Abstract: A mobile robot includes a body configured to traverse a surface and to receive debris from the surface, and a debris bin within the body. The debris bin includes a chamber to hold the debris received by the mobile robot, an exhaust port through which the debris exits the debris bin; and a door unit over the exhaust port. The door unit includes a flap configured to move, in response to air pressure at the exhaust port, between a closed position to cover the exhaust port and an open position to open a path between the chamber and the exhaust port. The door unit, including the flap in the open position and in the closed position, is within an exterior surface of the mobile robot.

Abstract: A self-propelled working device is provided with a housing and a pivot bearing arranged on the housing. At least one operating element is arranged on the housing. At least one lid is pivotably supported on the housing and is provided with a bearing section interacting with the pivot bearing. The at least one lid has a closed position and covers in the closed position the operating element. The lid has a first part and a second part connected to the first part. The bearing section is formed on the first part of the lid. The second part of the lid covers the operating element. When a constructively predetermined pulling force is applied to the second part, the second part detaches from the first part.

Abstract: A tungsten jewelry resurfacing kit for consumer end use comprises a buffing cloth; a container of tungsten resurfacing compound having less than 50 ml of resurfacing compound, wherein the resurfacing compound comprises a mixture of i) a diamond powder of at least 1000 grit size; and ii) a binder, such as a fat, which is a semi-solid at ambient temperatures. The kit may further include a plurality of swabs for removing the resurfacing compound from the container. The compound may be a mixture of about 25 to 75% by volume of a diamond powder of at least 1000 grit size; and about 25 to 75% by volume a binder, such as a fat, which is a semi-solid at ambient temperatures.

Abstract: A dishwasher with an integrated closure element, such as a pivoting door or sliding drawer front, having a metallic front panel extending from an upper edge to a lower edge of the closure element includes a user interface located on an upper face of the closure element such that when the closure element is in a closed position, the user interface faces upwardly and is inaccessible to a user. A radio system for the dishwasher includes an upwardly facing antenna located on the closure element adjacent the user interface.

Abstract: A lock and a home appliance having the same are disclosed. The lock includes a holder provided at one selected from between a cabinet and a door, a housing provided at the other selected from between the cabinet and the door, a first stopper provided at the housing, an actuation unit configured to reciprocate in the housing, the actuation unit being moved away from the introduction port by the holder when the door to the introduction port is closed, a fastening unit supported by the first stopper, the fastening unit being separated from the first stopper and coupled to the holder when the actuation unit is moved away from the introduction port, a first elastic member for providing force necessary to move the fastening unit away from the introduction port, and a second elastic member for providing force necessary to move the actuation unit toward the introduction port.

Abstract: A rack assembly for a dishwasher appliance is provided. The rack assembly includes one or more modular baskets placed in a primary rack. These baskets are easily removable and portable for loading and prewashing if desired. In addition, each of the modular baskets may have at least one sidewall that is collapsible. The collapsible sidewalls may be collapsed and adjacent baskets may be linked together using clips as needed based on the size of the dishware to be washed. In this manner, the rack assembly and modular baskets provide a convenient, configurable rack system that enables simple and effective loading, unloading, and prewashing of dishware.

Abstract: An insertion apparatus includes a distal end member formed at a distal end portion of an insertion section inserted into a subject, a cylindrical member disposed in the distal end member, and an annular coupling ring into which the distal end member is inserted, a projecting section of the cylindrical member being pinched between the coupling ring and the distal end member.

Abstract: The present invention comprises the provision and use of a novel endoscopic device which is capable of stabilizing, straightening, expanding and/or flattening the side wall of a body lumen and/or body cavity so as to better present the side wall tissue for examination and/or treatment during an endoscopic procedure. The present invention also comprises the provision and use of a novel endoscopic device capable of steadying and/or stabilizing the distal tips and/or working ends of instruments inserted into a body lumen and/or body cavity, whereby to facilitate the use of those instruments.

Abstract: An image pickup apparatus includes: a lens frame internally holding a movable lens, and including a magnet provided on an outer circumferential surface; a holding frame; and a magnetic member, in which the magnet includes a plurality of magnet pairs provided at uniform angles in a circumferential direction of the lens frame, each of the magnet pairs including magnets that are respectively disposed on distal end side and proximal end side along the optical axis direction of the movable lens, the magnet disposed on the distal end side has a polarity opposite in the radial direction to a polarity of the magnet disposed on the proximal end side, and the magnetic member is provided to face the magnets that configure one of the plurality of magnet pairs.

Abstract: Endoscopic instrument with a control element, an instrument shaft, an adjustment element, a pull element, an actuator, an intermediate element which is operatively connected to the control element and to the adjustment element such that a force applied to the control element by the user can be transmitted to the adjustment element via the intermediate element in order to move the adjustment element, a detection device for detecting a torsion of the intermediate element, and an abutment device, which defines a free rotatory movement range of the control element relative to the adjustment element.

Abstract: An endoscope includes: a first fiber provided with a first flat surface from which illuminating light is emitted; a pipe including a through hole to which a distal end portion of the first fiber is fixed and including a first surface that can be a flat surface identical to the first flat surface and a second surface which is a flat surface orthogonal to a central axis of the through hole; and a distal end component in which a stopper hole in which an end portion on the distal end side of the pipe is disposed is formed, the stopper hole including an abutting surface on which at least part of the second surface of the pipe abuts, on a bottom side, a concave portion which constitutes for obtaining a predetermined light distribution and is located closer to the front end side than the abutting surface.

Abstract: An endoscope reprocessor includes a medicinal solution tank configured to store a medicinal solution; a first detachable portion provided in the medicinal solution tank and configured to detachably hold the concentration meter such that a measuring surface of the concentration meter is placed in the medicinal solution tank; a preserving fluid tank configured to store a preserving fluid of the concentration meter; and a second detachable portion provided in the preserving fluid tank and configured to detachably hold the concentration meter such that the measuring surface of the concentration meter is placed in the preserving fluid tank.

Abstract: A laryngoscope (10) is disclosed, the laryngoscope (10) comprising a unitary body (11) formed of a first material and having portions shaped to define a handle (18) and a blade (28) of the laryngoscope (10), the body (11) having a recess (44) therein shaped to receive one or more electrical components (12,13,14,15) for operation of a light mounted in the blade portion (28), wherein blade (28) comprises a first surface (32) which faces away from the handle portion (18); and a cover material (17) molded over a portion of the first surface (32), said cover material (17) being softer than the first material so as to provide a resilient portion (17) which can be pressed against a patient's teeth during use of the laryngoscope (10).

Abstract: A surgical access system comprising a tissue dilation assembly and a tissue retraction assembly, both of which may be equipped with one or more electrodes for use in detecting the existence of (and optionally the distance and/or direction to) neural structures.

Abstract: Geographic atrophy of the eye can be detected and measured by imaging the eye at a depth greater than the retinal pigment epithelium (RPE) at a plurality of locations of the eye, for example, using optical coherence tomography (OCT); determining a ratio of the intensities of imaging signals of a retinal layer(s) with respect to the intensity of imaging signals of a sub-RPE layer(s) at each location; determining representative values based at least in part on the determined ratios; generating a map of the representative values; and identifying diseased areas from the map. Contours and binary maps may be generated based on the identified diseased areas. The size and shape of the identified areas may be analyzed and monitored over a period of time.

Abstract: A system and associated methods are disclosed for objectively assessing the vision of a user using a computing device. In at least one embodiment, upon an assessment application in memory on the computing device being initialized, a baseline profile is established for the user based on a current state of an at least one visual parameter associated with a display screen of the computing device. The assessment application selectively modifies the at least one visual parameter periodically, and then monitors and records the user's response to the modifications. The user's responses are compared to the baseline profile and, upon the responses exceeding a pre-defined threshold Delta value, the assessment application notifies the user of a possible change in their vision.

Abstract: A scanning laser ophthalmoscope (SLO) for imaging the retina of an eye comprises a source (12) of collimated light, a scanning device (14, 16, 1328, 1319), a scan transfer device (20) and a detector (1310). The scan transfer device has a first focus (16) at which an apparent point source is provided and a second focus (24) at which an eye (524, 1324) may be accommodated. The scan transfer device transfers a two-dimensional collimated light scan from the apparent point source into the eye. An optical coherence tomography (OCT) system (900) is combined with the SLO, the OCT system providing OCT reference and sample beams. The OCT sample beam (902) propagates along the same optical path as of the SLO collimated light through the scan transfer device. An aberration compensator (1204, 1316) automatically compensates for systematic aberrations and/or changes in wavefront introduced by scanning elements and the scan transfer device as a function of scan angle.

Abstract: Some embodiments of the present inventive concept provide optical coherence tomography (OCT) systems for integration with a microscope. The OCT system includes a sample arm coupled to the imaging path of a microscope. The sample arm includes an input beam zoom assembly including at least two movable lenses configured to provide shape control for an OCT signal beam; a scan assembly including at least one scanning mirror and configured for telecentric scanning of the OCT signal beam; and a beam expander configured to set the OCT signal beam diameter incident on the microscope objective. The shape control includes separable controls for numerical aperture and focal position of the imaged OCT beam.

Abstract: A subject (180) is illuminated whose movements of at least one eye are to be registered by an eye-tracker for producing resulting data (DEYE). To this aim, a coherent light source in light producing means (140) produces at least one well-defined light beam (L1, L2). A diffractive optical element is arranged between the coherent light source and an output from the light producing means (140). The diffractive optical element is configured to direct a light beam (L1) towards at least a first designated area (A1) estimated to cover the at least one eye of the subject (180). Image registering means (150) registers light from the at least one light beam (L1, L2) having been reflected against the subject (180). The resulting data (DEYE) are produced in response to these light reflections, which resulting data (DEYE) represent movements of the at least one eye of the subject (180).

Abstract: Some embodiments are directed to a system and a method for estimating gaze from a set of eye measurement points that are indicative of a gaze pattern of a user viewing a scene. Some other embodiments are directed to obtaining sets of eye measurement points from different users viewing the same scene. In another embodiment, the different sets of eye measurement points are mapped to a common coordinate system for reciprocal calibration In yet another embodiment, a scene transformation for mapping the common coordinate system to a coordinate system associated with the scene can be calculated by matching eye measurement points from the common coordinate system to interest points of the scene. The scene transformation is thereby calculated more accurately than individually calculated scene transformations, thereby providing a more accurate estimate of the gaze points.

Abstract: The present disclosure describes compact remote eye tracking systems that include depth sensing capacity. In one aspect, a method of eye tracking includes illuminating a subject's eye with illumination; detecting, in a depth sensor, optical signals reflected from the subject's face in response to the illumination; generating a depth map based on the optical signals detected by the depth sensor; acquiring an intensity image based on optical signals reflected from the subject's face in response to the illumination; determining, based on a portion of the depth map corresponding to the subject's eye, an estimated distance between the subject's eye and a target screen; determining an estimated gaze direction of the subject's eye based on information obtained from the intensity image; and determining, based on the estimated gaze direction and the estimated distance between the subject's eye and the target screen, a gaze point for the subject's eye.

Abstract: The methods and systems provided can automatically determine an Arteriolar-to-Venular diameter Ratio, AVR, in blood vessels, such as retinal blood vessels and other blood vessels in vertebrates. The AVR is an important predictor of increases in the risk for stroke, cerebral atrophy, cognitive decline, and myocardial infarct.

Abstract: A method for use within a WBAN, the method comprising creating a motion profile and a corresponding channel quality profile and using the motion profile to determining preferable conditions for MAC communication within the WBAN.

Abstract: A method of determining a required blood flow includes obtaining morphological information of a coronary artery in a cardiac image, segmenting the cardiac image into at least one myocardial region based on the morphological information of the coronary artery, and determining a blood flow required for each of the at least one myocardial region.

Abstract: A method for monitoring physiological parameters associated with a subject using a hand held device is described herein. In an implementation, the method includes obtaining a plurality of sample photoplethysmographic (PPG) features associated with a sample subject, from a video of a body part of the sample subject. From among the plurality of sample PPG features, at least one relevant sample PPG feature associated with the physiological parameter, is selected based on a ground truth value of the physiological parameter for the subject. Further, based on the at least one relevant sample PPG feature and the ground truth value of the physiological parameter, a mathematical model indicative of a correlation between the relevant sample PPG feature and the physiological parameter, is determined. The mathematical model can be deployed for monitoring the physiological parameter in real time.

Abstract: An optical coherence tomography (“OCT”) system that includes a planarizing transparent material is provided. The OCT system includes an OCT probe comprising: a body having a distal end and a proximal end; a positioner adapter located at the proximal end; a connector to an OCT analysis device, the connector located at the proximal end; and, an OCT scan lens located at the distal end. The OCT system further includes: a transparent material configured to planarize tissue at a scan plane of the OCT scan lens.

Abstract: A computed tomography apparatus capable of confirming the positional relationship of an imaging region and a field of view in a real space at the time of determining the position of the imaging region. The computed tomography apparatus according to an embodiment comprises a couch that moves a top board on which a subject is placed. A gantry comprises an opening into which a top board is inserted. A light projection part is provided in the gantry. A setting part sets a field of view with respect to the subject. A controller causes light indicating the set field of view to be projected by controlling the light projection part.

Abstract: An electromagnetic tomography system for gathering measurement data pertaining to a human head includes an image chamber unit, a control system, and a housing. The image chamber unit includes an antenna assembly defining a horizontally-oriented imaging chamber and including an array of antennas arranged around the imaging chamber. The antennas include at least some transmitting antennas and some receiving antennas. The control system causes the transmitting antennas to transmit a low power electromagnetic field that is received by the receiving antennas after passing through a patient's head in the imaging chamber. A data tensor is produced that may be inversed to reconstruct a 3D distribution of dielectric properties within the head and to create an image. The housing at least partially contains the antenna assembly and has a front entry opening into the imaging chamber. The head is inserted horizontally through the front entry opening and into the imaging chamber.

Abstract: A measurement device according to the present disclosure includes a light source for emitting measurement light which is used for measuring an in vivo component present in a living body and belongs to a predetermined wavelength band toward the living body, a detection unit in which a plurality of sensors is regularly arranged in a predetermined arrangement and which detects the measurement light emitted from the light source and passing through the living body with the plurality of sensors, and an analysis unit which analyzes an amount of the in vivo component based on an amount of light attenuated depending on an optical distance from the light source by use of a detection result detected by the detection unit.

Abstract: A method and device for analyzing and treating tonal imperfections on human skin. The method has the steps of taking at least one background image of at least 10 ?m2 of skin and calculating the average background L value of the image on a grey scale. One or more treatment images of the skin are taken and at least one localized L value of individual pixels or group of pixels is calculated within the treatment image. The local L value is compared to the background L value. Skin deviations are areas of skin where the absolute value of the difference between a local L and the background L is greater than a predetermined ?LS. Skin deviations are identified by this method and then treated with a treatment composition.

Abstract: Provided is an object information acquiring apparatus including a probe having a plurality of receiving elements that are arrayed along a first direction and receive an acoustic wave generated from an object irradiated with light from a light source and converting the acoustic wave into an electrical signal, a scanner that moves the probe in the first direction, a controller, and a generator that generates image data of inside of the object based on the electrical signal. The controller controls the apparatus such that light is emitted each time the probe is moved by a distance that is either (n+1/k) times or (n?1/k) times an array pitch between the receiving elements, where n is an integer of 1 or more and k is an integer of 2 or more.

Abstract: Various system embodiments comprise a stimulator adapted to deliver a stimulation signal for a heart failure therapy, a number of sensors adapted to provide at least a first measurement of a heart failure status and a second measurement of the heart failure status, and a controller. The controller is connected to the stimulator and to the number of sensors. The controller is adapted to use the first and second measurements to create a heart failure status index, and control the stimulator to modulate the signal using the index. Other aspects and embodiments are provided herein.

Abstract: Methods and apparatus for determining blood flow in tissue are disclosed. The methods and apparatus are used to establish a baseline for both thermal properties of the tissue and non-physiologic conditions. Periodic changes in either or both constituents of the baseline are determined and, when the changes correspond to a need for a new baseline, a new baseline is established.

Abstract: The invention relates to a fever detection apparatus for detecting fever of a living being. A heart rate providing unit (3) provides a heart rate value and a peripheral physiological value providing unit (3) provides a peripheral physiological value, wherein a heart rate characteristics determination unit (4) determines heart rate characteristics from the heart rate value and a peripheral characteristics determination unit (5) determines peripheral characteristics from the peripheral physiological value. A fever detection unit (6) detects fever depending on the heart rate characteristics and the peripheral characteristics. Since the heart rate characteristics and the peripheral characteristics are influenced by fever, the fever detection apparatus can be used to reliably and preferentially unobtrusively detect fever.

Abstract: A method implemented by a device to measure a bodily parameter includes transmitting, by a transmit (Tx) antenna of an antenna pair, a first radar pulse to a receive (Rx) antenna of the antenna pair. The method also includes receiving, by the receive (Rx) antenna, the first radar pulse. The first radar pulse travels through a radar target between the Tx antenna and the Rx antenna. The method further includes transmitting, by the Tx antenna, a second radar pulse to the Rx antenna. In addition the method includes receiving, by the Rx antenna, the second radar pulse, wherein the second radar pulse travels through the radar target between the Tx antenna and the Rx antenna. The method also includes determining a bodily parameter within the radar target as a function of the transmission and the reception of the first radar pulse and the second radar pulse.

Abstract: A pulse wave signal expressing a pulse is obtained by detecting a pulse of a measurement subject using a pulse wave sensor. The pulse wave signal is stored in a storage unit. A frequency spectrum of the pulse wave signal is found by converting the time-domain pulse wave signal stored in the storage unit into the frequency domain. It is determined whether or not the measurement subject is at rest by finding a frequency range, within a predetermined total frequency range the pulse rate of a person can take on, in which an intensity of a frequency component of the frequency spectrum exceeds a first threshold, and finding whether or not a ratio of the frequency range with respect to the total frequency range is less than a second threshold. A pulse rate from the point in time when the measurement subject has been determined to be at rest is found as the measurement subject's at-rest pulse rate.

Abstract: A biological information processing system includes a pulse wave information acquisition unit which acquires pulse wave information of a user, and a processing unit which determines the sleep state of the user based on the pulse wave information. The processing unit obtains index information relating to an arousal state during sleep based on the pulse wave information.

Abstract: Disclosed herein are neural probes comprising an L1 polypeptide functional fragment thereof on the exterior surface of the probe, devices including such electrodes, and methods of their use. The disclosed embodiments are useful, for example, for in methods of recording and/or stimulating neural signals in a subject.

Abstract: Systems, methods, and interfaces are described herein for identification of effective electrodes to be used in sensing and/or therapy. Two or more portions of a signal monitored using an electrode may be compared to determine whether the electrode is effective. The two or more portions may correspond to the same portion or window of a cardiac cycle. Further, signals from a first electrode and from a second electrode located proximate the first electrode may be compared to determine whether one or both of the electrodes are effective.

Abstract: An implantable medical device system includes an implantable cardioverter defibrillator (ICD) for detecting and treating ventricular tachycardia (VT). The ICD includes a sensing module for sensing a cardiac signal from available cardiac signal sensing vectors. A control module generates morphology templates of the cardiac signals for multiple patient postures for each of the available sensing vectors and determines a set of posture-independent template features. An unknown cardiac rhythm is classified in response to comparing features of a cardiac signal received during the unknown rhythm to the set of posture-independent features.

Abstract: The invention relates to a measuring device (1) for the non-invasive measurement of physiological parameters. The measuring device (1) is suited to detect and localize by way of self diagnosis diseases such as, for example, inflammations, tumors or arteriosclerosis. The invention proposes a measuring device (1) with at least one optical measuring unit (100) for the generation of oximetric and/or plethysmographic measuring signals, an evaluation unit (140) processing the measuring signals, and a unit (120, 130) for the acquisition of local tissue parameters such as fat content, water content and/or blood perfusion, with the evaluation unit (140) being designed such that at least one local metabolic parameter is determined, in particular the local oxygen consumption, from the signals furnished by the optical measuring unit and obtained from tissue parameters. Moreover, the measuring device (1) enables the non-invasive determination of the glucose concentration.

Abstract: There is provided a medical image display apparatus comprising a storage unit which stores data of a plurality of different types of medical images including the same region of a subject to be examined which are generated by the same type of image generating device, and a display control unit which displays the plurality of medical images at substantially the same position on a screen while sequentially switching the medical images one by one.

Abstract: A system and method for treating Parkinson's disease by delivery of an agent within the brain. At least one image of a target region is acquired, and at least one magnetic resonance diffusion tensor imaging (MR-DTI) scan of the target region is acquired. A diffusion tensor is calculated from the at least one MR-DTI scan, and at least one of an agent distribution and an agent concentration from the images and the calculated diffusion tensor is calculated. Using at least one of the calculated diffusion tensor, the images, the calculated agent distribution, and the calculated agent concentration, the placement of a delivery instrument is planned to deliver the agent to the target region to achieve a desired agent concentration and/or agent distribution within the target region. Delivery of the agent can be coordinated with an applied electrical stimulation.

Abstract: A method for transcranial magnetic stimulation (TMS) of a stimulation area of medical interest, combined with functional magnetic resonance imaging (fMRI) for visualization of the response of, for example neurons, is disclosed. An ultra-thin magnetic resonance coil, MR coil, positioned in the immediate vicinity over an area where the response of, for example neurons, is to be detected, and preferably sandwiched between the TMS coil and the area, provides an excellent signal-to-noise ratio. The TMS can be performed directly through the MR coil. A great deal of flexibility in the number of the TMS and MR coils in use and their spatial arrangement is provided. A corresponding system for the TMS/fMRI studies is also provided.

Abstract: An image alignment guide for producing images for producing a knee brace has an arm carrying a focal angle tube, a mechanism for positioning the arm against the lateral side of the leg of a patient, and a mechanism for setting the level of the brace. The guide is used in method of preparing such images involving taking images with the image alignment guide against the lateral side of a patient's leg at an anterior-posterior mid-line thereof with the focal angle tube at the side of the knee and at a distance therefrom, respectively, measuring the length of the patient's leg from the patella center to a position on the leg at which a shell of a brace to be produced is to be located, measuring the crest of the tibia using a tibial contour guide and sending all images, readings and measurements obtained to a knee brace manufacturer.

Abstract: An integrated blood glucose measuring device is described that has blood glucose metering device, a glucose metering test strip storage mechanism attachable to the metering device, a test strip feeding mechanism for feeding a single test strip from the storage mechanism for blood intake. The metering device, the test strip storage mechanism and the test strip feeding mechanism are integrated into a single device for blood glucose measurement. In another embodiment, a lancet mechanism is attachable to a side of the metering device and thus the metering device, the storage mechanism, the test strip feeding mechanism, and the lancet mechanism are integrated into a single device for blood glucose measurement.

Abstract: A system and a method for creating a stable and reproducible interface of an optical sensor system for measuring blood glucose levels in biological tissue include a dual wedge prism sensor attached to a disposable optic that comprises a focusing lens and an optical window. The disposable optic adheres to the skin to allow a patient to take multiple readings or scans at the same location. The disposable optic includes a Petzval surface placed flush against the skin to maintain the focal point of the optical beam on the surface of the skin. Additionally, the integrity of the sensor signal is maximized by varying the rotation rates of the dual wedge prisms over time in relation to the depth scan rate of the sensor. Optimally, a medium may be injected between the disposable and the skin to match the respective refractive indices and optimize the signal collection of the sensor.

Abstract: The present invention discloses a non-invasive method of measuring skin thickness and blood glucose concentration of a subject by a Raman system. The advantage of the present invention is that a single Raman spectrum is used to measure both the skin thickness and glucose concentration. The skin thickness and Raman intensity retrieved from the same Raman spectrum are both utilized to yield a more accurate blood glucose concentration. The present invention also discloses a Raman system for measuring physiological data of a subject. It comprises a Raman spectroscopic unit and a signal processing unit.

Abstract: A specialized spectrometer comprises a light source to generate a monochromatic light beam to generate resonance Raman peaks or resonance near infrared absorption peaks from a region of the subject and a reference light source to illuminate the region with a reference light beam. The light energy from the resonance Raman peaks can be measured with a detector coupled to an optical wavelength separator. A portion of the reference beam scattered from the region can be measured with a reference detector. An amount of the constituent can be determined with a processor in response to the resonance Raman peaks measured with the detector and the portion of the reference beam measured with the reference detector. The illumination of the region with reference beam with the monochromatic beam allows accurate determination of the amount of the constituent, and the amount may comprise a concentration, such as an amount per unit volume.

Abstract: A device for determining the concentration of a substance in the blood of a subject, such as the oxygen saturation, which device reduces or removes the influence of specular reflection and/or subject motion, comprises an input unit for receiving detection signals reflected back or transmitted through a skin area of the subject in response to irradiation of the skin area by a radiation signal, a signal extraction unit for extracting at least three photo-plethysmography, PPG, signals at different wavelengths from said detection signals, a processing unit for normalizing said at least three PPG signals and forming a first difference signal between a first normalized PPG signal and a second normalized PPG signal and a second difference signal between a third normalized PPG signal and one other of the at least three normalized PPG signals and for forming a ratio between said first difference signal and said second difference signal, and an concentration detection unit for calculating the concentration of a substan