A surgical microscope having at least two camera devices

Abstract

In order to achieve the object of the present invention of providing a surgical microscope capable of capturing and displaying images of tissue structures as accurately as possible, the surgical microscope is characterized in that it comprises a first camera device (1) for capturing and displaying a reflected image of an object, and a second camera device (2) for simultaneously capturing and displaying a further image of the object.

Description

Technical Field

[0001] The present invention relates to the surgical microscope described in the preamble of claim 1.

Background Art

[0002] It is already known to capture so-called reflection images of organic tissues. In this case, in order to generate a reflection image, light is guided onto the tissue to be examined, and the light reflected by the tissue is captured. It is also known to capture so-called fluorescence images of organic tissues. For example, fluorescein can be distributed in the tissue as an indicator and excited to a fluorescent state by light. Fluorescein is a dye that emits fluorescence and is used as an indicator particularly in ophthalmology.

[0003] Against such a background, currently, surgical microscopes capable of observing organic tissues are being used. Surgical microscopes are used by doctors in various specialties to capture images of organs or organ sites during surgery and perform medical diagnoses from those images.

[0004] Regardless of the medical field, the depth of field of camera-based surgical microscopes has always been criticized by surgeons.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Accordingly, an object of the present invention is to provide a surgical microscope that can record and display an image of a tissue structure as accurately as possible.

Means for Solving the Problems

[0006] The present invention achieves the above object by the features of claim 1. By using two camera devices operating simultaneously, a reflected image and a further image, for example a fluorescence image, can be captured and drawn simultaneously. By using two camera devices, two camera planes can be provided, and the camera devices can complement each other during image capture and drawing, and thus can compensate for quality losses during image capture. If at least one of the camera devices is composed of two cameras in a stereo arrangement, an optically spatial image can be generated for the user. The tissue can be inspected and observed very comprehensively. For example, the time-sequential alternating acquisition and drawing of two imaging modes, such as the reflection mode and the fluorescence mode, may be omitted due to the required flickering illumination and the distracting effect associated therewith.

[0007] According to the present invention, a surgical microscope has a second camera plane assigned thereto. In addition to performing fluorescence drawing simultaneously, the second camera plane further provides the possibility of improving optical drawing, such as so-called focus stacking, improving resolution by intermediate sampling, reducing noise and expanding the dynamic range due to different exposures of various camera units or camera devices.

[0008] For those skilled in the art, "focus stacking" means the concept of increasing the depth of field achieved by a combination of optical photography techniques and digital image editing or image processing. Therefore, an image with a very large depth of field can be generated.

[0009] Against such a background, each camera device can have at least two individual cameras. Each of the two preferred operating modes, namely the reflection mode and the fluorescence mode, generates a three-dimensional image for the user. To generate this three-dimensional image, two detection channels are used for each camera device. To make the structure of the optical arrangement as simple as possible, both pairs of detection channels preferably use the same zoom optical system.

[0010] At least one camera device or both camera devices can execute image recording in video mode. Therefore, the movement of the tissue can also be imaged well. Two preferred operating modes, namely the reflection mode and the fluorescence mode, can be implemented based on video recording. Therefore, in-situ inspection of the tissue and preferably subsequent chronological checks of the video recording outside the operating room can be carried out.

[0011] Further images can be configured as fluorescence images of the object. Therefore, the reflection image and the fluorescence image of the same object can be acquired, drawn, and evaluated simultaneously.

[0012] Against this background, one lighting device can have a fluorescence excitation light source. Alternatively, two lighting devices can be provided, each having a fluorescence excitation light source.

[0013] In this regard, initially there is only the basic design of the surgical microscope, but additional light sources can be supplemented.

[0014] In another embodiment of the surgical microscope, the light source existing for the generation of the reflection image can be turned off during the detection of fluorescence. In this case, an additional filter becomes unnecessary to block the wavelength range in which fluorescence occurs.

[0015] A blocking filter or other barrier filter can be provided, which is optically arranged in front of the two camera devices, and the light beam components incident on the two camera devices need to pass through the blocking filter. In the fluorescence mode, a sufficiently large spectral power density is required at the wavelength of the excitation light of the lighting device. The spectral range of the excitation light or the spectral range of the excitation light reflected as reflected light can be blocked simultaneously for both camera pairs by the blocking filter.

[0016] Against such a background, a blocking filter can, for example, not transmit or at least suppress light having a wavelength from the wavelength range from 480 nm to 490 nm. Fluorescein is excited to fluorescence by excitation light having a wavelength of 485 nm. Preferably, the excitation light can be blocked individually for each wavelength. In the case of narrowband excitation that can be generated by a laser, the blocking filter can also remain in the beam path between other modes and / or can be configured statically if white balancing is further possible. Preferably, the possibility of filter exchange is provided by the design of the optical arrangement.

[0017] When the surgical microscope is operating in the fluorescence mode, the wavelength regions detected during each fluorescence need to be filtered from the spectrum of the illumination device, and the excitation light reflected as reflected light or the returning excitation light should not overlap with the fluorescence acquisition on or by the second camera device. This is preferably achieved by an illumination module provided in the camera device.

[0018] In the fluorescence mode, the light incident on the second camera device needs to be filtered by an appropriate band-pass filter or bandwidth filter for the wavelength to be detected in order to block the reflected light of the excitation light incident on the second camera device. This band-pass filter is preferably switchable for different dyes or removable when other modes are active.

[0019] Against such a background, the band-pass filter can be optically arranged in front of the second camera device, and the light beam component incident on the second camera device needs to pass through the band-pass filter before colliding with the second camera device.

[0020] Accordingly, the band-pass filter can transmit light having wavelengths in the wavelength range of, for example, 510 nm to 540 nm and can either not transmit or at least suppress the remaining spectral range. In this case, most of the fluorescent light of fluorescein is transmitted to the second camera device, while unnecessary light is blocked instead.

[0021] In view of such a background, specifically, when the band-pass filter can completely suppress the excitation light reflected as reflected light in front of the second camera device and the high spectral power density at the wavelength of the excitation light can be tolerated or corrected during the drawing of the reflected image performed simultaneously via or by the first camera device, an optical arrangement without a blocking filter can also be considered. When there is no blocking filter, the band-pass filter also needs to suppress the high spectral power density of the excitation light. In that case, the blocking filter is preferably integrated into the band-pass filter.

[0022] At least one beam splitter, preferably a 50:50 beam splitter, which can direct the first light beam component to be split into a second light beam component and a third light beam component, can be arranged in the beam path between the objective lens above the specimen and the two camera devices. By means of this beam splitter, at least a part of the light reflected by the specimen or emitted as fluorescence, i.e., the reflected light and the fluorescent light, can be simultaneously directed to the two camera devices.

[0023] In view of such a background, the beam splitter can direct the second light beam component in the direction of the first camera device and direct the third light beam component to the second camera device via the band-pass filter in front of the second camera device. In this way, the light for the reflected image can be directed to the first camera device and the light for the fluorescent image can be directed to the second camera device in a filtered manner.

[0024] In addition, an OCT device for inspecting a specimen with sampling light can be additionally provided. Therefore, in addition to the reflection image and the fluorescence image, an OCT image can also be acquired by a known method. The term "optical coherence tomography" (usually abbreviated as OCT) refers to an image generation method. In this method, two-dimensional and three-dimensional images can be obtained from an optically scattering organic tissue.

[0025] The depth of field of a camera-based surgical microscope has always been criticized by surgeons, regardless of the medical field. Since it cannot be adjusted by the observer, the depth of field decreases to the numerical aperture determined by the geometric aperture of the objective lens of the surgical microscope.

[0026] Reducing the aperture diameter to increase the depth of field is only possible within a limited range because it is accompanied by an undesirable increase in brightness that ultimately leads to tissue heating, an increase in signal amplification with an accompanying increase in noise, and a decrease in MTF with an accompanying decrease in resolution.

[0027] The abbreviation MTF refers to the so-called modulation transfer function or contrast transfer function, and mathematically describes the comparison between the detailed contrast of the edge of an object and the detailed contrast of its pictorial rendering.

[0028] In view of such a background, a surgical microscope of the type described here includes an image processing device that combines at least one first image acquired by a first camera device with at least one further image acquired by a second camera device, and the images are selected and synthesized by the image processing device based on a predetermined sharpness quality of the images to form an overall image.

[0029] The second camera device described here, i.e., the second camera plane, can be used, among other things, to patch together regions with acceptable sharpness. In this case, the imaging plane of the second camera plane will be displaced relative to the first camera plane, for example, by half of the depth of field range of the subject. Next, the final image or the overall image will be algorithmically combined from two slice images.

[0030] A static or temporal noise removal algorithm for noise reduction that can suppress parameterizable noise can be further used. By synchronizing the sampling of the two camera planes or camera devices, a method based on time averaging can also be used. So-called temporal oversampling can be performed.

[0031] An image sensor sensitive to infrared rays, preferably in the wavelength range from 1000 to 1500 nm, can be provided in the first and / or second camera device. For hyperspectral image generation, for example, in the infrared region up to 1500 nm, an image sensor that is sensitive to far-infrared and is used for spectral tissue differentiation can be used. Tumor detection is preferably performed in the spectral region of 1000 - 1500 nm.

[0032] The resolution can be improved by oversampling. By displacing two sampling grids diagonally by half a pixel, the resolution can be increased by about 1.4 times, i.e., √2 times.

[0033] In the case of so-called downsampling for the display size of an image, such as HD or 4K, it may affect the shape of the MTF and thus the sharpness of the image.

[0034] The advantage of this technology mainly lies not in improving the resolution but in leading to the sharpness of the image. This is due to boosting low spatial frequencies. Furthermore, the oversampled image can be used for lossless digital enlargement and / or zoom.

[0035] The dynamic range can be increased by different amplifications, different illuminations, or different exposures of two camera planes or camera devices.

[0036] One specific feature is to balance the characteristic curves of two pairs of images, that is, to set the junction in the transition region so that an HDR image without artifacts can be obtained.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0038] FIG. 1 shows a surgical microscope including a first camera device 1 for capturing and rendering a reflected image of an object, and the surgical microscope has a second camera device 2 for simultaneously capturing and rendering a further image of the object.

[0039] Also, FIG. 1 shows a configuration for use in a surgical microscope, including a first camera device 1 for capturing and rendering a reflected image. This configuration features a second camera device 2 for simultaneously capturing and rendering a fluorescence image. In this regard, the further image is a fluorescence image.

[0040] Each of the camera devices 1 and 2 has at least two cameras. In this regard, each of the camera devices 1 and 2 is a pair of cameras. One or both of the camera devices 1 and 2 execute image recording in video mode. The first camera device 1 is used to capture a reflected image. The second camera device 2 is used to capture a fluorescence image.

[0041] At least one lighting device 4a, 4b having a fluorescence excitation light source 5 is provided or two lighting devices 4a, 4b each having a fluorescence excitation light source 5 are provided. The lighting devices 4a, 4b include a field illumination light source 6 and / or an SCI light source 7. The abbreviation SCI means "Stereo Confocal Illumination".

[0042] In this regard, illumination of the object, that is, the specimen 3, specifically an organic tissue, can be performed by two options. According to the first option, the first lighting device 4a includes a field illumination light source 6 as a fluorescence excitation light source 5. Fluorescence illumination is generated by the field illumination light source 6.

[0043] According to the second option, the second lighting device 4b includes an SCI light source 7 as a fluorescence excitation light source 5.

[0044] In the first embodiment of the configuration, the SCI light source 7 does not exist. This surgical microscope constitutes a basic design. In another design, the physically existing SCI light source 7 can be turned off during fluorescence detection.

[0045] The excitation light from the lighting devices 4a, 4b collides with the specimen 3 through the objective lens 8, and since fluorescein exists in the specimen 3, the specimen 3 is excited to emit fluorescence light. At the same time, the excitation light colliding with the specimen 3 is at least partially reflected by the specimen 3 as reflected light.

[0046] Furthermore, according to a specific embodiment of this configuration, the sampling light 9 of the OCT device 10 collides with the specimen 3 so that it can be inspected in more detail.

[0047] The reflected light and fluorescent light represented by the return light beam 11 in FIG. 1 and reflected by the specimen 3 toward the incident excitation light of the illumination devices 4a and 4b first pass through or bypass the first beam splitter 12 and then pass through the second beam splitter 13. The light 9a returned by the specimen 3 toward the sampling light 9 of the OCT device 10 is guided through the first beam splitter 12 of the OCT device 10 for further processing.

[0048] The second beam splitter 13 causes the first light beam component 14 to pass through a zoom optical system 15, such as a variable focus objective lens, pass through a blocking filter 16, and be sent to a third beam splitter 17, i.e., a 50:50 beam splitter. The first light beam component 14 is split into a second light beam component 18 and a third light beam component 19. In another embodiment, the third beam splitter 17 can be configured to be dichroic.

[0049] The second light beam component 18 impinges on the first camera device 1 to generate a reflected image. The third light beam component 19 impinges on the second camera device 2 to generate a fluorescent image after being deflected by the mirror 20 and passing through a bandpass filter 21.

[0050] In one embodiment of the configuration, since the blocking filter 16 is disposed in front of both camera devices 1 and 2, the first light beam component 14 impinging on the camera devices 1 and 2 needs to pass through the blocking filter 16. The blocking filter 16 does not transmit light having wavelengths in the wavelength range of 480 nm - 490 nm.

[0051] Since the bandpass filter 21 is disposed in front of the second camera device 2, the third light beam component 19 impinging on the second camera device 2 needs to pass through the bandpass filter 21. The bandpass filter 21 transmits light having wavelengths in the wavelength range from 510 nm to 540 nm and does not transmit light in other spectral regions.

[0052] In all embodiments, the third beam splitter 17 is arranged in the beam path between the objective lens 8 and the two camera devices 1, 2, and the first light beam component 14 can be directed onto the third beam splitter 17 for splitting into the second and third light beam components 18, 19. The third beam splitter 17 directs the second light beam component 18 in the direction of the first camera device 1 and directs the third light beam component 19 through the band - pass filter 21 in front of the second camera device 2 to the second camera device 2.

[0053] The optionally provided blocking filter 16 and band - pass filter 21 are specifically intended to filter out the excitation light that may collide with the second camera device 2 as reflected light and interfere with the detection of actual fluorescence.

[0054] The excitation of fluorescein of a known indicator by the excitation light of the illumination devices 4a, 4b is preferably performed at a wavelength of 485 nm. The light of this wavelength is blue. More than 80% of the fluorescence excited by this light occurs in the range from 510 nm to 540 nm. Depending on the width of the spectrum of the excitation light, the blocking filter 16 needs to block wavelengths near 485 nm with a width of approximately 5 nm as a result, while transmitting the rest of the visible range. This optical behavior is schematically shown in the upper part of FIG. 2. Since the blocking filter 16 is not essential, it can be omitted in one embodiment of the configuration.

[0055] The band - pass filter 21 passes the detected fluorescence light having wavelengths in the range from 510 to 540 nm and blocks the entire remaining spectral range that the second camera device 2 may be affected by. This optical behavior of the band - pass filter 21 is shown in the middle part of FIG. 2. Specifically, it is necessary to block the high spectral power density of the excitation light.

[0056] The spectral range from 510 nm to 540 nm can be excluded from the spectra of the excitation light of the illumination devices 4a, 4b. However, at a wavelength of 485 nm, it is necessary to enable the use of the required power density. This is shown in the lower part of FIG. 2. Therefore, the illumination devices 4a, 4b can be provided with a filter, preferably an adjustable filter, that can block each fluorescence light wavelength so as not to collide with the second camera device 2 as interference reflected light. Each adjustment position of this filter represents the achievable fluorescence light wavelength, and the basic position represents the neutral state.

[0057] To create the blocking filter 16, a filter wheel at the x position can be provided in the relevant beam path. Each adjustment position indicates the achievable fluorescence light wavelength, and the basic position indicates the neutral state. Similarly, to create the bandpass filter 21, a filter wheel at the x position can be provided in the relevant beam path in front of the second camera device 2. Each adjustment position indicates the achievable fluorescence light wavelength, and the basic position indicates the neutral state.

[0058] Therefore, each wavelength region where fluorescence is detected can be filtered from the excitation light reflected as the excitation light or the reflected light of the illumination devices 4a, 4b.

[0059] Also, the excitation of fluorescence can also be performed with a laser having a wavelength of about 488 nm. The fluorescence or the reflected image generated by the laser can be captured. In either case, about 1 / 10000 of the incident light is recovered, that is, the blue image has the same gray level as the fluorescence image.

[0060] FIG. 3 shows that a further embodiment of the surgical microscope has an image processing device that combines at least one first image 22 acquired by a first camera device 1 and at least one further image 23 acquired by a second camera device 2. The images 22, 23 are selected and synthesized by the image processing device based on a predetermined sharpness quality of the images 22, 23, and an overall image 24 is formed. Further, the overall image 24 also has a third image 25 selected based on its sharpness for patch synthesis of the overall image 24.

Explanation of Signs

[0061] 1 First camera device 2 Second camera device 3 Specimen 4a First lighting device 4b Second lighting device 5 Fluorescence excitation light source 6 Field illumination light source of 4a 7 SCI light source of 4b 8 Objective lens 9 Sampling light 9a Light returned from 3 10 OCT device / OCT interferometer 11 Return light beam 12 First beam splitter 13 Second beam splitter 14 First light beam component 15 Zoom optical system 16 Blocking filter 17 Third beam splitter 18 Second light beam component 19 Third light beam component 20 Mirror 21 Bandpass filter 22 First image 23 Second image or further image 24 Overall image 25 Third image

Claims

1. A first camera device (1) for capturing and rendering a reflected image of an object, and a second camera device (2) for simultaneously capturing and rendering a further image of the object, characterized in that the further image is configured as a fluorescence image of the object, each of the camera devices (1, 2) has at least two cameras for generating a three-dimensional image in respective imaging modes, the imaging modes being a reflection mode and a fluorescence mode. A surgical microscope.

2. The surgical microscope according to claim 1, wherein one or both of the camera devices (1, 2) perform image recording in a video mode.

3. The surgical microscope according to claim 1 or 2, wherein one or both of the camera devices (1, 2) perform three-dimensional image recording.

4. The surgical microscope according to any one of claims 1 to 3, wherein at least one lighting device (4a, 4b) having a fluorescence excitation light source (5) is provided.

5. Comprising a blocking filter (16), the blocking filter (16) being arranged in front of the two camera devices (1, 2) such that a light beam component (14) incident on the camera devices (1, 2) needs to pass through the blocking filter (16).

6. The surgical microscope according to claim 5, wherein the blocking filter (16) does not transmit or at least suppresses light having wavelengths in the wavelength range from 480 nm to 490 nm.

7. The surgical microscope according to claim 4, wherein the lighting device (4a, 4b) is configured such that the wavelength range of the fluorescence is excluded from the spectrum of the excitation light from the lighting device (4a, 4b).

8. Comprising a band-pass filter (21), the band-pass filter (21) being arranged in front of the second camera device (2) such that a light beam component (19) incident on the second camera device (2) needs to pass through the band-pass filter (21).

9. An image processing apparatus is provided, and the image processing apparatus combines at least one first image (22) acquired by the first camera device (1) with at least one further image (23) acquired by the second camera device (2), and the images (22, 23) are selected and synthesized by the image processing apparatus to form an overall image (24). The surgical microscope according to any one of claims 1 to 8.

10. The surgical microscope according to claim 9, wherein the criterion for the selection is a predetermined sharpness quality of the images (22, 23).

11. The surgical microscope according to any one of claims 1 to 10, comprising an OCT device (10), and the sample (3) can be inspected by the sampling light (9) thereof.

12. The surgical microscope according to any one of claims 1 to 11, wherein an image sensor sensitive to infrared rays is provided in the first and / or second camera device (1, 2).

Images