Camera-Based Patient Monitoring in MRI

Abstract

The present invention relates to a magnetic resonance imaging system 1 including an infrared camera system for monitoring a subject undergoing an examination while positioned in an examination zone 11 of the magnetic resonance imaging system. The infrared camera system includes an infrared camera 21. The magnetic resonance imaging system further includes a coating 2 on at least one wall of a room housing the magnetic resonance imaging system, on an interior wall of a magnet assembly 10 surrounding the examination zone, and / or on auxiliary equipment of the magnetic resonance imaging system for use within the examination zone, the coating absorbing and / or diffusely reflecting infrared light so as to avoid spurious reflections and / or to provide diffuse auxiliary illumination.

Description

[Technical field]

[0001] The present invention relates to the field of magnetic resonance imaging, more particularly, the present invention relates to a magnetic resonance imaging (MRI) system for camera-based patient observation and / or monitoring of parameters such as a patient's vital signs and / or movements based on camera observation, as well as a method for providing such a magnetic resonance imaging system. [Background technology]

[0002] Monitoring systems for monitoring an examination region of a magnetic resonance examination system with a camera are generally known in the art. For example, a camera for imaging a patient during a magnetic resonance imaging examination is mounted outside the bore of the MRI system, for example on or adjacent to a protective cover of the system. Many variations and extensions of this concept are known as well. For example, a mirror is installed in the bore of the MRI system. This allows the camera to observe the patient (such as the patient's face) even when a direct line of sight is not available or is difficult to achieve. In many configurations, the camera system is mounted at a position relatively far from the region to be observed, and the optical axis of the camera is generally oriented along the direction of the longitudinal axis of the magnet bore or has a major component in that direction. The use of such a mirror is particularly advantageous in providing a better view for the camera system, since patients are usually, or at least very often, examined with the longitudinal axis of their body substantially aligned with the longitudinal axis of the bore.

[0003] In addition to allowing an operator to observe the patient, for example to detect signs of anxiety, to ensure that the patient is awake, or to assess compliance with the imaging protocol (e.g., in functional imaging of the brain), the camera system can also be used in conjunction with an image analysis system to determine useful parameters, for example to detect and / or quantify movement, respiration, heart rate or other cardiac parameters, and / or other vital signs and / or parameters generally indicative of the patient's condition. For example, when movement is detected, data simultaneously collected by the MRI system can be labeled as either to be discarded or to be corrected, such as to compensate for the detected movement.

[0004] The camera system may include a camera that responds in the (human) visual range, but the use of infrared cameras is also known in the art. The use of the infrared range has several advantages. For example, JP 2004-041411 A discloses a method for presenting visual stimuli in an MRI system. A light path is directed substantially frontally to the patient's eye to present visual stimuli from a projector and a screen using a dichroic mirror. Furthermore, the eyeball illuminated by an infrared lamp is monitored by the infrared camera through the dichroic mirror. Thus, visual stimuli in the optical (i.e. visual) wavelength spectrum are reflected by the dichroic mirror, while infrared light for illuminating and monitoring the eye passes through.

[0005] Various MRI and infrared camera systems are disclosed in SONGXIANG et al., "Pattern independent deformation estimation illustrated by MRI," Nuclear Science Symposium Conference Record, NSS '08, pp. 5285-5291, TREMBLAY et al., "Retrospective coregistration of functional magnetic resonance imaging data using external monitoring," MR in Medicine 53(1), pp. 141-149, and JP 2004-201977 A. In these systems, infrared markers are used to detect the positions of the markers using a camera system to, for example, estimate patient motion or deformation or to assist in aligning the patient with respect to the scanner system. Summary of the Invention [Problem to be solved by the invention]

[0006] Embodiments of the present invention aim to provide an improved and efficient means and method for monitoring a subject in a magnetic resonance imaging system using an infrared camera system and / or quantifying vital signs, movement, and / or other parameters of interest indicative of the subject based on the output of the infrared camera system. [Means for solving the problem]

[0007] Embodiments of the present invention have the advantage that they can improve lighting conditions, e.g. to avoid underexposure and / or overexposure of areas in an image provided by a camera, e.g. to provide more uniform illumination of the camera's field of view (or at least the main area of ​​interest within the field of view).

[0008] Embodiments of the invention have the advantage that spurious reflections of infrared light emitted by one or more infrared light sources to illuminate a scene observed by a camera system can be avoided or reduced, e.g., thereby avoiding overexposure of parts of a camera image, e.g., reflections within the camera's field of view (or outside the field of view, if there are further reflections) from, for example, protective covers of the magnet bore, walls of the examination room, and / or auxiliary equipment can be reduced and / or avoided.

[0009] Embodiments of the invention have the advantage that the quality and / or robustness of image processing applied to the output of the camera system can be improved, for example by better utilising the dynamic range of the camera and / or by avoiding (or reducing) spurious reflections that may confound the applied algorithms, thus enabling reliable and accurate detection and / or quantification of vital signs, movements and / or other parameters of interest relating to the condition of a subject undergoing, for example, an MRI examination.

[0010] It should also be noted that the adverse effects of such reflections and stray light are not always easily predictable. For example, algorithms can in principle be adjusted to compensate for such disturbing factors when their position and influence are static and predictable. However, when auxiliary equipment such as auxiliary coils, additional patient immobilization devices, support pillows, etc. are used, these are usually not positioned and / or oriented in a precise, deterministic and reproducible manner. Of course, variations in the patient and their position and orientation from test to test can affect the lighting conditions. It should also be considered that such problems due to different lighting conditions can become even more unpredictable when the light from the light source is reflected multiple times before hitting the camera.

[0011] Systems and methods according to embodiments of the present invention achieve the above objectives.

[0012] In a first aspect, the present invention relates to a magnetic resonance imaging system having an examination zone and including an infrared camera system for monitoring a subject while undergoing an examination while positioned in the examination zone of the magnetic resonance imaging system. The infrared camera system includes an infrared camera, i.e. an infrared camera sensitive to infrared radiation (although the spectral range may extend in some embodiments up to the visible range, and embodiments in which the spectral range is substantially limited to the infrared range or a part thereof are not necessarily excluded in the embodiments). The magnetic resonance imaging system further includes a coating on at least one wall of a room housing the magnetic resonance imaging system, on an inner wall of a magnet assembly surrounding the examination zone, and / or on ancillary equipment of the magnetic resonance system for use in the examination zone, for example applied to at least one surface of the magnet bore, the walls of the examination room, and / or the ancillary equipment of the magnetic resonance imaging system (ancillary coil assembly (such as a head coil), a patient table or mattress, and / or other ancillary items for use in the examination zone). The coating further absorbs and / or scatters infrared light.

[0013] Thus, an infrared camera system serves to monitor an inspection zone based on an image collected by the camera (whether by a single image frame or by a dynamic image). The camera has a (volumetric) range or field of view to which the camera responds, from which it obtains image information. The coating serves to avoid spurious reflections of infrared light into the field of view of the camera, for example by absorbing infrared light on surfaces that are not intended to be observed by the camera, and / or to provide diffuse supplementary illumination, i.e. ambient (infrared) illumination. Coatings that diffuse reflected light are particularly advantageous to provide a uniform illumination of the inspection zone without sharp (unintended) contrasts such as shadows and highlights. In particular, the use of such infrared light diffusing coatings allows for an excellent illumination of the imaged scene to be achieved with one light source or even with only a few infrared light sources, even if the one light source is point-like (or relatively small). However, the use of multiple light sources is not necessarily excluded.

[0014] It is therefore advantageous for elements other than the patient (walls, equipment, ...) in the field of view of the camera to avoid excessive stray light (IR) (or more uniformly diffused light) and to allow sufficient exposure of the patient's area of ​​interest observed by the camera. The walls and / or auxiliary equipment are treated, for example, by a suitable coating. Additionally, to cover parts of the patient's body, fabric sheets or blankets with suitable spectral properties (see coatings above) can be used to cover irrelevant surfaces near the object to be observed.

[0015] In a magnetic resonance imaging system according to an embodiment of the present invention, the ancillary equipment may include radio frequency transmitter / receiver coils, a patient table, and / or other equipment for use within the examination zone while imaging a subject.

[0016] A magnetic resonance imaging system according to an embodiment of the invention includes walls of an examination zone (e.g. the inner walls of the housing of the magnet bore of the system), walls of an examination room (e.g. where the MRI system, and in particular its magnet bore, is located), and / or ancillary equipment, at least a part of said walls and / or ancillary equipment (in particular the part within the field of view of the camera) absorbing (or attenuating) and / or diffusely reflecting incident light in the infrared spectrum.

[0017] The use of infrared imaging allows subjects to be monitored under conditions of low ambient lighting (within the visible spectrum). For example, it has been observed that at least some patients perceive low lighting or complete darkness as more comfortable. However, such conditions do not preclude sufficient illumination in the infrared range for camera observation using a system according to embodiments.

[0018] In a magnetic resonance imaging system according to an embodiment of the invention, the coating may absorb infrared light in a spectral range, e.g. above 800 nm, e.g. in the range 800 nm to 900 nm, e.g. in the range 830 nm to 870 nm, e.g. in the range 840 nm to 860 nm, spanning the operating range of an infrared camera system as described in more detail below. For example, the coating absorbs at least 30%, preferably at least 50%, more preferably at least 70%, such as at least 80%, e.g. at least 90%, e.g. at least 95% of the light incident thereon in the above mentioned infrared ranges.

[0019] In a magnetic resonance imaging system according to an embodiment of the invention, the coating can, for example, diffusely reflect infrared light over the operating range of the infrared camera system, as described in detail below. For example, the coating reflects at least 30%, preferably at least 50%, more preferably at least 70%, such as at least 80%, such as at least 90%, such as at least 95% of the light incident thereon in the abovementioned infrared range. Furthermore, the light is diffused over a relatively wide angle, for example diffusing a unidirectional beam over an angle of at least 10°, such as at least 20°, such as at least 30°, or more, such as at least 45°, such as at least 60° (though of course the coating does not necessarily diffusely reflect only unidirectional beams).

[0020] In a magnetic resonance imaging system according to an embodiment of the invention, the coating can reflect and / or transmit at least 50% of incident light in the visible spectrum. For example, the coating, in addition to its properties in the infrared spectral range, can reflect, preferably diffusely reflect, light in the visual spectrum to avoid distraction and / or discomfort due to reflections from mirror-like surfaces. The coating may also be substantially transparent in the visible spectrum, such that the color effects (and / or other optical properties) of the underlying material are (almost) unaffected by the coating. For example, the coating reflects or transmits at least 50%, such as at least 70%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 99% of light in the visible spectrum (e.g. in the range 350 nm to 800 nm).

[0021] In a magnetic resonance imaging system according to an embodiment of the present invention, the coating is applied to at least 10 cm 2 of at least one wall of the room, the inner wall of the magnet, and / or the auxiliary equipment. 2 , e.g. at least 20 cm 2 , e.g. at least 50 cm 2For example, the coating can cover substantially the entire area (e.g., at least a portion of the area within the field of view of the camera) of at least one wall of the room, an interior wall of the magnet, and / or (an item, items, and / or all items of) ancillary equipment, such as at least 50%, such as at least 75%, such as at least 80%, such as at least 90%.

[0022] In a magnetic resonance imaging system according to an embodiment of the present invention, the infrared camera can operate in an infrared wavelength range that corresponds to or substantially overlaps with the range in which the above-mentioned coating absorbs and / or diffusely reflects infrared light.

[0023] In a magnetic resonance imaging system according to an embodiment of the present invention, an infrared camera system may include an infrared light source that directs infrared light into an examination zone.

[0024] In a magnetic resonance imaging system according to an embodiment of the invention, an infrared camera (or cameras) can operate (e.g., respond substantially exclusively) in a (e.g., narrow) infrared wavelength range and outside the visible wavelength range. This applies equally to the infrared light source, i.e., the infrared light source emits light only in the above infrared wavelength range or in another range that substantially overlaps with the above wavelength range of the camera (but is not limited to this). For example, the infrared camera system operates, for example, at infrared wavelengths greater than 800 nm, for example at wavelengths of about 850 nm±-20 nm.

[0025] In a magnetic resonance imaging system according to an embodiment of the invention, the infrared camera system is mounted outside the examination zone and positioned on or integrated into a flange of the inner wall of the magnet assembly. For example, the light source and camera are mounted outside the examination zone. In a cylindrical bore system, both the camera and light source are mounted on a flange of the bore enclosure at one end of the bore, leaving the other end substantially free and reducing potential claustrophobic effects for the subject while being imaged by the system.

[0026] A magnetic resonance imaging system according to an embodiment of the invention includes an image processor that obtains information about the subject from one or more collected camera images. The use of infrared imaging may be of particular advantage in certain applications and / or may overcome disadvantages of alternatives. For example, relatively bright lighting may be used without discomfort to the patient or staff. The image processor may process the image information collected by the camera system to obtain information from the patient, such as, for example, performing static or dynamic image analysis, such as the patient's vital signs, the patient's movements, indications of the patient's anxiety (or more generally, patient mood detection). The image processor may perform photoplethysmography (PPG) measurements and / or video-based speech detection (or recognition of instructions based on speech, e.g. simple words or facial features). Information about the patient's movements may include, for example, respiratory movements and / or cardiac movements indicative of the respiratory cycle and / or cardiac cycle phases. For example, information about the patient's movements may be obtained from image information outside the patient's body.

[0027] Respiratory and / or cardiac phase information can be applied to the MRI system's reconstructor (which reconstructs slice images from acquired magnetic resonance signals) to correct the acquired magnetic resonance signals for motion and to apply motion correction to the reconstructed magnetic resonance images. For example, a cardiac trigger signal is determined based on a video signal from a camera. Additionally, other types of motion may also be detected (e.g., quantified) and this information provided to the reconstructor to be taken into account. Examples of other sources of systematic and / or regular motion that are not physiologically induced and / or less predictable include coughing, sneezing, shivering, and / or generally voluntary movements of the imaged subject.

[0028] A magnetic resonance imaging system according to an embodiment of the present invention includes a reconstructor for reconstructing a magnetic resonance image from magnetic resonance signals acquired by the magnetic resonance system, wherein the information determined by the image processor includes respiratory phase and / or cardiac phase information, which the reconstructor takes into account in order to correct the acquired signals and / or the reconstructed magnetic resonance image for motion.

[0029] A magnetic resonance imaging system according to an embodiment of the invention includes a fabric sheet or blanket for covering a portion of a subject's body and / or another object in an examination zone that does not need to be observed by an infrared camera system, the fabric sheet or blanket absorbing, attenuating, and / or diffusely reflecting infrared light.

[0030] A magnetic resonance imaging system according to an embodiment of the invention includes a mirror (e.g. a non-metallic mirror) or reflective surface disposed within an examination zone to reflect infrared light from a body part of a subject, such as the face or parts thereof (e.g. eyes, eyeballs, forehead area, ...) onto an infrared camera and / or to reflect light from an infrared light source onto said body part.

[0031] Preferably, the mirror or reflective surface does not interfere with the high frequency operation of the magnetic resonance imaging system and / or does not perturb the magnetic field and RF dynamic transmission magnetic field of the MRI system. Non-metallic mirrors are particularly suited to achieve this advantage. For example, the non-metallic mirror is a dielectric mirror.

[0032] In a magnetic resonance imaging system according to an embodiment of the invention, the mirror or reflective surface preferably reflects light so as to form an infrared image of the body part on the imaging plane of the camera. Optionally, the mirror or reflective surface may also be transparent or semi-transparent to light in the (human) visual range.

[0033] The mirror or reflective surface thus positions an optical path between a portion of the examination zone and the camera, from which the camera can acquire image information. The mirror or reflective surface may be located within the examination zone, for example by mounting it on an inner wall of the magnet bore enclosure. Additionally or alternatively, the mirror or reflective surface may also be located on ancillary equipment within the examination zone, such as on a local radio frequency (RF) coil positioned on the patient table. For example, it is practical to mount a mirror / reflector on an RF head coil. Also, at least one mirror or reflective surface may alternatively or additionally be provided at a location outside the examination zone (for example outside the magnet bore).

[0034] In a second aspect, the invention relates to a method for adapting a magnetic resonance imaging system. The method according to embodiments may be a method for retrofitting a (e.g. already installed) magnetic resonance imaging system or may be integrated into a manufacturing process for producing a magnetic resonance imaging system.

[0035] The method includes acquiring a magnetic resonance imaging system having an examination zone for positioning a subject therein to be imaged by the magnetic resonance imaging system, the magnetic resonance imaging system including an infrared camera system including an infrared camera for monitoring the subject while undergoing the examination.

[0036] The method also includes applying a coating on at least one wall of a room housing the magnetic resonance imaging system, on an interior wall of a magnet assembly of the magnetic resonance imaging system, and / or on auxiliary equipment of the magnetic resonance imaging system for use within an examination zone. The coating absorbs and / or diffusely reflects infrared light. In particular, but not limited to, the coating is applied to one or more surfaces that are within the field of view of an infrared camera.

[0037] In a method according to an embodiment of the invention, acquiring the magnetic resonance system includes modifying an installed magnetic resonance imaging system by installing an infrared camera system as described above (e.g., in addition to applying the coating as described above). Alternatively, the system may be acquired with an infrared camera system already installed.

[0038] The independent and dependent claims set out particular and preferred features of the invention. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not necessarily as explicitly set out in the claims. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 illustrates a magnetic resonance imaging system according to an embodiment of the present invention. [Diagram 2] FIG. 2 shows a photograph of a flange end of a magnet bore of an exemplary magnetic resonance imaging system in accordance with an embodiment of the present invention. [Diagram 3]FIG. 3 shows an end-bore camera image that can be acquired with a conventional magnetic resonance imaging system in which regions of undesirably high exposure due to reflections are observed. [Figure 4] FIG. 4 illustrates a method according to an embodiment of the present invention.

[0040] The drawings are schematic and non-limiting. The elements in the drawings are not necessarily drawn to scale. The invention is not necessarily limited to the specific embodiments of the invention shown in the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments are described below, but the present invention is limited only by the claims appended hereto, which are hereby expressly incorporated into this detailed description, and in which each claim, and each combination of claims permitted by the dependency structure defined by the claims, forms a separate embodiment of the present invention.

[0042] When used in the claims, the word "comprising" is not limited to the subsequently described features, elements, or steps, and does not exclude additional features, elements, or steps. Thus, it specifies the presence of the preceding features without excluding the further or additional presence of one or more features.

[0043] In this detailed description, numerous specific details are presented. Embodiments of the present invention may be practiced without these specific details. Moreover, for the sake of clarity and conciseness of the present disclosure, well-known features, elements, and / or steps have not necessarily been described in detail.

[0044] In a first aspect, the present invention relates to a magnetic resonance imaging system having an examination zone and including an infrared camera system for monitoring a subject while undergoing an examination while positioned in the examination zone.

[0045] 1 shows a schematic representation of a magnetic resonance imaging system 1 according to an embodiment of the present invention. The magnetic resonance examination system includes a primary magnet assembly 10 defining an examination zone 11. For example, the examination zone is formed by a volume in which magnetic field conditions, substantially created and controlled by the magnet assembly, are suitable for magnetic resonance imaging. The examination zone thus corresponds to (at least a usable portion of) the volume enclosed by the magnet bore of the system (without being limited thereto; for example, the principles of the present invention apply equally to open bore systems and other less frequently used magnet assembly configurations).

[0046] In use of the system, a subject (e.g., a patient) 13 is positioned on a patient table 14 in an examination zone. The primary magnet assembly includes magnet windings, such as coaxial (e.g., superconducting) windings, to generate a steady uniform magnetic field in the examination zone. The examination zone is a cylindrical volume enclosed by these magnet windings.

[0047] The system includes a reconstructor 15 which reconstructs magnetic resonance images, such as tomographic MRI images, from magnetic resonance signals acquired by the system in use. The reconstructed images are provided via an output 16 for review, processing or storage.

[0048] In use, auxiliary equipment such as an RF T / R head coil 12 can be placed in the examination zone to collect magnetic resonance signals from the subject's head. While other auxiliary coil configurations are used to collect signals from other body parts or for different use cases, signals are also typically received by a receive coil already incorporated into the housing of the primary magnet assembly.

[0049] The system includes an infrared camera system including an infrared camera 21, i.e. an infrared camera sensitive to infrared light. The infrared camera system acquires information from the subject, for example to acquire vital signs, movement, anxiety indicators, etc. For example, respiratory movement and cardiac movement are obtained from image information outside the patient's body. The camera 21 is mounted near the entrance of one of the examination zones. For example, the camera is integrated into or attached to a flange of the MR bore (for example, this does not affect or only minimally reduces the usable free bore diameter and / or avoids or minimizes interference with the operation of the MR system). This is illustrated by the photograph in FIG. 2, which shows for example the integration of an (optional) infrared illumination source 29 into this flange.

[0050] The camera system may also include a Light Detection and Ranging System (LIDAR). This is useful for generating additional three-dimensional information about the observed scene (e.g. 3D localized surface point clouds) that can be taken into account, for example, in the image processing of the camera data. For example, a three-dimensional mesh of the (contours of) the patient and / or equipment in the examination zone can be generated to assist image processing tasks such as segmentation, feature recognition, signal extraction, etc. It is noted that coatings may be adapted to support such LIDAR data collection, or at least to minimize interference with such collection. For example, typical LIDAR systems use (but are not limited to) 905 nm and / or 1550 nm laser light. Thus, the coating is adapted to avoid reflections at the wavelengths at which the LIDAR system operates, or at least to avoid or reduce specular reflections at this wavelength. For example, the coating may diffusely reflect or absorb light at this wavelength.

[0051] The infrared camera system also includes a camera control unit 25 for adjusting parameters such as the orientation of the optical axis, focal length, etc. that control the camera 21. The infrared camera system may also include a display 26 for displaying images (raw or after suitable processing) of the area within the examination zone 11 collected by the camera 21, thereby allowing an operator to visually monitor the subject within the examination zone.

[0052] Images collected by camera 21 are also provided to an image processor 27 (which may be implemented in software, for example) that derives information about the subject from the collected camera image or images.

[0053] The image processor 27 can process image information collected by the camera system to, for example, perform static or dynamic image analysis to obtain information from the patient, such as the patient's vital signs, the patient's movements, indications of the patient's anxiety (or more generally, patient mood detection), and / or perform photoplethysmography (PPG) and / or video-based speech detection (or recognition of instructions based on speech, e.g. simple words or facial features). Information about the patient's movements may include, for example, respiratory movements and / or cardiac movements indicative of the respiratory cycle and / or cardiac cycle phases. For example, information about the patient's movements is obtained from image information outside the patient's body. The information is determined by processing (e.g. by an image-based movement detector) and / or by (direct) visual monitoring of the patient via the system by an operator or staff member.

[0054] Respiratory and / or cardiac phase information can be provided to the reconstructor 15 to correct the acquired magnetic resonance signals for motion and to apply motion correction to the reconstructed magnetic resonance images. For example, a cardiac trigger signal is determined based on a video signal from a camera. Cardiac triggering is particularly useful for cardiac MRI for obvious reasons, but may be applied more generally. For example, in neuroimaging, artifacts in head and / or neck scans caused by pulsatile flow of blood and cerebrospinal fluid are suppressed or reduced by such triggering techniques or other compensation approaches based on the cardiac phase signal. This is also useful for quantitative measurement of carotid blood flow. Furthermore, PPG signals can be extracted from video signals by analyzing subtle intensity changes of skin pixels, for example on the subject's face, such as the forehead and cheeks. The use of coatings in accordance with embodiments can avoid underexposure and / or overexposure (or at least strong contrast due to non-uniform lighting within the camera's field of view), thereby enabling an image processor to produce better, e.g., more accurate and reliable, results, or making the image processor simpler to design or construct (because the processing required to correct for such non-uniform lighting can be reduced or avoided).

[0055] The magnetic resonance imaging system further includes a coating 2 applied to at least one surface of the magnet bore, the walls of the examination room, and / or ancillary equipment of the magnetic resonance imaging system, such as the RF coil 12, the patient table 14, or other equipment that may be used within the examination zone 11. In particular, the coating is applied to one or more surfaces within the field of view of an infrared camera that images the subject when the system is in use.

[0056] The infrared camera system thus monitors the inspection zone on the basis of an infrared image. The coating serves to avoid spurious reflections of infrared light into the camera's field of view, for example by absorbing infrared light on surfaces that are not intended to be observed by the camera, and / or to provide diffuse auxiliary illumination, i.e. ambient (infrared) illumination. Coatings that diffuse reflected light are particularly advantageous for providing a uniform illumination of the inspection zone without sharp (unintended) contrasts such as shadows or highlights. In particular, the use of such light-diffusing coatings allows for an excellent (infrared) illumination of the imaged scene with only one light source or even with only a few infrared light sources 29, even if the one light source is point-like (or relatively small). However, the use of multiple light sources is not necessarily excluded, nor is it excluded when passive IR imaging is used.

[0057] Thus, walls of the examination zone and / or auxiliary equipment, such as (e.g., at least part of) the walls of the bore (or magnet assembly housing in general), (part of) the walls of the examination room, the receiving coils, and / or objects other than the patient in the examination zone, can absorb and / or scatter light in the infrared spectrum, particularly when in the field of view of the camera, e.g., absorbing and / or diffusing light emitted by the infrared light source 29 used to illuminate the field of view of the camera. The one or more walls (or part thereof) include walls of the examination zone, e.g., the inner walls of the magnet bore enclosure of the MR system, but also (additionally or alternatively) one or more walls of the room in which the MR system (particularly the bore and its associated equipment) is installed, for example, in cases where the camera 21 (e.g., positioned further away from the examination zone rather than being integrated into or attached to a flange of the bore) provides a wider overall view of the examination room and / or where stray light from the walls of the room can significantly affect the image collected by the camera. The examination room may have been purposely modified and / or constructed to protect the system from external magnetic fields. For example, including a Faraday cage or similar structure. It is therefore understood (but not necessarily limited to) that the examination chamber, and therefore its interior walls, may reasonably be considered an integral part of the MR imaging system, and not simply the place where the system is used. It is noted, however, that it is advantageous to locate the camera at the edge of the examination zone (with some tolerance) (such as the flange of the bore) since light reflections from the surrounding examination chamber walls often do not significantly affect the image.

[0058] It is therefore advantageous to have elements other than the patient in the field of view of the camera to avoid excessive stray light (IR) and to allow sufficient exposure of the patient's area of ​​interest observed by the camera, which can also improve the performance of image processing algorithms, e.g. for motion detection and determination of physiological parameters, when applied to the camera images.

[0059] The walls of the examination zone (and / or room) and / or other equipment (including but not limited to the coil assembly and / or patient table) may constitute a large part of the image collected by the camera. Stray light may therefore result in insufficient exposure of the actual area of ​​interest intended to be observed by the camera 21. Poor exposure may result in a poor signal-to-noise ratio, or the stray light may cause the image to be oversaturated. For example, FIG. 3 shows an exemplary camera image (acquired by a prior art system, in particular a system without the coatings described herein), in which the area of ​​interest 41 is underexposed due to excessive stray light 42. Underexposure may be overcome in accordance with embodiments of the present invention by appropriate selection of material properties of the walls and / or outer surfaces of the apparatus in the field of view and / or by appropriate treatment of the visible surfaces, for example by coatings.

[0060] Additionally, the system may include a fabric sheet or blanket 43 with suitable spectral properties (see coating properties above) to cover irrelevant surfaces near the object to be observed, for example to cover parts of the patient's body that do not need to be observed by the camera system. Unwanted reflection of infrared light can thus be further avoided by absorption or diffusion. The following description of the spectral properties of the coating can be considered to apply equally to the optical properties of the fabric sheet or blanket. This fabric sheet and / or blanket 43 absorbs, attenuates or diffusely reflects infrared radiation and optionally also reflects or transmits light in the visible spectrum.

[0061] Moreover, the use of such fabric sheets or blankets advantageously provides additional flexibility in tuning and / or optimizing the performance of the observation system during use. While such blankets can be easily added, rearranged, removed, etc. for a procedure, it will be appreciated that this is not typically feasible individually with fixed coatings on walls and / or ancillary equipment, except for the likely costly option of providing different versions of (for example) head coil assemblies and / or other equipment items with or without coatings, or with different coatings having different optical properties. However, fabric sheets or blankets are flexible (both figuratively and usually literally) and configurable.

[0062] This can be combined with the use of a quality control system (embodiments of the invention can include such a system or can include a quality control step as part of the method according to the embodiments), which can be implemented by dedicated hardware, software or both. For example, the light intensity observed in the acquired camera image (or in the calibration image acquired by the camera system) can be evaluated. It can be checked against a minimum threshold value, for example (in a region of interest of the image). Other quality criteria can also be used (alternatively or additionally), such as a minimum and / or maximum image contrast (for example in a ROI) or requirements imposed on the signal generated from the camera image (for example the signal-to-noise ratio of the signal obtained from the acquired image). Thus, if the quality control system detects camera observation settings that result in insufficient image / signal quality, the operator is alerted and prompted to remedy such situation, for example by adjusting and / or adding one or more of the above-mentioned cloth sheets and / or blankets. Such online guidance is provided, for example, in the preparation phase of the examination when the patient is placed in the scanner bore or immediately thereafter. For example, a corresponding software routine is executed. The quality control system may further identify problem areas within the camera view and generate suggestions on how to improve image quality, e.g., using decision logic and / or predictive algorithms, including machine learning algorithms trained on experiments or modeling for a particular imaging system or system type, to evaluate possible interventions (such as different blankets and / or different positions / configurations of the blankets) and, based thereon, suggest one or more options that may improve image / signal quality.

[0063] In a magnetic resonance imaging system according to an embodiment of the invention, the coating (sheet or blanket) absorbs infrared light in a spectral range, e.g. above 800 nm, e.g. in the range 800 nm to 900 nm, e.g. in the range 830 nm to 870 nm, e.g. in the range 840 nm to 860 nm, e.g. over the operating range of the infrared camera system, as described in detail below. For example, the coating absorbs at least 30%, preferably at least 50%, more preferably at least 70%, such as at least 80%, e.g. at least 90%, e.g. at least 95%, e.g. in the range 95% to 100% of the light incident thereon in the above mentioned infrared range. The infrared spectral range preferably coincides with or largely overlaps with the range of light sensitivity of the infrared camera.

[0064] Similarly, the coating may diffusely reflect infrared light, for example over the operating range of the infrared camera system. For example, the coating reflects at least 30%, preferably at least 50%, more preferably at least 70%, such as at least 80%, such as at least 90%, such as at least 95% of the light incident thereon in the abovementioned infrared range. The infrared light is spread over a relatively wide angle, for example spreading a unidirectional (incident) beam over an angle (of reflected light) of at least 10°, such as at least 20°, such as at least 30°, or more, such as at least 45°, such as at least 60° (of course, the coating does not necessarily diffusely reflect only unidirectional beams, but spreads and diffuses the incident light regardless of the focal properties of the incident wave).

[0065] Thus, a magnetic resonance imaging system according to an embodiment of the invention comprises walls of an examination zone, walls of an examination room (e.g. where the MRI system, in particular its magnet bore, is located), and / or auxiliary equipment, at least part of said walls and / or auxiliary equipment (in particular the part within the field of view of the camera) absorbing (or at least attenuating) and / or diffusely reflecting incident light in the infrared spectrum.

[0066] In a magnetic resonance imaging system according to an embodiment of the invention, the coating, in addition to its properties in the infrared spectral range, can reflect, preferably diffusely reflect, light in the visual spectrum to avoid distraction and / or discomfort due to reflections from mirror-like surfaces. For example, this makes the lighting of the room and of the MRI system comfortable for the subjects and good working conditions for the staff. The properties in the visual range can provide the coated surface with a predefined color or have a broad reflective / diffuse spectral response, for example to give the impression of white (when illuminated accordingly, of course). The coating can absorb a large part of the visual spectrum (for example to provide the system with such a preferred color) or even substantially the entire visual spectrum. For example, dim lighting conditions and / or complete darkness may be more comfortable for at least some subjects, which can be enhanced by coating over a wide or substantially the entire range of the visual spectrum by absorbing light. However, this is less preferred, since dim lighting / darkness can be easily provided by attenuating or turning off the ambient light source. On the other hand, coatings for reducing levels of ambient lighting (within the visual range) are less flexible and essentially static in nature, i.e. cannot be easily adapted to a subject to feel more comfortable in brighter environments.

[0067] However, the coating may also be applied as a modification of a pre-manufactured system (but not limited to this). In this case, the material to which the coating is applied is already designed to have predetermined properties within the visual range, e.g. to obtain a selected color and / or brightness for presentation to subjects and staff. Thus, the coating may also be substantially transparent in the visible spectrum, such that the color effects (and / or other optical properties) of the underlying material are (almost) unaffected by the coating. For example, the coating transmits at least 50%, such as at least 70%, such as at least 85%, such as at least 90%, such as at least 95%, such as at least 99% of the light in the visible spectrum (e.g. in the range 350 nm to 800 nm). That is, the coating may absorb less than 25%, such as less than 10%, of the light in the visible spectrum region perceptible by humans (e.g. in the range 380 nm to 740 nm or most thereof). (For example, alternatively) such a coating may reflect light in the visible spectrum, as explained above. This transparency or reflective property has the advantage of not affecting the appearance of the system (when viewed directly by eye), e.g., to improve patient comfort (e.g., where dark walls or equipment may be intimidating, frightening or depressing) and / or for aesthetic considerations.

[0068] Suitable coatings are known in the art, for example as used to coat heating elements. For coatings of heating elements, good absorption of infrared light is advantageous in terms of heat transfer and emissivity. Such coatings for heating elements are also visually transparent or reflective, for example, especially when applied to white or light-colored heating surfaces. Other suitable coating materials can be selected by the skilled artisan. More sophisticated materials can be used, for example, using metamaterial films to achieve efficient omnidirectional and broadband light absorption (or reflection), while at the same time absorbing or diffusing light in (at least relevant parts of) the infrared spectrum. For the purposes of this disclosure, surface treatments by applying paints, coatings, thin films, or foils are considered equivalent techniques and are therefore considered "coatings" in the general sense.

[0069] In magnetic resonance imaging systems according to embodiments of the present invention, the infrared camera system may also include one or more infrared light sources 29. While embodiments that rely on passive (infrared) illumination for imaging are not necessarily excluded, those skilled in the art will appreciate that the use of active illumination allows for better control of lighting conditions and more effective imaging.

[0070] The infrared light source 29 may be configured and positioned, possibly supported by a mirror or reflective surface, to direct a light beam directly into / onto the inspection zone. By using multiple mirrors, different areas of the subject can be effectively illuminated with a single light source. Embodiments of the invention are further particularly suitable for avoiding stray light due to undesired reflections of infrared light emitted by the infrared source, which directly or indirectly (by further reflection) reflects the light into the observation zone. This can be achieved, for example, by absorbing the infrared light incident on the coated surface of the system and / or by diffusely reflecting the light by the coating. It should be noted that even if active illumination is not used, heat sources or other sources of infrared radiation in the vicinity of the system may interfere with passive infrared observation, making coatings according to embodiments still advantageous in environments that do not explicitly rely on an infrared light source.

[0071] The light source and the camera can be located outside the examination zone, which simplifies the construction of the magnetic resonance imaging system and allows for a large free bore width in the examination zone. For example, in a cylindrical bore system, both the camera and the light source are located in a flange of the bore enclosure at one end of the bore, which leaves the other end substantially free to allow unhindered access to the examination zone, e.g. for entering the examination zone (for the patient and / or auxiliary equipment), reducing potential claustrophobic effects and therefore possible discomfort for the subject while being imaged by the system.

[0072] The light source 29 can be located next to or near the camera, e.g. adjacent to each other at the flange end of the bore or separated by an angle, but generally in the same flange area in the longitudinal direction. See, e.g., FIG. 2. If the light source and camera are positioned relatively close, mirrors or reflective surfaces can be used, e.g., to bring the infrared light emitted by the light source to the inspection zone (e.g., the body part being observed) and back again from the observed inspection zone to the camera, such that the same mirror is effectively used twice in the light path. Thus, the number of mirrors required can be reduced (but not limited to this). Positioning the light source and camera close to each other has further advantages, such as minimal impact on the available bore width and optionally sharing cables or conduits for power and / or control signals (which also simplifies the design of the system in terms of avoiding or reducing RF and / or magnetic field interference).

[0073] In a magnetic resonance imaging system according to an embodiment of the present invention, an infrared camera (or cameras) operates (e.g., responds substantially exclusively) to (e.g., narrow) infrared wavelength ranges and outside the visible wavelength range. This applies equally to the infrared light source, i.e., the infrared light source emits light only in the above infrared wavelength range or another range that substantially overlaps with the above camera wavelength range (but is not limited to this). For example, the infrared camera system operates at infrared wavelengths greater than, e.g., 800 nm, e.g., about 850 nm±-20 nm.

[0074] The use of infrared imaging has advantages for certain applications, such as blood flow and heart rate detection. Furthermore, it also allows the subject to be monitored under low ambient lighting conditions (in the visible spectrum). For example, it has been observed that at least some patients perceive low lighting or complete darkness as more comfortable. However, such conditions do not prevent sufficient illumination in the infrared range for camera observation using a system according to an embodiment.

[0075] The magnetic resonance imaging system includes a mirror 22, such as a non-metallic mirror, or a reflective surface that is positioned within the examination zone to reflect (infrared) light from a body part of the subject, such as the face or parts thereof (e.g. eyes, eyeballs, forehead area, ...) onto a camera and / or to reflect light from a light source onto said body parts. The (e.g. non-metallic) mirror 22 may be attached to an inner wall of the examination zone, for example of the magnet bore enclosure.

[0076] Preferably, the mirror or reflective surface does not interfere with the high frequency operation of the magnetic resonance imaging system and / or does not perturb the magnetic field and the RF dynamic transmission magnetic field of the MRI system. Non-metallic mirrors are particularly suitable for achieving this advantage. For example, non-metallic mirrors are dielectric mirrors, which are, for example, composed of a stack of layers with different refractive index, for example, a dielectric resonator is formed by the stack. Such dielectric mirrors, including multi-layer stacks, also have the advantage of reflecting light in a narrow wavelength range, such as the above-mentioned infrared wavelength range of operation of an infrared camera system, for example, advantageously even over a relatively wide range of incidence angles.

[0077] In a magnetic resonance imaging system according to an embodiment of the invention, the mirror or reflective surface preferably reflects light so as to form an infrared image of the body part on the imaging plane of the camera, Optionally, the mirror or reflective surface may also be transparent or semi-transparent to light in the (human) visual range.

[0078] The mirror or reflective surface thus positions the optical path between a portion of the examination zone (ie, where the body part is located when the subject is undergoing examination) and the camera.

[0079] The mirror or reflective surface thus positions an optical path between a portion of the examination zone and the camera, from which the camera can acquire image information. The mirror or reflective surface may be located within the examination zone, for example by mounting it on an inner wall of the magnet bore enclosure. Additionally or alternatively, the mirror or reflective surface may also be located on ancillary equipment within the examination zone, such as on a local radio frequency (RF) coil positioned on the patient table. For example, it is practical to mount a mirror / reflector on an RF head coil. Also, at least one mirror or reflective surface may alternatively or additionally be provided at a location outside the examination zone (for example outside the magnet bore).

[0080] The use of mirrors / reflectors is particularly advantageous when the region of interest to be observed cannot be seen directly by the camera. Obstacles may be formed, for example, by opaque objects such as auxiliary equipment, such as local radio frequency (RF) transmitting or receiving (T / R) antennas, placed in the camera's direct line of sight to the examination zone. Other possible obstacles include parts of the subject's body.

[0081] One or more mirrors may also be made repositionable and / or reorientable to take into account changing (camera) imaging conditions, for example by allowing the mirror to be attached to a support (such as a bore wall) at different positions, by using a sliding rail arrangement, by using a swivel mount to which the mirror is attached, and / or by other such means. That is, the mirror or reflective surface may be adjustably mounted, for example by a hinge or pivot to adjust the orientation, and / or by a sliding rail, a movable mount, or a removable attachment (particularly attachable to multiple possible attachment points) to adjust the position. This allows the orientation and / or position of the mirror to be changed, for example relative to the longitudinal axis of the inspection zone and / or along this axis (not excluding adjustments to other axes). This allows flexibility to avoid obstacles in the inspection zone that may vary from one inspection to another (or even within an inspection). Alternatively, the mirror may be mounted to an internal wall, for example in a fixed arrangement, so that the mirror takes up very little space in the inspection zone.

[0082] Alternatively (or additionally), the mirror may be attached to or formed as part of a head T / R coil, for example for use in neck, cranial, and / or neuroradiological MR examinations. Note that incorporating the mirror in or on the head coil avoids costly or complex modifications of existing equipment such as the scanner bore. The relatively large distance between the cameras, for example mounted on the flange of the bore, results in a very limited field of view, where only the forehead or parts thereof are shown, but in some applications this may be sufficient, for example for monitoring blood pulsations by small variations in pixel intensity.

[0083] In a second aspect, the invention relates to a method for adapting a magnetic resonance imaging system. The method according to embodiments may be a method for retrofitting a (e.g. already installed) magnetic resonance imaging system or may be integrated into a manufacturing process for producing a magnetic resonance imaging system.

[0084] FIG. 4 illustrates an exemplary method 70 according to an embodiment of the present invention.

[0085] The method includes a step 71 of acquiring a magnetic resonance imaging system having an examination zone for positioning a subject for examination by magnetic resonance imaging. For example, the examination zone is formed by a volume enclosed by a bore of a magnet assembly of the system, or by a substantial portion thereof (such as a portion usable for imaging).

[0086] The magnetic resonance imaging system includes an infrared camera system, including an infrared camera, for monitoring the subject while being examined while positioned in the examination zone. Step 71 of acquiring the magnetic resonance system may include modifying an installed magnetic resonance imaging system by installing an infrared camera system, or the infrared camera system may already be installed in the system. The infrared camera system, installed beforehand or as part of the method 70, includes one or more infrared light sources that direct infrared light into the examination zone. For example, the infrared camera system directs light from the light source into the examination zone, e.g., onto the subject during use of the system, such that a lighted part of the subject's body positioned within the field of view of the infrared camera can be imaged by the infrared camera. It is noted that mirrors or reflectors can optionally be used to direct the infrared light from the light source to the body part being imaged and / or from the body part being imaged to the camera. It is also noted that such mirrors or reflectors can be provided as configurable means, such as adjustable in position and / or orientation, i.e. when using the system to prepare an imaging session of the subject.

[0087] The method 70 includes applying 72 a coating onto at least one wall of a room forming a housing for a magnetic resonance imaging system, an inner wall of a magnet assembly of the system, and / or ancillary equipment of the magnetic resonance system for use within an examination zone. The coating further absorbs and / or diffusely reflects infrared light. Such ancillary equipment includes, for example, radio frequency transmitter / receiver coils and / or a patient table. For purposes of this disclosure, "coating" should not be construed narrowly and may refer to paint, film, foil, or other suitable surface treatment. The coating may be multi-layered, including, for example, multiple stacked coatings, paints, films, and / or foils, or combinations thereof.

[0088] In particular, the coating is applied to one or more surfaces that are within the field of view of an infrared camera that images the subject when the system is in use. The coating is capable of absorbing at least 30% of infrared light in the spectral range above 800 nm. The coating is capable of diffusely reflecting at least 30% of incident infrared light in the spectral range above 800 nm.

[0089] In methods according to embodiments of the present invention, the coating is further capable of reflecting and / or transmitting at least 50% of incident light in the visible spectrum.

[0090] The spectral characteristics of the coating can be tailored to the operating wavelength range of the infrared camera. For example, the infrared camera operates in an infrared wavelength range that corresponds to or substantially overlaps with the range in which the coating absorbs and / or diffusely reflects infrared light. In a particular example, the infrared camera system operates at infrared wavelengths of about 850 nm±−20 nm, and the coating substantially absorbs and / or reflects infrared light over at least this range.

[0091] An image processor may be provided as part of the method or may already be built into the MRI system, and such an image processor is typically capable of deriving information about the subject from camera images or images collected by an infrared camera system.

[0092] The method also includes providing a fabric sheet or blanket that covers a portion of the subject's body and / or other object in the examination zone when using a system modified by the method according to the embodiment. The fabric sheet or blanket absorbs, attenuates and / or diffusely reflects infrared light, e.g. having similar (optical / spectral) properties as the coating described above. The magnetic resonance system provided by the method can thus be considered as a kit of parts according to some embodiments, including a magnetic resonance imaging system with an infrared camera system, the MRI system modified by coating the surface of the MRI system as described above in combination with the fabric sheet or blanket. The infrared absorption and / or diffuse reflection provided by the coating and / or blanket thus allows an operator to obtain excellent infrared imaging quality (and / or robust data inferred therefrom) in use.

[0093] Other features of the method according to an embodiment of the second aspect of the invention, or details of the above features, will become apparent in light of the above description of the system according to an embodiment of the first aspect of the invention.

Claims

1. An infrared camera system including an infrared camera for monitoring a subject while the subject is being examined in a state of being positioned in an examination zone of a magnetic resonance imaging system, and a coating on at least one wall of a room housing the magnetic resonance imaging system, on an inner wall of a magnet assembly around the examination zone, and / or on auxiliary equipment of the magnetic resonance imaging system for use in the examination zone, comprising, in the magnetic resonance imaging system, the infrared camera operates in an infrared wavelength range corresponding to or substantially overlapping the range in which the coating absorbs and / or diffusely reflects infrared light, the magnetic resonance imaging system, characterized in that the coating absorbs and / or diffusely reflects infrared light so as to avoid spurious reflection of infrared light into the field of view of the infrared camera and / or to provide diffuse auxiliary illumination.

2. The magnetic resonance imaging system according to claim 1, wherein the auxiliary equipment includes a high-frequency transmitter / receiver coil and / or a patient table.

3. The magnetic resonance imaging system according to claim 1 or 2, wherein the coating absorbs at least 30% of infrared light in a spectral range above 800 nm.

4. The magnetic resonance imaging system according to any one of claims 1 to 3, wherein the coating diffusely reflects at least 30% of incident infrared light in a spectral range above 800 nm.

5. The magnetic resonance imaging system according to any one of claims 1 to 4, wherein the coating reflects and / or transmits at least 50% of incident light in the visible spectrum.

6. The coating covers at least 10 cm of the surface of at least one wall of the room, the inner wall, and / or the auxiliary device. ２ The magnetic resonance imaging system according to any one of claims 1 to 5.

7. The magnetic resonance imaging system according to any one of claims 1 to 6, wherein the infrared camera system includes an infrared light source that directs infrared light into the examination zone.

8. The magnetic resonance imaging system according to any one of claims 1 to 7, wherein the infrared camera system is installed outside the examination zone and is positioned on or incorporated into a flange of the inner wall of the magnet assembly.

9. The magnetic resonance imaging system according to any one of claims 1 to 8, further comprising an image processor that obtains information about the subject from one or more collected camera images.

10. The magnetic resonance imaging system according to claim 9, wherein the information includes values indicating vital signs, movement, and / or mood of the subject.

11. The magnetic resonance imaging system includes a reconstructor that reconstructs a magnetic resonance image from the magnetic resonance signals collected by the magnetic resonance imaging system, the information identified by the image processor includes respiratory phase and / or cardiac phase information, and the reconstructor takes into account the respiratory phase and / or cardiac phase information to correct the collected magnetic resonance signals and / or the reconstructed magnetic resonance image for movement. The magnetic resonance imaging system according to claim 9 or 10.

12. The magnetic resonance imaging system includes a cloth sheet or blanket for covering a part of the body of the subject and / or another object in the examination zone that does not need to be observed by the infrared camera system, and the cloth sheet or blanket absorbs, attenuates, and / or diffusely reflects infrared light. The magnetic resonance imaging system according to any one of claims 1 to 11.

13. The magnetic resonance imaging system according to any one of claims 1 to 12, including at least one mirror or reflecting surface arranged in the examination zone for reflecting infrared light from the body part of the subject to the infrared camera and / or reflecting light from an infrared light source to the body part.

14. A method of adapting a magnetic resonance imaging system, the method comprising: A step of obtaining a magnetic resonance imaging system, the magnetic resonance imaging system having the examination zone for positioning a subject to be imaged by the magnetic resonance imaging system inside the examination zone, the magnetic resonance imaging system including an infrared camera system for monitoring the subject being examined, the infrared camera system including an infrared camera, and the step of obtaining; A step of applying a coating on at least one wall of the room housing the magnetic resonance imaging system, on the inner wall of the magnet assembly of the magnetic resonance imaging system, and / or on auxiliary equipment of the magnetic resonance imaging system for use in the examination zone; Including In a method in which the infrared camera operates in an infrared wavelength range corresponding to or substantially overlapping the range in which the coating absorbs and / or diffusely reflects infrared light, The method is characterized in that the coating absorbs and / or diffusely reflects infrared light so as to avoid spurious reflection of infrared light into the field of view of the infrared camera and / or to provide diffuse auxiliary illumination.

15. The method according to claim 14, wherein the step of obtaining the magnetic resonance imaging system includes the step of modifying an installed magnetic resonance imaging system by installing the infrared camera system.

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