Controller and method for surgical microscope

Abstract

A controller (118) for a surgical microscope (100) controls an excitation unit (106) of the surgical microscope (100) to emit excitation light for exciting a fluorophore located in a target area (102) of a patient. A controller (118) controls an optical detection unit (108) of the surgical microscope (100) to receive light from a target region (102) and to separate the received light into at least two spectral channels. The first spectral channel corresponds to a first wavelength band and the second spectral channel corresponds to a second wavelength band. The controller (118) generates at least one image of the target area (102) comprising pixels based on the received light and determines a first intensity for each pixel based on the first spectral channel and a second intensity for each pixel based on the second spectral channel. The controller (118) further determines at least one first image area (122) based on the first intensity and the second intensity, and at least one second image area (124) based on the first intensity and the second intensity. The first image region (122) corresponds to a region in the target region (102) that exhibits fluorescence caused by the excited fluorophore. The second image region (124) corresponds to a region in the target region (102) in which fluorescence is exhibited by a fluorescence source other than the excited fluorophore.

Description

Technical Field

[0001] The invention relates to a controller for a surgical microscope and a surgical microscope. The invention also relates to a method for obtaining an image using a surgical microscope. Background Art

[0002] Fluorescence imaging is becoming increasingly important in microsurgery (i.e., surgery performed with the aid of an operating microscope). Fluorophores are introduced into the patient's body to mark specific substances and structures, such as blood vessels or cancer cells. Fluorophores are used to highlight substances and structures that are invisible or barely visible to the naked eye. For example, indocyanine green (ICG) binds to plasma proteins in the blood and can be used to highlight blood vessels (angiography). Other fluorophores, such as aminolevulinic acid (5-ALA), bind to cancer cells and can therefore be used to highlight the location of cancerous tissue.

[0003] Typically, fluorescence imaging is performed in a single narrow spectral band, for example in the near-infrared region when ICG is used as the fluorophore, and produces a monochrome image. In a monochrome image, it is not possible to distinguish diagnostic fluorescence signals (i.e., fluorescence signals from the fluorophore used) from unwanted fluorescence signals (i.e., signals from any other source) based solely on fluorescence intensity.

[0004] There are other applications of fluorescence imaging using wider spectral bands in the context of microsurgery, such as 5-ALA fluorescence imaging. In these applications, color images are produced, and the surgeon can theoretically distinguish diagnostic fluorescence signals from unwanted fluorescence signals by color. For example, in the case of 5-ALA fluorescence imaging, the diagnostic fluorescence signal is pink, while, for example, bone fluorescence is white. Other objects can have almost any color and can particularly exhibit the color of the diagnostic fluorescence signal. Therefore, it is not easy to distinguish diagnostic fluorescence signals from unwanted fluorescence signals, especially when the perceived colors of the diagnostic fluorescence signals and the unwanted fluorescence signals are similar. In some cases, it is simply impossible to distinguish diagnostic fluorescence from unwanted fluorescence, for example, soft tissue autofluorescence appears to be similar in color to 5-ALA fluorescence, especially at weak fluorescence intensities. Even in cases where it is possible to use color information to distinguish diagnostic fluorescence from unwanted fluorescence, this task places an additional burden on the surgeon.

[0005] Augmented reality (AR) platforms that merge fluorescence images with reflected or white light images of the operating room typically display the fluorescence image in a single color. Therefore, it is impossible to distinguish diagnostic fluorescence signals from unwanted fluorescence signals using these platforms. Summary of the invention

[0006] It is therefore an object to provide a controller for a surgical microscope and a method for acquiring images with a surgical microscope which allow the surgeon to easily distinguish diagnostic fluorescence signals from unwanted fluorescence signals.

[0007] The above mentioned objects are achieved by the subject-matter of the independent claims. Advantageous embodiments are defined in the dependent claims and in the following description.

[0008] The proposed controller for a surgical microscope is configured to control an excitation unit of the surgical microscope to emit excitation light for exciting a fluorophore located in a target area of ​​a patient. The controller is configured to control an optical detection unit of the surgical microscope to receive light from the target area and separate the received light into at least two spectral channels. The first spectral channel corresponds to a first wavelength band, and the second spectral channel corresponds to a second wavelength band. The controller is configured to generate at least one image including pixels of the target area based on the received light, and determine a first intensity of each pixel based on the first spectral channel and a second intensity of each pixel based on the second spectral channel. The controller is also configured to determine at least one first image area based on the first and second intensities, and determine at least one second image area based on the first and second intensities. The first image area corresponds to an area in the target area that exhibits fluorescence caused by the excited fluorophore. The second image area corresponds to an area in the target area that exhibits fluorescence caused by a fluorescence source other than the excited fluorophore.

[0009] The first and second regions may overlap. The overlap of the first and second regions corresponds to a region in the target region that exhibits fluorescence caused by the excited fluorophore and at least one fluorescent source other than the excited fluorophore. The first and second regions may be as small as a single pixel of an image of the target region. In particular, the controller may be configured to determine, for each pixel, whether the pixel corresponds to a region in the target region that exhibits fluorescence caused by the excited fluorophore and / or whether the pixel corresponds to a region in the target region that exhibits fluorescence caused by a fluorescent source other than the excited fluorophore.

[0010] The received light is separated into at least two different spectral channels. This provides additional spectral information about the received light compared to using a single narrow spectral band. Different fluorescent sources have different fluorescence spectra. For example, fluorescein has an emission maximum at 560nm, 5-ALA has an emission maximum for 5-ALA at 630nm, and ICG has an emission maximum at 830nm. However, all fluorophores emit light of other wavelengths except their emission maximum. By comparing the intensity in different spectral channels with the known spectrum of a specific fluorophore, the presence of the specific fluorophore can be determined. Similarly, other fluorescent sources, such as autofluorescence of tissue or bone, have their own unique spectral profiles, and therefore can be determined by comparing the intensity in different spectral channels with the known spectral profiles. Therefore, additional spectral information is used to distinguish diagnostic fluorescent signals from unwanted fluorescent signals. Diagnostic fluorescent signals are fluorescence caused by excited fluorophores, for example, the location of blood vessels indicated by the presence of ICG or the presence of cancerous tissue indicated by the presence of 5-ALA. Unwanted fluorescence signals are fluorescence caused by sources other than the excited fluorophores, for example, autofluorescence of bone or tissue. By distinguishing diagnostic fluorescence signals from unwanted fluorescence signals, the surgeon's additional mental burden is relieved, allowing them to perform their tasks more efficiently.

[0011] In a preferred embodiment, the controller is configured to determine the first and second image regions in real time. Real time in the context of this document specifically means without post-processing. This allows information about the first and second regions (i.e., the location of blood vessels or cancerous tissue) to be delivered to the surgeon without any noticeable delay. For example, the first and second regions can be presented to the surgeon as an overlay in an AR environment, thereby expanding the surgeon's field of view and thereby assisting the surgeon during microsurgery.

[0012] In another preferred embodiment, the controller is configured to determine the first and second image regions by spectral unmixing. Spectral unmixing refers to all methods that allow separation of different fluorescence sources based on intensities detected in different spectral channels. Spectral unmixing can be performed quickly and reliably, thereby allowing rapid determination of the first and second image regions. Methods for spectral unmixing include, but are not limited to, linear unmixing, principal component analysis, unsupervised means of learning spectra, support vector machines, neural networks, (spectral) phasor methods, and Monte Carlo unmixing algorithms.

[0013] In another preferred embodiment, the controller is configured to control the illumination unit of the surgical microscope to emit illumination light to illuminate the target area, and to generate at least one reflected image based on the received light. The reflected image, also referred to as a white light image, shows the target area as seen by a naked human eye. The reflected image can be used to generate a composite image comprising the reflected image and the first and / or second image area. Such a composite image can help the surgeon determine the position of the first and / or second image area in the target area.

[0014] In another preferred embodiment, the controller is configured to control the optical detection unit to separate the received light into at least three spectral channels. The third spectral channel corresponds to the third wavelength band. The third wavelength band is complementary to the first and second wavelength bands. The controller is also configured to generate a reflection image based on at least the third spectral channel. This allows the first and second wavelength bands to be processed separately from the reflection image. For example, the first and second spectral channels can be enhanced or reduced in intensity before being displayed to the surgeon. In this embodiment, the third wavelength band is complementary to the first and second wavelength bands, that is, the third wavelength band does not overlap with the first and second wavelength bands. In particular, the third wavelength band can cover all optical wavelengths except the first and second wavelength bands. In such an embodiment, the reflection image will not display the first and second wavelength bands.

[0015] In another preferred embodiment, the controller is configured to determine the first and second image regions based on the reflected image. In this embodiment, additional information in the form of the reflected image is used to determine the first and second image regions. For example, the controller can be configured to use image detection to detect non-biological objects, such as gloves or surgical instruments, in the reflected light image of the target area and determine that any fluorescence emitted by the glove cannot be a diagnostic fluorescence signal. Using additional information in the form of the reflected image enhances the reliability with which the controller can determine the first and second image regions.

[0016] In another preferred embodiment, the controller is configured to determine the first and second image regions using machine learning. In this embodiment, the controller uses machine learning to distinguish diagnostic fluorescence signals from unwanted fluorescence signals. In particular, additional information such as a reflected image of the target area is used to determine the first and second image regions using machine learning. For example, the controller can be configured to perform image detection facilitated by machine learning in order to detect non-biological objects. In other words, the controller can be configured to perform semantic segmentation of the image of the target area using machine learning. For example, certain areas can be determined to be non-biological objects, such as gloves or surgical instruments. The results of the image segmentation can then be used to exclude certain areas of the image of the target area as emitters of diagnostic fluorescence signals, such as the non-biological objects mentioned above. Therefore, the use of machine learning can greatly help determine the diagnostic fluorescence signal, thereby improving the reliability of the controller.

[0017] Machine learning techniques include, but are not limited to, support vector machines and neural networks. Most machine learning techniques require supervised or unsupervised training using an appropriate training data set. The choice of training data set depends on the specific task of the machine learning technique being used. In the above example of detecting non-biological objects in images of a target area, an appropriate training data set would consist of images of various foreign bodies in a patient's body (particularly images captured with the aid of a surgical microscope).

[0018] In another preferred embodiment, the controller is configured to generate a composite image from the first image area and the image of the target area, and control the output unit of the surgical microscope to display the image of the target area and / or the composite image. The composite image helps the surgeon determine the position of the first and / or second image areas in the target area, thereby reducing the psychological burden during microsurgery and allowing the surgeon to perform his task more efficiently. In the composite image, the first and second areas are preferably highlighted so that they are easily identified.

[0019] In another preferred embodiment, the controller is configured to generate a composite image from the first image area, the second image area, and the image of the target area. The first image area has a first color, and the second image area has a second color. The second color is different from the first color. Displaying different areas in different colors helps the surgeon distinguish diagnostic fluorescence signals from unwanted fluorescence signals. Displaying the second image area, i.e., the area that emits the unwanted fluorescence signal determined by the controller, further allows the surgeon to verify the determination made by the controller, thereby giving the surgeon all the information to make an informed decision during microsurgery.

[0020] In another preferred embodiment, the controller is configured to generate a composite image from the first image area, the second image area, and the image of the target area. The first image area or the second image area is a scintillation overlay on the image of the target area. Displaying the second area as a scintillation overlay helps the surgeon distinguish diagnostic fluorescence signals from unwanted fluorescence signals. In particular, this allows the surgeon to verify the determination made by the controller during microsurgery.

[0021] In another preferred embodiment, the first and second wavelength bands do not overlap. In this embodiment, the first and second wavelength bands complement each other, thereby allowing a more reliable determination of the first and second image regions.

[0022] The present invention also relates to a surgical microscope, comprising a controller as described above, an excitation unit configured to emit excitation light for exciting a fluorophore located in a target area of ​​a patient, and an optical detection unit configured to receive light from the target area and separate the received light into at least two spectral channels. The first spectral channel corresponds to a first wavelength band, and the second spectral channel corresponds to a second wavelength band.

[0023] The surgical microscope includes the controller described above and thus has the same advantages as the controller.

[0024] In a preferred embodiment, the surgical microscope further comprises an illumination unit configured to emit illumination light for illuminating the target area. The illumination unit can in particular be used to generate a reflection image.

[0025] In another preferred embodiment, the surgical microscope comprises an output unit. In particular, the output unit is one of a screen, an eyepiece, an augmented reality kit and a virtual reality kit. The output unit can be configured to display an image and / or a composite image of the target area.

[0026] In another preferred embodiment, the optical detection unit includes at least one microscope objective lens, the at least one microscope objective lens is directed toward the target area and is configured to receive light from the target area. The microscope objective lens can provide magnification, thereby allowing the surgeon to see smaller details in the target area than are visible to the naked eye. In other words, magnification allows the surgeon to perform microsurgery, for example, surgery on small blood vessels or nerves with a diameter of 1 mm or less.

[0027] In another preferred embodiment, the optical detection unit comprises at least two detector elements and a beam splitting component configured to direct received light having a wavelength in a first wavelength band onto a first detector element and to direct received light having a wavelength in a second wavelength band onto a second detector element. In this embodiment, the beam splitting element and the first and second detector elements are used as components for generating the first and second spectral channels. The use of the beam splitting element and the first and second detector elements is easy to implement, cost-effective and reliable compared to other components for generating the first and second spectral channels.

[0028] In another preferred embodiment, the optical detection unit is configured to separate the received light into at least three spectral channels. The third spectral channel corresponds to a third wavelength band. In particular, the third wavelength band is complementary to the first and second wavelength bands. An optical arrangement for separating the received light into three complementary wavelength bands can be easily realized with the aid of a beam splitter. An advantage of such an optical arrangement is that the received light is distributed between the detector elements, so that little or no received light is lost, as is the case, for example, with a multispectral camera.

[0029] In another preferred embodiment, the optical detection unit includes a multispectral camera or a hyperspectral camera configured to generate the first and second spectral channels. The multispectral camera is configured to capture a limited number of wavelength bands, typically less than 10 or about 10. Each of these wavelength bands can be a spectral channel of the surgical microscope. The hyperspectral camera is configured to capture tens or hundreds of wavelength bands per pixel. In other words, the hyperspectral image has a very high spectral resolution. More spectral channels allow for a finer distinction of fluorescent sources in the image of the target area based on their emission spectra, thereby improving the sensitivity and reliability of the surgical microscope.

[0030] The present invention also relates to a method for obtaining an image with a surgical microscope, comprising the steps of: exciting a fluorophore in a target area of ​​a patient. Receiving light from the target area. Separating the received light into at least two spectral channels, a first spectral channel corresponding to a first wavelength band, and a second spectral channel corresponding to a second wavelength band. Generating at least one image of the target area based on the received light, the image comprising pixels. Determining a first intensity of each pixel based on the first spectral channel, and determining a second intensity of each pixel based on the second spectral channel. Determining at least one first image area based on the first and second intensities, the first image area corresponding to an area in the target area that exhibits fluorescence caused by the excited fluorophore. Determining at least one second image area based on the first and second intensities, the second image area corresponding to an area in the target area that exhibits fluorescence caused by a fluorescence source other than the excited fluorophore.

[0031] The method has the same advantages as the controller described above and can be supplemented with the features of the dependent claims directed to the controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Specific embodiments are described below with reference to the accompanying drawings, in which:

[0033] Figure 1 is a schematic diagram of a surgical microscope according to an embodiment;

[0034] Figure 2 is a flow chart of a method for obtaining an image of a target area with a surgical microscope;

[0035] Figure 3 Three schematic diagrams are shown, each schematic diagram showing the spectrum of a different component of the detection light; and

[0036] Figure 4 is a schematic diagram illustrating the spectra of different components of detection light in the prior art. DETAILED DESCRIPTION

[0037] Figure 1 is a schematic diagram of a surgical microscope 100 according to an embodiment.

[0038] The surgical microscope 100 is adapted to provide a surgeon with a magnified image of a target region 102 in a patient, for example, during microsurgery. In particular, the surgical microscope 100 is adapted to obtain a fluorescent image of the target region 102. The image is an image generated by the fluorescence emitted by the fluorophores located in the target region 102.

[0039] An illumination unit 104 of the surgical microscope 100 is directed toward the target area 102 and is configured to illuminate the target area 102 with white light. An excitation unit 106 of the surgical microscope 100 is configured to emit excitation light for exciting fluorophores toward the target area 102. The excitation unit 106 may specifically include a coherent light source, such as a white light laser, a continuous wave laser, or a pulsed laser having a single emission wavelength.

[0040] The optical detection unit 108 of the surgical microscope 100 has at least one microscope objective 110, which is directed toward the target area 102 and is configured to receive detection light 112 from the target area 102. The detection light 112 includes a plurality of components. Among the components of the detection light 112 are fluorescence emitted by the excited fluorophore, fluorescence emitted by sources other than the excited fluorophore, and reflected light caused by white light illumination. The fluorescence emitted by the excited fluorophore is a desired fluorescence signal or a diagnostic fluorescence signal, while the fluorescence emitted by other sources is an unwanted fluorescence signal.

[0041] The optical detection unit 108 is illustratively configured to generate three spectral channels, ie, to detect the detection light 112 in the first, second and third wavelength bands, respectively. Figure 3 The three wavelength bands are described in more detail. To generate the three spectral channels, the optical detection unit 108 illustratively includes an arrangement of beam splitting elements 114a, 114b (e.g., dichroic elements or acousto-optic tunable filters (AOTFs)) and detector elements 116a, 116b, 116c. Optionally, the three spectral channels can be generated by other means, such as a multispectral or hyperspectral camera.

[0042] The first beam splitting element 114a is arranged in the beam path of the detection light 112 after the microscope objective 110. The first beam splitting element 114a is configured to direct the detection light 112 of the first wavelength band to the first detector element 116a. The remaining detection light 112 is directed to the second beam splitting element 114b. The second beam splitting element 114b is configured to direct the detection light 112 of the second wavelength band to the second detector element 116b. The remaining detection light 112 is then directed to the third detector element 116c.

[0043] The surgical microscope 100 further includes a controller 118. The controller 118 is connected to the illumination unit 104, the excitation unit 106, the optical detection unit 108, and the output unit 120. The controller 118 is configured to control the elements of the surgical microscope 100. In particular, the controller 118 is configured to perform the following reference Figure 2 A method for obtaining an image of a target area 102 is described.

[0044] One or more images of target area 102 generated by controller 118 are displayed to the surgeon via output unit 120 of surgical microscope 100. In this embodiment, output unit 120 is exemplarily shown as a monitor. Figure 1 In FIG. 1 , the output unit 120 exemplarily shows a composite image of the target area 102, which includes a reflection image or a white light image of the target area 102, a first image area 122, and a second image area 124. The first image area 122 corresponds to a diagnostic fluorescence signal, in this example, a tumor labeled by 5-ALA. The second area corresponds to an unwanted fluorescence signal, in this example, bone autofluorescence. Figure 1 In the embodiment, the first image area 122 and the second image area 124 are distinguished by different hatching lines. In an actual embodiment, the first image area 122 and the second image area 124 can be distinguished by different colors. Optionally, the first image area 122 or the second image area 124 can be displayed as a flashing overlay on the reflected image.

[0045] Figure 2 is a flow chart of a method for obtaining an image of a target area 102 using the surgical microscope 100 described above.

[0046] The process starts from step S200. In step S202, the controller 118 controls the excitation unit 106 to emit excitation light toward the target area 102 so as to excite the fluorophores located in the target area 102. In step 204, the controller 118 controls the optical detection unit 108 to receive light from the target area 102. The received light is split into at least two spectral channels, in this embodiment, three spectral channels. In this embodiment, the first spectral channel is generated by the first detector element and corresponds to the first wavelength band, the second spectral channel is generated by the second detector element and corresponds to the second wavelength band, and the third spectral channel is generated by the third detector element and corresponds to the third wavelength band.

[0047] In step S206, the controller 118 generates at least one image of the target area 102 based on the received light (i.e., the detection light), the image including pixels. In step S208, the controller 118 determines a first intensity of each pixel based on the first spectral channel, and determines a second intensity of each pixel based on the second spectral channel. In the present embodiment, the controller 118 generates a first image corresponding to the detection light 112 received by the first detector element, and a second image corresponding to the detection light 112 received by the second detector element. The first and second images are monochrome images corresponding to the intensity of the detection light 112 received in the first and second wavelength bands, respectively. That is, each pixel of the first and second images stores information about the intensity of the light received in the first and second wavelength bands, respectively. In addition, in this embodiment, the controller 118 generates a third image of the target area 102 based on the light received in the third wavelength band. The third image can specifically be a color image of the target area 102. That is, the third image is a reflection image. Alternatively, the controller 118 can generate a single image of the target area 102. In this alternative embodiment, each pixel of the single image includes information about the intensity of the light received in the three detection channels.

[0048] In step S210, the controller 118 determines the first image region 122 based on the first and second intensities, and in step S212, the controller 118 determines the second image region 124 based on the first and second intensities. Figure 3 The determination of the first image region 122 and the second image region 124 is described in more detail.

[0049] In step S214, the controller 118 generates an image of the target area 102 based on the first image area 122 and the second image area 124, and controls the output unit 120 to output the image of the target area 102 to the surgeon. If the output unit 120 is a monitor, a digital eyepiece, etc., the controller 118 can generate a composite image including a reflected image of the target area 102 and the first image area 122 and the second image area 124. If the output unit 120 is an AR kit, etc., the controller 118 can generate a composite image including the first image area 122 and the second image area 124, which can be displayed to the surgeon as an AR overlay. In step S216, the process ends.

[0050] Figure 3 Three schematic diagrams 300 , 302 , 304 are shown, each illustrating the spectrum of a different component of the detection light 112 .

[0051] The abscissa of each graph 300, 302, 304 represents wavelength. The ordinate of each graph 300, 302, 304 represents intensity. The first and second wavelength bands are indicated in the graphs 300, 302, 304 by dashed rectangles 306a, 306b.

[0052] The first diagram 300 shows the spectrum 308 of the fluorescence emitted by the fluorophore, ie the spectrum of the diagnostic fluorescence signal. The diagnostic fluorescence signal has its maximum value 310 in the first wavelength band. The intensity of the diagnostic fluorescence signal in the second wavelength band is approximately one fifth of its maximum value.

[0053] The second graph 302 shows the spectrum 312 of the autofluorescence emitted by the first tissue, ie the spectrum of the first unwanted fluorescence signal. The first unwanted fluorescence signal has its maximum value in the first wavelength band 314. The intensity of the first unwanted fluorescence signal in the second wavelength band is almost zero.

[0054] The third graph 304 shows a spectrum 316 of autofluorescence emitted by the second tissue, i.e., a spectrum of a second unwanted fluorescence signal. A maximum value 318 of the second unwanted fluorescence signal is located between the first wavelength band and the second wavelength band. The second unwanted fluorescence signal has approximately equal intensities in the first wavelength band and the second wavelength band.

[0055] As can be seen from the three graphs 300, 302, 304, each source of fluorescence has its characteristic spectrum 308, 312, 316, which can be determined by the intensity detected in the first and second wavelength bands (i.e., the first and second detection channels). Therefore, it is possible to determine the source of the received fluorescence for each pixel based on the first and second detection channels.

[0056] Figure 4 is a schematic diagram of the spectra of different components of the detection light 112 .

[0057] Figure 4 The prior art is illustrated, where only a single narrow wavelength band is used to capture diagnostic fluorescence signals. The abscissa of the graph 400 represents wavelength. The ordinate of the graph 400 represents intensity. The single narrow wavelength band is indicated in the graph 400 by the dashed rectangle 402.

[0058] exist Figure 4 , the spectrum 308 of the diagnostic fluorescence signal is shown as a solid line. The spectra 312, 316 of the two unwanted fluorescence signals are shown as dashed lines. As can be seen, the three sources of fluorescence are distinguished by their intensities in a single narrow wavelength band. However, since it is not possible to easily normalize the three signals, it is not possible to distinguish the signals only by their intensities in a single narrow wavelength band.

[0059] In all figures, identical or similarly acting elements are indicated by the same reference symbols. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ". The individual features of the embodiments and all combinations of the individual features of the embodiments with each other and with the individual features or feature groups of the preceding description and / or claims are considered disclosed.

[0060] Although some aspects are described in the context of an apparatus, it is clear that these aspects also represent the description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method step also represent the description of a corresponding block or item or feature of a corresponding device.

[0061] Reference Symbols List

[0062] 100 Surgical Microscope

[0063] 102 Target Area

[0064] 104 Lighting units

[0065] 106 Excitation Unit

[0066] 108 Optical detection unit

[0067] 110 Objective

[0068] 112 Detection Light

[0069] 114a, 114b beam splitting element

[0070] 116a, 116b, 116c Detection elements

[0071] 118 Controller

[0072] 120 Output Units

[0073] 122, 124 Image area

[0074] Figures 300, 302, 304

[0075] 306a, 306b Rectangular

[0076] 308 Spectrum

[0077] 310 Maximum

[0078] 312 Spectrum

[0079] 314 Maximum

[0080] 316 Spectrum

[0081] 318 Maximum

[0082] 400 images

[0083] 402 Rectangle

Claims

1. A controller (118) for a surgical microscope (100), configured to: Controlling an excitation unit (106) of the surgical microscope (100) to emit excitation light for exciting a fluorophore located in a target area (102) of a patient; Controlling an optical detection unit (108) of the surgical microscope (100) to receive light from the target area (102) and to separate the received light into at least two spectral channels, a first spectral channel corresponding to a first wavelength band, and a second spectral channel corresponding to a second wavelength band; generating at least one image of the target area (102) based on the received light, the image comprising pixels; determining a first intensity for each pixel based on the first spectral channel and determining a second intensity for each pixel based on the second spectral channel; determining at least one first image region (122) based on the first intensity and the second intensity, the first image region (122) corresponding to a region of the target region (102) exhibiting fluorescence caused by the excited fluorophore; and At least one second image region (124) is determined based on the first intensity and the second intensity, the second image region (124) corresponding to a region of the target region (102) exhibiting fluorescence caused by a fluorescence source other than the excited fluorophore.

2. The controller (118) of claim 1, configured to determine the first image region (122) and the second image region (124) in real time.

3. The controller (118) according to claim 1 or 2, configured to determine the first image area (122) and the second image area (124) by spectral unmixing.

4. The controller (118) according to any one of the preceding claims, is configured to control the illumination unit (104) of the surgical microscope (100) to emit illumination light to illuminate the target area (102), and to generate at least one reflected image based on the received light.

5. The controller (118) according to claim 4 is configured to control the optical detection unit (108) to separate the received light into at least three spectral channels; wherein the third spectral channel corresponds to a third wavelength band; wherein the third wavelength band is complementary to the first wavelength band and the second wavelength band; and wherein the controller (118) is configured to generate the reflected image based on at least the third spectral channel.

6. The controller (118) of claim 4 or 5, configured to determine the first image area (122) and the second image area (124) based on the reflected image.

7. The controller (118) of any one of the preceding claims, configured to determine the first image region (122) and the second image region (124) using machine learning.

8. The controller (118) according to any one of the preceding claims, is configured to generate a composite image from the first image area (122) and the image of the target area (102), and to control the output unit (120) of the surgical microscope (100) to display the image of the target area (102) and / or the composite image.

9. The controller (118) of claim 8, being configured to generate the composite image from the images of the first image area (122), the second image area (124), and the target area (102); wherein the first image area (122) has a first color and the second image area (124) has a second color, the second color being different from the first color.

10. A controller according to claim 8 or 9, configured to generate the composite image from the first image area (122), the second image area (124) and the image of the target area (102); wherein the first image area (122) or the second image area (124) is a flashing overlay on the image of the target area (102).

11. A controller according to any preceding claim, wherein the first wavelength band and the second wavelength band do not overlap.

12. A surgical microscope (100), comprising A controller (118) according to any one of the preceding claims, an excitation unit (106) configured to emit excitation light for exciting fluorophores located in a target area (102) of a patient, and The optical detection unit (108) is configured to receive light from the target area (102) and separate the received light into at least two spectral channels, a first spectral channel corresponding to a first wavelength band, and a second spectral channel corresponding to a second wavelength band.

13. The surgical microscope (100) according to claim 12, comprises an output unit (120); wherein the output unit (120) is particularly one of a screen, an eyepiece, an augmented reality kit and a virtual reality kit.

14. The surgical microscope (100) according to claim 12 or 13, wherein the optical detection unit (108) comprises at least one microscope objective (110), the at least one microscope objective (110) being directed toward the target area (102) and being configured to receive the light from the target area (102).

15. A surgical microscope (100) according to any one of claims 12 to 14, wherein the optical detection unit (108) includes at least two detector elements and a beam splitting component, and the beam splitting component is configured to direct received light having a wavelength in the first wavelength band to a first detector element, and to direct received light having a wavelength in the second wavelength band to a second detector element.

16. The surgical microscope (100) according to any one of claims 12 to 15, wherein the optical detection unit (108) comprises a multispectral camera or a hyperspectral camera configured to generate the first spectral channel and the second spectral channel.

17. A method for obtaining an image using a surgical microscope (100), comprising the steps of: a) exciting fluorophores in a target area (102) of a patient; b) receiving light from the target area (102); c) separating the received light into at least two spectral channels, a first spectral channel corresponding to a first wavelength band and a second spectral channel corresponding to a second wavelength band; d) generating at least one image of the target area (102) based on the received light, the image comprising pixels; e) determining a first intensity for each pixel based on the first spectral channel, and determining a second intensity for each pixel based on the second spectral channel; f) determining at least one first image region (122) based on the first intensity and the second intensity, the first image region (122) corresponding to a region of the target region (102) exhibiting fluorescence caused by the excited fluorophore; and g) determining at least one second image region (124) based on the first intensity and the second intensity, the second image region (124) corresponding to a region of the target region (102) exhibiting fluorescence caused by a fluorescence source other than the excited fluorophore.

Images