Medical imaging device, endoscope device, endoscope and method for imaging

Abstract

The invention relates to a medical imaging device (10) having a spectral camera (12) which is configured to record hyperspectral images. The spectral camera (12) comprises an optics (14) which is configured to spectrally split incident light through diffraction with respect to a spatial axis (16), and an image capture sensor system (18) which defines a light-sensitive region (20) and which is arranged with respect to the optics (14) such that the light-sensitive region (20) extends along the spatial axis (16) and the spectrally split light is incident on the light-sensitive region (20), wherein different diffraction orders overlap in a partial region (46) of the light-sensitive region (20). The image capture sensor system (18) is configured to capture spatially resolved intensity information for at least two different colour channels (48, 50, 52) which differ with respect to their wavelength-dependent sensitivity in that diffraction light of at least the second order can be detected to a different degree of intensity in the colour channels (48, 50, 52). The imaging device (10) further comprises a processing unit (44) which is configured to determine, based on the spatially resolved intensity of the colour channels (48, 50, 52), spectral information which describes a corrected spectrum which has been corrected with regard to the refraction light of at least the second order. The invention also relates to an endoscope device (74) having an imaging device (10), to an endoscope (76) having an endoscope device (74) and to a method for imaging.

Description

[0001] Medical imaging device, endoscope device, endoscope and method for imaging

[0002] The invention relates to a medical imaging device, an endoscope device, an endoscope and a method for imaging.

[0003] Imaging devices such as endoscopic, exoscopic, or microscopic devices that generate multispectral or hyperspectral images are known from the prior art. Multispectral or hyperspectral images have, in addition to two spatial dimensions, such as a conventional camera image, a spectral dimension. The spectral dimension encompasses several spectral bands (wavelength bands). Multispectral and hyperspectral images differ essentially in the number and width of their spectral bands. Such systems can, in principle, also be suitable for fluorescence imaging.

[0004] Several imaging devices for generating such multispectral or hyperspectral images are known, particularly in the context of medical applications. For example, DE 20 2014 010 558 U1 describes a device for capturing a hyperspectral image of an examination area of ​​a body. The device includes an input lens for generating an image in an image plane and a slit-shaped aperture in the image plane for masking out a slit-shaped region of the image. The light passing through the aperture is spread out by a dispersive element and recorded by a camera sensor. As a result, the camera sensor can record a plurality of spectra, each with an associated spatial coordinate, along the longitudinal direction of the slit-shaped aperture.The described device is further configured to record additional spectra along the longitudinal direction of the slit-shaped aperture in a direction different from the longitudinal direction of the slit-shaped aperture. The method underlying this disclosure for generating multispectral or hyperspectral images is also known as the so-called pushbroom method.

[0005] As described in DE 10 2020 105 458 A1, multispectral and hyperspectral imaging devices are particularly suitable as endoscopic imaging devices. In this context, multispectral and / or hyperspectral imaging is a fundamental field of application, for example, for diagnostics and for assessing the success or quality of a procedure.

[0006] The described devices and methods utilize image sensors that are light-sensitive over a specific spectral range, typically both in the visible and near-infrared ranges. A suitable dispersive element directs incident light, depending on its wavelength, to different positions and thus to different pixels of the image sensor used. The wavelength of the light can then be determined from the position of a pixel. The image sensor in question is often positioned such that one direction of dispersive splitting runs parallel to one of the two image axes of the image sensor. One or more adjacent image lines or one or more adjacent image columns can then be interpreted as the spectrum of a pixel.

[0007] Optical gratings are regularly used as dispersive elements in hyperspectral cameras. The angle at which light of a specific wavelength occurs is given by the well-known grating equation n ■ X = g ■ sin(cpn), where n is the order of the main maximum, X is the wavelength, g is the grating constant, and (p n the deflection angle of the main maximum.

[0008] Due to the grating equation, higher-order maxima for short wavelengths coincide with lower-order maxima for longer wavelengths. For example, the first principal maximum for a given wavelength, say 1000 nm, coincides with the second principal maximum of half the wavelength, say 500 nm. If a sufficiently large spectral range is observed, the actual wavelength cannot be reliably determined based on a deflection angle or observation position alone. In practice, the spectral range recorded by a hyperspectral camera is therefore restricted accordingly, for example, to the range from 500 nm to 1000 nm, so that no higher-order diffraction maxima occur.

[0009] Based on the prior art, the invention is based on the object of enabling the widespread applicability of hyperspectral imaging. This object is achieved according to the invention by a medical imaging device, an endoscope device, an endoscope, and a method as described herein and defined in the claims.

[0010] A medical imaging device may be provided with a spectral camera configured to capture hyperspectral images. The spectral camera comprises an optical system configured to spectrally split incident light by diffraction with respect to a spatial axis, and an image acquisition sensor system that defines a light-sensitive region and is arranged with respect to the optical system such that the light-sensitive region extends along the spatial axis and the spectrally split light falls on the light-sensitive region. The image acquisition sensor system may comprise a first image sensor that is light-sensitive in a first spectral range and that covers a first detection range of the light-sensitive region.Furthermore, the image capture sensor system can comprise a second image sensor that is light-sensitive in a second spectral range that differs from the first spectral range and that covers a second detection range of the light-sensitive region that differs from the first detection range. The second image sensor is arranged adjacent to the first image sensor with respect to the spatial axis. The first spectral range and the second spectral range can jointly define an at least substantially continuous overall spectral range that extends from a first wavelength to a second wavelength, the first wavelength being in the first spectral range.

[0011] Furthermore, an endoscope device with such an imaging device can be provided.

[0012] In addition, an endoscope with such an endoscope device can be provided.

[0013] Furthermore, a method for manufacturing a medical imaging device can be provided, wherein the imaging device can be an imaging device according to the invention. The method comprises providing an optical arrangement configured to spectrally split incident light and to image it in spectrally split form onto a spatial axis. Furthermore, the method can comprise providing a first image sensor that is light-sensitive in a first spectral range.Furthermore, the method may comprise providing a second image sensor that is light-sensitive in a second spectral range that is different from the first spectral range, wherein the first spectral range and the second spectral range together define an at least substantially continuous total spectral range that extends from a first wavelength to a second wavelength, wherein the first wavelength lies in the first spectral range, wherein the second wavelength lies in the second spectral range, and wherein the second wavelength is at least twice as large as the first wavelength.Furthermore, the method may comprise arranging the first image sensor and the second image sensor such that the second image sensor is located next to the first image sensor with respect to the spatial axis, and such that the first image sensor covers a first detection area of ​​a light-sensitive image area and the second image sensor covers a second detection area of ​​the light-sensitive image area different from the first detection area.

[0014] Furthermore, a medical imaging device can be provided. The imaging device comprises a spectral camera configured to capture hyperspectral images. The spectral camera comprises an optical system configured to spectrally split incident light by diffraction with respect to a spatial axis, and an image acquisition sensor system that defines a light-sensitive region and is arranged with respect to the optical system such that the light-sensitive region extends along the spatial axis and the spectrally split light falls onto the light-sensitive region, with different diffraction orders superimposing themselves in a partial region of the light-sensitive region.The image acquisition sensor system can be configured to acquire spatially resolved intensity information for at least two different color channels, which differ in their wavelength-dependent sensitivity such that diffraction light of at least the second order can be detected with different intensities in the color channels. The imaging device can further comprise a processing unit configured to determine, based on the spatially resolved intensity information of the color channels, spectral information describing a spectrum corrected for the diffraction light of at least the second order.

[0015] Furthermore, an endoscope device with such an imaging device can be provided. Furthermore, an endoscope with such an endoscope device can be provided.

[0016] In addition, a method for imaging can be provided, in particular by means of a medical imaging device according to the invention. The method comprises spectrally splitting incident light with respect to a spatial axis by diffraction. Furthermore, the method can comprise imaging the spectrally split light onto an image acquisition sensor which defines a light-sensitive region and is arranged such that the light-sensitive region extends along the spatial axis and the spectrally split light falls onto the light-sensitive region, with different diffraction orders superimposing themselves in a partial region of the light-sensitive region. In addition, the method can comprise capturing spatially resolved intensity information for at least two different color channels by means of the image acquisition sensor, which differ with regard to their wavelength-dependent sensitivity such that diffraction light has at least 2.The diffraction light can be detected with varying intensities in the color channels. Furthermore, the method can comprise determining spectral information that describes a corrected spectrum over the spectral range, which is corrected with respect to at least the second order of diffraction light, based on the spatially resolved intensity information of the color channels.

[0017] The features of the invention allow for widespread use of hyperspectral imaging. In particular, a large spectral range usable for hyperspectral imaging can be achieved. Despite a large usable spectral range, the image acquisition sensors used can be structurally simple and / or cost-effective. The inventors have recognized that for medical applications of hyperspectral imaging, spectral ranges below 500 nm and / or above 1000 nm are also relevant, and that these additional spectral ranges should advantageously be available simultaneously. In particular, the inventors have determined that relevant tissue information regarding tissue perfusion is available in the wavelength range between approximately 400 nm and 500 nm, provided that image data is acquired in this range in a suitable manner.The features of the invention make it possible to distinguish between different orders of diffracted light, making spectrally split object light comprehensively analyzable and usable for hyperspectral imaging. This makes a spectral range accessible for imaging that would otherwise require several different hyperspectral cameras. Accordingly, a compact design, a low degree of complexity, and a high degree of cost-effectiveness can be achieved.

[0018] The imaging device can be configured for medical imaging. "Medical imaging" is understood, in particular, to mean imaging that allows conclusions to be drawn about physiological properties of an examination area, such as tissue type and / or tissue properties, such as fat content, water content, oxygenation, presence of a dye, or the like. The imaging preferably uses spectral analysis to determine these physiological properties. The examination area is, in particular, an area that includes physiological components, such as tissue, blood, or the like. The examination area is located, for example, within a natural or artificially created cavity. Such cavities include, for example, the abdominal cavity, the intestine, the bladder, the kidney, or the like. However, open tissue could also serve as the examination area.In some embodiments, the imaging device is configured to be insertable into a cavity for inspection and / or observation, for example, into an artificial and / or natural cavity, such as the interior of a body, a body organ, tissue, or the like. The imaging device can also be configured to be insertable into a housing, casing, shaft, pipe, or other, particularly artificial, structure for inspection and / or observation.

[0019] An imaging process can be performed using the imaging device, and in particular using the spectral camera. A "capturing process" is understood to mean, in particular, an imaging process that comprises at least one or more method steps. In the medical imaging process, a spectral image or partial sections of the spectral image of an examination area are captured using the spectral camera.

[0020] The spectral camera can be a hyperspectral camera, in particular a pushbroom spectral camera, or operate according to the pushbroom principle. Spatial scanning is preferably used to acquire the hyperspectral images. The examination area is generated from individual subsections in several successive acquisition steps, particularly for the purpose of acquiring the spectral image, specifically by scanning the examination area line by line at staggered intervals. The subsections can then provide information about a spatial dimension and a spectral dimension through spectral fanning. A spectral image can then be assembled from the subsections, with these subsections being placed together along another spatial dimension to construct the image.The spectral image is formed, in particular, by a data cube comprising the spatial dimensions, the further spatial dimension, and the spectral dimension. In other words, the spectral camera, and in particular the image acquisition sensor system, is configured to generate and / or acquire image data comprising spatially and spectrally resolved information. The spatial and spectral information of the image data can be such that an associated spectrum can be obtained therefrom for a plurality of spatial pixels. The spectral camera can be spatially resolving in such a way that it delivers a resolution of at least 100 pixels, preferably of at least 200 pixels, more preferably of at least 300 pixels, and advantageously of at least 400 pixels in at least two different spatial directions.

[0021] The spectral camera, and in particular the optics and / or the image acquisition sensor system, can be configured for hyperspectral imaging, specifically for capturing and / or generating hyperspectral image data. Hyperspectral imaging or hyperspectral image data can refer in particular to imaging in which at least 10, at least 20, at least 50, or even at least 100 spectral bands can be and / or are captured independently of one another. The spectral camera can operate according to the pushbroom principle, the whiskbroom principle, the staring principle, and / or a snapshot principle.

[0022] In some embodiments, the imaging device can additionally enable stereoscopic functionality, by means of which additional three-dimensional spatial information can be recorded. In this case, a hyperspectral image is formed by a four-dimensional hypercube, which comprises the spatial dimensions, the further spatial dimension and the spectral dimension, as well as an additional spatial dimension. This can be achieved, for example, by combining two spectral cameras arranged offset from one another in their viewing direction. The spectral camera can be an endoscopic spectral camera. An "endoscopic spectral camera" should be understood in particular to mean a spectral camera that interacts with an endoscope, is coupled or can be coupled to it, or is preferably formed integrally with it. Alternatively or additionally, the spectral camera can be an exoscopic spectral camera.An "exoscopic spectral camera" is understood in particular to mean a spectral camera that interacts with, is coupled or can be coupled to, or is preferably formed integrally with an exoscope. An "exoscope" can also be understood in particular to mean a surgical microscope. However, an exoscope is preferably understood to mean a surgical imaging device, in particular a surgical microscope, that is free of an eyepiece and instead preferably comprises a camera device, preferably with at least one white-light camera.

[0023] Generally speaking, the imaging device can be a microscopic, macroscopic, and / or exoscopic imaging device. The imaging device can be configured as and / or comprise a microscope, macroscope, and / or exoscope. In some embodiments, the imaging device can be an endoscopic imaging device. The imaging device can be an endoscope device. It can comprise and / or be configured as an endoscope and / or an endoscope system and / or form at least a part and preferably at least a major part and / or a main component of an endoscope and / or an endoscope system. “At least a major part” can mean at least 55%, preferably at least 65%, more preferably at least 75%, more preferably at least 85%, and most preferably at least 95%, in particular with reference to a volume and / or a mass of an object.

[0024] In some embodiments, the image acquisition unit is configured to continuously generate updated image data. For example, the image acquisition unit may be configured to generate the image data substantially in real time, which may include, for example, generating updated image data at least every 30 seconds, in some cases at least every 20 seconds, and in some cases even at least every 10 seconds or at least every 5 seconds.

[0025] The imaging device may comprise an illumination device and / or be connectable, in particular detachably, to an illumination device comprising at least one luminous element configured to illuminate and / or illuminate an object to be imaged in at least one operating state. The luminous element may comprise a white light source, a monochrome light source, in particular a tunable one, a laser, a white light laser, at least one light-emitting diode and / or a light-emitting diode array, at least one laser diode and / or a laser diode array, or the like. The illumination device may comprise a plurality of different luminous elements that can be selectively activated. In particular, illuminating light can be provided in different illumination modes by suitable mixing and / or activating and / or deactivating one or more luminous elements.

[0026] The imaging device may comprise a control unit. The control unit may comprise suitable control electronics and / or a computer. In some embodiments, the control unit comprises at least one processor, computer-readable memory, an operating system, and / or suitable inputs and outputs. The control unit may contain at least one control program. In particular, functions thereof may be implemented by the control program or be part of it. The imaging device and in particular the control unit may each comprise at least one processor and / or an associated memory with program code that implements the described functions and steps, and / or an associated main memory and / or associated connections and / or data interfaces and / or an electronic circuit for implementing the functional units mentioned herein and / or for carrying out the method steps mentioned herein.One or more processors, memories, RAM, ports, data interfaces and / or circuits may also be assigned to one or more functional units and / or implement one or more method steps.

[0027] The imaging device may comprise an output unit configured to output to a user an output based on the hyperspectral images and / or a user output generated in accordance with the output. The output unit may be configured to output a visual output and / or an audio output and / or a haptic output and / or any other output perceivable by a user. For this purpose, the output unit may comprise suitable components, such as one or more lamps, illuminators, speakers, screens, vibrators, or the like. The output unit may comprise a computer and / or processor and / or memory and / or random access memory and / or ports and / or a data interface for receiving, processing, and outputting unprocessed, preprocessed, and / or processed output data.The output generation unit can be connected to the output unit via an interface. The generated output can be processed and / or output by the output unit.

[0028] The imaging device may comprise a display unit configured to display an image, in particular a moving image, for a user. The display unit may be part of the output unit and / or form the output unit. The displayed image may be based on the image data. The display unit may comprise a screen and / or control electronics. The display unit may comprise a computer and / or processor and / or memory and / or RAM and / or ports and / or a data interface for receiving, processing, and outputting unprocessed, preprocessed, and / or processed image data and / or display data. The output generation unit may be connected to the display unit via an interface. The generated output may be processed and / or output by the display unit.

[0029] The medical imaging device can comprise a shaft with at least a proximal section, a distal section, and / or an intermediate section. Alternatively or additionally, the imaging device can be configured to be coupled to such a shaft. The spectral camera can be optically connected and / or connectable to the proximal end of the shaft. The distal section is designed, in particular, to be inserted into and / or located in a cavity to be examined in an operating state, for example during the diagnostic and / or therapeutic procedure. The proximal section is designed, in particular, to be arranged outside the cavity to be examined in an operating state, for example during the diagnostic and / or therapeutic procedure. "Distal" should be understood, in particular during use, to mean facing a patient and / or facing away from a user.“Proximal” should be understood, in particular, as being used facing away from a patient and / or facing towards a user. In particular, proximal is the opposite of distal. The shaft can be an elongated object. Furthermore, the shaft can at least partially and preferably at least largely form the distal section. The optics can comprise at least one dispersive element, in particular at least one optical grating. Furthermore, the optics can comprise an observation slit. Imaging light can pass through the observation slit onto the optical grating, so that an imaging light strip defined by the observation slit can be spectrally split. The spatial axis along which the incident light is split extends, in particular, at least substantially perpendicular to the observation slit. The spectral camera can comprise an input optics, in particular an input lens.The spectral camera can comprise a scanning device configured to move at least the observation slit and in particular the optics and / or the image acquisition sensor system, for example, relative to the input optics. This movement of the observation slit can serve to scan an object to be imaged strip-by-strip, line-by-line, and / or column-by-column.

[0030] The image capture sensor system can have at least one image sensor. The at least one image sensor can define the light-sensitive region. The light-sensitive region can generally extend from a first, in particular smaller, wavelength to a second, in particular larger, wavelength. The image sensor, and in particular said first image sensor, can be a silicon sensor, for example a CCD sensor or a CMOS sensor. The image sensor and / or the first image sensor and / or the second image sensor can have a two-dimensional pixel pattern. Generally speaking, the image capture sensor system can define pixels that are arranged in the light-sensitive region and cover it, in particular according to a pixel pattern. The light-sensitive region can be an image capture sensor region defined by one or more image sensors.In some embodiments, the light-sensitive region is rectangular, wherein a first side of the light-sensitive region can be oriented parallel to the spatial axis along which the spectral splitting occurs, and wherein a second side can be oriented perpendicular to the first side. Image strips that extend parallel to the second side can thus correspond to monochromatic or narrowband spatial image strips. In particular, these are defined by the observation slit. Image strips that extend parallel to the first side can correspond to spectra of a specific image point. The first side can be longer than the second side. The term "image sensor" can refer to a complete electronic component. An image sensor within the meaning of this disclosure can accordingly comprise, in addition to a semiconductor chip, associated contacts, conductor tracks, frames, and / or structural elements.The first detection area and the second detection area can be disjoint from each other. The first detection area can define the first detection area. The second detection area can define the second detection area.

[0031] The first spectral range and the second spectral range can together form the overall spectral range. The overall spectral range can be at least substantially continuous in that a maximum spectral width of an uncovered spectral range lying between the first wavelength and the second wavelength is at most 100 nm, preferably at most 50 nm, particularly preferably at most 20 nm, and preferably at most 10 nm wide. The first spectral range and the second spectral range can overlap one another. In other embodiments, the first spectral range and the second spectral range can be directly adjacent to one another or spaced apart from one another. A spectral spacing can be selected such that the resulting overall spectral range is at least substantially continuous despite the spectral spacing.

[0032] The light-sensitive region can be flat and / or planar, at least in sections and in particular overall. The light-sensitive region can be oriented parallel to the spatial axis, at least in sections and in particular overall. In some embodiments, the light-sensitive region can also be inclined relative to the spatial axis, at least in sections and in particular overall. The statement that the light-sensitive region extends along the spatial axis is to be understood in particular such that a projection of the light-sensitive region onto the spatial axis extends over a length that corresponds to at least 50%, at least 60%, at least 70%, or even at least 80% of a length of the light-sensitive region.

[0033] The first image sensor and the second image sensor can be arranged in a plane. In particular, the first image sensor defines a first detection surface, and the second image sensor defines a second detection surface. The first detection surface and the second detection surface can be arranged parallel to one another. Furthermore, the first detection surface and the second detection surface can be arranged in a common plane. A plane parallel to the first detection surface and the second detection surface can exist, which plane is spaced from the first detection surface and the second detection surface by at most 5 mm, preferably at most 2 mm, particularly preferably at most 1 mm, and preferably at most 0.5 mm.

[0034] In some embodiments, the first image sensor and the second image sensor can be arranged next to one another in such a way that two adjacent edges of the image sensors run parallel to one another, but the image sensors are inclined relative to one another. This makes it possible to achieve an individually optimal orientation relative to the optics and in particular to the dispersive element of the optics for each image sensor. The image sensors can then have a different dispersion per unit distance. The light-sensitive region can be curved and / or bent accordingly. In this case, the light-sensitive region as a whole can extend along the spatial axis. One of the detection surfaces can be oriented parallel to the spatial axis. Alternatively, both the first detection surface and the second detection surface can be inclined relative to the spatial axis.The first image sensor and the second image sensor can be arranged directly adjacent to one another. In particular, the image sensors can touch one another. In some embodiments, the image sensors can be spaced apart from one another. A distance between the image sensors is in particular at most 5 mm, preferably at most 2 mm, particularly preferably at most 1 mm, and preferably at most 0.5 mm. A distance between the image sensors is in particular at most 20%, preferably at most 10%, particularly preferably at most 5%, and preferably at most 2% of an extension of a largest of the image sensors in a direction parallel to a spacing direction.

[0035] Information relating to spectral widths and / or minimum and / or maximum wavelengths of spectral ranges can be understood within the scope of this disclosure to mean those wavelengths or wavelength ranges in which an intensity is at most 10%, at most 5%, at most 2%, or even at most 1% of a maximum intensity of the relevant reference spectral range. For example, a spectral width of an emission spectrum of a luminous element can mean a distance between a first wavelength and a second wavelength, between which an emission maximum lies and at which an emission intensity is at most 10%, at most 5%, at most 2%, or even at most 1% of the emission intensity at the emission maximum.Likewise, within the scope of this disclosure, spectral widths and / or minimum and / or maximum wavelengths of spectral ranges may be understood as relating to transmission properties and / or reflection properties and / or other wavelength-dependent optical properties of objects.

[0036] The spatially resolved intensity information can be at least two-dimensional, point-resolved intensity information. In other words, the spatially resolved intensity information can refer to a matrix of pixels. The mentioned color channels can each contain point-resolved, two-dimensional intensity information. The color channels can comprise a first color channel and a second color channel. Furthermore, the color channels can comprise a third color channel. The first color channel can be a red color channel with respect to visible light. The second color channel can be a green color channel with respect to visible light. The third color channel can be a blue color channel with respect to visible light. The image sensor can be a color-sensitive image sensor, in particular a three-color image sensor, for example an RGB image sensor.The color channels can each be sensitive in a sub-range of the visible spectral range and additionally in at least a sub-range of the near-infrared range.

[0037] Particularly in embodiments with two image sensors, a processing unit can be provided that is configured to determine combined spectral information based on sensor signals from the first image sensor and sensor signals from the second image sensor, which spectral information describes a spectrum across the entire spectral range. In this case, the processing unit is not necessarily configured to determine a corrected spectrum, as mentioned above.

[0038] The processing unit may include a processor and / or a memory and / or a machine-readable medium. The machine-readable medium may contain program code that implements the function of the processing unit.

[0039] The corrected spectrum can differ from an intensity distribution of the light split with respect to the spatial axis in that the intensity of diffracted light of at least the 2nd order is reduced, in particular by at least 50%, preferably by at least 80%, particularly preferably by at least 90%, and preferably by at least 95%. Due to the diffraction by the dispersive element, diffracted light of a first wavelength of at least the 2nd order reaches a location on the light-sensitive area at which diffracted light of a second wavelength of the 1st order, which is greater than the first wavelength, falls. For example, at a specific position in the light-sensitive area, light with a wavelength of X nm of the 1st order coincides with light with a wavelength of X / 2 of the 2nd order, where X is a positive real number. The light intensity at this position is greater than the intensity of the 1st order light, since the 2nd order light also falls.Order contributes to the light intensity at this position. For a position-wavelength mapping, this would result in an erroneous spectrum because the intensity for wavelength X would be overestimated. The processing unit is configured to reduce or eliminate this overestimation by determining the corrected spectrum.

[0040] In the method for manufacturing a medical imaging device, the first image sensor and the second image sensor can be arranged such that they are positioned as described. The image sensors can be arranged on a common base plate and / or circuit board. In particular, the image sensors can be glued to one another and / or to the base plate and / or circuit board.

[0041] In some embodiments, the light-sensitive region and / or the image capture sensor can be movable relative to the optics and in particular relative to the dispersive element. This makes it possible to change which wavelength ranges fall on which positions of the light-sensitive region and / or the image capture sensor. For example, in the case of a spatial spacing of the first image sensor from the second image sensor and a concomitant spectral gap in the overall spectral range, the spectral gap can be changed. This makes it possible to close the spectral gap by recording multiple hyperspectral images for different positioning, in that each wavelength range between the first wavelength and the second wavelength in at least one of the hyperspectral images falls on the light-sensitive region and / or on a detection surface of at least one of the image sensors.In the case of a continuous light-sensitive area and / or in the case of a single image sensor, the change in position can also change the spectral range to be imaged.

[0042] In the context of this disclosure, visible light and / or a visible spectral range may refer to light having a wavelength of at least 500 nm, at least 450 nm, or at least 400 nm and at most 780 nm, at most 750 nm, or at most 700 nm. In the context of this disclosure, near-infrared light and / or a near-infrared spectral range and / or the term "near-infrared" may refer to light having a wavelength of at least 750 nm, at least 780 nm, or at least 800 nm and at most 3000 nm, at most 2000 nm, or at most 1500 nm.

[0043] In some embodiments, the second wavelength lies in the second spectral range, wherein the second wavelength is more than twice as large, preferably at least 2.1 times as large, particularly preferably at least 2.5 times as large, and preferably at least 3 times as large as the first wavelength. This allows a large spectral range to be used for imaging. Furthermore, the limitation that only a spectral range between a lower limit wavelength and twice the lower limit wavelength can be used due to interfering higher diffraction orders can be overcome.

[0044] The first wavelength may be at most 450 nm and preferably at most 400 nm. Alternatively or additionally, the second wavelength may be at least 1000 nm and preferably at least 1200 nm. In particular, for embodiments with a first image sensor and a second image sensor, the second wavelength may be at least 1400 nm, preferably at least 1500 nm, particularly preferably at least 1600 nm, and preferably at least 1700 nm.

[0045] Cost-effective and reliable sensor technology for detecting wavelengths in the visible range and just beyond the visible range into the near-infrared range can be used, in particular, when the first spectral range covers at least a wavelength range from 500 nm, preferably from 450 nm, to 800 nm, preferably to 900 nm. In particular, a silicon image sensor can be used as the first image sensor.

[0046] Widely available sensor technology for detecting visible light can be expediently supplemented, and a large spectral range of interest for medical applications can be made accessible, particularly if the second spectral range encompasses at least a wavelength range from 1000 nm, preferably from 900 nm, to 1500 nm, preferably to 1700 nm. The first and second spectral ranges can overlap. Depending on the design and arrangement of the dispersive element, it can be provided that the respective spectral range of the first image sensor and / or the second image sensor is not fully utilized for capturing hyperspectral images.

[0047] The first image sensor can be a monochromatic image sensor, in particular a monochromatic silicon image sensor. Alternatively or additionally, the second image sensor can be a SWIR (short-wave infrared) sensor, in particular an InGaAs sensor. This allows readily available sensor elements to be combined cost-effectively and easily to expand the available spectral range for hyperspectral medical imaging.

[0048] A high degree of information density over a large spectral range can be achieved in a structurally simple and cost-effective manner, particularly if the first image sensor and the second image sensor are arranged directly adjacent to one another and define the light-sensitive area as a substantially continuous area. The light-sensitive area can be defined exclusively by the first image sensor and the second image sensor, and in particular by their detection surfaces.

[0049] According to some embodiments, the optics are configured to spectrally split incident light such that, for light with a wavelength in the first spectral range, n-th order diffraction light reaches the first detection range and is detectable by the first image sensor due to its light sensitivity in the first spectral range, and (n+1)th order diffraction light reaches the second detection range but is not detectable by the second image sensor due to its lack of light sensitivity in the first spectral range, where n is a positive integer and in particular 1. The said lack of light sensitivity can be achieved by a filter element arranged in front of the second image sensor and / or can be inherent in the material of the second image sensor.In this respect, the second image sensor as such can be suitable for detecting the (n+1)-th order diffraction light, but can be integrated and / or adapted and / or arranged in the image acquisition sensor system in such a way that the (n+1)-th order diffraction light is not detected by the second image sensor. The information can refer to multiple values ​​of n. For example, the explained circumstance can apply both to 1st order diffraction light on the first image sensor and 2nd order diffraction light on the second image sensor, as well as to 2nd order diffraction light on the first image sensor and 3rd order diffraction light on the second image sensor. Furthermore, light of higher orders, for example (n+2)-th order, (n+3)-th order, etc., can also not be detected by the second image sensor.Generally speaking, the first image sensor and the second image sensor can be designed, arranged and / or provided with filters in such a way that the image acquisition sensor can distinguish between different diffraction orders or can be aligned to one diffraction order.

[0050] A high degree of reliability in the suppression of higher orders of diffraction can be achieved in particular if the imaging device and in particular the image capture sensor system further comprises at least one optical edge filter which is transparent to light with a wavelength above a cut-off wavelength and opaque to light with a wavelength below the cut-off wavelength, wherein the cut-off wavelength is less than twice the first wavelength, and wherein the optical edge filter is arranged at least partially in front of the second image sensor. In general, in the case of higher orders of diffraction, the cut-off wavelength can also be selected such that it is greater than the first wavelength by a factor of (n+1) / n, where n is a positive integer. Furthermore, a plurality of different edge filters can be provided which gradually make the light-sensitive area light-sensitive for different spectral ranges.which filter out gradually varying higher-order diffraction light. The edge filter can be arranged at least partially or completely in front of the second image sensor. This can prevent short-wavelength light of higher diffraction orders from reaching the second image sensor.

[0051] Alternatively or in addition to an edge filter in front of the second image sensor, the imaging device and in particular the image capture sensor system can comprise at least one optical edge filter which is transparent to light with a wavelength below a cut-off wavelength and opaque to light with a wavelength above the cut-off wavelength, wherein the cut-off wavelength is less than twice the first wavelength, and wherein the optical edge filter is arranged at least partially in front of the first image sensor. In general, in the case of higher diffraction orders, the cut-off wavelength can also be selected such that it is smaller than the first wavelength by a factor of (n+1) / n, where n is a positive integer. Furthermore, a plurality of different edge filters can be provided which gradually make the light-sensitive area light-sensitive for different spectral ranges.which filter out gradually varying higher-order diffraction light. The edge filter can be arranged at least partially or completely in front of the second image sensor. This can prevent short-wavelength light of higher diffraction orders from reaching the second image sensor.

[0052] The edge filters mentioned, i.e. the edge filter arranged at least partially in front of the first image sensor and / or the edge filter arranged at least partially in front of the second image sensor, can each be arranged at least partially in front of both image sensors. The position can be selected such that a physical edge of the edge filter coincides with a spatial position of the light-sensitive area at which a higher-order wavelength, in particular 2nd order, and a lower-order wavelength to be imaged, in particular 1st order, arrive. The edge filter can then ensure that the higher-order diffracted light is not detected. For example, the first image sensor can be sensitive up to a wavelength of at least 950 nm, at least 1000 nm, or at least 1100 nm. If the first wavelength is then, for example, at most 450 nm, cutoff should already occur at 900 nm.The edge filter can then be arranged partially in front of the first image sensor. It is also conceivable for the second image sensor to be sensitive in a spectral range that extends to wavelengths shorter than, for example, twice the first wavelength. In this case, higher-order light may only fall on a portion of the second image sensor. The edge filter can then be arranged such that it covers only this portion.

[0053] The suppression of higher orders of diffraction can efficiently lead to a broad usable spectral range, in particular if the optics are configured to spectrally split incident light in such a way that, for light with a wavelength in the first spectral range, n-th order diffraction light reaches the first detection range and is detectable by the first image sensor due to its light sensitivity in the first spectral range, and (n+1)th order diffraction light reaches the optical edge filter and is blocked by it, where n is a positive integer and in particular 1. Alternatively or in addition to a selective light intensity of the different image sensors, the edge filter can thus be used to suppress higher orders of diffraction.

[0054] The spectral information can relate to visible light and near-infrared light. The use of inexpensive and / or readily available image sensors as part of an image acquisition sensor system can be enabled, in particular, if the processing unit is configured to determine the spectral information relating to the near-infrared light based on wavelength and using different color channels. For example, the processing unit can be configured to access different color channels and / or different combinations of color channels for different subranges in the near-infrared range. The processing unit can include a lookup table that specifies which color channel and / or color channels are to be considered for different wavelengths.In addition, the processing unit can be configured to determine spectral information relating to visible light, depending on the wavelength, using different color channels.

[0055] The image capture sensor system can be configured to provide spatially resolved intensity information for at least three different color channels. Furthermore, the processing unit can be configured to determine spectral information for at least a first spectral range from a single color channel and to determine spectral information for a second spectral range from a combination of exactly two color channels. This allows an RGB image sensor or another multicolor image sensor to be used in a simple manner. Multiple spectral ranges can be provided, in each of which the processing unit determines spectral information from a single color channel. For example, this can be the case in the visible range for a red spectral range and / or a green spectral range and / or a blue spectral range.Furthermore, a plurality of spectral ranges can be provided in which the processing unit uses a combination of exactly two color channels. There can be two, three, four, or even more such spectral ranges. For example, a number of distinguishable spectral ranges can thereby exceed a number of color channels. An overall spectral range that can be captured by the image capture sensor system can be divided into a first number of partial spectral ranges, each of which is assigned a specific rule specifying which color channel and / or color channels are to be used by the processing unit to determine spectral information in this partial spectral range. Accordingly, a first number of determination rules can be present. Furthermore, a second number of color channels can be present. In some embodiments, the first number can be greater than the second number.

[0056] Available spectral information can be used efficiently and under

[0057] The use of simple electronic components can be effectively utilized if the processing unit is configured to determine spectral information for at least a third spectral range from a combination of exactly three color channels. For example, the processing unit can combine an R channel, a G channel, and a B channel for this purpose.

[0058] In some embodiments, the image capture sensor system comprises a filter pattern that defines the color channels. The filter pattern can in particular be a pixel pattern. The image sensor can comprise the filter pattern. The filter pattern can, for example, comprise a Bayer matrix. The image sensor can be a Bayer sensor. Other filter patterns are also conceivable according to the invention, for example an XTrans matrix. In addition, more than three color channels can be present, for example RGEB color channels, where e stands for "emerald" (emerald green). In addition to color channels, a broadband white light channel can also be present. The filter pattern can, for example, define white pixels and / or filterless pixels in addition to colored pixels.

[0059] In general, according to the invention, the image capture sensor system can be configured to provide spatially resolved intensity information for at least three different color channels, wherein the color channels comprise a red color channel, a green color channel, and a blue color channel. The color information can refer to the visible spectral range, i.e., the color channels can also be sensitive in the near-infrared range, in particular in different sub-ranges of the near-infrared range.

[0060] It is understood that the described targeted evaluation of different color channels can also be used in the described imaging device with two image sensors. For example, the first image sensor can comprise multiple color channels in the manner described and be combined with a second image sensor that is light-sensitive in a different spectral range. Alternatively or additionally, the second image sensor can provide multiple color channels in the manner described.

[0061] Furthermore, it is understood that according to the invention, three or four or even more different image sensors can be provided, which are arranged next to one another or whose detection surfaces and / or detection regions jointly define the light-sensitive region. The invention can generally comprise a method for imaging using an imaging device according to the invention. Furthermore, a method for operating an imaging device according to the invention can be provided.

[0062] The devices and systems according to the invention, as well as the methods according to the invention, are not intended to be limited to the application and embodiment described above. In particular, to fulfill a functionality described herein, they may comprise a number of individual elements, components, units, and method steps that differs from the number stated herein. Furthermore, in the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and can be used arbitrarily.

[0063] It is particularly noted that all features and properties described with reference to a device, as well as procedures, are transferable to methods and applicable within the meaning of the invention and are considered to be included in the disclosure. The same applies in reverse. This means that structural features mentioned with reference to methods, i.e., features related to the device, can also be considered, claimed, and included in the disclosure within the scope of the device claims.

[0064] The present invention is described below by way of example with reference to the accompanying figures. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will expediently consider the features individually and use them in meaningful combination within the scope of the claims.

[0065] If there is more than one instance of a particular object, only one of them may be provided with a reference symbol in the figures and in the description. The description of this instance can be transferred accordingly to the other instances of the object. If objects are named using numerical terms, such as first, second, third object, etc., these serve to name and / or assign objects. Accordingly, for example, a first object and a third object, but not a second object, may be included. However, a number and / or sequence of objects could also be derived using numerical terms.

[0066] Fig. 1 shows a schematic representation of a system with a medical imaging device;

[0067] Fig. 2 is a schematic representation of a spectral camera of the imaging device;

[0068] Fig. 3 is a schematic representation of an image acquisition sensor system of the imaging device;

[0069] Fig. 4 is a schematic representation of different spectral ranges;

[0070] Fig. 5 is a schematic representation of an image acquisition sensor system of an alternative imaging device;

[0071] Fig. 6 Transmission spectra of different color filters of the image acquisition sensor;

[0072] Fig. 7 is a schematic representation of the sensitivity of different color channels of the image acquisition sensor;

[0073] Fig. 8 is a schematic representation of a selection of spectral ranges from the color channels of the image acquisition sensor;

[0074] Fig. 9 schematic spectra illustrating a corrected spectrum;

[0075] Fig. 10 is a schematic flow diagram of a method for manufacturing an imaging device; and

[0076] Fig. 11 is a schematic flow diagram of an imaging method.

[0077] Fig. 1 shows a schematic representation of a system 78 with a medical imaging device 10. The imaging device 10 includes a spectral camera 12, which in this case is a hyperspectral imaging camera. The imaging device 10 further includes a processing unit 44 configured to process image data acquired by the spectral camera 12. The imaging device 10 may be part of an endoscope device 74. The endoscope device 74 may be part of an endoscope 76.

[0078] The system 78 comprises the endoscope 76. The system 78 can, as shown, comprise a supply unit 80 to which the endoscope 76 can be selectively coupled. The supply unit 80 can be configured to control the endoscope 76 and / or receive image data and / or other data from the endoscope 76. The supply unit 80 can be connectable and / or connected to a display 82 of the system 78, on which a user can display recorded images. The supply unit 80 can also supply illumination light for the endoscope 76 and / or the endoscope device 74. In the case shown, an illumination device 82 is provided which supplies illumination light for imaging. The endoscope 76 can be connectable and / or coupled to the illumination device 82 via a fiber optic cable 84. The endoscope 76 can further be coupled and / or connected to the supply unit 80 via an electrical cable 86.The electrical cable 86 may be configured to transmit electrical energy and / or data.

[0079] In other embodiments, a separate illumination device and / or illumination light source may be provided. Furthermore, the endoscope 76 may alternatively or additionally include integrated lighting elements for providing illumination light.

[0080] In other embodiments, the processing unit 44 may be part of the supply unit 82 to which the endoscope 76 can be connected. The endoscope device 74 may then, for example, comprise the imaging device 10 and the endoscope 76. In some embodiments, the endoscope device 74 may comprise the supply unit 82 and / or a lighting device and / or the display 84.

[0081] Fig. 2 shows a schematic representation of the spectral camera 12 of the imaging device 10. The spectral camera 12 operates according to the pushbroom principle. The spectral camera 12 is designed as a spectral scanning hyperspectral camera. The spectral camera 12 comprises an input optics 94. The spectral camera 12 further comprises an observation slit 96. In addition, the spectral camera 12 comprises an image acquisition sensor 18. Furthermore, the spectral camera 12 comprises an optics 14 configured to spectrally split incident light by diffraction with respect to a spatial axis 16. The optics 14 can comprise optical elements 98, 100 such as lenses. Furthermore, the optics 14 can comprise a dispersive element 102. The dispersive element 102 is designed here as an optical transmission grating.

[0082] The spectral camera 12 comprises a camera unit 104, which is movable by means of a scanning device 106. The camera unit 104 can comprise a carrier 108. The camera unit 104 further comprises at least the observation slit 96, the dispersive element 102, and the image acquisition sensor system 18. The scanning device 106 is configured to move at least the observation slit 96 and in particular the optics 14 and / or the image acquisition sensor system 18. In the present case, this movement occurs relative to the input optics 94. This movement serves to scan an object to be imaged strip-by-strip, line-by-line, and / or column-by-column. Thus, for each scan position, an image can be acquired by the image acquisition sensor system 18, one axis of which corresponds to a spatial axis, in particular perpendicular to the spatial direction 16, and the other axis of which corresponds to a spectral axis, in particular parallel to the spatial direction 16.Each captured image is thus a spectrally resolved image strip. Multiple images from a scan can be combined in a generally known manner to obtain a hyperspectral image. The spectral camera 12 can further comprise a housing 110 that encloses the camera unit 104 and the scanning device 106. A shaft of the endoscope 76 can be coupled to the housing.

[0083] Fig. 3 shows a schematic representation of the image capture sensor system 18 of the imaging device 10. The image capture sensor system 18 comprises a first image sensor 22, which defines a first detection area 26. The first image sensor 22 is in this case a monochromatic silicon image sensor. Furthermore, the image capture sensor system 18 comprises a second image sensor 28, which defines a second detection area 32. The second image sensor 28 is in this case embodied as a SWIR sensor. A resolution of the first image sensor 22 can be at least 0.5 megapixels, at least 1 megapixel, at least 2 megapixels, at least 5 megapixels, or at least 10 megapixels, although larger or smaller values ​​are also possible. A resolution of the second image sensor 28 can be at least 0.5 megapixels, at least 1 megapixel, at least 2 megapixels, at least 5 megapixels, or at least 10 megapixels, although larger or smaller values ​​are also possible.The first image sensor 22 and the second image sensor 28 are arranged directly next to one another. For example, the image sensors 22, 28 are mounted on a common circuit board and touch each other along an edge. The detection areas 26, 32 can be spaced apart from each other due to their design, because the corresponding detection surfaces of the image sensors 22, 28 do not extend to their outermost edges.

[0084] The two detection areas 26, 32 together form a light-sensitive area 20 of the image capture sensor system 18. The light-sensitive area 20 extends along the spatial axis 16, in the present case, for example, parallel to the spatial axis 16. The two detection areas 26, 32 lie in a common plane. The light-sensitive area 20 is thus a planar area that extends parallel to the spatial axis 16. The light spectrally split by the optics 14 falls onto different positions along the spatial axis 16 depending on the wavelength. In a direction perpendicular to the spatial axis 16, a monochromatic or narrow-band / single-color image strip of an object to be imaged is projected and / or focused onto the light-sensitive area 20, the spatial dimension of which is predetermined by the observation slit 96.

[0085] Fig. 4 shows a schematic representation of different spectral ranges relevant to image capture sensors. Reference is made to both Figures 3 and 4 below. Due to its nature, the first image sensor 22 is light-sensitive in a first spectral range 24, which extends, for example, from 450 nm to at least 900 nm, in this case approximately from 400 nm to 1000 nm. Due to its nature, the second image sensor 26 is light-sensitive in a second spectral range 30, which extends, for example, from 900 nm to at least 1500 nm, in this case to at least 1700 nm. The relative spatial arrangement of the optics 14 and the light-sensitive region 20 results in light of an overall spectral range 30 falling on the light-sensitive region 20, which is defined by the two spectral ranges 24, 30.The total spectral range 30 extends, for example, from a first wavelength 36 to a second wavelength 38. The first wavelength is, for example, 420 nm or 450 nm, the second wavelength is, for example, 1500 nm or 1600 nm.

[0086] As shown in Fig. 4, the total spectral range 34 can have at least one spectral gap 112, which is determined by the spacing of the two detection regions 26, 32. In this region, spectrally split light does not strike a light-sensitive part of the image capture sensor system 18, but rather, for example, frame elements of the image sensors 22, 28, and therefore cannot be detected. However, the total spectral range 34 is at least substantially continuous due to the arrangement of the image sensors 22, 28 next to one another.

[0087] Due to the large spectral width of the total spectral range 24, this includes diffracted light attributable to different orders of diffraction. For example, if the first wavelength 36 is 420 nm, a second order of diffraction occurs at twice this value, i.e., at a wavelength of 840 nm, and a third order of diffraction occurs at a wavelength of 1260 nm. Due to the different spectral sensitivities of the image sensors 22, 28, at least some of these higher orders of diffraction are not detected by the second image sensor 28. Additionally, an edge filter 40 is provided, located in front of the second image sensor 28. In the exemplary embodiment shown, this edge filter 40 also covers part of the first image sensor 22. A spectral edge of the edge filter 40 is selected at a cutoff wavelength 42 such that higher orders of diffraction are blocked.In the example, the cutoff wavelength 42 is twice the first wavelength 36, i.e., 840 nm. Higher diffraction orders of light with a wavelength between the first wavelength 36 and the cutoff wavelength 42 are thus blocked by both the covered part of the first image sensor 22 and the second image sensor 28. The second order of the cutoff wavelength 42, which occurs at 1680 nm, already lies outside the total spectral range 34. Thus, the present arrangement can ensure that only first-order diffraction light is imaged.

[0088] It goes without saying that several different edge filters can be used. This allows for higher diffraction orders, for which the critical wavelengths are closer together. Furthermore, an even larger overall spectral range can be used.

[0089] In some embodiments, the image sensors 22, 28 can also be selected or provided with their own filters such that a transition between the two image sensors 22, 28 coincides with the second order of the first wavelength 36. Higher diffraction orders then only fall on the second image sensor 28 and can thus be easily filtered out. The processing unit 44 is configured to determine a common image and thus combined spectral information from the sensor signals of the two image sensors 22, 28. This then describes a spectrum across the entire spectral range 34.

[0090] If the optics 14 are suitably rotated relative to the image acquisition sensor 18, the spectral position of the gap 112 can be shifted. If necessary, multiple scans can be performed consecutively to obtain spectral information for the gap 112 as well. In some embodiments, the gap 112 can simply be accepted by foregoing spectral resolution in the relevant narrow spectral range.

[0091] It should be noted that the edge filter 40 does not necessarily have to cover the entire second image sensor 28. In some embodiments, an edge filter 40 can also be provided exclusively in front of a partial area of ​​the first image sensor, for example, if the spectral sensitivity of the second image sensor 28 already ensures that it does not detect any undesired higher-order diffracted light.

[0092] Fig. 5 shows a schematic representation of an image acquisition sensor system 18' of an alternative imaging device. For clarity, the reference numerals of this embodiment are provided with inverted commas. Regarding the structure and functioning of the alternative imaging device, reference is generally made to the above description of the imaging device 10. This applies analogously to the alternative imaging device 10. In this embodiment, some or all of the components of the system described above may also be present. Therefore, the embodiment described below also relates to a system with this structure.

[0093] The image capture sensor system 18' includes an image sensor 54' that defines a light-sensitive area 20'. The image sensor 54' is, for example, a silicon-based color sensor, such as an RGB CCD sensor. This is used in a spectral camera, as shown in Fig. 2.

[0094] The image sensor 54' defines a light-sensitive region 20' extending along a spatial axis 16'. Incident light is spectrally split along the spatial axis 16' by optics of the spectral camera, as described above. The image sensor 54' is light-sensitive in a spectral range within which light of different diffraction orders can occur. In the present case, for example, the image sensor 54' is light-sensitive in a spectral range between 400 nm and 1300 nm. Therefore, in a sub-region 46' of the light-sensitive region 20', light of the first and second diffraction orders overlap. For example, the sub-region 46' extends from 800 nm, i.e., twice the smallest detectable wavelength, to 1300 nm, i.e., the largest detectable wavelength.

[0095] In the following, reference is also made to Figures 6 and 7. Figure 6 shows transmission spectra of different color filters of the image acquisition sensor system 18'. Figure 7 shows a schematic representation of the sensitivity of different color channels of the image acquisition sensor system 18'. In the present example, the image sensor 54' detects light in a first color channel 48', a second color channel 50', and a third color channel 52'.

[0096] The three color channels 48, 50, 52 can, for example, be a red color channel, a green color channel, and a blue color channel with respect to visible light. The image sensor 54' comprises, for example, a filter pattern 72', which can comprise a Bayer matrix, as schematically shown in Fig. 5. The filter pattern 72' comprises a plurality of pixel filters, which are shown excessively large and in too few numbers for illustrative purposes in Fig. 5. The pixel filters are designated R for red, G for green, and B for blue. The resolution of the image sensor 54' can be at least 0.5 megapixels, at least 1 megapixel, at least 2 megapixels, at least 5 megapixels, or at least 10 megapixels, although larger or smaller values ​​are also possible.

[0097] The filters used define three different spectral sensitivities 88', 90', 92' according to three different transmission spectra 162, 164, 166. In Fig. 7, the transmission spectra 162, 164, 166 are shown for a wavelength range extending approximately from 450 nm to 1000 nm. The transmission spectrum 166' belongs to a red filter or the red pixel filters, the transmission spectrum 164' belongs to a green filter or the green pixel filters, and the transmission spectrum 162' belongs to a blue filter or the blue pixel filters. The transmission spectrum 166' belongs to the first color channel 48', the transmission spectrum 164' belongs to the second color channel 50', and the transmission spectrum 162' belongs to the third color channel 52'.In other words, the color channels 48', 50', 52' each relate to light that is detectable by the respective color pixels of the image sensor 54' due to the associated spectral sensitivity 88', 90', 92'.

[0098] As can be seen, the transmission spectra 162', 164', and 166' each define a specific color sensitivity in the visible range, which is why they are assigned to the three color channels 48', 50', and 52'. The spectral sensitivity varies depending on the wavelength. In particular, it is not negligible outside the visible range. Instead, each of the color channels 48', 50', and 52' also exhibits a specific spectral sensitivity in the near-infrared. The spectral sensitivity is different for the three color channels 48', 50', and 52'.

[0099] In Fig. 7, the spectral sensitivities are divided into three categories for illustrative purposes. High spectral sensitivity in a specific spectral range is represented by white boxes. Medium spectral sensitivity is represented by light gray boxes. Low spectral sensitivity is represented by dark gray boxes. Due to diffraction by the optics 14, the spatial axis 16' shown in the transverse direction corresponds to a spectral position. Thus, the relevant wavelength can be determined from a position on the image sensor 54' relative to the spatial axis.

[0100] If imaging is to take place over the entire available spectral range, this also includes the sub-range 46', in which light of different diffraction orders overlaps. In order to distinguish between diffraction orders, the color channels 48', 50', 52' are considered according to their respective spectral sensitivities 88, 90, 92. For this purpose, the alternative imaging device comprises a processing unit 44', which is configured to determine spectral information based on the spatially resolved intensity information of the color channels 48', 50', 52', which spectral information describes a corrected spectrum that is corrected to at least the second order with respect to the diffracted light.

[0101] The corresponding procedure is described with reference to Fig. 8, which shows a schematic representation of a selection of spectral ranges from the color channels 48', 50', 52'. The rectangles drawn with thick frame lines mark selected spectral ranges or corresponding position ranges on the image sensor 56'. For detection in the respective range, those color channels 48', 50', 52' are selected that are suitably spectrally sensitive and that have transmission properties that allow light of higher diffraction orders to be filtered out. For example, for the detection of light in a range of twice the wavelength of blue light, the blue color channel 56' is not used because its filter transmits short-wave light and therefore, for wavelengths between 800 and 900 nm, corresponding to second-order light with a wavelength of 400 to 450 nm falls on the pixels of the color channel 56'.This light, however, is blocked by the filters of the red color channel 48' and the green color channel 50', as can be seen in Fig. 6.

[0102] In this case, the following selection is made as an example. For blue, green, and red light, a spectral range 56', 58', 60' is considered in exactly one of the color channels 48', 50', 52'. In a spectral range 66' immediately adjacent to the visible range, all three color channels 48', 50', 52' are combined. In a subsequent spectral range 68', two color channels 48', 50' are combined, but the third color channel 52' is excluded. In a spectral range 62' lying even further in the red, only the first color channel 48' is considered.

[0103] For example, two color channels 48', 52' are combined further in the red in a spectral range 70', and finally, only the third color channel 52' is combined in a spectral range 64'. Here, the first color channel 48' and the second color channel 50' would each contribute second-order diffraction light, which, however, is blocked due to the spectral sensitivity of the third color channel 52' (see Fig. 6).

[0104] By combining the light detected in the color channels 48', 50', 52' as described, the processing unit 44' can perform a spectral correction. As described, the processing unit 44' obtains spectral information from a single color channel 48', 50', 52' in the spectral ranges 56', 58', 60', 62', 64', from two of the color channels 48', 50', 52' in the spectral ranges 66', 68', and from all three color channels 48', 50', 52' in the spectral range 70'.

[0105] Fig. 9 shows schematic spectra to illustrate a correction made possible by this. The solid line shows the corrected spectrum obtained by the processing unit 44', which is free of higher orders of diffraction. If, however, the light of higher orders of diffraction were also detected, a corrupted spectrum 116 would be obtained. This would, for example, contain the second-order contribution shown as spectrum 118. By selecting suitable color channels 48', 50', 52', higher orders can be reliably suppressed using an already existing filter pattern.

[0106] It is understood that an image sensor 56' with a filter pattern can also be used as the first image sensor 22 in the above-described imaging device 10' with two image sensors 22, 28. The described color-channel-based correction can then be performed in a spectral range covered by this image sensor. Additionally, if necessary, the different spectral sensitivity of the second image sensor 28' can be utilized and / or an additional edge filter can be used.

[0107] Fig. 10 shows a schematic flow diagram of a method for manufacturing an imaging device 10, which, as described above, has two image sensors 22, 28 arranged next to one another. The method sequence is also clear from the above description. A step S11 comprises providing an optical system 14 configured to spectrally split incident light and to image it in spectrally split form onto a spatial axis 16. A step S12 comprises providing a first image sensor 22, which is light-sensitive in a first spectral range 24.A step S13 comprises providing a second image sensor 28 which is light-sensitive in a second spectral range 30 which is different from the first spectral range 24, wherein the first spectral range 24 and the second spectral range 30 together define a substantially continuous total spectral range 34 which extends from a first wavelength 36 to a second wavelength 38, wherein the first wavelength 36 lies in the first spectral range 24, wherein the second wavelength 38 lies in the second spectral range 30, and wherein the second wavelength 38 is at least twice as large as the first wavelength 36.A step S14 comprises arranging the first image sensor 22 and the second image sensor 28 such that the second image sensor 28 is located next to the first image sensor 22 with respect to the spatial axis 16, and such that the first image sensor 22 covers a first detection area 26 of a light-sensitive image area 20 and the second image sensor 28 covers a second detection area 32 of the light-sensitive image area 20 that is different from the first detection area 26.

[0108] An optional step S15 comprises applying at least one edge filter 40 over at least a portion of the first image sensor 22 and / or over at least a portion of the second image sensor 28. Fig. 11 shows a schematic flow diagram of a method for imaging using an imaging device that, as described, comprises an image sensor with a plurality of different color channels 48', 50', 52'. The method sequence also follows from the above description. A step S21 comprises spectral splitting of incident light with respect to a spatial axis 16' by diffraction.A step S22 comprises imaging the spectrally split light onto an image acquisition sensor 18', which defines a light-sensitive region 20' and is arranged such that the light-sensitive region 20' extends along the spatial axis 16' and the spectrally split light falls onto the light-sensitive region 20', with different diffraction orders superimposing in a partial region 46' of the light-sensitive region 20'. A step S23 comprises capturing spatially resolved intensity information for at least two different color channels 48', 50', 52' by means of the image acquisition sensor 18', which differ in terms of their wavelength-dependent sensitivity such that diffraction light of at least the second order can be detected with different intensities in the color channels 48', 50', 52'.A step S24 comprises determining spectral information describing a spectrum over the spectral range that is corrected for at least the second order diffracted light, based on the spatially resolved intensity information of the color channels 48', 50', 52'.

[0109] List of reference symbols

[0110] 10 Imaging device

[0111] 12 spectral camera

[0112] 14 Optics

[0113] 16 spatial axis

[0114] 18 image capture sensors

[0115] 20 light-sensitive area

[0116] 22 image sensor

[0117] 24 spectral range

[0118] 26 Detection range

[0119] 28 image sensor

[0120] 30 spectral range

[0121] 32 detection range

[0122] 34 total spectral range

[0123] 36 wavelength

[0124] 38 wavelength

[0125] 40 edge filters

[0126] 42 Cutoff wavelength

[0127] 44 processing unit

[0128] 46 sub-area

[0129] 48 color channels

[0130] 50 color channels

[0131] 52 color channels

[0132] 54 image sensor

[0133] 56 spectral range

[0134] 58 spectral range

[0135] 60 spectral range

[0136] 62 spectral range

[0137] 64 spectral range

[0138] 66 spectral range

[0139] 68 spectral range

[0140] 70 spectral range

[0141] 72 filter patterns

[0142] 74 Endoscope device

[0143] 76 Endoscope

[0144] 78 systems

[0145] 80 Supply unit 82 Display

[0146] 84 fiber optic cables

[0147] 86 cables

[0148] 88 Spectral sensitivity

[0149] 90 spectral sensitivity

[0150] 92 Spectral sensitivity

[0151] 94 Entrance optics

[0152] 96 Observation slit

[0153] 98 optical element

[0154] 100 optical elements

[0155] 102 dispersive element

[0156] 104 Camera unit

[0157] 106 Scanning device

[0158] 108 carriers

[0159] 110 housings

[0160] 112 gap

[0161] 114 Spectrum

[0162] 116 Spectrum

[0163] 118 Spectrum

[0164] 162 Transmission spectrum

[0165] 164 Transmission spectrum

[0166] 166 Transmission spectrum

Claims

Claims 1. A medical imaging device (10), comprising: a spectral camera (12) configured to capture hyperspectral images, the spectral camera (12) comprising: an optic (14) configured to spectrally split incident light by diffraction with respect to a spatial axis (16);and an image capture sensor system (18) which defines a light-sensitive region (20) and which is arranged with respect to the optics (14) in such a way that the light-sensitive region (20) extends along the spatial axis (16) and the spectrally split light falls on the light-sensitive region (20), wherein different diffraction orders are superimposed in a partial region (46) of the light-sensitive region (20), wherein the image capture sensor system (18) is configured to capture spatially resolved intensity information for at least two different color channels (48, 50, 52) which differ in terms of their wavelength-dependent sensitivity in such a way that diffraction light of at least the 2nd order can be detected with different intensities in the color channels (48, 50, 52);and a processing unit (44) which is configured to determine, on the basis of the spatially resolved intensity information of the color channels (48, 50, 52), spectral information which describes a corrected spectrum which is corrected to at least the second order with respect to the diffracted light; 2. The medical imaging device (10) of claim 1, wherein the image acquisition sensor system (18) comprises an image sensor (54) defining the light-sensitive region (20) and being light-sensitive in a spectral range extending from a first wavelength to a second wavelength, the second wavelength being more than twice the first wavelength.

3. Medical imaging device (10) according to claim 2, wherein the first wavelength is at most 450 nm and preferably at most 400 nm and / or wherein the second wavelength is at least 1000 nm and preferably at least 1200 nm.

4. The medical imaging device (10) according to any one of the preceding claims, wherein the spectral information relates to visible light and near-infrared light; and wherein the processing unit (44) is configured to determine the spectral information relating to the near-infrared light in a wavelength-dependent manner using different color channels (48, 50, 52).

5. Medical imaging device (10) according to one of the preceding claims, wherein the image acquisition sensor system (18) is configured to provide spatially resolved intensity information for at least three different color channels (48, 50, 52), and wherein the processing unit (44) is configured to determine spectral information for at least a first spectral range (56, 58, 60, 62, 64) from a single color channel (48, 50, 52) and to determine spectral information for a second spectral range (66, 68) from a combination of exactly two color channels (48, 50, 52).

6. The medical imaging device (10) according to claim 5, wherein the processing unit (44) is configured to determine spectral information for at least a third spectral range (70) from a combination of exactly three color channels (48, 50, 52).

7. Medical imaging device (10) according to one of the preceding claims, wherein the image acquisition sensor system (18) comprises a filter pattern (72) defining the color channels (48, 50, 52).

8. The medical imaging device (10) of claim 7, wherein the filter pattern (72) comprises a Bayer matrix.

9. Medical imaging device (10) according to one of the preceding claims, the image acquisition sensor system (18) is configured to provide spatially resolved intensity information for at least three different color channels (48, 50, 52), and wherein the color channels (48, 50, 52) comprise a red color channel (48), a green color channel (50) and a blue color channel (52).

10. Medical imaging device (10) according to one of the preceding claims, wherein the spectral camera (12) operates according to the pushbroom principle.

11. Endoscope device (74) with an imaging device (10) according to one of the preceding claims.

12. Endoscope (76) with an endoscope device (74) according to claim 11.

13. A method for imaging, in particular by means of a medical imaging device (10) according to one of claims 1 to 10, comprising: Spectral splitting of incident light with respect to a spatial axis (16) by diffraction; imaging the spectrally split light onto an image capture sensor (18) which defines a light-sensitive region (20) and which is arranged such that the light-sensitive region (20) extends along the spatial axis (16) and the spectrally split light falls onto the light-sensitive region (20), wherein different diffraction orders are superimposed in a partial region (46) of the light-sensitive region (20), Acquiring spatially resolved intensity information for at least two different color channels (48, 50, 52) by means of the image acquisition sensor system (18), which differ in terms of their wavelength-dependent sensitivity such that diffraction light of at least 2nd order can be detected with different intensities in the color channels (48, 50, 52); and Determining spectral information describing a spectrum over the spectral range that is corrected for at least 2nd order diffracted light, based on the spatially resolved intensity information of the color channels (48, 50, 52).

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