Device for coupling coherent light into an endoscopy system

Abstract

Devices, systems, and methods are described for coupling coherent light and incoherent light into a first light guide of a light delivery system of an endoscopic system. The endoscopic system includes an incoherent light source for generating the incoherent light, e.g., white light. The coupling device includes a first light source for generating coherent light of a first wavelength or a coherent light input for receiving the coherent light of the first wavelength. The coupling device also includes an optical input having an optical input connector for releasably connecting the coupling device to the incoherent light source via a second light guide, and an optical output having an optical output connector for releasably connecting the coupling device to an endoscope via the first light guide. The optical input is configured to receive the incoherent light from the endoscopic system. The optical output is configured to provide the incoherent light of the first wavelength and the coherent light to the first light guide. In one embodiment, the coupling device may be configured in a first state and a second state, wherein in the first state, the coupling device may comprise an unobstructed incoherent light beam path for propagating the incoherent light from the light input to the light output; and in the second state, the coupling device comprises an unobstructed coherent light beam path for propagating the coherent light from the coherent light source or from the coherent light input to the light output. The coupling device may further comprise an optical coupler for simultaneously and / or alternately injecting the incoherent light and the coherent light of the first wavelength into the first light guide.

Description

[Technical Field]

[0001] The present disclosure relates to coupling coherent light into an optical delivery system of an endoscopic system, and particularly, but not exclusively, to devices, systems, and methods for coupling coherent light into an optical delivery system of an endoscopic system, and computer program products employing such methods. [Background technology]

[0002] Endoscopic systems are typically used to view or image internal parts of the human or animal body during medical procedures, such as surgery or diagnosis. Within the scope of this disclosure, endoscopic systems may include systems for internally inspecting both naturally accessible body parts and cavities with artificially created openings, such as laparoscopic systems, arthroscopic systems, bronchoscopy systems, and neuroendoscopic systems. Endoscopic systems typically include an endoscope with a light delivery system and an image guide, a white light source, and an imaging device, such as a camera head. Endoscopes typically include a rigid or flexible, elongated insertion tube, which includes a first light guide, such as a fiber bundle, for illuminating a target and a second light guide, such as a rod lens, for transmitting an image of the target to the imaging system. Other endoscopes may have an imaging sensor at or near the tip, known as a chip-on-the-tip system. The endoscope can be connected to an external light source and screen via a cable. White light illumination provides the surgeon or endoscopist with an image that is easy to interpret.

[0003] Many modern medical imaging techniques require coherent light, e.g., laser light. For example, laser speckle contrast imaging (LSCI), sometimes called laser speckle contrast analysis (LASCA), provides a fast, full-field, inexpensive, and relatively simple in vivo imaging method for determining two-dimensional perfusion maps of living tissue using coherent light. Perfusion can be an indicator of tissue viability, potentially providing valuable information during diagnosis and surgery. As a further example, fluorescence imaging, e.g., indocyanine green (ICG)-based perfusion imaging, may require coherent light to excite a fluorescent marker.

[0004] Therefore, it would be desirable to combine the benefits of white light imaging and coherent light imaging using a single endoscope.

[0005] International Publication WO 2015 / 176294 A1 describes a laparoscopic system for imaging subsurface blood flow in tissue based on laser speckle contrast imaging. The system includes a laparoscopic mirror having a white light source and a light guide for transmitting the white light to a field of view, a laser light source, and an optical fiber for transmitting the laser light to the field of view. The optical fiber may be inserted into the patient's body through a separate incision, or the optical fiber may be incorporated into or on the shaft of the laparoscopic mirror as a separate channel, which requires replacing or at least substantially modifying the laparoscopic mirror.

[0006] U.S. Patent Application Publication US 2016 / 0022126 A1 describes an endoscopy system with a single light source that can provide both white light and infrared laser light for exciting fluorescent markers. However, using this system would result in replacing the entire endoscopy system, or at least the entire light source, which is relatively expensive.

[0007] Therefore, from the above, it can be seen that there is a need in the art for a system that combines the advantages of coherent optical imaging with existing endoscopic systems. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of embodiments of the present disclosure to reduce or eliminate at least one of the known disadvantages in the prior art. [Means for solving the problem]

[0009] In a first aspect, the present invention relates to a coupling device for coupling coherent light and incoherent light into a first light guide of a light delivery system of an endoscopic system, the endoscopic system including an incoherent light source for generating the incoherent light, e.g., white light. The coupling device may include an optical input section having an optical input connector for preferably releasably connecting the coupling device to the incoherent light source via a second light guide, the optical input section configured to receive the incoherent light from the endoscopic system; a first light source for generating coherent light of a first wavelength, or a coherent light input section for receiving the coherent light of the first wavelength; and an optical output section having an optical output connector for releasably connecting the coupling device to an endoscope via the first light guide, the optical output section configured to provide the incoherent light of the first wavelength and the coherent light to the first light guide. In one embodiment, the coupling device may be configured in a first state and a second state, wherein in the first state, the coupling device may comprise an unobstructed incoherent light beam path for propagating the incoherent light from the light input to the light output; and in the at least second state, the coupling device may comprise an unobstructed coherent light beam path for propagating the coherent light from the coherent light source or from the coherent light input to the light output. The coupling device may further comprise an optical coupler for simultaneously and / or alternately inputting the incoherent light and the coherent light of the first wavelength into the first light guide, wherein the coherent light and the incoherent light have a shared optical path at the light output.

[0010] The light output comprises a single output channel, possibly multiple fibers, for delivering the incoherent light and / or the coherent light to the first light guide of the light delivery system of the endoscopic system. Thus, the coherent light and the incoherent light have a shared optical path at the light output of the coupling device and, consequently, at the entrance to the first light guide. The first and second states may fully or partially overlap, resulting in a state where both the incoherent light and the coherent light share an optical path in a simultaneous manner. Alternatively, the first and second states may also be separate states, resulting in a state where both the incoherent light and the coherent light share an optical path in a time-division manner.

[0011] In some cases, the cable comprising the first light guide may comprise additional channels, and the coupling device may comprise additional outputs (i.e., in addition to the optical output) to provide inputs to such additional channels.

[0012] As used herein, when light is provided to a light guide it means that the light is incident on a light inlet of the light guide. When light is provided to a light output it is understood that the light is also provided to a light guide, if one is connected to the light output.

[0013] The incoherent light may be white light or colored light, such as blue light. The incoherent light source may also comprise multiple coherent light sources providing coherent light simultaneously or alternately, e.g., in a time-multiplexed manner. The endoscopic system may be any system for internal visual inspection of a subject, preferably a human or animal body, preferably a living organism. Internal visual inspection may be relevant to naturally accessible body parts, such as the bladder, intestines, or bronchi, as well as to cavities with artificially created openings, e.g., the abdominal cavity, or in neurosurgery for dental caries. Thus, the endoscopic system may be, for example, a laparoscopic system, an arthroscopic system, a bronchoscopy system, a neuroendoscopic system, etc. The endoscopic system may further comprise a surgical instrument, e.g., a robotic surgical system.

[0014] By connecting the coupling device between the incoherent light source and the endoscope body of the endoscope system, coherent light may be guided to the first light guide of the light delivery system of the endoscope, thus enabling additional imaging capabilities, such as LSCI and / or fluorescence imaging, such as indocyanine green (ICG) imaging for perfusion imaging or angiography. Other fluorescent markers may be used for other applications. For example, fluorescence imaging may also be used to detect tumor tissue. Generally, different markers are activated by different wavelengths of light.

[0015] By using a separate device, there is no need to replace the light source or the entire endoscope system, or to disconnect and reconnect the first light guide of the optical delivery system every time a user wishes to switch between an incoherent light source and a coherent light source, thus providing a relatively economical, flexible, and easy-to-operate option.

[0016] The coupling device can be connected to the first light guide of a light delivery system rather than directly to the light input of the endoscope body. In this way, the coupling device can be located outside the sterile area of, for example, an operating room. In this way, the device does not need to be sterilized after each use, making it easy to use and reducing both manufacturing and operating costs. In contrast, devices that are attached directly to an endoscope must be compatible with conventional sterilization methods. This can be particularly problematic in embodiments that include a coherent light source, which can be sensitive to, for example, heat and disinfectants.

[0017] However, since the coupling device can be connected to the endoscope via the first light guide, light needs to be coupled into the first light guide with sufficient intensity. This is particularly relevant for the incoherent light. Therefore, the coupling device can be configured to minimize light losses, particularly incoherent light losses, between the light input and the light output.

[0018] The coherent light may be generated by the coupling device itself or by another device, and may be fed to the coupling device, for example, via an optical fiber. The use of a coherent light input may result in a smaller device that can be positioned in an endoscope system in an almost unlimited manner. In addition, different coherent light sources may be attached based on different needs, for example, for different fluorescent markers.

[0019] On the other hand, using a first coherent light source within the coupling device may result in higher quality coherent light (e.g., higher power, smaller spectral bandwidth, and / or longer coherence length) because the coherent light may propagate through free space to the optical output or at least to the optical coupler without the use of optical components, such as optical fibers, that may adversely affect the quality of the coherent light. As described in more detail below, the optical coupler may additionally include a second coherent light source and / or a coherent light input for receiving coherent light at a second wavelength.

[0020] The optical coupler may be a static optical coupler for combining a relatively wide incoherent beam and a relatively narrow coherent beam on a single optical path and for injecting both the incoherent light and the coherent light into a first light guide of a light delivery system of an endoscope system via an optical output. Alternatively, the optical coupler may be an optical switch for (selectively) injecting either the coherent beam or the incoherent beam or both into the first light guide.

[0021] In one embodiment, the optical coupler may be an optical switch configured to switch between a first state in which the coherent light is not incident on the first light guide and a second state in which the coherent light is incident on the first light guide, In this way, an operator can select whether to use the laser light or not without removing the coupling device.

[0022] In one embodiment, in the first state, the optical switch may be configured to provide the incoherent light at the optical output. In the second state, the optical switch may be configured not to provide the incoherent light at the optical output. In many applications, a user may want to switch between only incoherent light and only coherent light.

[0023] In one embodiment, the optical switch may be configured to switch to a third state, in which the optical switch is configured to provide both the coherent light and the incoherent light at the light output. Imaging a target area using both coherent and incoherent light simultaneously can be particularly advantageous when the coherent light is outside the visible spectrum, for example, infrared or ultraviolet.

[0024] In one embodiment, the optical switch may include a first movable part, e.g., a rotatable mirror, movable between a first position in which a reflective surface of the first mirror is arranged to reflect incoherent light propagating beyond the incoherent light beam path and a second position in which the reflective surface of the first mirror is arranged to reflect the incoherent light away from the incoherent light beam path. Additionally or alternatively, the optical switch may include a second mirror movable between a first position in which a reflective surface of the second mirror is arranged to reflect coherent light propagating beyond the coherent light beam path and a second position in which the reflective surface of the first mirror is arranged to reflect the coherent light away from the coherent light beam path.

[0025] The second mirror may be the same mirror as the first mirror, a different portion of the same mirror, or a separate mirror. Moving mirrors may be inexpensive and easy to manufacture.

[0026] In one embodiment, the optical switch may comprise a first switchable mirror switchable between a transparent state and a reflective state and arranged to reflect incoherent light propagating beyond the incoherent light beam path in the reflective state. Additionally or alternatively, the optical switch may comprise a second switchable mirror switchable between a transparent state and a reflective state and arranged to reflect coherent light propagating beyond the coherent light beam path in the reflective state.

[0027] The first and / or second switchable mirrors may be, for example, electrically switchable mirrors. Switching a mirror between a transparent and a reflective state may be faster than moving the mirror, and the lack of moving parts may reduce contamination of optical elements in the optical switch. The first and second switchable mirrors may be the same mirror or different mirrors.

[0028] In one embodiment, the optical switch may comprise a first optical beam blocker configured to block the coherent light in the one state, preferably the first beam blocker comprises a mechanical shutter, preferably a rotating shutter, more preferably a motorized rotating shutter, or an optical beam blocker, preferably one of the following: a liquid crystal light valve, an acousto-optical modulator, an electro-optical modulator or a photo-elastic modulator.

[0029] Optionally, the optical switch may comprise a second optical beam blocker configured to block the incoherent light in the second state, preferably the second beam blocker comprises a mechanical shutter, preferably a rotating shutter, more preferably a motorized rotating shutter, or an optical beam blocker, preferably a liquid crystal light valve.

[0030] Mechanical shutters are easy and inexpensive to manufacture and operate. In some embodiments, both the coherent light and the incoherent light may be switched using a shutter. By using a rotating shutter in antiphase, alternating illumination with incoherent and coherent light may be achieved at a relatively high frame rate. This allows, for example, multiplexing of coherent and incoherent light images.

[0031] Optical beam blockers have no moving parts and are therefore dust-free. Optical beam blockers are also typically electronically operated, making them fast and relatively simple.

[0032] In one embodiment, the optical coupler includes a first converging lens for reducing the divergence of the incoherent light from the optical input, a second converging lens for focusing the incoherent light into the first light guide (or onto the optical output), and a mirror disposed between the first lens and the second lens for focusing the laser beam into the first light guide (or onto the optical output). lead The mirror may be configured so that:

[0033] Using a lens to focus the incoherent light into the first light guide results in very little light loss. In one embodiment, one or more lenses may be replaced by mirrors, for example, a converging lens may be replaced by a concave mirror, optionally with a hole or window to allow an unobstructed coherent light beam path through the concave mirror.

[0034] In one embodiment, the optical coupler may comprise a tapered light pipe having a wide end for receiving the incoherent light from the optical input and a narrow end for providing the incoherent light to the optical output. The tapered light pipe may be divided into a first section and a second section by a plane that intersects the tapered light pipe between the wide end and the narrow end, the normal to the plane defining a non-zero angle with a longitudinal axis of the tapered light pipe. Preferably, the tapered light pipe may further comprise a protrusion having a surface perpendicular to the coherent light path for receiving the coherent light. The optical coupler is disposed on the longitudinal axis of the tapered light pipe, on the plane between the first and second sections of the tapered light pipe, and couples the laser beam to the first light guide (or onto the optical output). lead The optical system may further include a mirror configured to:

[0035] The use of a tapered light pipe results in less chromatic aberration. The protrusions can increase the amount of coherent light entering the light guide.

[0036] The tapered light pipe and lens embodiments allow for independent switching between the coherent and incoherent light using mechanical or optical shutters in each beam path, so that incoherent and coherent light may be used separately or in combination.

[0037] In one embodiment, the optical switch may comprise an inner light guide for guiding the incoherent light from a first end of the inner light guide to a second end of the inner light guide. The optical switch may further comprise a switch body comprising at least the second end of the inner light guide, wherein the switch body is movable between a first position corresponding to a first state and a second position corresponding to the second state. In the first position, the switch body is configured to interrupt the coherent light beam path and to switch the first end of the inner light guide to receive incoherent light from the light input. of Positioning R and at the second end for injecting the incoherent light into the first light guide. of Positioning R In the second position, the switch body is configured to unblock the coherent light beam path and to block at least the second end of the inner light guide so that the incoherent light does not enter the first light guide. of Positioning R It is structured as follows.

[0038] For example, the beam path from the first coherent light source to the light output may be a path through free space. In the first position, the light guide may be configured to guide the incoherent light to the light output while simultaneously blocking the beam path of the coherent light. By moving the light guide to another position, the coherent light beam path to the light output may be unblocked. In this way, fewer optical components are used to provide the coherent light at the light output, and thus to the first light guide, which is beneficial for the spectrum and coherence length of the coherent light.

[0039] By using an internal light guide to transport the incoherent light, light loss and chromatic aberration can be minimized. Although some incoherent light sources can automatically compensate for the reduction in incoherent light intensity, this compensation is typically limited. Therefore, it is desirable to minimize light loss even in such systems.

[0040] In one embodiment, the inner light guide may be a flexible light guide, preferably a fused fiber bundle or a liquid light guide, and the first end of the inner light guide may be connected to the light input. By connecting the light guide to the light input, the number of interfaces between light guide segments is reduced, which may be beneficial for the light intensity and light quality of the incoherent light.

[0041] In one embodiment, the optical switch may be an electrically operated switch comprising a motor and optionally a servo motor, where the optical switch may be moved between a first position corresponding to a first state and a second position corresponding to a second state. The switch body may be moved via a cam or crank. In another embodiment, the optical switch may be manually operated.

[0042] Manually operated switches can be easier and cheaper to manufacture than electrically operated switches. Electrically operated switches can be substantially faster and easier to operate remotely than manually operated switches. Electrically operated switches can include a motor to move a moving part of the optical switch, such as a movable mirror or the switch body, between a first position and a second position. A servo motor can be used to move the optical switch quickly and accurately.

[0043] In one embodiment, the optical switch may include a first end stop configured to stop the switch at a first position corresponding to the first state and a second end stop configured to stop the switch at a second position corresponding to the second state. The optical switch may further include a spring configured to maintain the switch in the first or second position when the switch is not actuated. This configuration may be reliable and accurate, as well as less expensive than using a servo motor.

[0044] In one embodiment, the optical switch is configured to automatically switch back and forth between the first state and the second state, preferably at a frequency of at least 10 Hz, more preferably at a frequency of at least 30 Hz, and even more preferably at a frequency of at least 100 Hz.

[0045] By alternating between the two illumination conditions, alternating images can be acquired that are useful for further processing, where, for example, an image based on coherent light imaging is overlaid onto a preceding or subsequent incoherent light image, thus combining information from the two imaging modalities.

[0046] In one embodiment, the optical input connector is configured to connect, preferably releasably connect, to the incoherent light output of the endoscopic system via a light pipe; i.e., the second light guide may be a light pipe. In another embodiment, the optical input connector is configured to connect, preferably releasably connect, to the incoherent light output of the endoscopic system via a flexible light guide, preferably a fiber bundle, a fused fiber bundle, or a liquid light guide; i.e., the second light guide may be a flexible light guide. A rigid connection using a light pipe results in very little light loss, while a flexible connection using an optical fiber allows for more flexible placement of the coupling device relative to the incoherent light source of the endoscopic system.

[0047] In one embodiment, the first light source is a narrow bandwidth laser, preferably having a spectral bandwidth of less than 1 nm, more preferably less than 0.2 nm, and even more preferably less than 0.1 nm.

[0048] In one embodiment, the first light source may have a coherence length of at least 0.35 mm, preferably at least 1.5 mm, more preferably at least 3.5 mm.

[0049] In one embodiment, the first light source can be a laser having an output power of at least 20 mW, preferably at least 100 mW, and more preferably at least 150 mW.

[0050] High-quality laser speckle contrast images can be obtained using a coherent light source with a narrow spectral bandwidth and a long coherence length. A coherent light source with a power output of at least 20 mW can prevent underexposure during imaging, depending on the area to be imaged.

[0051] In one embodiment, the first wavelength may be selected in the red portion of the electromagnetic spectrum, preferably 600 to 700 nm, more preferably 630 to 660 nm, hi another embodiment, the first wavelength may be selected in the infrared portion of the electromagnetic spectrum, preferably 700 to 1200 nm, more preferably 700 to 900 nm, even more preferably 770 to 790 nm or 820 to 840 nm.

[0052] For laser speckle contrast imaging, such as perfusion imaging, red light is preferred because it has a relatively large penetration depth and is well reflected by red blood cells. If an RGB camera or equivalent component of the endoscopy system is used, the first wavelength can be selected to be imaged by the red channel of the RGB camera. Infrared light can also be used for laser speckle contrast imaging and has a larger penetration depth than red light. Infrared light can also be used for ICG-based fluorescence imaging. Infrared light imaging can be simultaneously combined with white light imaging. A further advantage of using infrared light is that laser speckle contrast imaging and ICG-based fluorescence imaging can be performed simultaneously.

[0053] Some endoscopes may be equipped with filters that block infrared light and / or may not be configured to detect infrared light. Thus, using coherent light in the visible spectrum may allow the coupling device or imaging system to be used with a wider range of endoscopes.

[0054] In one embodiment, the coupling device may further comprise a second light source for producing light at a second wavelength; and an optical coupler for combining light at the first wavelength with light at a second wavelength, wherein the optical coupler preferably comprises a dichroic mirror for selectively reflecting light at the first wavelength or light at the second wavelength.

[0055] A second coherent light source can be advantageous for laser speckle contrast imaging because images obtained using the second wavelength can be used to correct images obtained using the first wavelength.

[0056] In one embodiment, the second wavelength may be selected in the blue or green portion of the electromagnetic spectrum, preferably between 380 and 590 nm, more preferably between 470 and 570 nm, and even more preferably between 520 and 560 nm.

[0057] For laser speckle imaging, it is advantageous if the second wavelength has a small penetration depth and is largely reflected by the tissue being imaged. If an RGB camera or equivalent component of an endoscopy system is used, the second wavelength can be selected to be imaged by the green or blue channel of the RGB camera. Preferably, the first and second wavelengths are sufficiently separated in the electromagnetic spectrum to limit crosstalk between the RGB channels.

[0058] The endoscope system may further include a camera, preferably an RGB camera, configured to provide a video signal. In one embodiment, the coupling device may further include a video signal input connector for receiving the video signal, a video signal output connector for providing a video output, and an image processing module for generating a coherent light image, preferably a fluorescence image and / or a laser speckle contrast image, based on the video signal when the optical coupler guides coherent light through the first light guide.

[0059] In general, instead of an RGB camera, a dual or triple monochrome camera, e.g., a CCD camera, with different color filters, e.g., red and green filters, or a wavelength-selective beam splitter, e.g., a prism, may be used. Alternatively, a single monochrome camera with a mechanically, optically, or electrically switchable color filter or other wavelength-based selection device may be used. In such cases, the red channel of the RGB camera may be read, for example, as a monochrome camera configured to measure light in the red portion of the electromagnetic spectrum, and similarly, mutatis mutandis, for references to the green and blue channels, as appropriate. This relates both to cameras in endoscopic systems and to cameras in imaging systems according to embodiments of the present invention.

[0060] In one embodiment, in the first state, the video signal may be looped to the video output. In the second state, the video signal may be provided to the image processing module. The image processing module may be configured to determine one or more output images, preferably laser speckle contrast images or fluorescence images, based on the video signal. One or more output images may be provided to the video signal output connector.

[0061] The inclusion of an image processing module avoids the need to use a separate image processing module to process the coherent light image.

[0062] In one embodiment, the coupling device may further comprise a frame grabber for converting the continuous video input signal into discrete frames for processing by the video processing module.

[0063] In one embodiment, the coupling device may further comprise a first sensor, preferably an optical sensor, and a controller connected to the first sensor, which may be configured to send the first signal to the controller only if the first light guide is connected to the optical output connector, and the controller configured to switch off or block the first coherent light source and optionally the second coherent light source if the controller does not receive the first signal.

[0064] In one embodiment, the coupling device may further comprise a second sensor, preferably an optical sensor, and a controller connected to the second sensor, which may be configured to send a second signal when the optical switch is in the second state, and configured to switch off or block the first coherent light source and optionally the second coherent light source if the controller does not receive the second signal.

[0065] Such a sensor may increase the safety of the coupling device by preventing coherent light from leaving the coupling device when a first light guide is not connected to supply the coherent light.

[0066] In one embodiment, the coupling device may further comprise a control switch for generating a trigger signal or a trigger input for receiving a trigger signal, and the optical switch is configured to switch from the first state to the second state in response to receiving a trigger signal.

[0067] In one embodiment, the coupling device may further comprise a data storage medium or a data output.

[0068] The endoscopic systems described in this disclosure are not limited to medical endoscopic systems and may include similar systems equipped with incoherent light sources and light delivery systems from other fields, such as manufacturing, gunsmithing, or aviation. Endoscopic systems in non-medical fields are sometimes called borescopes or fiberscopes. They may be used, for example, for visual inspection of the inside diameters of engines and firearms.

[0069] In a further aspect, the present invention may relate to an image processing system for generating a coherent light image in an endoscopy system. The endoscopy system may comprise an incoherent light source, a video processing unit, and an endoscope, wherein the endoscope may be connected to a camera. In one embodiment, the image processing system may comprise a coupling device according to one of the embodiments described above and a video processing device. The video processing device may include a video signal input connector for receiving a video signal from the camera. device may further comprise a first video signal output connector for providing a video output, wherein the first video signal output connector is configured to be connected to a video signal input of the video processing unit of the endoscope system. device may include an image processing module for generating a coherent light image based on the video signal when the optical switch is in a first state.

[0070] In one embodiment, the image processing system may further comprise a second video signal output connector configured to be connected to a second display, wherein the image processing system is configured to provide an incoherent light image to the first video output when the optical switch is in a first state, and to provide a coherent light image to a second video signal output when the optical switch is in a second state.

[0071] In one aspect, the present invention may relate to an imaging system for generating an infrared coherent light image in an endoscopic system, the endoscopic system including an incoherent light source, an endoscope, and a light delivery system for delivering light to the endoscope. In one embodiment, the imaging system may include the coupling device described above, wherein the first wavelength may be selected in the infrared portion of the electromagnetic spectrum, preferably between 700 and 1200 nm, more preferably between 700 and 900 nm, and even more preferably between 770 and 790 nm or between 820 and 840 nm. The imaging system may further include an infrared imaging sensor configured to receive light collected by the endoscope, and an image processing module configured to receive a video signal from the infrared imaging sensor and determine a coherent light image based on the received video signal.

[0072] The infrared imaging sensor may be included in an RGB / IR camera or equivalent device, i.e., a camera configured to image images in both the visible and infrared portions of the electromagnetic spectrum using a single sensor array. Alternatively, the imaging sensor may further include a beam splitter to split light reflected by a target into an infrared portion that is imaged by the infrared imaging sensor and a visible portion that is imaged by an RGB camera included in any of the endoscopy systems or imaging systems described above.

[0073] In one aspect, the present invention can relate to an endoscopic system, preferably a laparoscopic system, including the above-described coupling device.

[0074] In one aspect, the present invention may relate to a method for generating a coherent light-based image of a target region in a patient's body using an endoscopic system. The endoscopic system may include an incoherent light source for generating incoherent light, e.g., white light; and an endoscope, wherein the endoscope includes an insertion tube for insertion into the patient's body, a light delivery system for illuminating the target region, and an image sensor for acquiring an image of the target region. The endoscope may be connected, preferably releasably connected, via a first light guide to a coherent light coupling system, wherein the coherent light coupling system receives incoherent light from the incoherent light source via a second light guide; receives or generates coherent light of a first wavelength; and selectively provides the coherent light and / or the incoherent light to the first light guide, wherein the coherent light and the incoherent light preferably have a shared optical path in the first light guide. In one embodiment, the method may include receiving a first trigger signal; and providing coherent light to the light delivery system in response to receiving the first trigger signal. The method may further include receiving the video stream from the image sensor, where the video stream includes a signal representing the light intensity of the coherent light reflected or dispersed by the target area. The method may further include determining a coherent light image, such as a laser speckle contrast image or a fluorescence image, based on the video stream.

[0075] In one embodiment, the method may further include displaying and / or storing the determined coherent light image.

[0076] In one embodiment, the method may further include, in response to receiving a second trigger signal or a predetermined time after receiving the first trigger signal, providing the incoherent light to the light delivery system, and preferably blocking the coherent light from entering the light delivery system.

[0077] The present invention may also relate to a computer program or a suite of computer programs including at least one software code portion, or a computer program product storing at least one software code portion, which software code portion is configured to perform one or more of the method steps described above when said software code portion is executed on a computer system.

[0078] The present invention may also relate to a non-transitory computer-readable storage medium storing at least one software code portion, the software code portion being configured to perform one or more of the method steps described above when executed or processed by a computer.

[0079] The invention will be further explained with reference to the accompanying drawings, which show, in a schematic manner, embodiments according to the invention, it being understood that the invention is in no way limited to these particular embodiments.

[0080] The following description of illustrative embodiments of the present invention is merely exemplary in nature and is in no way intended to limit the present teachings, their application, or uses. [Brief explanation of the drawings]

[0081] [Figure 1] FIG. 1 illustrates a schematic diagram of an endoscope system enhanced with a coupling device to provide coherent optical imaging in accordance with an embodiment of the present invention. [Figure 2A] FIG. 2A illustrates a schematic diagram of a coupling device according to an embodiment of the present invention. [Figure 2B] FIG. 2B schematically illustrates a coupling device according to an embodiment of the present invention. [Figure 3] FIG. 3 illustrates a schematic diagram of a coupling device according to one embodiment of the present invention. [Figure 4A]FIG. 4A illustrates a schematic diagram of a coupling device according to an embodiment of the present invention. [Figure 4B] FIG. 4B schematically illustrates a coupling device according to an embodiment of the present invention. [Figure 5A] FIG. 5A illustrates a schematic diagram of an optical switch according to an embodiment of the present invention. [Figure 5B] FIG. 5B schematically illustrates an optical switch according to an embodiment of the present invention. [Figure 5C] FIG. 5C schematically illustrates an optical switch according to an embodiment of the present invention. [Figure 5D] FIG. 5D schematically illustrates an optical switch according to an embodiment of the present invention. [Figure 6A] FIG. 6A illustrates a schematic diagram of an optical switch according to an embodiment of the present invention. [Figure 6B] FIG. 6B schematically illustrates an optical switch according to an embodiment of the present invention. [Figure 6C] FIG. 6C schematically illustrates an optical switch according to an embodiment of the present invention. [Figure 7A] FIG. 7A schematically illustrates a connection between a light source unit and a coupling device of an endoscope system, according to an embodiment of the present invention. [Figure 7B] FIG. 7B schematically illustrates a connection between a light source unit and a coupling device of an endoscope system, according to an embodiment of the present invention. [Figure 8] FIG. 8 illustrates a schematic diagram of a system for adding coherent optical imaging capabilities to an endoscopic system, in accordance with an embodiment of the present invention. [Figure 9] FIG. 9 illustrates a method for generating a coherent light image according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0082] 1 schematically illustrates an endoscopic system enhanced with a device providing coherent optical imaging according to an embodiment of the present invention. Endoscopic systems 1001 and 1002 may comprise a light source unit 102, a display unit 104, and an endoscope 106, such as a laparoscope. Endoscopic systems 1001 and 1002 may comprise a light source unit 102, a display unit 104, and an endoscope 106, such as a laparoscope.

[0083] The light source unit 102 may include a light source 108, e.g., a white light source, for generating incoherent light. The light source unit may further include a controller 110 for controlling the light source, e.g., for controlling the light intensity or spectral quality of the light source. The controller may be configured to receive input from a user and / or from other system components. The light source unit may further include an optical output connector 112 for connecting to an optical input of the endoscope 106, e.g., a light guide 124.

[0084] The endoscope 106 may include a handle 114 for manipulating the endoscope and an insertion tube 116. The insertion tube may have a proximal end connected to the handle and a distal end with a tip 118 for insertion into a patient. The insertion tube may be a rigid tube or shaft, or may be a flexible tube.

[0085] The endoscope may further include an optical input for receiving light via an input light guide 124, for example, a fiber optic bundle, which may be connectable to a handle or to an insertion tube.

[0086] The insertion tube may include a light guide 120 for guiding light from the light input to the tip 118 for illuminating a target area 130. The optical components between the light output 112 of the light source unit and the tip of the endoscope may be collectively referred to as the light delivery system of the endoscope system.

[0087] The endoscope may further include an image sensor 116, such as an RGB camera, for imaging the target area. In some endoscopes, the image sensor may be located at the tip of the endoscope, and such systems are also referred to as chip-on-the-chip systems. In other endoscopes, the image sensor may be located in the handle, and the insertion tube may include an optical guide, such as a rod lens, for guiding light reflected or emitted by the target area to the optical sensor.

[0088] In some endoscopes, the handle 114 and insertion tube 116 may be detachable, so it may be possible to replace the image sensor 122 with a different type of image sensor while retaining the same insertion tube 116.

[0089] The endoscope may be connectable to a video input connector 132 of the display unit 104 using a video signal cable 126. The endoscope may further include a wired or wireless connection, for example, for remotely controlling the light source unit 102 and / or the display unit 104. For example, the video signal cable may also be a data cable that allows bidirectional data transfer. The endoscope may further include a power supply or power connector for receiving power to operate the image sensor.

[0090] The display unit 104 may include a video input connector 132 for receiving video input from the endoscope 106. The display unit may further include a video processor 134 for processing the video input signal, and a display 136 for displaying video or images received from the endoscope. The display may receive video input from the video processor via an (external) video cable 138 connecting the video processor's video output connector 133 and display input connector 135. In other embodiments, the display may receive input from the video processor via an internal connection.

[0091] The display unit 104 may further include a controller configured to receive input from a user and / or from other system components, for example, to pause the video or take a snapshot. The display unit may also provide output to other system components; for example, the display unit may communicate with the light source unit 102 to adjust the light intensity if an image in the video input signal appears overexposed or underexposed. The display unit may further include or be connectable to a storage device, for example, for storing image data. In other endoscopic systems, the display may be a separate device from the coupling device that includes the video processor. In some endoscopic systems, the video processor and light source may be included in a single device.

[0092] Thus, the endoscopic systems 1001, 1002 described thus far can be (commercially available) endoscopic systems for imaging a target region 130 within a patient's body using incoherent light, e.g., white light. Certain embodiments of the present disclosure relate to a device that allows the same or essentially the same endoscopic system for imaging the target region using coherent light, e.g., laser light, to be used together with or alternately with incoherent light imaging. Thus, imaging capabilities, particularly fluorescence imaging and / or laser speckle contrast imaging, can be added to existing endoscopic systems without the need to replace the light source or at least the insertion tube of the endoscope.

[0093] Therefore, a coupling device 140 for coupling coherent light into the light delivery system of the endoscopic system may be inserted between the light output 112 of the light source unit and the light input of the endoscope. The coupling device may include a light input 142 for receiving the incoherent light from the endoscopic system and a light output 144 for providing the incoherent light to the light delivery system. The light input may include a light input connector for releasably connecting a light guide 158. Similarly, the light output may include a light output connector for releasably connecting a light guide 124.

[0094] In the illustrated embodiment, the optical input 142 of the coupling device may be connectable to the optical output 112 of the light source unit 102 of the endoscopic system via a light guide 158, e.g., a fiber bundle. The optical output 144 of the coupling device may be connectable to the optical input of the endoscope via a light guide 124. In a setup without the coupling device, the light guide 124 may be connected directly to the optical output 112 of the light source unit. A releasable connection to connect and disconnect the light guide to the light source is a standard feature of endoscopic systems.

[0095] Coupling device 140 may further include a first light source 146, e.g., a laser, for generating coherent light at a first wavelength. In a different embodiment, the laser source may be a separate device, and the coupling device may include a coherent light input for receiving coherent light at the first wavelength from the separate laser source. The coupling device may further include an optical switch 148 for selectively coupling the coherent light at the first wavelength into optical output 144 and thus into light guide 124 when light guide 124 is connected. The coupling device may also include a controller for controlling the optical switch.

[0096] In one embodiment, the coupling device 140 may further comprise a video signal input connector 152 for receiving a video input signal. The video signal may be pre-processed by a video processor 134 or may be obtained directly from the image sensor 122 in the endoscope. The coupling device may also comprise a video signal output connector 154 for providing a video output signal. The coupling device may further comprise an image processing module 156 for processing the video signal. Dedicated image processing software may exploit the possibilities of coherent light imaging, for example, by implementing laser speckle contrast imaging. In another embodiment, the image processing module and the video signal input / output connector may be embodied in separate devices.

[0097] In the illustrated embodiment, the video signal input connector 152 of the coupling device may be connectable to the video signal output of the display unit 104 via a signal cable 138. In other embodiments, the video signal input connector of the coupling device may be connectable directly to the video signal output of the endoscope 106. In some such embodiments, the signal cable may enable bidirectional data transfer, as well as sending trigger or control signals, for example, from the endoscope to the coupling device or vice versa. The video signal output connector 154 of the coupling device may be connectable to the display input connector 135 of the display unit 104 via a signal cable 160. In a setup without the coupling device, the signal cable 138 may be connected directly to the display input connector 135.

[0098] 2A and 2B schematically illustrate a coupling device according to an embodiment of the present invention. In particular, FIG. 2A illustrates a very basic embodiment of a coupling device 200 for coupling coherent light into a light delivery system of an endoscopic system. The depicted coupling device includes an optical input 202 for receiving incoherent light, e.g., white light, from a light source of the endoscopic system and an optical output connector 204 for connecting to the light delivery system of the endoscopic system. The coupling device further includes a coherent light input 206 for receiving coherent light of a first wavelength. The coherent light input optionally includes a collimator for preventing or reducing divergence of the coherent light beam. The coupling device further includes an optical coupler 208 for receiving the incoherent light and the coherent light and for providing a coupled light beam. The coupled light beam may include the coherent light and the incoherent light simultaneously and / or alternately. The coupling device is further configured to couple the coupled light beam to the light output 204 .

[0099] Thus, the coupling device may be configurable in a first state and a second state, which may partially or completely overlap. In the first state, the coupling device may comprise an unobstructed incoherent light beam path for propagating the incoherent light from the light input to the light output. In the second state, the coupling device may comprise an unobstructed coherent light beam path for propagating the coherent light from the coherent light source or the coherent light input to the light output. The optical coupler may couple or combine the incoherent light beam path and the coherent light beam path onto a shared optical path configured to simultaneously and / or alternately input the incoherent light and the coherent light into the light output, and thus, if present, into a light guide connected to the optical output connector.

[0100] The optical coupler 208 may be a static optical coupler that simultaneously combines the incoherent light and the coherent light onto a single optical path, such as a Y-cable that joins the fiber connected to the incoherent light input and the fiber connected to the coherent light input into a single fiber bundle. However, such an implementation is not preferred due to optical losses associated with a Y-cable, particularly with respect to the incoherent light. Therefore, the optical output 204 may simultaneously provide both incoherent light and coherent light to the light delivery system. Alternatively, the optical coupler 208 may be an optical switch for selectively coupling coherent light to the optical output 204. Thus, the optical output may provide either only the incoherent light or only the coherent light, and / or both the incoherent light and the coherent light, depending on the optical switch. Optical coupler implementations are discussed in more detail with reference to FIGS. 5A-5D.

[0101] Figure 2B illustrates a similar coupling device 210, as described above with reference to Figure 2A, comprising an optical input 212, an optical output 214, and an optical coupler 218. The coupling device 210 further comprises a first coherent light source 216 for generating coherent light at a first wavelength.

[0102] Using a coherent light input configured to receive coherent light from an external coherent light source, as in Figure 2A, can result in a small coupling device that can be positioned in an endoscope system in an almost unlimited manner. For example, in some embodiments, the coupling device can be inserted directly into the light output of the light source unit of the endoscope system. This can result in very low white light loss, as described below with reference to Figure 7.

[0103] Additionally, the use of a coherent light input allows different laser sources to be connected, which can be selected based on different imaging needs.

[0104] On the other hand, if the coupling device includes an (internal) first coherent light source, as in Figure 2B, the coherent light may propagate through free space to the optical output, or at least to the optical coupler. This may result in higher quality coherent light (e.g., higher power, smaller spectral bandwidth, and / or longer coherence length) because there is no need to use optical components, such as optical fibers, that may adversely affect the quality of the coherent light. External coherent light sources and free-space coherent light propagation are typically not possible due to safety issues and alignment difficulties.

[0105] Figure 3 schematically illustrates a coupling device according to an embodiment of the present invention. In particular, Figure 3 illustrates a coupling device 300 comprising an optical input 302, an optical output 304, and a first coherent light source 306 for generating coherent light of a first wavelength as described above with reference to Figures 2A and 2B. The coupling device also comprises an optical switch 308 for selectively coupling the coherent light into the optical output 304.

[0106] The coupling device 300 may further include an interface 310 for operating the light switch 308. The interface may include a physical trigger, such as a button, on the coupling device, or a software-based trigger, such as a function on a touchscreen (a virtual button). In other embodiments, the interface may include an input for receiving a wired or wireless trigger signal from an external device, such as part of the endoscope system or an external control device. A wireless trigger signal may use, for example, Wi-Fi, Bluetooth, or an acoustic or optical communication protocol. Some endoscope systems may be configured to provide a trigger signal when a function of the endoscope system, such as a photo-taking function, is activated. Such a trigger signal may be used to activate the light switch. The external control device may be operable by an operator of the endoscope system, such as a surgeon or endoscopist, and may include a foot switch or remote control, preferably a foot switch or remote control that can be attached to the handle of the endoscope, for example, using an elastic band. The interface may also include, for example, a microphone and voice recognition software for voice-based operation of the light switch. The interface may further provide feedback, preferably visual feedback, regarding the state of the light switch.

[0107] The optical switch 308 may be configured to switch between a first state in which the coherent light is not coupled to the optical output 304 and a second state in which the coherent light is coupled to the optical output 304. In this way, an operator may choose to use or not use the laser light without removing the coupling device.

[0108] In one embodiment, in the first state, the optical switch 308 may be configured to provide the incoherent light at the optical output 304. In the second state, the optical switch may be configured not to provide the incoherent light at the optical output 304. In many applications, a user may want to switch between only incoherent light and only coherent light.

[0109] In some embodiments, optical switch 308 may be configured to switch to a third state, in which the optical switch may be configured to provide both the coherent light and the incoherent light at optical output 304.

[0110] Interface 310 may include a mechanical or electrical trigger. In the case of a mechanical trigger, the switch may be manually operated by shifting it between a first position corresponding to the first state and a second position corresponding to the second state. In such an embodiment, the coupling device may not include a controller.

[0111] In another embodiment, coupling device 300 may further include a controller 312 for controlling the optical switch. In such an embodiment, the interface may send a trigger signal to the controller, which in turn operates the optical switch. In a typical embodiment, the optical switch is an electrically actuated switch having a movable mechanical part actuated by a motor controlled by the controller.

[0112] In some embodiments, the controller may control the optical switch to switch between the first state and the second state independently of a trigger signal, e.g., at fixed time intervals. In such embodiments, the coupling device need not include an interface.

[0113] 4A and 4B schematically illustrate coupling devices according to embodiments of the present invention. In particular, FIG. 4A illustrates a coupling device 400 comprising an optical input 402, an optical output 404, an optical switch 408, an interface 410, and a controller 412, as described above with reference to FIGS. 2A, 2B, and 3.

[0114] The coupling device further includes a first coherent light source 4061 for generating coherent light of a first wavelength, a second coherent light source 4062 for generating coherent light of a second wavelength, and a laser coupler 407, e.g., a dichroic mirror or a polarizing beam splitter, for coupling the coherent light of the first wavelength with the coherent light of the second wavelength. Alternatively, fiber-based laser coupling, as described below with reference to FIG. 4B , may be used. Typically, the second wavelength is different from the first wavelength. By using a laser coupler, the coherent light of the first wavelength and the coherent light of the second wavelength can be combined onto a single optical path.

[0115] A second coherent light source can be advantageous for laser speckle contrast imaging because the image obtained using the second wavelength can be used to correct the image obtained using the first wavelength. A dichroic mirror is an efficient way to couple or combine the light of the second wavelength with the light of the first wavelength. In some embodiments, more coherent light sources can be added in a similar manner. This can be useful, for example, for three-dimensional laser speckle contrast imaging based on laser speckle contrast images obtained with coherent light of multiple different wavelengths.

[0116] The coupling device 400 may further include an image processing module 420. The image processing module may receive a video signal from a video input connector 422 and provide a video signal to a video output connector 424. Typically, an endoscope may be connected to the video signal input connector, either directly or indirectly, for example via a video processor of the endoscope system, and a display unit may be connected to the video signal output connector.

[0117] The video signal may be an analog signal or a digital signal. The video processing module 420 may include a frame grabber 426 for converting the video signal into individual images suitable for further processing. The video processing module may include a buffer 428 for temporarily storing one or more images. The one or more images may then be processed by an image processor 430. The image processor may include a computer-readable storage medium having computer-readable program code embodied therein and a processor, preferably a microprocessor, coupled to the computer-readable storage medium.

[0118] The image processor may be configured to compute, for example, laser speckle contrast images or fluorescence images. For example, the image processor may be configured to perform an LSCI-based clinical perfusion imaging scheme, such as that described in the review article by W. Heeman et al., "Clinical applications of laser speckle contrast imaging: a review," J. Biomed. Opt. 24:8 (2019), which is hereby incorporated by reference. Additionally or alternatively, the image processor may be configured to perform a fluorescence-based clinical perfusion imaging scheme, preferably ICG-based fluorescence imaging, as described in A.V.D. Souza et al., "Review of fluorescence-guided surgery systems: identification of key performance capabilities beyond indocyanine green imaging," J. Biomed. Opt. 21:8 (2016).

[0119] The video processing module 420 may further include a signal converter 426 for converting the output generated by the image processing device into an output video signal that is compatible with the input video signal. For example, if the video processing module receives an SDI signal from the video input and the image processing device outputs an HDMI signal, the image converter may be an HDMI to SDI converter. Thus, the video output signal is compatible with the video input signal, ensuring that it can be processed by the display unit in the same way as the signal from the endoscope.

[0120] In one embodiment, the coupling device may include a screen or be connectable to another display, in which case a signal converter may not be necessary. Similarly, if the image processing device provides the same type of output as that received from the endoscope, a signal converter may not be necessary. In one embodiment, the coupling device may have multiple video output connectors, for example, a first output connector for outputting an unprocessed video signal and a second output connector for outputting a processed signal.

[0121] In one embodiment, the video processing module 420 may be in communication with the controller 412. The video processing module may then, for example, cause the optical switch to provide an unprocessed signal in the first state, providing only incoherent light, e.g., only white light, to the endoscope, and the optical switch to provide a processed signal in the second state, providing coherent light to the endoscope. In one embodiment, the video processing module and the controller may be implemented as software modules on the same hardware module.

[0122] The coupling device 400 may further include a storage 434 for storing images, or a storage output connector for connecting to an external storage device. The coupling device may be configured to store only when a storage signal is received from the controller 412, for example, to store all image data, to store only processed and / or unprocessed image data when the optical switch is in the second state, or to store only processed and / or unprocessed image data when the optical switch is in the second state.

[0123] The coupling device 400 also includes electrical components, such as one or more laser sources 406 1~2The laser source 408 may include a power supply 416 for providing power to the laser source, the optical switch 408, the controller 412, the video processing module 420, and any other components requiring power. One or more thermal control units 414, which may include, for example, a heat sink and / or a fan, may control the temperature of one or more of the components, the laser source, and the video processing module. One or more status LEDs 436 may indicate the status of various components, such as power provided by the power supply, the status of the optical switch, whether the optical output connector is engaged, etc. A housing may protect the components.

[0124] Figure 4B schematically illustrates a system including a coupling device 440 and a processing device 450. The coupling device 440 may include an optical input 442, an optical output 444, and an optical switch 448, as described with reference to Figure 4A. The processing device 450 may include an interface 460, a controller 462, a thermal control 464, a power supply 466, a video input connector 472, a video output connector 474, a storage means 484, one or more status LEDs 486, and a video processing module 470, which may include a frame grabber, a buffer, an image processor, and a signal converter, as described with reference to Figure 4A.

[0125] Processing device 450 may further comprise a first coherent light source 4561, a second coherent light source 4562, and a laser coupler 457. In the depicted example, the laser coupler may comprise a fiber coupler. The coherent light is guided from processing device 450 to coupling device 440 using optical fiber 447, thereby providing an efficient way of combining multiple laser light sources. In other embodiments, the first coherent light and the second coherent light may first be combined using a laser coupler, as described with reference to feature 407 in FIG. 4A, and the coupled or combined coherent light beam may subsequently be launched into a fiber.

[0126] An optical fiber 447 may be connectable to a coherent light input 446 of the coupling device 440. Optionally, the coherent light input may include a collimator. The coupling device may include one or more cables 449 for receiving power and control signals to operate an optical switch 448. 1~2 may be further connectable to the processing device 450 by

[0127] 5A-5D schematically illustrate optical switches according to embodiments of the present invention. Some of the embodiments described below with reference to FIGS. 5A-5D may be implemented as non-switching optical couplers. These embodiments are typically more optically efficient than, for example, the Y-cable coupler described above with reference to FIG. 2A.

[0128] In particular, FIG. 5A illustrates an optical switch 500 including an incoherent light input 502, a coherent light input 520, and an optical output 506. The incoherent light input may be configured to receive incoherent light via a first light guide 504, such as a light pipe or fiber bundle. The incoherent light input may be an optical input of a coupling device or may be optically connected to the optical input. The optical output may be an optical output of the coupling device or may be optically connected to the optical output. The optical output may then provide light to a second light guide 508, which may be an internal light guide or a light guide of an endoscopic system.

[0129] The optical switch 500 may further include a first converging lens 512 for reducing the divergence of the incoherent light 510 from the coherent light input 502 and a second converging lens 514 for focusing the incoherent light onto the light output 506. In an alternative embodiment, one or more of the converging lenses may be replaced by one or more concave mirrors. Concave mirrors may have better optical qualities than lenses, e.g., less light absorption and / or less chromatic aberration; however, lenses may be less expensive than concave mirrors. It will be apparent to those skilled in the art that if a concave mirror is used, the position of the incoherent light input, and optionally the position of the coherent light input, may be adjusted accordingly.

[0130] Optical switch 500 may be further configured to receive coherent light from a coherent light source 522 or via a third light guide, such as an optical fiber. If the coherent light propagates through free space, coherent light input 520 may simply be a hole or window in the housing of the optical switch. In some embodiments, particularly if the coherent light input receives the coherent light via a third light guide, the optical switch may include a third converging lens 524 to reduce the divergence of coherent light beam 526.

[0131] The optical switch 500 may further include a mirror 528 disposed between the first converging lens 512 and the second converging lens 514. The mirror may be configured to steer the coherent light beam 526 onto the optical output 506. Because the coherent light beam has a much smaller diameter than the incoherent light beam 510, the mirror may be small relative to the diameter of the incoherent light beam. The mirror may be mounted using a compact, optionally transparent, holder. Thus, the intensity loss of the incoherent light may be small. Because both the incoherent light 510 and the coherent light 526 travel through free space between the optical inputs 502 and 520 and the optical output 506, intensity loss is further minimized.

[0132] Optical switch 500 may further include a first shutter 530, preferably a rotating shutter, disposed between coherent light input 520 and mirror 528. The first shutter may be configured to move between a first state in which it blocks coherent light beam 526 and a second state in which it does not block the coherent light beam. By closing and opening the first shutter, the optical switch may be switched between a first state in which no coherent light is coupled to the light output and a second state in which the coherent light is coupled to the light output.

[0133] In alternative embodiments, the first shutter 530 may be a non-mechanical light blocking mechanism, such as a liquid crystal light valve, an acousto-optic modulator, an electro-optic modulator such as a Pockels cell, or an opto-elastic modulator. In some cases, the coherent light may need to be polarized, for example, by using a polarized laser source or by inserting a polarizer between the coherent light source and the first shutter.

[0134] In other embodiments, the coherent light beam 526 may be steered onto or away from the light output 506 by moving the mirror 528. In such embodiments, the first shutter 530 may be removed. Alternatively, the mirror may be a switchable mirror, such as an electro-optically switchable mirror. The switchable mirror may be switched between a transparent state in the first state of the optical switch and a reflective state in the second state of the optical switch. Depending on the size of the mirror, the movable or switchable mirror may also be used to block the incoherent light in the second state, thus eliminating the need for the second shutter 532.

[0135] By choosing appropriate placements for the incoherent light input and the coherent light input, a single mirror may be used to reflect either the incoherent light or the coherent light to the light output.

[0136] In yet another embodiment, the coherent light may be switched on and off by switching on and off a coherent light source. In this way, no moving parts need be involved. However, using a shutter may be faster than switching on and off the coherent light source.

[0137] Optionally, optical switch 500 may include a second shutter 532, preferably a rotating shutter, disposed between incoherent light entrance 502 and mirror 528. The second shutter may be configured to move between a first state that does not block incoherent light beam 510 and a second state that blocks the incoherent light beam. Alternatively, the second shutter may be implemented as a liquid crystal light valve.

[0138] The first shutter 530 and optionally the second shutter 532 may be moved by one or more actuators 534 .

[0139] In one embodiment, the first shutter 530 and the second shutter 532 may be operated in conjunction such that when the first shutter blocks the coherent light beam 526, the second shutter does not block the incoherent light beam 510, and vice versa. In other embodiments, the first shutter and the second shutter may be operated independently, and the incoherent light and the coherent light can be used separately or together.

[0140] The first shutter 530 and the second shutter 532 may be rotating shutters, allowing for rapid switching between the first and second states. By using rotating shutters in antiphase, alternating illumination with incoherent and coherent light may be obtained at relatively high frame rates.

[0141] Thus, the optical switch 500 may be configured to automatically switch back and forth between the first and second states, preferably at a frequency of at least 10 Hz, more preferably at a frequency of at least 30 Hz, and even more preferably at a frequency of at least 100 Hz. By alternating between the two illumination states, alternating images may be acquired, which may be useful for further processing; for example, an image based on coherent light imaging may be superimposed or shown alongside a preceding or subsequent incoherent light image, thereby combining information from the two imaging modalities.

[0142] In another embodiment, a static optical coupler can be obtained by removing the shutters 530 and 532 and the actuator 534 .

[0143] In other embodiments, the positions of incoherent light entrance 502 and coherent light entrance 520 may be swapped, and mirror 528 may be configured to reflect incoherent light from the incoherent light entrance to light output 506. The mirror may further comprise a hole or window to allow the coherent light beam to propagate from the coherent light entrance to the light output.

[0144] In yet another embodiment, both the incoherent light entrance portion 502 and the coherent light entrance portion 520 may be positioned obliquely downward relative to the light output portion 506, and the mirror 528 may have two or more reflective surfaces for reflecting the coherent light and / or the incoherent light to the light output portion.

[0145] In yet another embodiment, the coherent light input may be located near the incoherent light input, for example, both on opposite walls of the light output, and the coherent light and / or the incoherent light may be positioned to input light at a small angle to the light output. In such an embodiment, the mirror may be eliminated. However, an embodiment including a mirror may be easier to align and have less light loss, since both the coherent light and the incoherent light may be input to the light output at an optimal angle.

[0146] Figure 5B illustrates an optical switch 540 comprising an incoherent light input portion 542, a coherent light input portion 550, and an optical output portion 544, as described with reference to Figure 5A. Optical switch 540 may further comprise a first shutter 558, a second shutter 560, and an actuator 562, as described with reference to Figure 5A.

[0147] 5A, optical switch 540 may include a tapered light pipe 548 having a wide end for receiving incoherent light 546 from incoherent light input 542 and a narrow end for providing the incoherent light and / or the coherent light to optical output 544. The incoherent light beam leaving the incoherent light input is typically highly divergent. Therefore, the optimal width of the wide end depends on the distance between the incoherent light input and the wide end.

[0148] The tapered light pipe 548 may be divided into first and second sections by a plane 549 that intersects the tapered light pipe between the wide end and the width end, with a normal to the plane defining a non-zero angle with the longitudinal axis of the tapered light pipe. The optical switch may further include a mirror 554 disposed on the plane and configured to steer the coherent light beam 552 onto the optical output 544. The tapered light pipe may include a protrusion 556 having a surface perpendicular to the coherent light path to minimize light reflections off the surface of the tapered light pipe.

[0149] The use of tapered light pipes instead of lenses can minimize chromatic aberration, especially for the incoherent light.

[0150] FIG. 5C illustrates an optical switch 570 comprising an incoherent light input portion 572, a coherent light input portion 578, and an optical output portion 574, as described with reference to FIG. 5A.

[0151] Optical switch 570 may further comprise a switch body 584 that may be moved between a first position corresponding to a first state of optical switch 570 and a second position corresponding to a second state of the optical switch. In the first state, the optical switch may be configured to provide only incoherent light at optical output 574, while in the second state, the optical switch may be configured to provide only coherent light at the optical output. The figure illustrates the optical switch in the second state.

[0152] Switch body 584 may include a light guide 576, e.g., a light pipe, configured to guide the incoherent light from incoherent light input 572 to light output 574 when the switch body is in the first position. In the second position, incoherent light 575 may be blocked by shutter 586. Thus, in the second position, the switch body is configured not to guide the incoherent light to the light output.

[0153] The switch body 584 may further comprise a mirror 582 configured to steer the coherent light beam 580 onto the light output 574 when the switch body is in the second position. The mirror may further be configured not to steer the coherent light beam onto the light output when the switch body is in the second position.

[0154] The switch body 584 may be moved between the first position and the second position by an actuator 588 .

[0155] In one embodiment, optical switch 570 may include a first end stop configured to urge switch body 584 to a first position corresponding to the first state and a second end stop configured to urge the switch body to a second position corresponding to the second state. The optical switch may further include a spring configured to hold the switch body in the first position or the second position when the switch is not actuated. This configuration is reliable, accurate, and relatively inexpensive.

[0156] Alternatively, a servo motor may be used to move switch body 584 between the first and second positions, in which case end stops may not be necessary. Using a servo motor may be faster and quieter than using a (normal) motor and end stops.

[0157] In yet another alternative, the switch element 584 may be moved manually, for example using a lever, which is an inexpensive but relatively slow and potentially less accurate mode of switching.

[0158] The switch body 584 is moved between the first and second positions by, for example, translational or rotational motion. In one embodiment, motion can be transmitted to the switch body via a cam or via a crank. This is discussed in more detail below with reference to Figures 6A and 6B.

[0159] The use of light guide 576 introduces little light loss and minimizes chromatic aberration. Alternatively, a system with lenses such as that depicted in Figure 5A can be used.

[0160] FIG. 5D illustrates an optical switch 590 comprising an incoherent light input 591, a coherent light input 593, and an optical output 592, as described with reference to FIG. 5A.

[0161] The optical switch 590 may further include a switch body 596 configured to be moved between a first position and a second position. The switch body may include at least one end of a flexible light guide 594, such as a fiber bundle, a fiber bundle with fused ends, or a liquid light guide. In the first position, the switch body may be configured to guide incoherent light from the incoherent light input to the light output via the flexible light guide. The flexible light guide may extend beyond the incoherent light input and may be directly connectable to, for example, a light output of a light source unit of an endoscope system. An advantage of this configuration is that the coupling device may have the light input and light output on the same side, such as the front, thereby facilitating operation of the coupling device.

[0162] In the second position, switch body 596 may be configured to provide coherent light 595 to light output 592. In the depicted example, the beam path from coherent light input 593 to light output 592 may be a path through free space. In the second position, the coherent light beam path to the light output may be unobstructed. The switch body may have a hole to allow the coherent light to pass through. Alternatively, the switch body may be sized and shaped such that, in the second position, a portion of the switch body does not obscure the path between the coherent light input and the light output.

[0163] In this way, very few optical components are used to provide the coherent light at the light output, thereby benefiting the spectrum and coherence length of the coherent light.

[0164] In another embodiment, an optical fiber may be used to guide the coherent light from the coherent light input 593 to the light output 592. This may provide additional flexibility in the setup as well as make the coupling device less sensitive to component misalignment.

[0165] Optical switch 590 may further include an actuator 597, end stops, springs, etc., as described with reference to Figure 5C.

[0166] 6A-6C schematically illustrate an optical switch according to an embodiment of the present invention. In particular, FIG. 6A illustrates a drive mechanism for a switch body 602 of an optical switch. The switch body may be configured to rotate about an axis 604. As discussed in more detail with reference to FIGS. 5C and 5D, the switch body may include a first light guide 606, e.g., a light pipe, fiber bundle, or liquid light guide, configured to guide incoherent light from an incoherent light input to an optical output of the optical switch when the switch body is in a first position (as depicted). The switch body may further include a second light guide 608, e.g., a hole or optical fiber, configured to guide coherent light from the coherent light input to the optical output of the optical switch when the switch body is in a second position (shown in dashed lines). If the coherent light propagates through free space, the switch body may be shaped so as not to block the coherent light beam in the second position and need not include a hole.

[0167] The switch body 602 may be connected to a motor 612 via a crank 610. One end of the crank may be rotatably connected to the switch body 602. The other end of the crank may be rotatably connected to an off-axis connection point of the motor. In the first position, the crank may be pulled against a first end stop 6181 by a spring 620 attached to the switch body in this embodiment. In other embodiments, the spring may be attached to a separate component. The spring may also push rather than pull. The end stop and spring ensure that the switch body is accurately positioned in the first position. In different embodiments, the spring and, optionally, the end stop may be omitted.

[0168] When the motor receives the switching signal 612, the motor may rotate about axis 614 to a second position. In the second position, a portion of the switching signal crank or other suitable component may be pulled against a second end stop 6182 by a spring 620.

[0169] In one embodiment, a servo motor may be used to drive the switch body. The servo motor may be very accurate and therefore may not be able to rotate the end stop 618. 1~2 And spring 620 may be omitted.

[0170] In one embodiment, the switch body 602 may be attached directly to the shaft 604 of a motor, for example a servo motor.

[0171] Figure 6B schematically illustrates a drive mechanism for moving a switch body 630 of an optical switch between a first position and a second position using a cam. The switch body depicted corresponds to the optical switch depicted in Figure 5C, although the same drive mechanism may be used to move any suitable switch body, such as that depicted in Figure 5D.

[0172] The switch body 630 may comprise a first optical path 632 for guiding light from a coherent light input to an optical output 636 when the switch body is in the second position (as depicted). The optical path may comprise, for example, a mirror 634. Alternatively, the optical path may comprise, for example, an optical fiber. In the second position, a portion of the switch body may block light from an incoherent light input 638. The switch body may further comprise a light guide for guiding incoherent light from the incoherent light input to an optical input when the switch body is in the second position (the relative positions of the incoherent light input and the optical input with respect to the light guide are shown using dashed lines).

[0173] A shaft 640 may be connected to the switch body 630. An actuator 644 may be configured to move a cam 642. By moving the cam in a first direction, e.g., parallel to the longitudinal axis of the switch body, the switch body may be moved in a second direction, e.g., a lateral direction perpendicular to the first direction. The cam may be shaped with high precision, thus ensuring accurate positioning of the switch body. The positioning, particularly in the first state, may be further improved by a spring 646.

[0174] 6C schematically illustrates a portion of an optical switch including a rotating shutter. The shutter 650 may include one or more shutter blades 652 mounted on a rotatable shaft 654. The shutter may be disposed in the optical switch as described above with reference to FIGS. 5A and 5B. As the shutter rotates about the shaft, the shutter blades may alternately obstruct and leave unobstructed an optical beam path 656 of incoherent or coherent light.

[0175] The light switch may further include a light sensor 658 disposed on one side of the shutter and a light emitter disposed on the other side of the shutter, together forming an optical sensor arrangement substantially parallel to the axis of rotation. In the illustrated embodiment, the optical sensor arrangement is configured such that the optical sensor can receive light from the light emitter when the light beam path is unobstructed by the shutter blades and does not receive light when the light beam path is obstructed by the shutter blades. Thus, the light sensor may provide a signal to the controller of the light switch and / or to the interface associated with whether the beam path is obstructed or unobstructed.

[0176] Alternatively or additionally, the optical sensor arrangement may be positioned such that the optical sensor receives light when the light beam path is blocked and does not receive light when the light beam path is unblocked. Similar optical sensor arrangements may also be included in other embodiments, such as the embodiment depicted in Figures 6A and 6B.

[0177] 7A and 7B schematically illustrate connections between a light source unit and a coupling device of an endoscopic system according to an embodiment of the present invention. Figure 7A illustrates a light source unit 702 of an endoscopic system comprising an incoherent light source 704, e.g., a white light source, and an optical output 706 for providing light to an optical output connector 708. The optical output connector is shaped to receive a connector from a light delivery system. Different manufacturers or brands may have optical output connectors with different shapes.

[0178] FIG. 7A further illustrates a coupling device 710 for coupling coherent light into the light delivery system of the endoscopic system. The coupling device includes an optical input connector 712 for connecting to the optical output connector 708 of the light source unit 702. In the illustrated embodiment, the optical input connector includes a rigid light pipe 714 for guiding light from the light output 706 of the light source unit to an optical coupler 720. The optical input connector may further include a shaft 716, preferably an opaque shaft, to protect the light guide and prevent unwanted light from entering the light pipe. The shaft may cover the entire length of the light guide or a portion of it, e.g., only the exposed portion. The optical input connector may also include a holder portion 718 for securing the light pipe to the optical output connector 708 of the light source unit. The holder portion may extend over a portion of the entire length of the light pipe and / or the connector to provide mechanical support and protection for the light pipe. A rigid light pipe allows for a connection with little loss in intensity to the incoherent light and limited change in spectrum.

[0179] Preferably, the shape and dimensions of the optical input connector 712 are selected to be compatible with a given type of optical output connector 708. In some embodiments, the optical input connector may be interchangeable or adjustable so that the coupling device 710 is compatible with multiple optical output connector types.

[0180] The optical coupler 720 may include an incoherent light input 722 for receiving incoherent light from the optical input connector. The optical coupler may further include a coherent light input 724 and an optical output 726. The coherent light input may receive light directly from a coherent light source or via a coherent light input connector 728. An advantage of receiving coherent light via a coherent optical connector is that the coupling device can be relatively small and lightweight, allowing it to be mounted to the front of the light source unit 702 when the light source unit is mounted on a light tower, for example, without requiring a dedicated external support structure and without extending far and becoming cumbersome to the user. The optical coupler may be, for example, an optical switch as described above with reference to FIGS. 5A-5D, or preferably an optical switch as shown in FIGS. 5A-5C.

[0181] The coupling device 710 may further comprise an optical output connector 730 for connecting to and providing light to an optical delivery system of an endoscope system. Preferably, the optical output connector is shaped and dimensioned to be compatible with the same type of optical connector as the optical input connector 712 of the coupling device. In this manner, the coupling device may be connected to an optical delivery system that is also directly connectable to the light source unit 702.

[0182] Because the coupling device 710 provides coherent light at its optical output 726, the optical output connector 730 of the coupling device may advantageously include one or more laser safety features 732-740. For example, the optical output connector may include a shutter 732 to block light, particularly coherent light, from exiting the optical output connector 730 when there is no light delivery system connected to the optical output connector 730. The shutter may be pushed to a closed position, e.g., by a spring 734, when the output connector is empty and may be pushed to an open position when an input connector is inserted. Alternatively or additionally, the optical output connector may include optical sensors 736 and 738. The optical sensor may include a light source 736 and a sensor 738. The sensor may provide a first signal to the coupling device controller when more than a predetermined amount of light from the light source 736 is detected by the sensor 738, and a second signal when less than the predetermined amount is detected. When the controller receives the first signal, the controller may, depending on the embodiment, interrupt the coherent light path, for example, by switching off the first and / or second laser sources and / or switching them to a state where the coherent light is not input to the optical output connector.

[0183] In the illustrated embodiment, the light guide 714 from the optical input connector 712 connects directly to the optical coupler 720. The advantages of this configuration are structural simplicity and low loss in optical power. However, in other embodiments, there may be intermediate structures between the optical input connector and the optical coupler. Similarly, the optical output 726 of the optical coupler connects directly to the optical output connector 730. This is again advantageous for the optical power and quality of the output light. Again, in other embodiments, there may be intermediate structures to guide the light from the optical output 726 to the optical output connector 730.

[0184] 7B illustrates an alternative type of connection between a light source unit 752 and a coupling device 760 of an endoscopic system. The light source unit may include an incoherent light source 754, e.g., a white light source, an optical output 756, and an optical output connector 758, as described above with reference to FIG.

[0185] The coupling device 760 may include an optical input connector 762, including a shaft 766 and a holder 768, as described above with reference to FIG. 7A. The input connector also includes a light guide 764, which in this embodiment is a flexible light guide, such as a fiber bundle, a fiber bundle with fused ends, or a liquid light guide. This allows for flexible placement of the coupling device, for example, on different platforms of a light tower housing a light source unit. As a result, compared to a situation in which the coupling device is attached to the front of the light source unit, there are fewer constraints, for example, on size and weight, and it is easier to incorporate one or more coherent light sources 778 within the coupling device. This has a beneficial effect on the optical quality of the coherent light, as the coherent light can travel almost entirely through free space without safety concerns.

[0186] Coupling device 760 may further include an optical coupler 770 having an incoherent light input portion 772, a coherent light input portion 774, and an optical output portion 776. The optical coupler may be an optical switch, such as those described above with reference to Figures 5A-5D, and preferably is the optical switch shown in Figure 5D. If the optical coupler is an optical switch as shown in Figure 5D, flexible light guide 764 may be the same as flexible light guide 594, thus minimizing transitions and maximizing light quality.

[0187] The coupling device 760 may further include an optical output connector 780, as described above with reference to FIG. 7A, and a safety feature, such as a shutter 782 actuated by a spring 784 and / or an optical sensor (not shown).

[0188] 8 schematically illustrates a coherent light system for adding coherent light imaging capabilities to an endoscopic system in accordance with an embodiment of the present invention. Coherent light system 800 may include a coupling device 810 including an optical input 812 for receiving incoherent light from a light source of the endoscopic system via a light guide 813, an optical output 814 for providing light to a light guide 815 of a light delivery system of the endoscopic system, and a coherent light input for receiving coherent light of at least a first wavelength and / or one or more coherent light sources 816 for generating light of at least a first wavelength. The coupling device may further include an optical coupler 818 for simultaneously or alternately providing the incoherent light and the coherent light to the light delivery system.

[0189] Optionally, coherent optical system 800 may comprise a controller 820 operably connected to optical coupler 818 for controlling the optical coupler. The controller may be provided in the same device as the optical coupler and / or in the same device as one or more laser sources, or may be embodied in a separate controller device and configured to communicate with coupling device 810 using a wired or wireless connection.

[0190] Optionally, the coherent optical system 800 may include a user interface 822 connectable to the controller 820 to receive inputs for controlling the system and / or to provide outputs regarding the status of the system. The user interface may include one or more buttons, such as a power button and a button for generating a trigger signal. The user interface may also include one or more status lights. The user interface may be included on the same device as the controller and / or optical coupler 818. Alternatively, the user interface may be embodied in a different device, such as a handheld device, configured to communicate with the controller and / or the coupling device 810 via a wired or wireless connection. The user interface may also be distributed across several components of the system, such as a button mounted on the handle of the endoscope 870 configured to send a trigger signal to the coupling device, and a status light on the coupling device that indicates the status of the optical coupler 818. The status of the optical coupler is particularly relevant when the optical coupler is an optical switch.

[0191] Optionally, coherent optical system 800 may include or be connectable to internal or external data storage 824 for storing information related to the status of the coupling device and / or for storing images acquired by the endoscopic system if the system includes a video processing module 830. The data storage may be operatively connectable to controller 820 via a wired or wireless connection.

[0192] Optionally, the coherent optical system 800 may include a video processing module 830. The video processing module may include a first video input connector 832 for receiving a first video stream from a camera for capturing the endoscopic images, which camera is preferably included in or attached to the endoscope 870. The video processing module may further include a video output connector 834 for providing the video input stream or a derivative thereof to the video processing module of the endoscopic system. In some embodiments, the video processing module may include a second video input connector 836 for receiving a second video stream from a camera for capturing the endoscopic images. The video processing module may further include a video processor 838 for processing the first video stream and, optionally, the second video stream. Preferably, the video processor includes a dedicated graphics processor for processing the video streams. The video processor may further include a general processing unit and memory for storing software, such as image processing software for generating laser speckle contrast images and / or fluorescence images. The video processing module may further comprise, for example, a frame grabber, a video converter, and a buffer.

[0193] The image processor may comprise a computer readable storage medium having computer readable program code embodied therein and a processor, preferably a microprocessor, coupled to the computer readable storage medium, the computer readable program code comprising instructions for performing method steps for determining a coherent light image, preferably a fluorescence image, such as an ICG-based image or a laser speckle contrast image.

[0194] The video processing module may be implemented as a cloud-based module. In such an embodiment, the video processing module may include a network connection for connecting to the Internet, and the image processor may be an Internet-connected computing device.

[0195] In one embodiment, the video processor may process the first video stream and / or the second video stream depending on the state of the optical coupler. For example, if the optical coupler is an optical switch, the video processor may be configured or controlled by controller 820 to process one or more video streams only when the optical switch is in a state that provides the coherent light to the light delivery system.

[0196] The video processing module 830 may be included in the same device as the controller 820, or alternatively may be embodied in a separate image processing device and configured to communicate with the controller using a wired or wireless connection. The video processor and the controller may be embodied as software modules running on shared hardware, for example, an embedded computing module comprising a central processing unit (CPU), memory, and optionally, a graphics processing unit (GPU).

[0197] Coherent light system 800 may further include a display 840 connectable to video processing module 830. Thus, the system is configured to display images or video based on coherent light imaging on display 840, while images or video based on incoherent light imaging are displayed by the endoscopy system on a display included therein.

[0198] The endoscopic system may include an endoscope 870. The endoscope may include a flexible or rigid insertion tube 860 having a distal tip 862 for insertion into a subject, preferably a patient, e.g., a human or animal body, preferably a living body. Some endoscopic systems, typically systems with a flexible insertion tube, may include an image sensor mounted at or near the distal tip 862. Other endoscopic systems, typically systems with a rigid insertion tube, may include an imaging unit including an image sensor, e.g., an RGB camera, located in or near the handle of the endoscope. In some systems, the imaging unit is detachable from the insertion tube.

[0199] Optionally, the coherent light system 800 may include an imaging unit 850 configured to be attached to the proximal end of the insertion tube of the endoscope. The imaging unit may include a camera, such as an RGB or RGB / IR camera 852. An advantage of an RGB / IR camera is that infrared coherent light can be acquired simultaneously with an incoherent light image or a white light image. In this way, an image acquired using coherent light and an image based on the incoherent light may be combined in a relatively simple manner, for example, without the need to align the coherent light image with the incoherent light image. If the first wavelength is in the visible spectrum, a coherent light image may be acquired by reading each channel of an RGB camera; for example, if the first wavelength is in the red portion of the electromagnetic spectrum, a coherent light image may be acquired by reading or using only the red pixels of the captured RGB image while illuminating a target with red coherent light, preferably without simultaneously illuminating it with incoherent light.

[0200] Alternatively, coherent light system 800 may include a dedicated imaging module 854 for acquiring an image of light at a first wavelength. The dedicated imaging module may include a beam splitter 856, such as a dichroic mirror or a polarizing beam splitter, for splitting light collected by the endoscope into a first beam containing primarily light at the first wavelength or light at a wavelength emitted by a fluorescent marker and a second beam containing the remaining light. The dedicated imaging module may further include a dedicated image sensor 858 for imaging the first beam.

[0201] A dedicated imaging module 854 may be configured to be attached to the proximal end of an insertion tube 860 of an endoscope 870. The dedicated imaging module may further be configured to receive an imaging unit 850 configured to be attached to the proximal end of the insertion tube of the endoscope. In this manner, dedicated imaging, such as infrared imaging, may be added to an endoscope having a detachable camera. If the first wavelength is in the infrared portion of the electromagnetic spectrum, an endoscope without an infrared filter on the insertion tube or connection should be selected.

[0202] In some embodiments of the coherent light system 800, the optical coupler 818 may be configured as an optical switch capable of switching at a high frequency, e.g., 60 Hz. In such embodiments, the imaging unit 850 may be an RGB camera configured to acquire images or video streams at a high frame rate, e.g., 120 frames per second. The camera may be operably connected to the controller 820. Thus, the coherent light system may alternately capture coherent light images and incoherent light images, e.g., white light images. The video processing module 830 may output a video stream based on the incoherent light images at a frame rate of 60 fps on the video signal output 834, for example, and may transmit the video stream based on the coherent light images to the display 840, also at a frame rate of 60 fps. In some embodiments, images acquired when the optical switch is switching between the first and second states may be of lower quality. In that case, the camera may acquire a video stream including a sequence of, for example, an incoherent light image, a switching image, a coherent light image, and another switching image, and the video processing module may ignore the switching image and generate a coherent light-based video stream and an incoherent light-based video stream, each at 30 fps.

[0203] 9 illustrates a method of generating a coherent light image using a coherent light coupling system according to an embodiment of the present invention. The coherent light coupling system may include an optical input for receiving incoherent light from a light source of an endoscope system, a first coherent light source for generating coherent light at a first wavelength, and an optical output for alternately supplying the incoherent light and the coherent light at the first wavelength to a light delivery system of the endoscope system. The optical output may be connected to the endoscope via a first light guide, and the optical input may be connected to the incoherent light source via a second light guide.

[0204] The coherent optical coupling system may further comprise an optical switch configured to switch between a first state in which the incoherent light is incident on the optical output portion and the coherent light is not incident on the optical output portion and therefore not incident on the first optical guide, and a second state in which the coherent light is incident on the optical output portion and the incoherent light is not incident on the optical output portion and therefore not incident on the first optical guide.

[0205] In a first step 902, a controller within the coherent optical coupling system may receive a first trigger signal. In response to receiving the first trigger signal, the controller may switch the optical switch to the second state (step 904). Thus, coherent light may be provided to the light delivery system of the endoscope system. As a result, the endoscope may illuminate a target area with the coherent light and collect light reflected or emitted by tissue within the target area in response to illumination. A camera of the endoscope system may capture a video stream based on the collected light.

[0206] Next, in step 906, a video processing module within the coherent optical coupling system may receive the video stream from the camera of the endoscope system, where the video stream includes image information based on illuminating the target area with coherent light at the first wavelength. Subsequently, the video processing module may determine (step 908) one or more coherent light images, such as laser speckle contrast images or fluorescence images, e.g., ICG-based images, based on the received video stream. In one embodiment, the video stream may comprise frames, or the video processing module may be configured to determine frames based on the received video stream. A single coherent light image may be based on multiple frames of the received video stream.

[0207] In a next step 910, the coherent optical coupling system may provide the one or more determined coherent light images to a video signal output of the coherent optical coupling system, display the one or more determined coherent light images on a display of the coherent optical coupling system, and / or store the one or more determined coherent light images in a database included in or connected to the coherent optical coupling system.

[0208] In optional step 912, the coherent optical coupling system may cause the optical switch to switch to the first state after a predetermined number of coherent light images have been determined, after a predetermined time, or upon receiving a second trigger signal.

[0209] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that as used herein, the words "comprise" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0210] Corresponding structures, materials, acts, and equivalents of all means- or step-plus-function elements in the appended claims are intended to include any structure, material, or acts for performing a function in combination with other claim elements as specifically claimed. The detailed description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the invention and spirit. The embodiments were chosen and described to best explain the principles and practical applications of the invention and to enable those skilled in the art to understand the invention in various embodiments with various modifications as suited to the particular uses contemplated. The present invention may be configured as follows. [Section 1] 1. A coupling device for coupling coherent light and incoherent light into a first light guide of a light delivery system of an endoscopic system, the endoscopic system comprising an incoherent light source for generating the incoherent light, e.g., white light, the coupling device comprising: an optical input comprising an optical input connector for releasably connecting the coupling device to the incoherent light source via a second light guide, wherein the optical input is configured to receive the incoherent light from the endoscope system; a first light source for generating coherent light of a first wavelength, or a coherent light input unit for receiving coherent light of the first wavelength; an optical output section including an optical output connector for releasably connecting the coupling device to an endoscope via the first light guide, wherein the optical output section is configured to provide the incoherent light of the first wavelength and the coherent light to the first light guide; an unobstructed incoherent light beam path for propagating the incoherent light from the light input to the light output in at least a first state of the coupling device; an unobstructed coherent light beam path for propagating the coherent light from the coherent light source or from the coherent light input to the light output in at least a second state of the coupling device; and an optical coupler for simultaneously and / or alternately injecting the incoherent light and the coherent light of the first wavelength into the first light guide, wherein the coherent light and the incoherent light have a shared optical path at the optical output; The coupling device. [Section 2] Item 1. The coupling device of item 1, wherein the optical coupler is an optical switch configured to switch between a first state in which the coherent light is not incident on the first light guide and a second state in which the coherent light is incident on the first light guide. [Section 3] Item 3. The coupling device of item 2, wherein in the first state, the optical switch is configured to allow the incoherent light to enter the first light guide, and in the second state, the optical switch is configured to prevent the incoherent light from entering the first light guide. [Section 4] The optical switch a first mirror movable between a first position, in which a reflective surface of the first mirror is arranged to reflect incoherent light propagating beyond the incoherent light beam path, and a second position, in which the reflective surface of the first mirror is arranged to reflect the incoherent light away from the incoherent light beam path; and / or a second mirror movable between a first position, in which a reflective surface of the second mirror is arranged to reflect coherent light propagating beyond the coherent light beam path, and a second position, in which the reflective surface of the first mirror is arranged to reflect the coherent light away from the coherent light beam path; Item 2 or 3, a coupling device comprising: [Section 5] The optical switch a first switchable mirror switchable between a transparent state and a reflective state, and arranged to reflect incoherent light propagating beyond the incoherent light beam path in said reflective state; and / or a second switchable mirror switchable between a transparent state and a reflective state, and positioned to reflect coherent light propagating beyond the coherent light beam path in the reflective state; Item 2 or 3, a coupling device comprising: [Section 6] The optical switch a first optical beam blocker configured to block the coherent light in the first state, preferably wherein the first beam blocker comprises a mechanical shutter, preferably a rotating shutter, more preferably a motorized rotating shutter, or an optical beam blocker, preferably one of the following: a liquid crystal light valve, an acousto-optic modulator, an electro-optic modulator, or a photoelastic modulator; and optionally, a second light beam blocker configured to block the incoherent light in the second state, preferably wherein the second beam blocker comprises a mechanical shutter, preferably a rotating shutter, more preferably a motorized rotating shutter, or a light beam blocker, preferably a liquid crystal light valve; The coupling device according to claim 2 or 3, [Section 7] The optical coupler is a first converging lens for reducing the divergence of the incoherent light from the light input and a second converging lens for focusing the incoherent light into the first light guide; and a mirror disposed between the first lens and the second lens, the mirror configured to direct the coherent light beam and / or the incoherent light beam into the first light guide; Item 7. The coupling device according to any one of items 1 to 6, comprising: [Section 8] The optical coupler is a tapered light pipe having a wide end for receiving the incoherent light from the light input and a narrow end for providing the incoherent light to the light output, wherein the tapered light pipe is divided into a first section and a second section by a plane that intersects the tapered light pipe between the wide end and the narrow end, a normal to the plane defining a non-zero angle with a longitudinal axis of the tapered light pipe, preferably the tapered light pipe further comprising a protrusion having a surface perpendicular to the coherent light path for receiving the coherent light; and a mirror disposed on the longitudinal axis of the tapered light pipe in the plane between the first and second portions of the tapered light pipe, the mirror configured to direct the laser beam into the first light guide; Item 8. The coupling device according to any one of items 1 to 7, comprising: [Section 9] The optical switch an inner light guide for guiding the incoherent light from a first end of the inner light guide to a second end of the inner light guide; and a switch body comprising at least the second end of the internal light guide, the switch body being movable between a first position corresponding to the first state and a second position corresponding to the second state; and In its first position, the switch body is configured to interrupt the coherent light beam path, position a first end of the inner light guide to receive incoherent light from the light input, and position the second end to direct the incoherent light into the first light guide; and In its second position, the switch body is configured to unobstruct the coherent light beam path and to position at least the second end of the inner light guide so that the incoherent light does not enter the first light guide. Item 2 or 3. The coupling device according to item 2 or 3. [Section 10] Item 10. A coupling device as described in item 9, wherein the internal light guide is a flexible light guide, preferably a fused fiber bundle or a liquid light guide, and the first end of the internal light guide is connected to the light input portion. [Section 11] Item 5. The coupling device of item 4, wherein the optical switch is an electrically operated switch comprising a motor and optionally a servo motor, wherein the motor is configured to move the first mirror and optionally the second mirror between the first position and the second position. [Section 12] Item 11. The coupling device of item 9 or 10, wherein the optical switch is an electrically operated switch comprising a motor and optionally a servo motor, wherein the motor is configured to move the switch body between the first position and the second position via a cam or crank. [Section 13] The optical switch a first end stop configured to stop the first mirror or switch body in the first position; a second end stop configured to stop the first mirror or switch body in the second position; and a spring configured to maintain the first mirror or the switch body in the first position or the second position when the switch is not operated; Item 13. The coupling device according to item 11 or 12, comprising: [Section 14] Item 14. The coupling device according to any one of items 2 to 13, wherein the optical switch is configured to automatically switch back and forth between the first state and the second state, preferably at a frequency of at least 10 Hz, more preferably at a frequency of at least 30 Hz, and even more preferably at a frequency of at least 100 Hz. [Section 15] Item 15. The coupling device according to any one of items 1 to 14, wherein the second light guide is a light pipe. [Section 16] Item 15. The coupling device according to any one of items 1 to 14, wherein the second light guide is a flexible light guide, preferably a fiber bundle, a fused fiber bundle, or a liquid light guide. [Section 17] Item 17. The coupling device according to any one of items 1 to 16, wherein the first light source is a narrow bandwidth laser, preferably having a spectral bandwidth of less than 1 nm, more preferably less than 0.2 nm, and even more preferably less than 0.1 nm. [Section 18] Item 18. A coupling device according to any one of items 1 to 17, wherein the first light source is a laser having an output of at least 20 mW, preferably at least 100 mW, and more preferably at least 150 mW. [Section 19] Item 19. The coupling device according to any one of items 1 to 18, wherein the first wavelength is in the red part of the electromagnetic spectrum, preferably 600 to 700 nm, more preferably 630 to 660 nm, or the first wavelength is in the infrared part of the electromagnetic spectrum, preferably 700 to 1200 nm, more preferably 700 to 900 nm, even more preferably 770 to 790 nm or 820 to 840 nm. [Section 20] a second light source for generating coherent light at a second wavelength, preferably different from the first wavelength; and a laser coupler for combining the coherent light of the first wavelength and the coherent light of the second wavelength, wherein the laser coupler preferably includes a dichroic mirror that selectively reflects light of the first wavelength or light of the second wavelength; Item 20. The coupling device according to any one of items 1 to 19, further comprising: [Section 21] Item 21. A coupling device according to item 20, wherein the second wavelength is in the blue or green part of the electromagnetic spectrum, preferably 380 to 590 nm, more preferably 470 to 570 nm, and even more preferably 520 to 560 nm. [Section 22] the endoscope system comprises a camera, preferably an RGB camera, configured to provide a video signal, and the coupling device comprises: A video signal input connector for receiving a video signal; a video signal output connector for providing a video output; and an image processing module for generating a coherent light image, preferably a fluorescence image and / or a laser speckle contrast image, based on a video signal when the optical coupler couples coherent light into the first light guide; Item 22. The coupling device according to any one of items 1 to 21, further comprising: [Section 23] in the first state, looping the video signal to the video output; and wherein in a second state, the video signal is provided to an image processing module, the image processing module being configured to determine one or more output images, preferably laser speckle contrast images or fluorescence images, based on the video signal, wherein the one or more output images are provided at the video signal output connector; Item 23. The coupling device according to any one of items 2 to 22. [Section 24] 24. A coupling device according to clause 22 or 23, further comprising a frame grabber for converting a continuous video input signal into discrete frames for processing by the video processing module. [Section 25] further comprising a first sensor, preferably an optical sensor, and a controller connected to the first sensor, wherein: the first sensor is configured to send a first signal to the controller only when the first light guide is connected to the optical output connector; and wherein the controller is configured to switch off or block the first coherent light source and optionally the second coherent light source if the controller does not receive the first signal. Item 25. The coupling device according to any one of items 1 to 24. [Section 26] further comprising a second sensor, preferably an optical sensor, and a controller connected to the second sensor, wherein: the second sensor configured to transmit a second signal when the optical switch is in the second state; and and wherein the controller is configured to switch off or block the first coherent light source and optionally the second coherent light source if the controller does not receive the second signal. Item 26. The coupling device according to any one of items 2 to 25. [Section 27] 27. The coupling device of any one of items 2 to 26, further comprising a control switch for generating a trigger signal or a trigger input for receiving a trigger signal, wherein the optical switch is configured to switch from the first state to the second state in response to receiving the trigger signal. [Section 28] Item 28. The coupling device according to any one of items 1 to 27, further comprising a data storage medium or a data output unit. [Section 29] An image processing system for generating a coherent light image in an endoscope system, the endoscope system comprising an incoherent light source, a video processing unit, and an endoscope, wherein the endoscope is connected to a camera, and the image processing system comprises a coupling device and a video processing device according to any one of items 2 to 21, wherein the video processing device: a video signal input connector for receiving a video signal from said camera; a first video signal output connector for providing a video output, wherein the first video signal output connector is configured to be connected to a video signal input of the video processing unit of the endoscope system; and an image processing module for generating a coherent light image based on the video signal when the optical switch is in a first state; The image processing system comprises: [Section 30] 30. The image processing system of claim 29, further comprising a second video signal output connector configured to be connected to a second display, wherein the image processing system is configured to provide an incoherent light image to the first video output when the optical switch is in a first state, and to provide a coherent light image to the second video signal output when the optical switch is in a second state. [Section 31] 31. The image processing system of clause 30, further comprising a display for displaying a coherent light image, wherein said display is connectable to said second video signal output connector. [Section 32] 1. An imaging system for generating an infrared coherent light image in an endoscopic system, the endoscopic system comprising an incoherent light source, an endoscope, and a light delivery system for delivering light to the endoscope, the imaging system comprising: 15. The coupling device according to any one of items 1 to 14, wherein the first wavelength is selected in the infrared part of the electromagnetic spectrum, preferably 700 to 1200 nm, more preferably 700 to 900 nm, even more preferably 770 to 790 nm or 820 to 840 nm; an infrared imaging sensor configured to receive light collected by the endoscope; and an image processing module configured to receive a video signal from the infrared imaging sensor and determine a coherent light image based on the received video signal; Preferably, an RGB / IR camera, or a beam splitter for splitting the light reflected by the target into an IR beam and a white light beam, and an IR camera. The imaging system comprises: [Section 33] Item 29. An endoscope system, preferably a laparoscopic system, comprising the coupling device according to any one of items 1 to 28. [Section 34] 1. A method for generating a coherent light-based image of a target area in a subject, preferably a human or animal body, preferably a living body, using an endoscope system, the endoscope system comprising: an incoherent light source for generating incoherent light, e.g., white light; and an endoscope, the endoscope comprising an insertion tube for insertion into a patient's body, a light delivery system for illuminating a target area with light, and an image sensor for acquiring an image of the target area; It is equipped with The endoscope is releasably connected to a coherent optical coupling system via a first light guide, wherein the coherent optical coupling system comprises: generating or receiving a trigger signal; receiving incoherent light from the incoherent light source via a second light guide; receiving or generating coherent light at a first wavelength; and selectively providing the coherent light and / or the incoherent light to the first light guide, wherein the coherent light and the incoherent light have a shared optical path in the first light guide. It is structured as follows: The method comprises: receiving a first trigger signal; providing coherent light to the light delivery system in response to receiving the first trigger signal; receiving a video stream, wherein the video stream includes a signal representative of the light intensity of coherent light reflected or dispersed by the target area; and determining a coherent light image, such as a laser speckle contrast image or a fluorescence image, based on the video stream; The method comprising: [Section 35] Displaying and / or storing the determined coherent light image. Item 35. The method of item 34, further comprising: [Section 36] providing the incoherent light to the light delivery system in response to receiving a second trigger signal or a predetermined time after receiving the first trigger signal, and preferably blocking coherent light from entering the light delivery system. Item 36. The method of item 34 or 35, further comprising: [Section 37] A computer program or a suite of computer programs including at least one software code portion, or a computer program product storing at least one software code portion, wherein the software code portion is configured to perform the method according to at least one of paragraphs 34 to 36 when the software code portion is executed on a computer system. [Section 38] A non-transitory computer-readable storage medium storing at least one software code portion, the software code portion being configured to perform a method according to at least one of paragraphs 34 to 36 when executed or processed by a computer.

Claims

1. 1. A coupling device for coupling coherent light and incoherent light into a first light guide of a light delivery system of an endoscopic system, the endoscopic system including an incoherent light source for generating the incoherent light, the coupling device comprising: an optical input comprising an optical input connector for releasably connecting the coupling device to the incoherent light source via a second light guide, wherein the optical input is configured to receive the incoherent light from the endoscope system; a first light source for generating coherent light of a first wavelength, or a coherent light input unit for receiving coherent light of the first wavelength; an optical output section including an optical output connector for releasably connecting the coupling device to an endoscope via the first light guide, wherein the optical output section is configured to provide the incoherent light of the first wavelength and the coherent light to the first light guide; an unobstructed incoherent light beam path for propagating the incoherent light from the light input to the light output in at least a first state of the coupling device; an unobstructed coherent light beam path for propagating the coherent light from the coherent light source or from the coherent light input to the light output in at least a second state of the coupling device; and an optical coupler for simultaneously and / or alternately injecting the incoherent light and the coherent light of the first wavelength into the first light guide, wherein the coherent light and the incoherent light have a shared optical path at the optical output; The coupling device.

2. 2. The coupling device of claim 1, wherein the optical coupler is an optical switch configured to switch between a first state in which the coherent light is not incident on the first light guide and a second state in which the coherent light is incident on the first light guide.

3. 3. The coupling device of claim 2, wherein in the first state, the optical switch is configured to allow the incoherent light to enter the first light guide, and in the second state, the optical switch is configured to prevent the incoherent light from entering the first light guide.

4. The optical switch a first mirror movable between a first position, in which a reflective surface of the first mirror is arranged to reflect incoherent light propagating beyond the incoherent light beam path, and a second position, in which the reflective surface of the first mirror is arranged to reflect the incoherent light away from the incoherent light beam path; and / or a second mirror movable between a first position, in which a reflective surface of the second mirror is arranged to reflect coherent light propagating beyond the coherent light beam path, and a second position, in which the reflective surface of the first mirror is arranged to reflect the coherent light away from the coherent light beam path; 4. The coupling device according to claim 2 or 3, comprising:

5. The optical switch a first switchable mirror switchable between a transparent state and a reflective state, and arranged to reflect incoherent light propagating beyond the incoherent light beam path in said reflective state; and / or a second switchable mirror switchable between a transparent state and a reflective state, and positioned to reflect coherent light propagating beyond the coherent light beam path in the reflective state; 4. The coupling device according to claim 2 or 3, comprising:

6. The optical switch a first optical beam blocker configured to block the coherent light in the first state; and / or a second optical beam blocker configured to block the incoherent light in the second state; 4. The coupling device according to claim 2 or 3, comprising:

7. The optical coupler is a first converging lens for reducing the divergence of the incoherent light from the light input and a second converging lens for focusing the incoherent light into the first light guide; and a mirror disposed between the first lens and the second lens, the mirror configured to direct the coherent light beam and / or the incoherent light beam into the first light guide; A coupling device according to any one of claims 1 to 6, comprising:

8. The optical coupler is a tapered light pipe having a wide end for receiving the incoherent light from the light input and a narrow end for providing the incoherent light to the light output, wherein the tapered light pipe is divided into a first portion and a second portion by a plane that intersects the tapered light pipe between the wide end and the narrow end, a normal to the plane defining a non-zero angle with a longitudinal axis of the tapered light pipe; and a mirror disposed on the longitudinal axis of the tapered light pipe in the plane between the first and second portions of the tapered light pipe, the mirror configured to direct the laser beam into the first light guide. A coupling device according to any one of claims 1 to 7, comprising:

9. The optical switch an inner light guide for guiding the incoherent light from a first end of the inner light guide to a second end of the inner light guide; and a switch body comprising at least the second end of the internal light guide, the switch body being movable between a first position corresponding to the first state and a second position corresponding to the second state; and In its first position, the switch body is configured to interrupt the coherent light beam path, position a first end of the inner light guide to receive incoherent light from the light input, and position the second end to direct the incoherent light into the first light guide; and In its second position, the switch body is configured to unobstruct the coherent light beam path and to position at least the second end of the inner light guide so that the incoherent light does not enter the first light guide. A coupling device according to claim 2 or 3.

10. 10. The coupling device of claim 9, wherein the inner light guide is a flexible light guide, and the first end of the inner light guide is connected to the light input.

11. 10. The coupling device of claim 9, wherein the optical switch is an electrically operated switch including a motor, wherein the motor is configured to move the switch body between the first position and the second position via a cam or crank.

12. A coupling device according to any one of claims 2 to 6 or 9, wherein the optical switch is configured to automatically switch back and forth between the first state and the second state.

13. A coupling device according to any one of claims 1 to 12, wherein the second light guide is a flexible light guide.

14. The coupling device according to any one of claims 1 to 13, wherein the first light source is a narrow bandwidth laser.

15. A coupling device according to any preceding claim, wherein the first wavelength is in the red part of the electromagnetic spectrum.

16. the endoscope system includes a camera configured to provide a video signal, and the coupling device includes: a video signal input connector for receiving a video signal; a video signal output connector for providing a video output; and an image processing module for generating a coherent light image based on a video signal when the optical coupler couples the coherent light into the first light guide; The coupling device according to any one of claims 1 to 15, further comprising:

17. 17. An image processing system for generating a coherent light image in an endoscopy system, the endoscopy system comprising an incoherent light source, a video processing unit and an endoscope, wherein the endoscope is connected to a camera, the image processing system comprising a coupling device and a video processing device according to any one of claims 2 to 16, the video processing device comprising: a video signal input connector for receiving a video signal from said camera; a first video signal output connector for providing a video output, wherein the first video signal output connector is configured to be connected to a video signal input of the video processing unit of the endoscope system; and an image processing module for generating a coherent light image based on the video signal when the optical switch is in a first state; The image processing system comprises:

18. 18. The image processing system of claim 17, further comprising a second video signal output connector configured to be connected to a second display, wherein the image processing system is configured to provide an incoherent light image to the first video output when the optical switch is in a first state, and to provide a coherent light image to the second video signal output when the optical switch is in a second state.

19. 1. A method for generating a coherent light-based image of a target area in an object via an endoscopic system, the endoscopic system comprising: an incoherent light source for generating incoherent light; and an endoscope, the endoscope comprising a light delivery system for illuminating a target area and an image sensor for acquiring an image of the target area; It is equipped with The endoscope is releasably connected to a coherent optical coupling system via a first light guide, wherein the coherent optical coupling system comprises: generating or receiving a trigger signal; receiving incoherent light from the incoherent light source via a second light guide; receiving or generating coherent light at a first wavelength; and selectively providing the coherent light and / or the incoherent light to the first light guide, wherein the coherent light and the incoherent light have a shared optical path in the first light guide. It is structured as follows: wherein the coherent light-based image is generated by the coherent light coupling system; The method comprises: receiving a first trigger signal by the coherent optical coupling system; in response to receiving the first trigger signal, the coherent optical coupling system providing coherent light to the light delivery system; the coherent optical coupling system receiving a video stream, wherein the video stream includes a signal representative of the light intensity of coherent light reflected or dispersed by the target area; and the coherent optical coupling system determining a coherent light image based on the video stream. The method comprising:

20. providing the incoherent light to the light delivery system in response to receiving a second trigger signal or a predetermined time after receiving the first trigger signal.

20. The method of claim 19 further comprising:

21. 21. A non-transitory computer-readable storage medium storing at least one software code portion, the software code portion being configured to perform a method according to at least one of claims 19 or 20 when said software code portion is executed or processed by a computer.

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