Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/44—Detecting, measuring or recording for evaluating the integumentary system, e.g. skin, hair or nails
  • A61B5/441—Skin evaluation, e.g. for skin disorder diagnosis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/0059—Measuring for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
  • A61B5/0077—Devices for viewing the surface of the body, e.g. camera, magnifying lens

Definitions

• the invention relates to a device for providing a quality and standardized lighting on a skin area to allow the study of its surface state.
• Quality lighting is understood to mean lighting that makes it possible simultaneously to obtain a spatial homogeneity over an area of interest defined for the study of the colorimetric aspect, and a directional characteristic that makes it possible to highlight the relief of the cutaneous tissue.
• the examination of the surface condition of the skin is an essential step in the dermatological clinical examination.
• various characteristics of this surface a large part of the information on its state resides in its relief, its color and its reflection. The highlighting of these characteristics will depend on the lighting used.
• FR2589242 describes a system for highlighting cutaneous relief from impression. However, the system is intended for the study of inert samples and does not allow to study in vivo the state of the skin surface.
• FR2826857 describes a system of general lighting of the skin.
• the measurement of the relief characteristic of the cutaneous tissue is not the objective of the proposed device and this measurement is mentioned without any precision on the demonstration of this characteristic.
• a good homogeneity of lighting on the area of interest is essential to avoid influencing the evaluation.
• Omnidirectional lighting will for example provide a good homogeneity on the area of interest to properly assess the color, but will erase the relief by removing drop shadows, making it impossible to evaluate the latter parameter.
• An effective way to reveal relief is to create drop shadows. A grazing light will thus bring out this relief by maximizing the shadows worn, but will provide poor homogeneity in the study area making it difficult to assess color. It is necessary to create a lighting combining these two characteristics simultaneously.
• the reflection properties of the observed tissue should be considered. It is best to avoid visible direct reflection of the light sources in order to avoid disturbing the evaluation.
• Non-exhaustive examples include the forearm, the arm, the cheek, the legs, the area of dark circles and puffiness, the contour of the eyes. From a general point of view, any zone of the body may, in certain cases, be of interest to be observed with such a type of illumination (observation of all dyskeratoses).
• the lighting device is placed on the cutaneous tissue.
• the lighting constraints described above, which are necessary for optimal observation, are supplemented by constraints on the physical characteristics of the device, the dimensions and weight of which must be as small as possible in order to have no influence on the state of the cutaneous tissue. .
• the dimensional aspect is also important to allow the device to be placed on all areas of the human body.
• the present invention aims to bring together all the conditions described above to provide optimal illumination for the study of the relief and the colorimetric appearance of a skin area on the entire human body.
• a method for determining an optimized illumination of a zone of human skin in order to allow the study of its surface state, the skin zone having relief zones, the illumination being derived from a device comprising one or more light sources and generating shadow zones in the vicinity of the relief zones, is characterized in that it comprises the following steps:
• first parameter P1 as a function of the contrast between the brightness inside the shadow zones and the brightness outside the shadow zones
• second parameter P2 function of the homogeneity of the brightness
• the search for a maximum for the function C can comprise a step where the variations of C are studied as a function of the variations of at least one parameter among: the type of light source, the height (h) of the light source relative to to the skin, the distance (e) of the light source with respect to the skin and the angle (a) of illumination of each light source with respect to the area of skin under consideration.
• the invention also relates to a device for illuminating an area of human skin with at least one of: the height (h) of the light source relative to the skin, the distance (e) of the light source relative to the skin and the angle (a) of illumination of each light source with respect to the skin zone considered, was determined according to the method according to the invention.
• At least one light source is punctual
• the device may include a window for observation.
• the device may comprise a shooting system fixed to its structure.
• the device can be connected to a system for recording and sending the shot to a remote user.
• the device may include a support plate on the skin minimizing the influence of the device on the measurement zone.
• the plate may include centering means for automatically centering the device around an outer element attached to the skin.
• the device may comprise projection means capable of transmitting structured light.
• the device may comprise means for measuring the reflected light.
• the device may comprise means for projecting luminous symbols for repositioning assistance.
• the device may include sensors for measuring one or more physical properties of the skin.
• Fig. 1 is a schematic perspective view illustrating a skin portion of a plane P illuminated according to the method of the invention
• Fig. 2 is a diagram illustrating an example of light intensity distribution of a point source
• Fig. 3 is a schematic view illustrating the implementation of the method according to the invention by an example of linear module with 3 point sources,
• Fig. 4 is a diagram illustrating the resulting light distribution of the association of 3 sources as a function of their spacing.
• Fig. 6 is a cross section of FIG. 4 for d close to 40
• Fig. 8 is a view similar to FIG. 3 in the case of a particular embodiment with 2 modules and 2 point sources,
• Fig. 9a and 9b are diagrams illustrating the light distribution obtained for 2 sets of different geometrical parameters
• Fig. 10 is a diagram illustrating the highlighting of the relief by a device according to the invention.
• Fig. 1 1 a and 1 1 1 b are diagrams illustrating examples of flux obtained for the demonstration of the contrast for 2 sets of different parameters
• Fig. 12 and 13 are perspective views of a device according to the invention.
• Fig. 14 is a perspective view illustrating a shooting system attached to the shell of the device of FIG. 12 and 13,
• Fig. 15 is a view similar to FIG. 14 illustrating a system of independent shooting of the hull
• Fig. 16 is a view similar to FIG. 12, with parts torn off, illustrating the presence of a graduated ruler on the edge of the area of interest,
• Fig. 17 is a view similar to FIG. 16, illustrating the presence of a color chart fixed around the area of interest
• Fig. 18 is a view similar to FIG. 16, illustrating the presence of a pivoting disk with color charts for colorimetric evaluation by a observer
• Fig. 19 is a top view of the device of FIG. 12 illustrating the presence of a device for enlarging the area of interest
• Fig. 20 is a view similar to FIG. 12, on a smaller scale, illustrating the presence of repositioning aid projection modules, and
• Fig. 21 is a perspective view of a device according to the invention in a situation using an external module for repositioning assistance.
• Light is provided by one or more modules.
• Each module consists of a combination of several light sources that can be point, linear or flat. These sources can be of the incandescent bulb type, neon, LED bulb or discharge bulb.
• the shape of a module can be linear, circular, planar or any.
• the modules consist of point sources.
• the realization of the constraints described above is made by considering the light distribution of each source and by determining the optimal geometrical parameters of the relative arrangement between the sources and between the modules with respect to the area of interest.
• FIG. 2 An example of light distribution of a source is shown in Figure 2.
• the use of a single source of this type will obviously produce a non-homogeneous illumination.
• the association of different sources can also provide a non-homogeneous source if their arrangement is not correct.
• the present invention uses sources whose spacing, height with respect to the studied surface as well as the angle of illumination with respect to the normal to the studied surface allow a lighting both homogeneous and the highlighting of the relief .
• the light sources are white.
• the type of wavelength used by the present invention is not restrictive and may range from ultra violet to infrared.
• FIG. 3 An exemplary embodiment is shown in FIG. 3 based on the assumption of 3 sources positioned on the same straight line parallel to the studied plane with a spacing between each source noted d as represented in FIG. 3 and with each source having a Gaussian brightness distribution of which the direction of maximum intensity is shown schematically by a dotted arrow.
• the lighting directions of each source are assumed, in the present embodiment, parallel. This reasoning can be applied to any type of light distribution with any direction lighting direction.
• the resulting illumination is observed on a line denoted L in FIG. 3 parallel to the source disposition line.
• FIGS. 4 to 7. This resulting illumination is shown in FIGS. 4 to 7. It can be seen that for a small gap, the association of the 3 sources generates a Gaussian-shaped illumination.
• this distance d 40 is optimal for the particular light distribution described above. In the case of a different distribution, this value is likely to change.
• the present invention provides the different sources so as to obtain this optimum.
• each module used is also optimized.
• the parameters studied are the height h of each module relative to the reference surface P, the distance e with respect to the point O, and the illumination angle a. These parameters are represented in FIG. 8.
• the highlighting of the relief and the creation of homogeneous illumination is done by arranging each module at an optimal height and an angle of incidence with respect to the area of interest studied.
• Determining the optimal values of each parameter is made by studying from a theoretical point of view the homogeneity of the lighting of the area of interest as well as the quality of the highlighting of the relief. This study is done using optical simulation tools and allows to simulate for each parameter its influence on the final result of the lighting obtained. The theoretical results can of course be verified experimentally by the implementation of the device.
• the methodology used to determine the optimal values of h, e and a can be iterative.
• a test is performed from basic parameters. The influence of each parameter on the result is studied based on a visual approach, or on indicators representative of the homogeneity such as the standard deviation of the light distribution.
• a new test with the updated parameters to optimize the lighting is done, and so on until the result is optimal.
• Simplex or Levenberg-Marquardt type optimization algorithms can be used. This approach is combined with the observation of an experienced practitioner who validates and orients the parameters, this time with a clinical approach to the result obtained.
• the optimum light output is a feature that can not be optimized solely by considering the actual observation of the user.
• FIGS. 9A and 9B An example of luminous flux obtained for the particular embodiment with 2 modules is shown in FIGS. 9A and 9B for the homogeneity.
• Figure 9A there is a low quality lighting homogeneity, with a point of maximum central brightness.
• Figure 9B where the parameters have been optimized. There is greater homogeneity with a lower gradient.
• FIGS. 1A and 1B An example of a flux obtained is represented in FIGS. 1A and 1B. As shown, in the first case, FIG. 11A, a contrast of 0.67 is observed whereas the illumination of the second configuration, FIG. 11B, generates a contrast of 0.63 in the particular embodiment described.
• optimization can be done by successively considering the homogeneity and the contrast, or by considering the 2 parameters at the same time.
• the structure of the present invention completely surrounds the area of interest for isolating the area from outdoor lighting.
• the structure may be a shell having a parallelepipedal shape as shown in FIG. 12.
• the support of the shell on the skin is done by a special plate.
• This plate may be a simple plane around the area of interest as shown in Figure 13, or be of a particular shape to allow a centering around a particular device glued to the skin.
• the device may for example be a ring used in cutaneous measurements with a confocal microscope.
• the plate and the shell may also have lower edges of particular shape to best adapt to areas whose morphology is not flat.
• a curved plate can better stick to the surface to ensure a continuous contact between the area of interest and the device.
• a flexible deformable plate can also be used. Observation of the area of interest can be done in two ways.
• the observation is direct and the user visualizes through a window made on the top of the hull the area of interest as shown in Figure 12.
• the camera system is fixed on the shell as shown in FIG. 14.
• the weight of the system is taken up by the shell on the tissue zone around the observed zone.
• the camera system is not fixed on the shell.
• an outer frame with support around the shell allows to work at a constant distance from the area of interest as shown in FIG.
• the camera can be a camera, a compact camera or a SLR camera.
• the device used is a camera
• a live view on an external screen can be realized with the possibility of using live geometric measurement tools or colorimetric evaluation.
• a camera In the case where a camera is used, it can be connected to an outdoor unit for recording and transmission of the shooting to a remote user.
• the transmission can be both wired and wireless.
• tools can be placed inside the shell to facilitate evaluation.
• a graduated ruler see Figure 16, can be placed at the level of the lighting plan to evaluate for example the size of spots or scars.
• Fixed calibrated color patterns can also be positioned on the edge or inside the area of interest in order to perform a colorimetric calibration of the shots as in the embodiment shown in FIG. 17.
• a specific target can be used to perform including the white balance.
• a pivoting disk with color patterns corresponding to the desired hues on its periphery may be fixed on the plate as in the embodiment shown in FIG. scroll through the different hues to evaluate which one is closest to the area to be evaluated.
• a magnification device may be placed in front of the observation window as in the embodiment shown in FIG. 19.
• the filters can be placed in front of the light sources and / or in front of the observation window. These filters can be used to filter a particular wavelength, to polarize the light, or to highlight a particular feature.
• a structured light projection device on the zone of interest which may be lines, a grid or any pattern.
• This structured light projection helps the user to assess the relief of the area studied and can if a recording of the projection of this structured light is made, serve to reconstruct the relief observed using calculation algorithms.
• modules projecting light marks may be fixed on the shell of the device as in the embodiment shown in FIG. 20.
• the repositioning may also be performed by modules attached to another structure and projecting marks on the skin for placing the device as in the embodiment shown in Figure 21.
• one or more sensors for measuring the physical properties of the skin with or without contact can be integrated with the platen in order to measure, for example, the temperature or the hydration.
• the sensors can be capacitive, resistive or thermal type.
• the power supply of the device can be battery-powered or battery-powered, via a transformer or other source such as a computer USB port.
• the device eliminates external light conditions.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Medical Informatics (AREA)
• Biophysics (AREA)
• Pathology (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
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• Molecular Biology (AREA)
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• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Dermatology (AREA)
• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
• Measuring And Recording Apparatus For Diagnosis (AREA)
• Circuit Arrangement For Electric Light Sources In General (AREA)

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• 2011
  • 2011-03-04 FR FR1151757A patent/FR2972109A1/fr not_active Withdrawn
• 2012
  • 2012-03-01 BR BR112013022128A patent/BR112013022128A2/pt not_active IP Right Cessation
  • 2012-03-01 CN CN201280018843.3A patent/CN103517671B/zh not_active Expired - Fee Related
  • 2012-03-01 WO PCT/IB2012/050972 patent/WO2012120413A1/fr unknown
  • 2012-03-01 EP EP12708960.5A patent/EP2680751A1/de not_active Withdrawn

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