Abstract: A trocar including a trocar head attached to a cannula having a lumen with a distal opening, the cannula includes at least one elastomeric band positioned across said lumen.

Abstract: An image pickup apparatus includes an image pickup member including an image pickup device, a stacked device in which a plurality of semiconductor devices are stacked, a wiring board having a first principal surface and a second principal surface, the wiring board including a central section having a substrate thicker than the image pickup device, an intermediate section that is extended from the central section and is bent, and a terminal section that is extended from the intermediate section, the image pickup member being bonded to the first principal surface of the central section, the stacked device being bonded to the second principal surface of the central section, and a plurality of signal cables bonded to the terminal section.

Abstract: A tip part assembly for an endoscope, a method for assembling the tip part assembly, and an endoscope including the tip part assembly. The tip part assembly includes a flexible printed circuit having connection points, a camera module including a connection surface comprising connection points arranged in a first connection point pattern for electrical communication with the connection points of the flexible printed circuit, and a converter circuit board including a first surface including connection points arranged substantially in the first connection point pattern and a second surface including connection points arranged in a second connection point pattern being different than the first connection point pattern, wherein the first surface connection points are connected to the connection surface connection points, and wherein the second surface connection points are connected to the connection points of the flexible printed circuit.

Abstract: First illumination light and second illumination light having different emission spectra are automatically switched so as to be emitted for a light emission period of at least one or more frames under specific light amount conditions, respectively. First image signals obtained in a case where an image is picked up using the first illumination light and second image signals obtained in a case where an image is picked up using the second illumination light are acquired. A first specific color signal for specific biological tissue among the first image signals and a second specific color signal for the specific biological tissue among the second image signals match.

Abstract: An endoscope includes a shaft assembly having proximal and distal ends and a longitudinal axis therebetween. A handle is coupled to the proximal end of the shaft assembly, and an elastomeric body housing an image sensor and at least one LED is comprises a distal end of the shaft. The elastomeric body is deformable between a repose straight insertion profile and a deflected offset profile by the insertion of a tool shaft through the shaft assembly and an expandable-collapsible working channel in the elastomeric body. The viewing angle of the image sensor is moved from a first selected angle to a second selected angle when the elastomeric body is actuated from the repose profile to the deflected offset profile.

Abstract: A tip part assembly for an endoscope having a proximal end and a distal end positioned oppositely from the proximal end, the tip part assembly including: a working channel extending in a longitudinal direction extending from the proximal end toward the distal end, and a camera assembly including a flexible printed circuit and a camera module having an image sensor, a lens, and a proximal connection surface, wherein the camera module is positioned above the working channel in a top-down direction providing a lateral direction extending laterally from both the camera module and the working channel, and wherein the flexible printed circuit continues from a connection to the connection surface of the camera module in the lateral direction into a first fold of the flexible printed circuit toward the proximal end of the tip part assembly.

Abstract: A method for image classification includes accessing a plurality of images of at least a portion of a gastrointestinal tract (GIT) captured by a capsule endoscopy device and for each image of the plurality of images: providing a classification score for each segment of a plurality of consecutive segments of the GIT by a deep learning neural network, and providing a classification probability for each segment of the plurality of consecutive segments of the GIT based on the classification scores by a classical machine learning classifier. The method further includes determining a classification for each image to one segment of the plurality of consecutive segments of the GIT based on processing a signal corresponding to the classification probabilities of the plurality of images.

Abstract: There is provided herein a tip section for an endoscope assembly that includes a fluid distribution device for circulating fluid for cleaning a body cavity. In an embodiment, the tip section includes a groove aligned with side jet channels, where multiple holes drilled above the groove, through the periphery of a tip cover covering the tip section, provide an exit for the fluid circulated by the side jet channels in all directions around the tip cover. In another embodiment, the tip section includes a removable attachment that covers jet channel openings. Multiple holes drilled through the cover provide a multiple jet exit for the fluid circulated by the jet channels in multiple directions around the tip cover.

Abstract: An endoscope system capable of automatically turning on/off a light source during a surgical procedure is disclosed. This endoscope system includes: an endoscope module; a light source module coupled to the endoscope module; and a light-source control module. Moreover, the light-source control module controls an ON/OFF state of the light source by: (1) receiving real-time video images captured by the endoscope module; (2) processing the real-time video images to determine whether the endoscope module is inserted into a patient's body or is outside of the patient's body; and (3) in response to determining the endoscope module being outside of the patient's body while the light source is turned on, generating a control signal to immediately turn off the light source to the endoscope module, thereby ensuring safety of people in the operating room and preventing sensitive information in the operating room from being captured by the endoscope module.

Abstract: Controlling integral energy of a light pulse in a laser mapping imaging system is disclosed. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation. The system includes an electromagnetic sensor for sensing energy emitted by the emitter. The system includes a controller configured to synchronize timing of the emitter and the image sensor. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter is a laser mapping pattern.

Abstract: A surgical system including a surgical instrument, a surgical visualization system, a display, and a feedback controller are presented. The feedback controller is in signal communication with the surgical instrument and the surgical visualization system. The feedback controller is configured to display, on the display, during an operation, live images derived from the surgical visualization system in a first layer and a status of the surgical instrument in a second layer. The status is configured to locate itself in said second layer in relation to a depiction of a feature of the surgical instrument and/or a feature of tissue in the first layer. The surgical instrument can include a surgical stapler, a knife, a robotic surgical instrument, combination thereof, or variation thereof.

Abstract: An endoscope image-capturing device includes: a first case inside of which is sealed; an image sensor arranged inside the first case; an electro-optic conversion element arranged outside the first case and configured to convert an image signal output from the image sensor into an optical signal; and a sealing member sealing the electro-optic conversion element.

Abstract: A circuit assembly that includes a circuit board, a switching element that is mounted on one side of the circuit board, a folded portion that extends from a peripheral edge portion of the circuit board and is folded towards the one side, and a temperature measuring device that is mounted on the folded portion and is in contact with the switching element.

Abstract: First and second images are displayed of anatomical structure segments with an attached fixator. Indications may be received of first image hinge locations of a plurality of hinges of the fixator in the first image. Projected second image hinge locations may be determined based at least in part on the first image hinge locations. Hinge candidates may be detected in the second image having shapes associated with the plurality of hinges. The hinges candidates may be detected by computer software using automated software-based image analysis techniques. Adjusted second image hinge locations may then be calculated based at least in part on the projected second image hinge locations and candidate second image hinge locations. The adjusted second image hinge locations may be used to determine physical locations of the fixator and anatomical structure segments in three-dimensional space, which may be used to determine manipulations to the fixator for deformity correction.

Abstract: An OSS animated display system for an interventional device (40) including an integration of one or more optical shape sensors and one or more interventional tools. The OSS animated display system employs a monitor (121) and a display controller (110) for controlling a real-time display on the monitor (121) of an animation of a spatial positional relationship between the OSS interventional device (40) and an object (50). The display controller (110) derives the animation of the spatial positional relationship between the OSS interventional device (40) and the object (50) from a shape of the optical shape sensor(s).

Abstract: A medical image processing device includes: an acquisition unit configured to acquire an image signal obtained by capturing a subject image; and an image processor configured to set, in the image signal, a first area for displaying an image, and a second area having a smaller average luminance than the first area, set the second area on a screen according to a depth of field at a time of capturing the subject image.

Abstract: A method for stitching images of a capsule endoscope, an electronic device, and a readable storage medium are provided. The method comprises: performing image rectification and circular edge masking on original images to form pre-processed images, and performing image enhancement (S1); completing detection and pairing of feature points (S2); calculating a transformation model of all pre-processed images to a same optimal plane according to a set of the feature points (S3); performing projective transformation for each enhanced image to a same coordinate system (S4); and stitching images according to an obtained sequence to form a fused image for output (S5), thus expanding the field of view of a single image of the capsule endoscope.

Abstract: Medical borescopes, such as laparoscopes. In some embodiments, a medical borescope may comprise a handle and a tube extending from the handle, which tube may be configured to reduce electromagnetic interference within the tube. The borescope may further comprise a tip assembly positioned at a distal end of the tube, which may comprise an image sensor configured to take images through the distal end of the tube. The borescope may further comprise a dongle comprising an image processor configured to receive image data from the image sensor. The dongle may be removably coupleable with the medical borescope such that the dongle can be coupled with a plurality of distinct medical borescopes.

Abstract: The invention relates to a device for superimposing known patterns, characteristic of a region, on (real) images of said region. The device comprises, a memory in which patterns are stored, which are representative of a selected region, of known position and orientation with relation to a common reference and processing means, for determining a pattern representative of the selected portion in the memory, on receipt of the designation of at least one portion of an observed image of the selected region, taken at a selected angle and at least one representative attribute of said region, taking account of the attribute selected, then superimposing the determined pattern on the selected portion of the image taking account of the selected angle.

Abstract: A wireless magnetic ultrasonic cavitation in-vivo therapeutic robotic device, including a micro-robot and an in-vitro control device; the in-vitro control device has an outer housing in which provided with electromagnetic coils and wireless power emitting coils; the micro-robot has a capsule shaped housing in which a super magnetic module is provided; a micro ultrasonic vibrator and a micro wireless power receiving coil electronically connected with each other are provided inside the housing; the wireless power emitting coils emit electromagnetic field to the micro wireless power receiving coil, which receives and then transforms the electromagnetic field to electrical current to supply power to the micro ultrasonic vibrator. The robotic device creates ultrasonic cavitation effect in the blood, causing rapid vibration of blood cells, which enhances cell regeneration power, burn blood lipids, clear blood clots and ensures good condition of blood vessels.

Abstract: A stereo endoscope for capturing a first image which is provided to be observed by a first eye and a second image which is provided to be observed by a second eye, including a shaft with a distal end region, a first image sensor in the distal end region of the shaft, for capturing the first image, and a second image sensor in the distal end region of the shaft, for capturing the second image. The first image sensor and the second image sensor are arranged offset relative to one another in a direction which is parallel to at least either a light-sensitive layer of the first image sensor or a light-sensitive layer of the second image sensor and which is orthogonal to a longitudinal axis the distal end region of the shaft. The first image sensor and the second image sensor are oriented in opposite directions.

Abstract: Apparatus, systems, and methods for cleaning an endoscope during a procedure, are disclosed. One method comprises utilizing a trocar comprising a main body defining a cavity for receiving an endoscope, a wash orifice disposed in the main body and configured allow a flow of wash solution into the cavity, and a gas orifice disposed between the distal end of the main body and the wash orifice, the gas orifice configured allow a flow of gas into the cavity, the method comprising: washing the endoscope; drying the endoscope; and managing residual fluids on the endoscope or in the cavity, or both.

Abstract: A method for monitoring a colonoscope withdrawal speed, the method including: 1) acquiring, a real-time video of colonoscopy, decoding the video into images, cropping the images, and zooming-out the images cropped where texture information of the images is retained; 2) converting the images including the texture information to grayscale images; 3) obtaining Hash fingerprints of the images; 4) calculating a Hamming distance between the images; 5) comparing the Hash fingerprints of a current colonoscopy image with n previous colonoscopy images, to obtain an overlapping rate of the current colonoscopy image with any one of the n previous colonoscopy images; 6) calculating a weighted similarity of the images at a point in time t; 7) converting a weighted overlapping rate of the images at the point in time t into a stability coefficient; and 8) calculating a mean stability coefficient of colonoscopy images within a period of time 0-t.

Abstract: Removable barrier devices (e.g., sleeves) for covering medical scanning devices to reduce the chance of cross-contamination between patients and/or to protect the scanning devices from physical damage. The barrier device can include a cover that has an integrated window for passing optical signals between the scanning device and an external environment. The cover can include a sleeve that covers a handle portion of the scanning device to prevent contamination of the handle from a user's hand or glove. The cover and sleeve may both be formed of the same flexible material, or the cover may be rigid to maintain the window in a fixed position and the sleeve may be flexible to allow a user to activate a button or touchpad on the handle. An interface region between the cover and sleeve may provide a hermetic seal. The window may include a nanostructured antireflective material to limit internal reflections.

Abstract: An endoscope apparatus including: a light source configured to emit illumination light including light in a first wavelength band included in a blue wavelength band, light in a first narrowband included in a green wavelength band, and light in a second narrowband having a same light absorption coefficient of hemoglobin as that of the light in the first narrowband; an imager configured to acquire a first image of an object in the first wavelength band, a first narrowband image of the object in the first narrowband, and a second narrowband image of the object in the second narrowband; and a processor including hardware. The processor is configured to implement acquiring scattering characteristics information based on a comparison result between the first narrowband image and the second narrowband image, and generating an observation image using the first image, the first narrowband image, and the scattering characteristics information.

Abstract: A light source device includes: a laser light source configured to emit laser light having a peak wavelength included in a wavelength range of light absorbed or reflected by a first region or a second region of an object under study, the laser light source being configured to form a speckle pattern having speckle contrasts that differ between the first region and the second region; and a speckle variable device configured to control a coherence of the laser light in response to an external control signal.

Abstract: The present disclosure provides systems and methods for medical imaging. The system may comprise an optical adapter. The optical adapter may comprise a housing that comprises (1) a first end configured to releasably couple to a scope and (2) a second end configured to releasably couple to a camera. The optical adapter may comprise an image sensor coupled to the housing. The optical adapter may comprise an optics assembly disposed in the housing. The optics assembly may be configured to (1) receive light signals that are reflected from a target site within a subject's body and transmitted through the scope, and (2) reflect a first portion of the light signals onto the image sensor while permitting a second portion of the light signals to pass through to the camera.

Abstract: A method and system for medical imaging employs an excitation source configured to cause an object having a plurality of cells to at least one of emit, reflect, and fluoresce light. An optical receptor is employed that is configured to receive the light from the object. A filter assembly receives the light from the optical receptor and filters the light. An image processor having a field of view (FOV) substantially greater than a diameter of a cell of the object and an analysis resolution substantially matched to the diameter of a cell of the object that receives the filtered light from the filter and analyzes the filtered light corresponding to each cell in the FOV. A feedback system is provided that is configured to provide an indication of a state of each cell in the FOV and a location of a cell in the FOV meeting a predetermined condition.

Abstract: A method for image-capturing of an internal organ by a miniature imaging device, comprising: generating a light at a first light intensity on to a subject area of an internal organ and capturing an image of the subject area by a miniature imaging device configured under default exposure parameter values; computing a second light intensity and optimized exposure parameter values based on brightness of the captured image, an orientation, a position, and a motion of the miniature imaging device; and generating a light at the second light intensity on to the subject area and recapturing the image of the subject area by the miniature imaging device configured under the optimized exposure parameter values. The second light intensity and optimized exposure parameter values are derived by an ex vivo processing unit in wireless data communication with the miniature imaging device.

Abstract: An endoscope includes a plurality of illuminating optical systems, an objective optical system, and an optical-path splitting member. The optical-path splitting member has an optical element which forms a first optical path and a second optical path, and an optical-path length of the first optical path differs from an optical-path length of the second optical path. Illumination light is irradiated to an object from the plurality of illuminating optical systems. The objective optical system has an object-side incidence surface which is located nearest to the object, and each of the plurality of illuminating optical systems has an object-side emergence surface which is located nearest to the object. Each of the object-side emergence surfaces is located on an image side of the object-side incidence surface, and following conditional expression (1) is satisfied: 2.0<Dmin/OPLdiff<50??(1).

Abstract: A family of endoscopes includes a non-zero degree endoscope and a zero degree endoscope. The zero degree endoscope includes a first image capture unit mounted in a distal portion of the zero degree endoscope with a lengthwise axis of the first image capture unit substantially parallel to a lengthwise axis of that distal portion. The non-zero degree endoscope includes a second image capture unit mounted in a distal portion of the non-zero degree endoscope with a lengthwise axis of the second image capture unit intersecting a lengthwise axis of that distal portion at a non-zero angle. The first and second image capture units have substantially identical non-folded optical paths.

Abstract: Pulsed fluorescence imaging without input clock or data transmission clock is disclosed. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation. The system includes a plurality of bidirectional data pads and a controller in communication with the image sensor. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter comprises one or more of: electromagnetic radiation having a wavelength from about 770 nm to about 790 nm.

Abstract: A dynamic anatomic atlas is disclosed, comprising static atlas data describing atlas segments and dynamic atlas data comprising information on a dynamic property which information is respectively linked to the atlas segments.

Abstract: Fluorescence videostroboscopy imaging is described. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation. The system includes a controller configured to cause the emitter to emit the pulses of electromagnetic radiation at a strobing frequency determined based on a vibration frequency of vocal cords of a user. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter comprises electromagnetic radiation having a wavelength from about 795 nm to about 815 nm.

Abstract: A multifunctional laryngoscope is provided that includes a handle comprising a proximal end and a distal end and a display screen on the handle. The laryngoscope includes a laryngoscope camera at the distal end of the handle and connects to an introducer comprising an orientation sensor at a distal end of the introducer. The laryngoscope includes a processor programmed to execute instructions for receiving from a steering input a steering command in a first reference frame, and mapping the steering command to a second reference frame oriented to the distal end of the introducer based on an orientation signal from the orientation sensor.

Abstract: A medical endoscopy/stereo colposcopy instrument is configured to selectively take stereo colposcopy images of a patient's uterus and endoscopy images of the patient's bladder or uterus. Any of the images can be white light images or images for a selected narrow wavelength band or fluorescence images. The images can be displayed individually or as spatially registered composite images to highlight selected features of the imaged anatomy. A cup-shaped device can be positioned at the patient's cervix and provided with a light source and a fluorescence camera module to monitor changes in fluorescence in response to a photoactivated substance.

Abstract: Systems, methods, and devices for hyperspectral imaging with increased dynamic range are disclosed. A system includes an emitter for emitting pulses of electromagnetic radiation and an image sensor comprising a pixel array for sensing reflected electromagnetic radiation, wherein the pixel array comprises a plurality of pixels each configurable as a short exposure pixel or a long exposure pixel. The system includes a controller comprising a processor in electrical communication with the image sensor and the emitter. The system is such that at least a portion of the pulses of electromagnetic radiation emitted by the emitter comprises one or more of electromagnetic radiation having a wavelength from about 513 nm to about 545 nm, electromagnetic radiation having a wavelength from about 565 nm to about 585 nm, or electromagnetic radiation having a wavelength from about 900 nm to about 1000 nm.

Abstract: A light source includes a first LED to provide light of a first light wavelength spectrum along a first light path; a second LED to provide light of a second light wavelength spectrum along a second light path; a dichroic filter for passing light emitted from at least one of the first LED and the second LED and reflecting light emitted from at least one of the first LED and the second LED; an optical filter movable between a first position in which the optical filter receives light from the first light path and a second position of which the optical filter does not receive light from the first light path; a light output; a controller which is capable of switching the light source between a first mode for providing a first light to the light output and a second mode for providing a second light to the light output.

Abstract: A probe includes a working channel, at least one optical element provided in the working channel and configured to acquire a spectral image of surface information of an object, and an ultrasonic transducer arranged in the working channel and configured to acquire an ultrasonic image of depth information of the target and move with respect to the at least one optical element.

Abstract: There is provided a method of manufacturing an imaging device including a plurality of imaging elements in an imaging area, where each imaging element includes a photoelectric conversion unit in a substrate and a wire grid polarizer arranged at a light-incident side of the photoelectric conversion unit. The method generally includes forming the wire grid polarizer that includes a plurality of stacked strip-shaped portions, where each of the plurality of stacked strip-shaped portions includes a portion of a light-reflecting layer and a portion of a light-absorbing layer. The light-reflecting layer may include a first electrical conducting material that is electrically connected to at least one of the substrate or the photoelectric conversion unit. The light-absorbing layer may include a second electrical conducting material, where at least a portion of the light-absorbing layer is in contact with the light-reflecting layer.

Abstract: A method for producing an image of a body tissue surface. The method includes transforming a source 3-D model of the body tissue surface into a flattened model comprising details of the body tissue surface represented visually on an unwrapped and flattened surface, wherein the flattened model represents transformed positions of the source 3-D model of the body tissue surface defined between a first edge and a second edge. The first edge is formed about a lumen defined by the body tissue surface, and the body tissue surface projects about the lumen to the second edge. The method further includes producing an image from the flattened model.

Abstract: An image capturing module includes a flexible circuit board and an image sensor. The flexible circuit board includes a plurality of first pads and a plurality of second pads. The first pads are disposed on a first surface of the flexible circuit board and the second pads are disposed on a second surface of the flexible circuit board, wherein the first surface is opposite to the second surface. The image sensor is disposed on the first surface. A distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads. The flexible circuit board is folded to align and weld the first pads with the second pads, such that a light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads.

Abstract: Provided are: an image diagnosis assistance apparatus capable of assisting diagnosis of an endoscopic image captured by an endoscopist; a data collection method; an image diagnosis assistance method; and an image diagnosis assistance program. The image diagnosis assistance apparatus is provided with: a lesion assessment unit that assesses, by a convolutional neural network, the denomination and the position of a lesion which is present in a digestive system endoscopic image of a patient captured by a digestive system endoscopic imaging device and information about accuracies thereof; and a display control unit that performs control for generating an analysis result image in which the denomination and the position of the lesion and the accuracies thereof are displayed and for displaying the image on the digestive system endoscopic image.

Abstract: An open cell foam is used to create a seal between a camera and a shell piece. The shell piece, camera, seal and a transparent window form a closed front cavity. Because the cavity is closed, dust can remain away from a lens of the camera.

Abstract: An endoscope image-capturing device includes: a first case inside of which is sealed; an image sensor arranged inside the first case; an electro-optic conversion element arranged outside the first case and configured to convert an image signal output from the image sensor into an optical signal; and a sealing member sealing the electro-optic conversion element.

Abstract: Endoscopic camera head devices and methods are provided using light captured by an endoscope system. Substantially afocal light from the endoscope is manipulated and split. After passing through focusing optics, another beamsplitter is used to split the light again, this time in image space, producing four portions of light that may be further manipulated. The four portions of light are focused onto separate areas of two image sensors. The manipulation of the beams can take several forms, each offering distinct advantages over existing systems when individually displayed, analyzed and/or combined by an image processor.

Abstract: An endoscope system includes: a light source that is configured to emit primary light; plural illuminators that are configured to be irradiated with the primary light to emit plural respective illumination light generated based on the radiated primary light toward an observation object so that at least part of the plural illumination light overlap on the observation object; and an adjuster that is configured to desirably adjust a ratio of light quantities of the primary light that travels from the light source to the respective illuminators, so as to distribute the primary light to the respective illuminators.

Abstract: A method includes grasping a user input device in communication with a surgical tool of a robotic surgical system, the surgical tool including an end effector with opposing jaws, squeezing the user input device and thereby actuating a motor that closes the jaws and clamps down on tissue at a surgical site, and calculating with a computer system in communication with the surgical tool work completed by the motor to close the jaws and clamp down on the tissue. The computer system generates one or more effort indicators when the work completed by the motor meets or exceeds one or more predetermined work increments corresponding to operation of the motor, and communicates the one or more effort indicators to an operator.

Abstract: An imaging module includes: a support substrate that includes a first surface, a second surface on an opposite side of the first surface, and a first mounting terminal disposed on the first surface; a planar light emitter including a light-emitting face, and a light-emitter terminal disposed on the first surface of the support substrate and connected to the first mounting terminal; and a solid-state image sensing device disposed adjacent to the planar light emitter and that includes a light-incident surface that has a quadrangular shape in plan view and that captures an image of an imaging object that is irradiated with light emitted from the light-emitting face.

Abstract: Improved fluorescent imaging and other sensor data imaging processes, including hyperspectral imaging, devices, and systems are provided to enhance endoscopes with multiple wavelength capabilities and providing sequential imaging and display. A first optical device is provided for endoscopy imaging in a white light and a fluoresced light mode with an imaging unit including one or more image sensors. A mechanism in the first optical device to automatically adjust the focus of the first optical device using one or more deformable, variable-focus lenses, wherein the automatic focus adjustment compensates for a chromatic focal difference between the light collected at distinct wavelength bands caused by the dispersive or diffractive properties of the optical materials or optical design employed in the construction of the first or second optical devices, or both. Further variable spectrum imaging is enhanced with the use of adjustable spectral filters.