses a circulation of air or water as needed.

  A refrigeration element 25 of the light guide 23 may provide for the evacuation of calories accumulated in the epidermis and the dermis.

  This element may comprise, for example, two Peltier effect modules placed on either side of the light guide.

  In the case of water refrigeration, the calories extracted by the Peltier modules are evacuated via a suitable exchanger.

  The Peltier effect modules are supplied with electrical energy from the pulse generator 14. Alternatively, they can be powered from a specific generator, such as, for example, the generator 16 supplying the refrigeration device 34.

  The refrigerating element is controlled according to a set temperature, a temperature information at the light guide being transmitted to the calculation unit via the supply 14 or 16 for comparison with a preset set temperature, input, for example, by means of the touch screen 13.

  According to a possible embodiment of the present invention, an optical sensor 24 such as, for example, a reverse biased PIN diode is coupled to the light guide 23. This sensor takes a fraction of the output beam and sends back information, for example a current, representative of the parameters of the salvo emitted. After formatting and amplification, this information is sent back to the computing unit in order to slave the burst parameters.

  The refrigeration device 34 comprises a Peltier effect module 31 whose cold face is coupled to an applicator 30 made of a material of good thermal conductivity, for example aluminum. On the hot face side, the calories are discharged via a finned heatsink 32. For higher refrigeration requirements, a fan (not shown) may provide forced convection. Another alternative is to ensure cooling of the hot face by water circulation (not shown).

  Advantageously, the applicator 30 has a skin contact surface slightly greater than that of the light guide 23.

  The image capture device 4 comprises a camera module with a programmable charge coupled device (CCD) equipped with a Macro lens 2. The CCD camera module makes it possible in particular to program the shutter, red and blue parameters. the Macro lens has a magnification between 10 and 50 depending on the application. For example, for an application of the system to a hair removal treatment, the magnification is 25.

  A calibrated illumination means of the area to be analyzed comprises, for example, a ring of light-emitting diodes 1.

  The whole is enclosed in an opaque box in order to eliminate any external parasitic lighting that can alter the accuracy of the analysis. The lower portion of the housing is adapted to be applied against a skin surface to be analyzed. The surface of the lower opening of the housing corresponds substantially to the contact surface of the light guide 23 with the skin.

  The operation of the system according to the invention will be described for an application to an epilation treatment.

  Firstly, the image pickup device 4 is applied against a surface 50 of skin to be analyzed. The video data passes to the computing unit 12 via the connecting cord of the device 4.

  In order to suitably control the light source, the video data is analyzed to extract information for setting the light source. For this, a specific program 10 extracts in real time luminance and chrominance components. Specifically, these are the L (luminance), a (chrominance range ranging from green to red) and b (chrominance range from yellow to blue), Lab-compliant components. A second specific program 11 is adapted to calculate a global phototype from the components L, a and b.

  Indeed, in a light-emitting dermatological treatment system, the wavelengths absorbed are in the red / infrared range for melanin and largely around the green for hemoglobin. It is therefore necessary to take into account not only the components L and b, as in the case of the determination of a phototype according to the definition of Fitzpatrick, but also of the component a to determine a global phototype.

  The overall phototype is weighted by values representative of the specificities of the skin of a patient to be treated. These values make it possible to take into account important physiological or ethnic type data in the parameterization of a dermatological treatment system by light emission.

  These values are determined by means of a multiple-choice questionnaire whose questions are displayed on the touch screen 13. The answer to each question is entered by simply pressing on a corresponding area of the touch screen. The data thus collected are stored in the database 15.

  In an epilation treatment, the physical characteristics of the hair, such as its size and pigmentation, in the area concerned are also stored in the database. These characteristics can be entered by an operator or extracted from images filmed by the camera by means of a specific processing software associated with the calculation unit 12.

  The database also contains statistical information about the area to be treated and the sex of the patient.

  The set of data obtained stored in the database 15, namely the weighted phototype of the area to be treated, the diameter and the pigmentation of the hair, the sex and the location of the area to be treated, determine at the level of the central unit the choice of a set of burst parameters transmitted to the pulse generator.

  In a second step, the device 4 is substituted for the pulsed light generating device 26 which is applied against the skin zone 50. After authorization of the operator via the touch screen, activation of the control pedal 60 leads to the issuance of a salvo whose parameters are those which have just been determined.

  In the case of epilation, the emitted band is between a lower limit of 650 nm (imposed by the filter 22) and an upper limit of between 950 and 1000 nm.

  After applying a burst, the pulsed light generating device can be removed and replaced by the refrigeration device. The successive use of the two devices will be necessary in particular when applying high fluences (> 20 J / cm2) and for so-called rejuvenation acts.

  The advantage of the anesthetic effect of cold can advantageously be exploited by applying the refrigeration device 34 before the pulsed light generator device 26. This additional comfort is particularly appreciated by sensitive subjects.

  According to one embodiment of the present invention, the image pickup device makes it possible to perform image capture for capillary density measurement.

  The camera and its Macro lens for viewing an area of 8 x 6 mm, or 48 mm 2, a densitometry function performed by means of a specific software associated with the calculation unit 12 makes it possible to count the number of hairs cm2, for example to see the evolution of hair removal. The software allows the display on the screen 13 of the image filmed by the camera. A user points to each visible hair and presses there, which increments a counter. At the end of the input, the conversion in number of hairs / cm2 is performed by the central unit and displayed.

  It can also be stored in the device's memory.

  According to another embodiment, the image captured by the camera is stored for comparison, either with another image of this same zone, or with reference images contained in the database (15). Because of its contact macro camera character, the scale of measurement is constant. Thus, any comparative examination of an area of the epidermis can be performed.

  According to another embodiment, an extension connection, for example a USB connection, makes it possible to increase the storage capacity of the device database while allowing file exchanges with the user's computer environment. .

  A specific file management and archiving software associated with the computing unit 12 makes it possible to order the images, for example to establish comparisons, to intervene on these images in order to extract additional data from them. to follow the evolution of the specific behavior of a given area in a given patient, to define the parameters concerning his hair cycles, to deduce the periodicity of the sessions of hair removal, to analyze the redness of the skin, to follow various healing processes, to analyze the evolution of fine lines in the context of rejuvenation treatments, to distinguish between melanin spots and other pathological spots, etc.

Claims (16)

  1. A method of parameterizing a skin treatment device using at least one light source (26) for processing, characterized in that it comprises the steps of: - acquiring image data of a zone of the skin (50) by means of an image acquisition device (4), - extracting luminance and chrominance data from said image data, and - calculating light source processing parameters from from said luminance and chrominance data.   2. Parametrization method according to claim 1, characterized in that the luminance and chrominance data taken into account comprise a component L (luminance), a component a (range of chrominance extending from green to red) and a component b (chrominance range from yellow to blue), compliant with Lab standard. 3. Parametrization method according to claim 1 or 2, characterized in that said light source parameters are calculated according to said luminance and chrominance data and information stored on a treated individual.   4. Parametrization method according to claim 3, characterized in that said stored information on a treated individual is stored in a database associated with a control means.   2872405 15 5. Method according to claim 4, characterized in that said stored information is obtained by means of a multiple choice questionnaire managed by said control means.   6. Method according to claim 4, characterized in that said stored information is extracted from images obtained by said image acquisition means.   7. Device configurable by a process according to any one of the preceding claims, characterized in that it comprises a pulse generator (14) which supplies current-regulated pulses of which independently adjustable parameters form said light source parameters. .   The parameterizable device according to claim 7, characterized in that said light source (26) comprises a low-pressure discharge tube (20) containing a gas for generating the discharge.   9. Parametrable device according to claim 7 or 8, characterized in that said light source (26) comprises an optical filter (22) for selecting the wavelength of the light and a reflector (21) and a light guide ( 25) for bringing the luminous flux into contact with said skin area (50).   10. Parametrable device according to any one of claims 7 to 9, characterized in that said light source (26) and said acquisition device (4) are associated with respective movable members can be taken in hand by an operator and applied alternately to said skin area (50).   2872405 16 11. Parametrable device according to claim 10, characterized in that it further comprises a refrigeration device (34) associated with a movable member that can be taken in hand by an operator and applied to said area of the skin alternately with said light source (26).   12. Parametrable device according to claim 11, characterized in that said refrigeration device is controlled according to a set temperature.   Parametric device according to one of claims 7 to 12, characterized in that a light source (24), an image acquisition device (4) and a refrigeration device (34) are controlled by a same control means (12).   14. Parametrable device according to any one of claims 7 to 13, characterized in that said light source comprises an optical sensor (24) adapted to transmit to a control means (12) light source characteristics corresponding to parameters of light source control for servocating said light source parameters.   15. Parametrable device according to any one of claims 7 to 14, characterized in that said image acquisition device 4 comprises a color camera module with charge coupled device (CCD).   16. Use of a method of parameterizing a treatment device according to any one of the preceding claims for a treatment device for depilation, treatment of pigment spots, treatment of certain dermatological conditions such as acne. or psoriasis, or treatment of superficial vascular disorders.