The present invention relates to remotely capturing biometric data of a human and/or other animal. In particular, the apparatus and method relate to remotely capturing pulse waveforms and/or blood oxygen levels.

Photoplethysmography (PPG) has been well accepted within medical and health monitoring fields, providing measurements of physiological variables including pulse waveforms and dual spectroscopic analysis to provide estimates of blood oxygen levels (oxygen saturation, or pulse oximetry) in humans and animals.

Known measurement techniques require contact transducers which emit either a narrow wavelength of light (for example green light), or two narrow wavelength emitters (for example red and infrared). The former is generally used for pulse waveform detection only, and the latter for pulse oximetry. A transducer provides illumination through being in direct contact with the skin or tissue of the subject. A single sensor (usually a photodiode) is utilised to detect reflected light from the tissue, or transmitted light through the tissue. Pulse oximeters detect differences between reflected or transmitted light from two incident wavelengths, in view of differential absorption or transmission characteristics of light of different wavelengths being related to a percentage of haemoglobin which is bound to oxygen. It is relatively standard practice to provide a single detector (often a photodiode) which is sensitive to both of the two incident wavelengths of light (although separate detectors are known), such that incident light emitters are alternately activated to provide separate signals for analysis. A relatively well-known contact transducer of this type is of the form applied to a tip of a finger during analysis.

Disadvantages of known measurement techniques include that direct contact sensors are sensitive to movement of the sensor and/or subject, ambient light, skin colour or pigmentation, and/or contamination, and require specific sensors and algorithms to time signals from any changes in incident light signal. A finger-tip contact transducer, of course, minimises movement and ambient light disadvantages, at least.

Newer techniques have been developed which utilise PPG sensors to detect pulse waveforms from camera sensors, for example from smartphones or tabletcomputers, which detect subtle changes in colour of the skin. However, these techniques are again sensitive to movement of the subject and/or camera, ambient light, skin colour and acquisition times.

PPG sensors are also known to be used within the ear, to provide PPG detection from a transducer within the ear-canal. This is; however, limited to incorporation in an ear-bud or similar device, in which the ear-canal setting itself reduces or prevents the effect of ambient light and/or reduces the occurrence of movement of the sensor and/or subject.

PPG detection, although well accepted, appears to have limited take-up beyond the contact transducers and ear-canal sensors mentioned above, and it is understood that there are no current reliable methods for analysing tissue remotely located from a sensor.

According to a first aspect, the invention provides an apparatus for capturing biometric data from a human or other animal, the apparatus comprises: one or more sensor means comprising: a light emitter, for illuminating remotely located target biological tissue(s) of said human or other animal; and a detector, for capturing light reflected and/or emitted by said target biological tissue(s), and means for controlling a distance between, position and/or location of the one or more sensor means and/or emitter, and or with respect to, said remotely located target biological tissue(s); and/or means for controlling a direction of focus and/or point of focus of emitted light, with respect to said remotely located target biological tissue(s).

Preferably, the means for controlling provides adjusting and/or fixing: a relationship between the one or more sensor means and/or emitter, and said remotely located target biological tissue(s); and/or a relationship between the emitted light and said remotely located target biological tissue(s).

Preferably, the light emitter is configured to illuminate target biological tissue(s) across a void or volume of air separating the emitter and detector from the target biological tissue(s).

Preferably, the detector is configured to capture light reflected by said target biological tissue(s) across the void or volume of air.

Preferably, the light emitter is configured to direct emitted light: across a volume separating the light emitter and said target biological tissue(s); to pigmented biological tissue(s); and/or to non-pigmented biological tissue(s).

Preferably, the volume is substantially air or a void, or comprises a transmissive fluid.

Preferably, a direction and/or point of focus of emitted light is adjustable by physical, electronic, and/or software means, or combinations thereof.

Preferably, the one or more sensor means and/or emitter is/are moveably mounted so as to: change the direction and/or point of focus of emitted light; and/or adjust its/their distance, position and/or location, to or with respect to, said remotely located target tissue(s).

Preferably, the emitter is directed to the pharynx, palate and/or trachea of said human or other animal.

Preferably, light reflected and/or emitted from said biological tissue(s) is analysed to determine one or more biometric properties of said biological tissue(s).

Preferably, the emitter comprises a first light source of first wavelength, and a second light source of second wavelength, such that reflectance properties of the first and second light source can be analysed so as to determine an oxygen saturation of said biological tissue(s).

Preferably, the detector is configured to capture substantially only emitted light that is reflected and/or emitted by said target biological tissue(s).

Preferably, the apparatus comprises means for isolating emitted light reflected and/or emitted by said target biological tissue(s) from ambient light.

Preferably, the means for controlling comprises: a partition, sleeve, tube, collar or flange, preferably of predetermined dimensions and/or length, surrounding at least part of the one or more sensor means, emitter, detector or a part of a housing thereof, and/or said target biological tissue(s); a partition, sleeve or tube, preferably of predetermined dimensions and/or length, surrounding the emitter and detector; or an optical fibre. Preferably, a predetermined distance, volume, separation or gap is defined between the one or more sensor means and said target biological tissue(s).

Preferably, the partition, sleeve or tube blocks ambient and/or external light.

Preferably, the one or more sensor means is/are one or more PPG sensor means. Most preferably, the one or more PPG sensor means is/are configured to detect oximetry, heart rate, heart rate variability, and/or respiration rate data.

Preferably, the apparatus comprises two or more PPG sensor means, at least a first of which is configured to be directed to a first distinct region of biological tissue(s) and at least a second of which is configured to be directed to a second distinct region of biological tissue(s) to allow comparison of blood supply and/or oxygen saturation data from said first and second distinct regions of biological tissue(s).

Preferably, the first region is abnormal or damaged biological tissue(s) and the second region is normal or undamaged biological tissue(s).

Preferably, the means for controlling is capable of adjusting: a distance, position and/or location of the one or more sensor means and/or emitter from at least a first condition to a second condition of the emitter; and/or a direction and/or point of focus of emitted light from at least a first condition to a second condition of emitted light.

Preferably, following adjusting, the means for controlling is capable of securing the adjusted relationship, so as to maintain it.

Preferably, the means for controlling is capable of fixing: the one or more sensor means and/or emitter at a predetermined distance, position and/or location of the emitter; and/or the emitted light at a predetermined direction and/or point of focus of emitted light.

Preferably, the means for controlling is capable of adjusting: distance, position and/or location of the one or more sensor means and/or emitter with respect to said remotely located target biological tissue(s); and/or direction and/or point of focus of emitted light with respect to said remotely located target biological tissue(s).

Preferably, the means for controlling aligns the optical length of the point of focus of the emitter with optics of an associated laparoscope and/or endoscope.

Preferably, the apparatus comprises a processor and/or associated algorithm configured to analyse light reflected from the biological tissue(s) to determine one or more biometric properties of the biological tissue(s), including: blood flow, blood supply, pulsation; pulse waveforms, including amplitude, rate, rhythm, shape, variability, etc.; oxygen saturation, oximetry; heat mapping.

Preferably, the light emitter and detector are provided by a laparoscope and/or endoscope. Most preferably, an output (for example video output) of the laparoscope and/or endoscope is additionally analysed by the processor and/or algorithm to calculate blood flow, heart rate and/or oxygen levels I oxygen saturation.

Preferably, the apparatus comprises guide means, for providing line of sight with respect to said target biological tissue(s), and/or for providing a predetermined spacing or distance between the emitter and said target biological tissue(s).

Preferably, the apparatus comprises at least part of a housing, sleeve, tube or member upon or within the one or more sensor means are located, for insertion into an orifice or cavity of said human or other animal. Preferably, at least a portion of the housing, sleeve, tube or member is disposable, allowing re-use of the sensor means.

Preferably, the apparatus comprises a gynaecological apparatus comprising an elongate housing having a distal end capable of contacting or providing line of sight with: a presenting part of a foetus, baby or neonate; and/or a cervix or vaginal wall of a pregnant or non-pregnant subject.

Preferably, a length of the elongate housing is optimised so as to locate the sensor means a predetermined distance from the distal end.

Preferably, the sensor means is mountable directly to a head and/or face of said human or other animal, or mountable to an item wearable about the head and/or face of said human or other animal.

Preferably, the sensor means comprises a retinal imaging device, in which the emitter is configured to illuminate at least part of a retina and/or other eye structure(s) of said human or other animal.

Preferably, the sensor means is mountable to spectacles or eyewear, providing the sensor means in direct line of sight with said retina and/or other eye structure(s).

Preferably, the apparatus further comprises a speculum, tongue depressor or other tissue contact means for providing line of sight between the emitter and said target biological tissue(s).

Preferably, the apparatus is configured to be mountable on or as part of a nasal apparatus; a mouthguard; a tracheal apparatus; an endotracheal tube; a dedicated oral PPG monitoring apparatus; a breathing apparatus; a scuba diving mouthpiece or mask; an anaesthetic mouthpiece; an endoscopic apparatus; a laparoscopic apparatus; a peak flow apparatus; a spirometry apparatus; a capnometer; an augmented or virtual reality headset; or any combinations thereof.

According to a second aspect, the invention provides a method for capturing biometric data from a human or other animal, the method comprising: controlling a distance between, position and/or location of one or more sensor means and/or an emitter, and or with respect to, remotely located target biological tissue(s); and/or controlling a direction of focus and/or point of focus of emitted light with respect to remotely located target biological tissue(s), and illuminating the remotely located target biological tissue(s) and detecting light reflected and/or emitted by the remotely located target biological tissue(s) so as to capture biometric data therefrom.

Preferably, controlling provides adjusting and/or fixing: a relationship between the one or more sensor means and/or emitter, and the remotely located target biological tissue(s); and/or a relationship between the emitted light and the remotely located target biological tissue(s).

Preferably, illuminating target biological tissue(s) across a void or volume of air separating an emitter and detector from the target biological tissue(s).

Preferably, detecting light reflected by the target biological tissue(s) across the void or volume of air.

Preferably, the emitted light is directed: across a volume separating the emitter and the remotely located target biological tissue(s); to pigmented biological tissue(s); to non-pigmented biological tissue(s); and/or to the pharynx, palate and/or trachea of the human or other animal.

Preferably, the volume is substantially air or a void, or comprises a transmissive fluid.

Preferably, the method comprising: changing the direction and/or point of focus of emitted light; and/or adjusting its distance, position and/or location, to with respect to, the remotely located target tissue(s).

Preferably, analysing light reflected from the biological tissue(s) to determine one or more biometric properties of the biological tissue(s). Most preferably, analysing utilising a processor and/or associated algorithm to calculate blood flow, heart rate and/or oxygen levels I oxygen saturation.

Preferably, the method comprising illuminating the remotely located target biological tissue(s) with a first light source of first wavelength and a second light source of second wavelength, and analysing the reflectance properties of the first and second light sources so as to determine an oxygen saturation of the biological tissue(s).

Preferably, capturing substantially only emitted light that is reflected by the target biological tissue(s).

Preferably, isolating emitted light reflected by said target biological tissue(s) from ambient light.

Preferably, illuminating and detecting utilises one or more PPG sensor means. Most preferably, the one or more PPG sensor means detects oximetry, heart rate, heart rate variability, and/or respiration rate data.

Preferably, the method comprising utilising two or more PPG sensor means, at least a first of which is directed to a first distinct region of biological tissue(s) and at least a second of which is directed to a second distinct region of biological tissue(s), and comparing blood supply and/or oxygen saturation data from said first and second distinct regions of biological tissue(s).

Preferably, the first region is abnormal or damaged biological tissue(s) and the second region is normal or undamaged biological tissue(s).

Preferably, the method comprising any one or more of the group comprising: adjusting a distance, position and/or location of the one or more sensor means and/or emitter from at least a first condition to a second condition of the emitter; adjusting a direction and/or point of focus of emitted light from at least a first condition to a second condition of emitted light; fixing the one or more sensor means and/or emitter at a predetermined distance, position and/or location of the emitter; fixing the emitted light at a predetermined direction and/or point of focus of emitted light; adjusting distance, position and/or location of the one or more sensor means and/or emitter with respect to the remotely located target biological tissue(s); and/or adjusting direction and/or point of focus of emitted light with respect to the remotely located target biological tissue(s).

Preferably, following adjusting, the means for controlling is capable of securing the adjusted relationship, so as to maintain it.

Preferably, the method comprising aligning the optical length of the point of focus of the emitter with optics of an associated laparoscope and/or endoscope. Preferably, the method comprising guiding the emitter and a/the detector to: provide line of sight with respect to the target biological tissue(s); and/or provide a predetermined spacing or distance between the emitter and the target biological tissue(s).

Preferably, the method comprising contacting or providing line of sight of a sensor apparatus with: a presenting part of a foetus, baby or neonate; and/or a cervix or vaginal wall of a pregnant or non-pregnant subject.

Preferably, the method comprising mounting a sensor apparatus directly to a head and/or face of the human or other animal, or mounting to an item wearable about the head and/or face of said human or other animal.

Preferably, the method comprising mounting a retinal imaging device, in which an emitter illuminates at least part of a retina and/or other eye structure(s) of said human or other animal.

Preferably, the method comprising mounting a sensor apparatus to spectacles or eyewear, providing the sensor apparatus in direct line of sight with said retina and/or other eye structure(s).

Preferably, the method comprising utilising continuous light (white or red I Infra-Red) and a CMOS (complementary metal-oxide-semiconductor) camera providing synchronous readings of red, green, blue and/or IR.

Advantageously, the present invention provides an alternative PPG apparatus and method providing non-contact / remote location of the light source and sensor at a predefined distance from the target tissue.

Advantageously, this provides devices suitable for diagnostic and monitoring uses for application to multiple users, with a reliable and predefined light source, and an optimal distance and mounting to provide a stable signal.

Advantageously, remote PPG analysis provides a more reliable and stable signal when the light source and sensor are mounted at a stable and/or a predefined distance from the target tissue. This improves not only signal acquisition but also the accuracy of analysis of that/those signal(s).

Advantageously, the invention provides: real-time monitoring; and improved detection of biometric data irrespective of skin colour.

Advantageously, the invention provides health monitoring of a neonate during third-stage labour.

Advantageously, when the apparatus is a breathing apparatus or mask, a stand-off sensor may be directed to the face of an individual and detection of PPG waveforms would not be subject to respective movement nor the effects of water pressure.

Advantageously, retinal PPG provides ‘heat maps’, using reflected light amplitude(s) and ratio(s), identifying blood flow and oxygen levels across a video image of the retina.

Advantageously, laparoscopic or endoscopic PPG provides ‘heat maps’ identifying: poor blood flow, e.g. in a bowel that is ischaemic owing to lost blood flow or following bowel anastomosis; reconnection surgery, to detect if the join has reasonable blood flow; increased blood flow, owing to inflammation, e.g. appendicitis; abnormal blood flow, e.g. tumours or cancer; and/or structures that are blood vessels, e.g. to differentiate between the common bile duct or a nerve from a blood vessel. Advantageously, in a peak flow apparatus, measuring oximetry and PPG at the same time as peak flow.

Those skilled in the art will understand that ‘controlling’ is intended to mean, in general, adjusting and/or fixing. With respect to adjusting, the relative relationship between the sensor means and the target biological tissue(s) may be altered or adjusted to suit requirements. Once altered or adjusted, the relationship may be additionally secured to maintain the relative relationship. With respect to fixed, the relationship between the sensor means and the target biological tissue(s) cannot be adjusted or altered, and defines a predetermined or set (fixed) relationship.

Means for controlling, thereby, provides either a fixed physical limitation (for example, a predetermined dimension and/or length of a part of the apparatus) which maintains the sensor means at a correct or an optimal distance and/or position, and/or in a correct or an optimal focus, direction and/or orientation with respect to the target biological tissue(s), or provides variable control to alter and adjust to an optimal distance, position, focus, direction and/or orientation of the sensor means with respect to the target biological tissues.

Those skilled in the art will understand that ‘remotely located’, with respect to the target biological tissue(s), is intended to define a form of separation and/or a defined volume, gap or distance between the sensor means (emitter and/or detector) and the target biological tissue(s). In context, as the sensor means is not in direct contact with the target biological tissue(s), they can be said to be ‘remotely located’ with respect to each other.

Those skilled in the art will understand that biometric data includes physiological data (for example oximetry, heart rate, heart rate variability, and/or respiration rate data) and biomolecular data (for example spectroscopy data).

The invention will now be disclosed, by way of example only, with reference to the following drawings, in which:

Figure 1 is a schematic view of a generic apparatus for remotely capturing biometric data from a human or other animal;

Figure 2 is a schematic view of a further generic apparatus for remotely capturing biometric data from a human or other animal;

Figure 3a is a perspective view of a mouthpiece embodiment;

Figure 3b is a cross-sectional view of the mouthpiece of Figure 3a, along the line A-A;

Figure 3b is a cross-sectional view, again along line A-A, of an alternative embodiment of mouthpiece of Figures 3a;

Figure 4a is a schematic view of a peak flow meter embodiment;

Figure 4b is a schematic view of an alternative embodiment of peak flow meter;

Figure 5 is a schematic view of an obstetric and gynaecological embodiment;

Figure 6 is a schematic view of a retinal imaging embodiment;

Figure 7 is a schematic view of a cutaneous imaging embodiment; and

Figure 8 is a schematic view of an augmented reality imaging embodiment.

Figures 1 and 2 provide examples of generic apparatus for remotely capturing biometric data from a human or other animal. Although these Figures will be described more generically, the skilled person will understand that some or all of the attributes of the generic apparatus are present in the more specific examples described in relation to Figures 3 to 8.

In a first embodiment, Figure 1 shows a generic apparatus, identified generally by reference 10, for remotely capturing biometric data from a human or other animal.

The apparatus 10 includes: a transducer 11 , being both an emitter and detector; a moveable housing 12, upon which the transducer 11 is mounted; and a sleeve 13, along which the housing 12 may slide to control a distance, position and/or location of the transducer with respect to remotely located target biological tissue(s) 14.

The housing 12 includes a processor 15 and associated electronics - circuitry, power source, etc. - for controlling the transducer 11 to emit light 16 across a volume of air 17, for remotely illuminating the target biological tissue(s) 14, and detect reflected light 18 from the target biological tissue(s) travelling again across the volume of air 17. In addition, the processor 15 includes an algorithm for analysing the reflected light 18.

The housing 12 is slideable within the sleeve 13; however, the mounting of the transducer 11 onto the housing 12 provides additional freedoms of movement so that the transducer 11 itself may be moved in a three-dimensional sense, in respective x, y, and z planes with respect to the target biological tissue(s) 14, as exemplified by the arrows having reference 19.

The sleeve 13 may include a first end 13a, for directly contacting the target biological tissue(s). Alternatively, the sleeve 13 may be configured such that no direct contact is envisaged. Although slideable within the sleeve 13, once a desired position of the housing 12 has been chosen, the housing may be secured, which fixes a distance between the transducer and the target biological tissue(s).

Should it be required, additional freedoms of movement may be provided by moveable optics, as elaborated upon in relation to Figure 2, although this is not essential.

By way of an alternative, the sleeve (or tube) may be used to isolate emitted and reflected light from ambient light illuminating the target tissue(s), and the sensor may emit light and detect light solely along the tube or sleeve. In this variant, one could detect light reflected by any skin located at a far end of the tube or sleeve, including light reflected from a palm of a hand obscuring the far-end of the tube or sleeve.

In use, emitted light 16 illuminates target biological tissue(s) 14 across the volume of air 17 and, depending upon the absorption of wavelengths of such light 16 by the target biological tissue(s), the reflected light 18 has detectable differences. The reflected light again travels through the volume of air 17, towards the transducer 11 , where it is detected. The processor 15 analyses the data signals of the detected, reflected light 18 and the analysis provides biometric data relating to the pulse waveform, oxygen saturation, and/or other optical spectroscopic characteristics of the target biological tissue(s) 14.

By way of an alternative, data signals of the detected, reflected light may be communicated to a remote processor for analysis.

Figure 2 shows a further generic apparatus, identified generally by reference 20, for remotely capturing biometric data from a human or other animal.

The apparatus 20 includes: a transducer 21 , being both an emitter and detector; a housing 22 and moveable optics 23, for controlling a direction and/or point of focus of emitted light with respect to remotely located target biological tissue(s) (not shown). In addition, the moveable optics 23 may control a direction of the reflected light, prior to detection.

The housing 22 is a generic housing, and could be one of many different types of housing. Its role is simply to provide a support upon which the transducer 21 , processor 25 and associated electronics - circuitry, power source, etc. - are mounted or located.

The processor 25 is capable of controlling the transducer 21 and moveable optics 23 to emit focussed light 26 across a volume of air 27 to a defined focal point 27a, for remotely illuminating target biological tissue(s) at that focal point 27a. The processor 25 is also capable of controlling movement of the moveable optics 23 to adjust a direction of focus and/or point of focus of the light 26. By way of example, a closer focal point 27b may be utilised for nearer biological tissue(s) and a farther focal point 27c may be utilised for more distant biological tissue(s). The processor is also capable of controlling the transducer 21 to detect reflected light 28 from the target biological tissue(s) travelling again across the volume of air 27. In addition, the processor 25 includes an algorithm for analysing the reflected light 28.

The moveable optics 23 may be moved to provide a range of directions of focus and/or focal points - in addition to exemplary focal points 27a, 27b and 27c - in a three-dimensional sense, in respective x, y, and z planes within the volume of air 27, as exemplified by arrows having reference 29. In that way, the direction of focus and/or point of focus can be optimised for biological tissue located a defined distance from the transducer 21 .

Should it be required, additional stability may be provided by an apparatus which fixes a distance between, or respective positions of, the transducer and the biological tissue as elaborated upon in relation to Figure 1 , although this is not essential.

In use, focussed, emitted light 26 illuminates target biological tissue(s) at focal point 27a across the volume of air 27 and, depending upon the absorption of wavelengths of such light 26 by the target biological tissue(s), the reflected light 28 has detectable differences. The reflected light 28 again travels through the volume of air 27, towards the transducer 21 , where it is detected. The processor 25 analyses the data signals of the detected, reflected light 28 and the analysis provides biometric data relating to the pulse waveform, oxygen saturation, and/or other optical spectroscopic characteristics of the target biological tissue(s).

Those skilled in the art will understand that there may be occasions where an intended use requires control of a distance, position and/or location of the transducer with respect to remotely located target biological tissue(s) - as per Figure 1 - and control of a direction and/or point of focus of emitted light with respect to remotely located target biological tissue(s) - as per Figure 2. Accordingly, an apparatus may include a moveable housing for the transducer and moveable optics to achieve both of those requirements, even though they are described separately.

In both the first and second embodiments, the processor and associated electronics are described as located within the housing, and the processor is further capable of communicating either wirelessly or through wired communications with a computer, for additional analyses of the detected signals and/or recording of data signals. Alternatively, the analyses of data signals may be conducted remotely from the transducer, such that the transducer and associated electronics are capable of communicating either wirelessly or through wired communications with an external computer, for analyses of the detected signals and/or recording of data signals. The emitter may be: a single light source, for example a white light source or light of narrow wavelength; be a multi-spectral light source; or be multiple light sources providing different wavelengths of light. For example, a red light source in addition to an infrared or near-infrared light source. The sensor/detector may be a single sensor, or multiple sensors, responsive to multiple wavelengths of light, for example a CMOS camera sensor sensitive to Red, Green, Blue (RGB), RGB and infrared, or light of narrow wavelength.

The algorithm of the processor receives data signals from the sensors and analyses those signals to compare synchronous data on received amplitude and wavelengths of light from single or multiple sensors, or conduct this in an asynchronous manner, for example if the emitters alternate between emitting different wavelengths of light.

The sensors/detectors may include those consisting of arrays, for example CMOS camera sensors, and receive transmitted I reflected light data from the tissue. Such data is represented graphically by the algorithm as two-dimensional data, images or maps of the tissue. For example, such two-dimensional data, images or maps may be used to define “heat-maps” of relative perfusion and/or oxygenation of target tissues, which may be further represented as one or more individual static images or video images (in real-time or retrospective).

The sensor of the apparatus may be an optical sensor that detects a range of wavelengths of light, which may be achieved by optical filters, gratings, multiple sensors or sensor arrays, or optoelectronics mechanisms, whereby the sensor(s) response to different wavelengths of light is varied (for example tuneable filters including those incorporating a MEMS Fabry-Perot Interferometer tuneable filter), or camera, which may be of CCD (charge-coupled device) or CMOS sensor type.

By way of an alternative, or in addition, the sensor of the apparatus may be a molecular spectroscopy means comprising at least part of an emitter and associated detector configured to capture biometric data relating to the molecular constituents of blood or tissue of the human or other animal. The spectroscopy means is, preferably, Raman spectroscopy means or infrared spectroscopy means. In this alternative, light reflected and/or emitted by the biological tissue(s) is Raman scattered light.

In a third embodiment, Figures 3a, 3b and 3c show a mouthpiece, identified generally by reference 30. The mouthpiece 30 includes a guard 31 , which provides or maintains a sensor means in its preferred / optimal position - and/or optionally guards the lips of an individual (or which may rest against the teeth or gums) - and a tubular bite block 32, for receipt between the alveolar ridges of the jaws in the mouth of the individual. A PPG sensor (transducer) 33, being both an emitter and detector, is located within the tubular bite block 32, and is configured to be directed towards an inside of the mouth of the individual. The tubular bite block 32 preferably provides a passage for inhaling and/or exhaling, and/or assisted ventilation.

A first variant is shown in Figures 3a and 3b, in which the position and orientation of the PPG sensor 33 is fixed with respect to the mouthpiece 30, and PPG detection is directed substantially in planes parallel to the axis of the tubular bite block 32, as exemplified by the arrow having reference 34.

A second variant, similar to the first, is shown in Figure 3c, in which the orientation of the PPG sensor 33’ may be adjusted such that detection may occur in a plurality planes, as exemplified by the arrows having references 34’. Although arrows 34’ show examples of detection in a plurality of planes, the orientation of PPG sensor 33’ may be adjusted in x, y, and/or z planes, so as to adjust the site of detection within the mouth of the individual.

Although only the mouthpiece 30 and PPG sensor 33 are shown, both variants include a processor and associated electronics, providing communication and/or analysis of PPG data signals received by the transducer following reflection by target biological tissue(s). In a variant, the PPG sensor may be replaced by a spectroscopic sensor, and analysis of optical data signals be conducted by the processor.

The mouthpiece 30 may include an integrated tongue depressor or speculum, or the bite block 32 may be sized or otherwise configured to depress the tongue once in situ in an individual’s mouth, and provide line of sight between the transducer I PPG sensor 33 and target biological tissue(s).

In use, the mouthpiece is directed to detect PPG data from the oropharyngeal I upper airway of an individual, and the bite block 32 of the mouthpiece 30 is located in the mouth of the individual, where an outwardly facing surface 32a can be gripped between the jaws of the individual, or the individual’s lips be pursed against surface 32a. Once located, or as part of such location (depending upon the exact configuration of the PPG sensor and whether it is movably mounted), the PPG sensor 33 is directed at a pharynx, palate, and/or trachea of the individual. Reflected light is analysed in a similar way to such analysis of the first and second embodiments, to provide data relating to the pulse waveform and/or oxygen saturation of the pharynx, palate, and/or trachea.

Although small adaptions may be required, the general principles of this third embodiment lend themselves to a variety of different specific apparatus, including as part of: a mouthguard; a tracheal apparatus; an endotracheal tube; a dedicated oral PPG monitoring apparatus; a breathing apparatus; a scuba diving mouthpiece or mask; medical airway, or an anaesthetic mouthpiece.

Further, the above apparatus may include one or more disposable parts, including one or more disposable tubes, sleeves, housings, lip guards and/or mouthpiece parts.

Furthermore, the above apparatus may include a positioning sensor, to ensure correct positioning of the PPG sensor for obtaining optimum data signals. In this context, a CMOS camera may be used as a dual positioning sensor and PPG sensor, or the CMOS camera may be utilised as a separate sensor.

In a fourth embodiment, Figures 4a and 4b show a peak flow meter, identified generally by reference 40.

The peak flow meter 40 includes an essentially tubular body 41 , through which an individual may exhale, and includes a mouthpiece 42. The mouthpiece 42 includes a PPG sensor 43 fixed near to or adjacent an opening 44 of the mouthpiece 42.

A first variant is shown in Figure 4a which includes a disposable mouthpiece 42’, which can be separated from the tubular body 41 . In this variant, the PPG sensor 43 is affixed to an internal surface of a sleeve or collar 45 of the tubular body 41 , and an outer surface thereof provides an interference fit connection with the disposable mouthpiece 42’. The tubular body 41 and associated PPG sensor 43 may be re-used multiple times through the addition of a further disposable mouthpiece 42’. A second variant is shown in Figure 4b which includes a fixed mouthpiece 42. In this variant, the PPG sensor 43 is affixed to an internal surface of the mouthpiece 42.

In each variant, the PPG sensor 43 is oriented to detect along planes essentially parallel to the axis of the tubular body 41 I opening of the mouthpiece, as exemplified by the arrow having reference 46.

Although the mouthpiece 42 should function to depress the tongue and provide line of sight between the PPG sensor 43 and the target biological tissue(s), the mouthpiece 42 may include an integrated tongue depressor or speculum.

Although not shown, both variants include a processor and associated electronics, providing communication and/or analysis of PPG data signals received by the PPG sensor following reflection by target biological tissue(s).

In use, an individual receives the mouthpiece 42 in his/her mouth, which locates the PPG sensor 43 within or in close proximity to the individual’s mouth, such that the PPG sensor 43 is directed at a pharynx, palate, and/or trachea of the individual. Reflected light is analysed in a similar way to such analysis of the first and second embodiments, to provide data relating to the pulse waveform and/or oxygen saturation of the pharynx, palate, and/or trachea.

Although small adaptions may be required, the general principles of this third embodiment lend themselves to a variety of different specific apparatus, including as part of: a nasal apparatus, for location within a nasopharyngeal airway; a tracheal tube (including tracheostomy tube), spirometry apparatus; and/or other respiratory or gaseous analysis apparatus.

In a fifth embodiment, Figure 5 shows an obstetric and gynaecological apparatus, identified generally by reference 50. The apparatus 50 is wearable by a woman, or female animal, within the vagina to monitor the PPG (including heart rate, heart rate variability and oximetry) from a presenting part of the foetus, baby or neonate.

The apparatus 50 includes a sensor 51 , and housing 52 for mounting the sensor 51 , processor 55 and associated electronics. The housing 52 is removably located within a disposable sleeve 53, which includes a soft flange 54 provided for positioning against a presenting part of a baby, for example its head.

The sensor 51 is oriented to detect along planes essentially parallel to the axis of the sleeve 53 through its open end 56, as exemplified by the arrow having reference 57. The sensor 51 is a PPG sensor (transducer) 51 or an imaging camera sensor and light source, or combinations thereof that provide(s) PPG data and/or optical data, including information regarding the dilatation of the cervix within labour.

In a variant, the apparatus 50 may be single subject use such that the housing 52 is fixed within the sleeve 53. The apparatus 50 may be introduced into the vagina within an applicator having a smooth and/or soft outer surface, for example, of a form similar to a tampon or menstrual cup.

The apparatus 50, although disclosed as being intended for monitoring the PPG from a presenting part of the foetus, baby or neonate, may have wider utility. For example, the apparatus 50 may be employed to visualise the cervix or vaginal wall of a non-pregnant or pregnant subject, and provide data related to visual appearances (images) and blood flow, including PPG mapping, to provide information regarding the health and/or structure of the cervix, including inflammation, tumours, cancer, pre-cancerous change, infection, benign cyst and/or cervical ectropion.

The sleeve 53 has the effect of controlling a distance, position and/or location of the PPG sensor I camera 51 with respect to the presenting part I cervix.

In use, a distal end of the apparatus 50, being the open end 56 of the sleeve 53 is positioned near to the presenting part of the foetus, baby or neonate, and preferably so as to rest the soft flange 54 thereon, such that the PPG sensor I camera 51 and light is positioned at an optimum distance from the presenting part. The PPG sensor I camera 51 is directed at the presenting part to illuminate it. Reflected light is analysed in a similar way to such analysis of the first and second embodiments, to provide data relating to the pulse waveform and/or oxygen saturation of the presenting part, or indeed the cervix if required.

Although small adaptions may be required, the general principles of this fifth embodiment lend themselves to a variety of different specific apparatus, including as part of a laparoscopic / endoscopic apparatus.

The laparoscopic I endoscopic apparatus may be configured to have a form similar to apparatus 50, such that it can be easily used during surgery and/or during diagnosis. The sleeve 53 again functions to control a distance, position and/or location of the PPG sensor I camera 51 with respect to target biological tissue during surgery or diagnosis, and detect signs of ischaemia or inflammation of the tissue.

In a variant, the laparoscopic I endoscopic apparatus may use either a light source and imaging equipment of standard laparoscopic I endoscopic apparatus, or a combination of that and PPG sensor / camera 51 to provided data signals which can be analysed to detect ischaemia or inflammation of the tissue.

In a further variant, one or more PPG transducers may be directly mounted to a surgical device having a form similar to the laparoscopic / endoscopic apparatus mentioned above, which apparatus may be located remotely, i.e. a defined distance from the target biological tissue(s) through use of a physical guide or spacer, or is/are focusable upon the remote target biological tissue to improve detection. After processing, the output provides a ‘heat map’ on a visual display, to provide a surgeon a view of the blood supply, so as to determine intraoperatively whether, for example, a region of the bowel is ischaemic.

In a sixth embodiment, Figure 6 shows a retinal imaging apparatus, identified generally by reference 60, which is intended for PPG mapping a retina of an individual.

The apparatus 60 includes a PPG sensor 61 , lens 62 (being focusable or of fixed focus) and mounting 63, for mounting the apparatus 60 to a head or face of an individual. The apparatus 60 also includes a processor 64, and associated electronics.

The mounting 63 and lens 62 are configured to direct emitted light through a cornea of an eye 64 of the individual, and illuminate the retina. The mounting 63 is configured to provide line of sight between the PPG sensor 61 and retina, and may provide an amount of control of a distance, position and/or location of the PPG sensor 61 with respect to the retina. Further, the lens 62 provides control of a direction and/or point of focus of emitted light on the retina. Both forms of control may act separately, or in combination to improve detection.

The PPG sensor 61 includes an emitter, being a light source, and a detector, being camera sensor. The lens 62, in one variant, may be actively focusable, so as to enable focusing of an image of the retina, or other eye structure, on the camera sensor.

In use, the apparatus 60 is mounted to a facial region of an individual so as to locate the PPG sensor 61 in line of sight with the retina of an eye 65 of the individual. Light is emitted by the PPG sensor 61 and illuminates the retina (or other eye structure). The mounting 63 and/or lens 62 are adjusted to focus an image 66 of the retina, or perhaps another eye structure, on the camera sensor.

An algorithm of the processor 65 receives a signal from the PPG sensor 61 relating to light reflected by the retina (or other eye structure) and analyses the signal to provide an output corresponding to two-dimensional mapping of blood flow, retinal venous pressure waves, and/or oxygenation of the retina (or other eye structure), which output may be at single or multiple time points, or be video graphical imaging.

In a seventh embodiment, Figure 7 shows a cutaneous apparatus, identified generally by reference 70, which is intended for comparison of blood supply and oxygenation between target tissue and normal tissue.

The apparatus 70 includes a pair of PPG transducers, 71a; 71 b mounted to a housing 72, which includes a processor 75 and associated electronics. The housing 72 is configured such that both PPG transducers detect in parallel planes of detection - although this is not essential - the first PPG transducer 71a being directed to target biological tissue(s) 73 and the second PPG transducer 71b being directed to normal tissue 74. PPG transducers 71a; 71 b are capable of independently illuminating tissue, to provide separate reflected light data signals for analysis. Illumination of the transducers 71a ; 71 b is, preferably, asynchronous; however, this is not essential.

In use, light emitted by PPG transducer 71 a, reflected by target tissue and then detected by that transducer 71a provides a first data signal, and light emitted by PPG transducer 71b, reflected by normal tissue then detected by that transducer 71 b provides a second data signal. The first and second data signal are analysed for comparing blood supply and oxygenation between the target tissue and normal tissue. For example, one can assess the viability of target tissue, such as a surgical skin flap or surgical wound, or assess whether an ulcer has an ischaemic component (in contrast or addition to a component of venous insufficiency). Further, one can determine if an ulcer or the toes is/are ischaemic. Further one can determine whether a transplanted organ, a kidney, an appendix, tumour, organ or other body part is receiving appropriate blood supply.

Advantageously, comparison between two tissue sites of the same individual provides a benefit that such detection it is not adversely affected by any difference in skin colour between a population based level, because the individual’s normal tissue acts as its own comparator / reference.

In an eighth embodiment, Figure 8 shows an intra operative I augmented reality apparatus, identified generally by reference 80, both of which are intended to provide PPG mapping of target biological tissue.

The intra operative apparatus 80 includes a pair of PPG transducers, 81a; 81 b mounted to a pair of spectacles 82, which include a processor 85 and associated electronics. The spectacles 82 are of standard form having a pair of arms 83, for location over ears (not shown) of an individual, and a frame 84 for receipt of lenses 86. Although not essential, the individual may be a surgeon or other medical practitioner. The PPG transducers 81a; 81 b are configured to have converging fields of detection - as exemplified by arrows having reference 87 - and are focusable upon target biological tissue at a location in the foreground of the wearer so as to provide PPG mapping of the tissue. Each transducer 81 a; 81 b includes an emitter, being a light source, and a detector, being a camera. After processing, the output provides a PPG map on a visual screen to provide the operator a view of the blood supply and/or oxygen supply to an area of biological tissue positioned in front of the user.

The augmented reality variant differs from the spectacles variant of the intra operative apparatus in that the lenses, or at least parts in a field of view, have visual displays, which show images created by the PPG transducers 81 a; 81 b.

This embodiment may, optionally, demonstrate a ‘heat map’ of the blood flow and/or oxygenation of the tissue that is being viewed.