LV14749B - Multimodal displaying device for non-contact skin diagnosis - Google Patents

Abstract

The invention refers to devices designed for use for skin status non-contact evaluation, namely for evaluation of distribution of skin pigment concentration and the subcutaneous microcirculation. The proposed device for skin status non-contact evaluation comprises: LED emitters of a number of spectrum bands, adapted for specific skin illumination according to the skin spectral characteristics; optical lens system for the skin surface imaging; device for skin image recording and conversion to a video signal, a processor for the control of skin irradiation mode, where the processor being adapted for sequential switching on and off spectral emitters in spectral image mode at the respective spectrum of light, switching on definite spectral emitters at monochromatic video mode by simultaneous video tape recording of the skin, and calculating at the mapping mode of the skin chromophores, microcirculatory and fluorophores photo-fading maps; memory device for image and video signal recording; output device for display of skin chromophore concentrations, microcirculation and fluorescence photo-fading maps.

Description

DESCRIPTION OF THE INVENTION

Technical i oma

The present invention relates to devices for use in the evaluation of contactless skin conditions, in particular for the evaluation of concentration distribution of skin pigments (chromophores, fluorophores) and microcirculation of the skin.

State of the art

Skin condition assessment is required in various medical-related fields of dermatology, oncology, cosmetology, surgery, traumatology, burn treatment, and more. This requires quantitative and objectively documented information, which can be obtained with the help of specialized apparatus.

State of the art skin diagnostic apparatus - confocal microscopes, siascopes, laser dopplerographs, etc. - are expensive and provide one-sided information. For example, the distribution of melanin and other skin pigments on the skin surface, as well as the characteristics of the subcutaneous microcirculation, play an important role in distinguishing melanoma from basal cell carcinoma. Even in the most modern siascopes, only a few skin-absorbing chromophores are available, but they do not provide any information about fluorescent skin pigments (fluorophores) and skin blood pulsations. The distribution of skin blood supply can be estimated from laser dopplerography images, but data on arterial pulsation phase, etc., cannot be obtained from them. dynamic parameter distribution, which also has diagnostic significance. Complex devices for simultaneous mapping of skin pigments and microcirculation parameters in the medical device market are not yet available.

There is known a portable portable device for photographing a subject in monochromatic illumination of various colors with further processing of images for the purpose of obtaining images in high color resolution (U.S. Pat. No. 7889919 - nearest patent). The resulting high spectral resolution images can be useful for accurate color tone in an object image for use in dermatology, dentistry, the food industry, plant vegetation analysis and industry. Spectral imaging also often involves the use of digital photocells with a set of different spectral filters, such as a rotating disk with a set of different color filters (E.C. Ruvolo et al., Proc. SPIE, Vol. 7548, 75480A, 2010) or electrically controlled liquid crystal filters.

Various methods are known for determining skin chromophore concentrations. As is known, skin color is determined by the absorption of radiation in the skin, which is different for light of different spectral composition. The decisive components of the skin are melanin, which gives the skin a yellowish-brown tone, and hemoglobin in the blood, which gives the skin a reddish tint. Three-band (RGB) or four-band spectral beams (555-565nm, 570-585nm, 620-650nm, 680-750nm) are used to determine the concentration of hemoglobin, oxyhemoglobin and melanin (EP 1810614 A3, EP2181649A1). The concentrations of chromophores are calculated from the absorption spectrum of the skin and the reflected radiation of different spectra. There are known methods to determine the bilirubin concentration in the skin (EP 0747002 Al, WO 2001072222 Al, EP 0747002 Al, using two (450nm, 540nm) or more color emitters. Bilirubin monitoring is used to diagnose and monitor neonatal hyperbilirubinemia. for measurement (US 2010/0249731 Al), where three color (RGB) spectral analysis is used to map the erythema of the skin.

Fluorescence of skin fluorophores is a process by which the intensity of fluorescence is reduced as a result of long-term irradiation. This property is used in living cell fluorescence microscopy (WO 2010082048 A2) as well as in tissue photodynamic therapy for drug concentration determination (Johansson, A. et al., J. Biomed.Opt, 11 (3) 034029, 2006). The properties of fluorophores on healthy skin and pathological formations are different, thus it is possible to visualize areas of skin with different photo-fading times.

Photoplethysmography (PPG) is a non-invasive optical method for measuring microcirculation of the skin. The method is based on the ability of optical radiation to penetrate the tissue to a depth of several millimeters, where the radiation is absorbed into the tissue and blood. As a result of heart rate and respiration, the volume of blood changes periodically as a result of which the intensity of radiation is modulated. Changes in blood volume can be detected using a non-contact PPG method, using a video camera and special computer processing to record radiation, resulting in a distribution of microcirculation parameters in the skin (US2009226071 Al). Contactless PPG method can be used to determine contactless oxygen concentration (WO2009030934 A2) in skin microcirculation monitoring, skin graft surgery and regional anesthesia control (LV14444). Disclosure of Invention

A multimodal imaging device for assessing skin pathologies is provided, specifically designed to measure and evaluate skin chromophore and fluorophore concentration and microcirculation of the subcutaneous circulation in each image pixel. The device uses monochromatic light sources for skin irradiation, which are switched on and off sequentially. At the same time, the skin surface is recorded using a color (RGB) camcorder with variable frame rate. The resulting images are digitally processed, resulting in skin chromophore and fluorophore concentration maps and a skin blood perfusion map. Acquired skin cards show skin color changes, incl. pathologies (such as skin tumors). The device operates in a number of sequential modes: (i) Polarized white light photography is used to evaluate the skin's condition on a color scale; (ii) multispectral analysis of color images is used to obtain the distribution of the concentration of certain skin pigments (melanin, oxy- and deoxy-hemoglobin, bilirubin) in the skin; (iii) time parameter analysis for a series of monochromatic images (video) is used to detect changes in blood circulation and microcirculation in the skin; (iv) Time parameter analysis for a series of monochromatic fluorescence images (video) is used to determine the distribution of endogenous fluorescent pigments (fluorophores) in the skin.

a brief description of the drawings

FIG. Fig. 1 is a flowchart showing the operation of a custom-imaging device;

FIG. Figure 2 shows a general view of the custom-modal imaging device;

FIG. 3 is a flowchart of the device operating algorithm;

FIG. 4 is a flowchart of the device operating algorithm in spectral measurement mode for calculating skin chromophore concentration distribution and detecting skin unfavorable lesions;

FIG. 5 shows a flow diagram of a device operating algorithm for measuring the microcirculation intensity when calculating and visualizing the distribution of the amplitudes of skin blood pulsations, which helps in detecting undesirable skin formations;

FIG. 6 shows a flowchart of the device operating algorithm in fluorophore measurement mode for calculating and visualizing areas of skin with different fluorophore photo-fading times, which are different for healthy skin and its unfavorable formations.

The structure of the custom modal display device is shown in Figs. 1. It contains the following units:

- a combined light source 1 comprising a plurality of spectral bands emitting light emitting diode (LED) emitters which irradiate the skin surface 2;

an optical system 3 comprising a UV filter and a polarization filter;

a lens-mounted image sensor 4 which converts the optical image into an electrical signal;

- a processor 5 which controls the LED, image sensor, memory, calculates skin pigments and microcirculation;

an external storage device 6 adapted for data storage and storing spectral images, chromophore card images and other diagnostic information;

- a data transmission unit 7 for the wireless transmission of data (for example, to a smartphone, computer or other equivalent device);

- an output device 8, such as a display on which chromophore card images and other diagnostic information are output.

The light source 1 is connected to a processor 5 which is connected to an output device 8, a sensor 4, a storage device 6 and a data transmission unit 7 with the ability to send and / or receive digital signals. The optical system 3 is connected to the sensor 4. The multimodal device is shown in FIG. 2.

The proposed device may further include a data input module suitable for input of the measured personal data and for storage to a storage device. According to the best embodiment of the invention, the proposed device is adapted to capture color RGB images in multi-spectral measurement mode; for microcirculation monitoring of the skin, it is adapted for turning on a green emitter and for capturing a series of skin images in video mode; for monitoring the photo-fading of skin fluorophores, it is adapted to turn on an ultraviolet light and capture a series of skin images in video mode. The device is adapted to calculate skin chromophores, microcirculation and fluorophore photo fading maps from acquired skin images. In addition, the proposed multimodal device may be adapted to assess diagnostic parameters of the skin such as melanoma, erythema, bilirubin. The multimodal device can be customized to use motion compensation algorithm in video mode that eliminates skin motion artifacts in microcirculation and fluorophore photo fading cards. The device may also include a data input module suitable for input and output of data to be measured to a storage device, and a data transmission module suitable for wireless transmission of recorded data to a smartphone, computer, or other equivalent device.

The operating scheme and algorithms of the device are detailed in Figs. 3-6. The proposed device can operate in multifunction mode. To measure the concentration of skin chromophores (melanin, hemoglobin, bilirubin), the device operates in a spectral mode where the skin is sequentially illuminated with four monochromatic light emitters and simultaneously photographed, identifying the RGB values of each pixel in the image. To estimate the fluorophore concentration of the skin, the skin is irradiated with ultraviolet radiation and simultaneously filmed, identifying the G signal values at each pixel of the image from which clusters with different fluorophore healing times are calculated.

In subcutaneous microcirculation mode, the skin is irradiated with green radiation, simultaneously captured by identifying the G signal values in each pixel of the image, and the changes in light intensity associated with light absorption in the blood are calculated. The proposed device is portable and is designed for non-invasive optical measurements.

Claims (8)

Claims A multimodal imaging device for non-contact skin condition evaluation, comprising: (i) multi-band LED light emitters adapted for specific skin illumination according to the spectral characteristics of the skin; (ii) an optical lens system for imaging the skin surface; (iii) a device for recording and converting a skin image into a video signal; (iv) a processor for controlling skin irradiation mode and spectral image registration, adapted to turn the spectral emitters on and off sequentially in spectral imaging mode, simultaneously recording skin images in the appropriate spectral illumination, monochromatic video mode on a specific spectrum emitter, and mapping mode calculate skin chromophore, microcirculation and fluorophore photo-fading cards; (v) a storage device for recording images and video signals; (vi) an output device for displaying photo-fading maps of skin chromophore concentration, microcirculation and fluorescence. The multimodal device according to claim 1, characterized in that it is adapted to take color RGB images in a multispectral measurement mode. The multimodal device according to claim 1, characterized in that it is adapted for monitoring the microcirculation of the skin by switching on a green emitter and imaging a series of skin images in video mode. The multimodal device according to claim 1, characterized in that it is adapted to turn on an ultraviolet emitter and to capture a sequence of skin images in video mode for photo-fading monitoring of skin fluorophores. The multimodal device according to claim 1, characterized in that the processor is adapted to evaluate diagnostic parameters of the skin, such as melanoma, erythema, bilirubin. The multimodal device according to claim 1, 3 or 4, characterized in that it is adapted for use in a motion compensation algorithm in a video mode that prevents skin motion artifacts in microcirculation and fluorophore photo-fading cards. The multimodal device according to any one of the preceding claims, characterized in that it further comprises a data input module suitable for input and output of data to be measured to a storage device. The multimodal device according to any one of the preceding claims, further comprising a data transmission module suitable for wireless transmission of recorded data to a smartphone, computer or other equivalent device.