Test bench, system, method for testing an imaging apparatus and method for operating a test bench

Abstract

The present invention relates to a test bench (10), comprising a base (12), an illumination apparatus (14) which is arranged at least partially on the base (12) and is designed to provide test light, a device receptacle (16) which is arranged on the base (12) and is designed to receive an imaging apparatus (18) to be tested, and a reflection target (20) which can be arranged and / or is arranged on the base (12) in a target position (22) and which comprises a reflection surface (24) which is designed to diffusely reflect incident test light, wherein the imaging apparatus (18) to be tested can be arranged, for a test, in the device receptacle (16) in such a manner that the reflection surface (24) can be imaged by the imaging apparatus (18).

Description

[0001] Test bench, system, method for testing an imaging device and method for operating a test bench

[0002] The present invention relates to a test bench, a system, a method for testing an imaging device and a method for operating a test bench.

[0003] According to the state of the art, the condition and / or imaging quality of an imaging device such as an exoscope is checked using a reference imaging device and a fluorescent target. The target is, for example, a fluorescent test card or a fluorescent phantom.

[0004] To perform the inspection, the fluorescent target is illuminated, imaged using the reference imaging device, and a reference image of the target is generated. Then, with the same illumination of the fluorescent target, it is imaged using the imaging device under test, and a verification image of the target is generated. The verification image is then compared with the reference image by trained personnel. Based on the comparison, they decide whether the verification image is of sufficient quality compared to the reference image. If the quality is sufficiently good, the condition and / or imaging quality of the imaging device under test is assessed as positive.

[0005] The present invention is based on the finding that the described review is based on a subjective assessment step by trained personnel. This can lead to different assessments of the same imaging device by different personnel.

[0006] Furthermore, the reference imaging device is necessary for implementation, which entails several disadvantages. The reference imaging device itself could be damaged, degrade, have an undetected defect, and / or generally not provide sufficiently good imaging quality. In such a case, the meaningfulness of the assessment of the imaging device under test can no longer be guaranteed. Furthermore, a separate reference imaging device must be provided for each test system for verifying imaging devices, which must itself meet strict imaging quality requirements. This is expensive and potentially difficult to achieve with a nationwide distribution of test systems, since the reference imaging device can change at least slightly, for example, during transport, and the imaging quality can therefore deteriorate.In general, duplicating a test system that operates at least essentially the same is difficult and / or expensive.

[0007] Finally, the fluorescent target itself can degrade over time and with continuous irradiation, meaning consistent light emission cannot be guaranteed. This can lead to a falsely negative assessment of an imaging system, since poor image quality of an image of the fluorescent target may not necessarily be due to poor imaging quality, but rather to the target's emission being too low. To rule this out, imaging using a reference imaging device is always necessary. However, as already described, this can be expensive and / or difficult to perform.

[0008] Based on the prior art, the invention is particularly based on the object of enabling a reliable, repeatable and / or cost-effective checking of a condition and / or imaging quality of an imaging device.

[0009] The object is achieved according to the invention by a test bench, a system, a method for testing an imaging device and a method for operating a test bench, as described herein and defined in the claims.

[0010] The present invention provides a test bench. The test bench comprises a base, an illumination device arranged at least partially on the base and configured to provide test light, and a device holder arranged on the base and configured to receive an imaging device to be tested.

[0011] In one embodiment, the test bench further comprises a reflection target which can be arranged and / or is arranged on the base in a target position and which comprises a reflection surface which is configured to diffusely reflect incident test light, wherein the imaging device to be tested can be arranged in the device holder for a test in such a way that the reflection surface can be imaged by the imaging device.

[0012] In another embodiment, the test bench comprises, in particular in addition to the reflection target or instead of the reflection target, a diffusion target which can be arranged and / or is arranged on the base in a target position and is configured to transmit test light incident on a first side and to diffusely emit it from a radiation surface on a second side, wherein the imaging device to be tested can be arranged in the device holder for a test in such a way that the radiation surface can be imaged by the imaging device.

[0013] Furthermore, the present invention provides a system. The system comprises a test bench according to the invention and an imaging device, in particular an exoscope.

[0014] Furthermore, the present invention provides a method for testing an imaging device using a test bench according to the invention and / or a system according to the invention. The method comprises a step of illuminating a reflection surface of a reflection target using an illumination device, imaging the reflection surface using the imaging device and generating image data, and checking a camera function of the imaging device based on the image data.

[0015] Furthermore, the present invention provides a method for operating a test bench according to the invention and / or a system according to the invention.

[0016] These features enable a reliable, repeatable, and / or cost-effective verification of the condition and / or imaging quality of an imaging device. The imaging quality can be objectively quantifiable and / or measurable. There is no need to rely on subjective assessment by trained personnel. Furthermore, a reference imaging device can be dispensed with. This allows for a nationwide test bench that operates reliably and repeatably. Costs can also be saved. The illumination device can provide targeted and reliable test light. It is not necessary to use an illumination device of the imaging device under test, and / or the imaging device under test does not need to have its own illumination device. Advantageously, the reflection target can operate without fluorescence.This allows degradation of the target to be avoided and / or at least reduced. The invention is based on the finding that a diffusely reflecting reflective surface can exhibit significantly lower degradation than a fluorescent surface. This makes it possible to achieve reliability, repeatability, and / or safety during inspection. By using a diffusely reflecting reflective surface, a homogeneous image of a target and / or a more homogeneous section in an inspection image can be generated. For example, it may be conceivable to image an emitting surface of an illumination device using the imaging device to be tested and to generate an inspection image based on the image. Such an inspection image may have a color and / or brightness gradient, which may be formed depending on the illumination device.The inspection image can, for example, include a ring-shaped section with higher brightness. Using the diffusion target, a compact test bench can be provided.

[0017] In principle, the test bench can be a test bench for testing an imaging device under test. Using the test bench, the sensitivity of the imaging device can be quantified and / or objectively measured. Furthermore, a threshold value can be determined using the test bench. The threshold value can, for example, indicate the object brightness above which an object can be imaged and / or the brightness above which an image of a fluorescent surface can be generated on which the fluorescent surface is recognizable. It can, for example, be verified whether the imaging device under test is suitable for performing fluorescence imaging. Furthermore, a threshold value can be determined that indicates a brightness value and / or intensity value above which the imaging device is overdriven, and / or operating points can be determined that relate to the exposure system of an image sensor of the imaging device under test.The operating point can include, for example, a shutter speed, in particular the longest, before electronic amplification is activated, and / or a point in time from which increasing image brightness changes to constant image brightness. Using the test bench, image sharpness, image aberration, illumination, and / or the like of the imaging device under test can be checked. The test bench and / or the base can be designed to be movable and / or handled by a user. This can mean, for example, that the test bench and / or the base has a weight of less than 50 kg, less than 30 kg, less than 10 kg, or even less. Furthermore, the test bench can include an enclosure.The housing can be configured to enclose at least the base and / or define an interior space that is configured and / or optically separated from the surroundings in such a way that ambient light is at least substantially almost completely excluded. The interior space can be dark. A high inspection quality can be achieved. The housing can comprise a frame that is movable and / or handled independently of the base. Opaque panels can be attached and / or mounted to the frame. Furthermore, the housing can comprise a flexible cover, in particular made of a synthetic fiber fabric and / or the like, which can be configured in a manner similar to a dust cover for a microscope.

[0018] The base can be formed from a system profile, an aluminum profile, a rail, an aluminum rail, and / or the like. The base can define a support surface by means of which the test bench and / or the base can be placed on a surface. The base can form at least one fastening section to which further components, in particular of the test bench, can be fastened, in particular detachably. By means of the base, further components, in particular the reflection target, the device holder, and / or the lighting device, can be arranged, fastened, and / or secured at a fixed distance from one another. The base can be configured to mechanically couple at least the device holder and / or the reflection target to one another, in particular rigidly and / or immovably. The base can comprise a table, in particular an optical table, a test table, a measuring table, a perforated plate, a plug board, and / or the like.

[0019] The illumination device can be a separate and / or stand-alone illumination device. This can mean that the illumination device can be moved and / or handled independently of the imaging device to be tested. The illumination device can comprise at least one, in particular optical, element configured to couple out the test light. The element can be designed independently of the imaging device to be tested. According to some embodiments, the illumination device comprises a light source configured to generate light, the element, and a light guide configured to guide the generated light from the light source to the element. The element can comprise a lens, in particular a scattering lens. The light guide can comprise a light guide cable, an optical waveguide, at least one glass fiber, and / or the like.

[0020] The element and / or a portion of the light guide can be arranged on the base and / or on the reflection target by means of a holding device. The holding device can be rigid. The element can be arranged at an illumination position, wherein the illumination position is known and / or adjustable relative to the target position and / or the device holder. According to some embodiments, the element can define and / or comprise a light source. For example, the element can comprise an LED and / or the like.

[0021] The test light can comprise white light and / or colored light. Furthermore, the test light can comprise infrared light, particularly near-infrared light, and / or ultraviolet light. Colored light, for example, can have a narrower spectral range than white light.

[0022] The imaging device to be tested can be releasably attachable to the device receptacle. The device receptacle can comprise a clamping mechanism configured to clamp the imaging device to the base. The clamping mechanism can comprise, for example, a locking screw. The device receptacle can be formed at least partially by a carrier that is fixed to the base and form a receiving portion configured to receive the imaging device to be tested. The receiving portion can define an opening through which the imaging device can be at least partially guided and / or in which the imaging device can be at least partially arranged. The device receptacle can be formed integrally with the base.

[0023] The imaging device can be configured to image a location of a patient accessible from the environment, such as an open surgical site, and / or preferably comprise an exoscope. The imaging device can be configured, in particular, for use with an external illumination device, which can be configured to provide illumination light for illuminating an object region, in particular the surgical site to be imaged and / or the like. The imaging device can not comprise its own illumination device. According to some embodiments, the imaging device is configured for fluorescence imaging. The imaging device can comprise at least one optical element, in particular an objective lens and / or an objective lens arrangement, and an image sensor. The optical element can be configured to image an object region onto an active area of ​​the image sensor.The image sensor can be configured to generate image data and / or create an image of the object area. The imaging device, in particular the exoscope, can be arranged in the device holder such that the object area of ​​the imaging device, in particular of the optical element, comprises the reflective surface of the reflective target. Arranged in this way, the imaging device can be configured to generate an inspection image comprising an inspection section generated by imaging the reflective target, in particular the reflective section. This can be understood as "wherein the imaging device to be tested can be arranged in the device holder for a test such that the reflective surface can be imaged by the imaging device."Analogously, this can be understood as "wherein the imaging device to be tested can be arranged in the device holder for testing in such a way that the emission surface can be imaged by the imaging device." Accordingly, the imaging device can be arranged such that it is configured to generate a test image comprising a test section generated by imaging the diffusion target, in particular the emission surface. The test bench can, in particular, be provided to test a function of the image sensor and / or a function of the image sensor can be testable by means of the test bench.

[0024] In principle, features of the reflection target and / or the reflection surface described herein can be transferred to the diffusion target and / or the emission surface. This applies primarily to features relating to the target position.

[0025] A reflection target may comprise a structure, a body, and / or the like that provides at least one reference point, a reference, and / or the like for inspection. In particular, the reflection target is configured to provide at least one reference point through diffuse reflection. The term "target" may refer to the fact that the reflection target is intended for imaging by the imaging device under test. In this context, the reflection target may be intended to define the inspection section in the inspection image.

[0026] The target position can be arranged at a distance from the device holder and / or the illumination device, in particular the illumination position. The target position can be arranged, for example, at a distance of up to 50 cm, in particular up to 40 cm, preferably up to 30 cm from the device holder. The target position can be arranged, for example, at a distance of at least 3 cm, in particular at least 5 cm, preferably at least 10 cm from the device holder. A distance between the target position and the device holder can approximately correspond to a typical working distance of the imaging device to be tested. The working distance can approximately correspond to the typical distance between the imaging device and the object area when used outside the test bench.

[0027] The reflection target can be detachably attached to the target position. The reflection target can be detachably attached, attachable, and / or fixed to the target position by means of a target holder. The target holder can hold the reflection target at a distance from the base, in particular perpendicular to the support surface of the base and / or perpendicular to a substrate. The distance between the reflection target and the base can be between 1 cm and 20 cm, 2 cm and 12 cm, and / or 3 cm and 8 cm. Other distances are also conceivable.

[0028] The reflection target can be a diffuse reflection standard. The reflection target can be disk-shaped, in particular circular disk-shaped, wherein one side of the disk can form the reflection surface. The reflection target, in particular the disk side and / or the reflection surface, can have a diameter of approximately 3.8 cm and / or 1.5 inches. Deviating from this, the diameter can be up to 2 cm larger or smaller. The thickness of the reflection target can be approximately 1.4 cm and / or 0.55 inches. A deviation of up to 2 cm and / or 3 cm from these values ​​is also conceivable, if possible. The reflection surface can comprise at least one coating. According to some embodiments, one of the coatings comprises a polymer, in particular a porous polymer. The polymer can be coated using a highly reflective surface coating. The coating can in particular comprise Spectralon.

[0029] The illumination device, in particular its test light-coupling element, can define an optical axis, and the illumination device can be arranged and / or positioned on the base such that the optical axis intersects the reflection surface. The optical axis can comprise an imaginary line that runs through the center of the test light-coupling element and / or defines the direction and / or center line of a light beam emitted by the illumination device. The optical axis can be aligned along an axis in which the light is emitted most intensely.

[0030] Diffuse reflection can refer to the scattering of light in many different directions. In contrast to specular reflection, in which the light is reflected according to an angle of incidence, in diffuse reflection the light is scattered in all directions. According to some embodiments of the reflection surface, the reflection target can be configured to scatter incident test light at least substantially independently of the angle of incidence of the test light. The reflection target can define a principal backscattering axis, which is arranged, in particular, perpendicular to the reflection surface. The principal scattering axis can comprise a normal of the reflection surface.The target position can be provided and / or the reflection target can be arranged and / or positioned in the target position such that the normal and / or the main backscattering axis intersects the device holder and / or the optical element of the imaging device under test when arranged in the test bench. The reflection surface can be designed such that the diffuse reflection is distributed homogeneously over at least substantially the entire reflection surface.

[0031] The device holder can define a recording axis that can be arranged at least substantially parallel and / or coaxial with an imaging axis of the imaging device to be tested when arranged in the test bench. The recording axis can be arranged such that it intersects the target position and / or the reflection surface. The normal and / or the principal backscattering axis can be arranged at least substantially parallel and / or coaxial with the recording axis and / or the imaging axis of the imaging device to be tested when arranged in the test bench. The imaging axis can comprise an imaginary central line of an image cone that defines a region in space from which light rays can be imaged onto an image plane by the optical element of the imaging device. The imaging axis can be arranged perpendicular to the image plane.

[0032] The diffusion target can be configured to scatter and / or emit light uniformly and / or homogeneously distributed across the emission surface. Uniform and / or homogeneous illumination of the imaging device under test can be achieved by means of the diffusion target when arranged in the test bench. The diffusion target can define an at least partially translucent surface that forms the emission surface and defines the first side. The translucent surface can be formed by a diffuser, which comprises, for example, a diffusion film and / or the like. At least one diffusion property of the diffusion target can be known in advance such that, given knowledge of at least one parameter of the test light, the luminance of the diffusion target in the target position can be determined.

[0033] According to some embodiments, the test bench further comprises a sensor that can be arranged interchangeably with the reflection target in the target position, wherein the sensor is configured to determine at least one parameter relating to the test light, in particular the irradiance, in the target position. Advantageously, this makes it possible to determine parameters of the test light striking the reflection target for a specific target position and a specific relative arrangement of the illumination device. The parameters can include the light intensity, the light power, the illuminance, the irradiance, the luminous flux, and / or the like. The sensor can comprise a lux meter, for example, and / or be configured to determine the light intensity, in particular specified in the SI unit lux (Ix). Alternatively or additionally, the sensor can measure the irradiance, in particular specified in the unit W / m 2The sensor can, for example, have an active surface by means of which incident light can be measured. The sensor can be arranged in an exchangeable manner such that the active surface can be arranged at the position relative to the device holder and / or the illumination device at which the reflection surface is arranged in a state in which the reflection target is arranged at the target position. The sensor can be fastened to the target holder. The replacement can be carried out quickly and in a user-friendly manner. "Replaceable" does not mean that the test bench has to be disassembled and / or a cover and / or the like has to be removed in order to be able to replace the sensor and the reflection target. The replacement can be carried out within a short time, for example within 2 minutes, 1 minute, 30 seconds and / or even less time.

[0034] Furthermore, a reflectance of the reflection target can be known, in particular pre-known, and / or profiled in such a way that a luminance of the reflection target in the target position can be determined by determining the at least one parameter of the test light. Advantageously, it can be determined and / or objectively ascertained with what intensity, luminous intensity, luminance, and / or the like the reflection target diffusely reflects test light, in particular in the direction of the device receptacle. It can be determined and / or objectively ascertained how an image of the reflection target should appear in the inspection image if the imaging device to be tested is of sufficiently good quality. The inspection of the imaging device can be objectified. Reflectance can be understood as a degree of reflection.The reflectance and / or reflectance can relate a parameter of the test light related to the reflection target to a parameter of the light emitted by the reflection target. This allows the parameter of the light emitted by the reflection target to be determined.

[0035] The reflection target can be used flexibly if it has a reflectance of at least 95%, in particular at least 98%, in a wavelength range from 350 nm to 1250 nm. In other words, the reflection target is designed to operate in a wavelength range that covers the wavelength range of visible light and / or extends into the near-infrared range.

[0036] It is also conceivable that a reflection target with a lower reflectance is used. The reflectance can, for example, have an amount of 50% to 55% or any other amount. In order for the reflection target to have at least a similar brightness to a reflection target with a higher reflectance, the illumination power of the illumination device could be increased, in particular doubled (with a reflectance of, for example, 50%). In this context, the reflectance can be known, in particular previously known, and / or profiled so that a luminance of the reflection target in the target position can be determined by determining the at least one parameter of the test light. In order to set a sufficiently high and / or desired brightness of the reflection target, the illumination power can be adjustable.

[0037] A reliable and accurate inspection of an imaging device can be achieved if the reflection target has an at least approximately Lambertian surface. This can mean that the reflection target, in particular the reflection surface, is configured to diffusely reflect the incident light at least approximately and / or substantially uniformly and / or independently of the angle of incidence of the test light.

[0038] The reflection surface can be provided such that a main backscatter is arranged perpendicular to the reflection surface. The reflection surface can comprise such a number of scattering centers that the reflection follows Lambert's law. The reflection surface can preferably be oriented such that a main backscattering axis, which can describe the main backscattering, intersects the device holder and / or intersects the optical element of the imaging device under test when arranged in the test bench.

[0039] Furthermore, the target position can be adjustable relative to the device mount. The test bench can be adapted to a specific imaging device. Furthermore, an imaging quality check can be performed at different distances between the reflection target and the imaging device under test. The target position can be adjustable, in particular, along the main backscattering axis, the mount axis, a connecting line between the device mount and the target position, and / or a main extension direction of the base. In particular, the base can comprise a rail in which the reflection target and / or a target holder is displaceable and / or mounted. The main extension direction can refer to the longest side of a smallest cuboid into which the base can be completely arranged.

[0040] According to some embodiments, the holding device is arranged on the target holder. The holding device can comprise a spacer that is arranged on the target holder and is configured to fix a base of the holding device at a distance from the target holder. The base of the holding device can be configured to partially hold the illumination device. For example, the light guide of the illumination device can be coupled to the base of the holding device, wherein the base of the holding device can comprise the element configured to emit the test light, in particular in the direction of the reflection target. It is also conceivable that the light source, for example an LED, is arranged on the base of the holding device.

[0041] Furthermore, the illumination device can be arranged next to the device holder, in particular with respect to a connecting line between the device holder and the target position. This makes it possible to ensure that light emitted at least substantially by the reflection target falls on the device holder, the imaging device to be tested, and / or the optical element of the imaging device to be tested. A precise and accurate test can be performed. The illumination device can be arranged next to the base. In principle, this can mean that an element of the illumination device that couples out test light is arranged next to the device holder and / or the base.

[0042] Furthermore, the device holder can define the recording axis along which the target position is arranged. The illumination device, in particular its test light-coupling element, defines the optical axis along which the test light can be provided. The recording axis and the optical axis are arranged at an angle to one another. Advantageously, the illumination device can be prevented from directly irradiating the imaging device to be tested. The imaging device is irradiated indirectly by means of the reflection target. The optical axis can be arranged such that it does not intersect the device holder. "Angled" can be understood as an angle different from 0° and 180°.

[0043] A high level of reliability during testing can be achieved if the lighting device is arranged next to the device holder in such a way that the holder axis and the optical axis enclose an angle of a maximum of 45°, in particular a maximum of 30°. In particular, this can mean that the element coupling out the test light is arranged obliquely next to the device holder. The test light can be coupled out in a direction away from the device holder. The angle can be defined starting from the device holder. In particular, the device holder can be arranged outside a light cone defined by the lighting device. The optical axis can define an imaginary central line of the light cone.

[0044] Furthermore, at least one irradiation parameter, in particular a radiant power, of the illumination device can be adjustable. This makes it possible, for example, to determine threshold values ​​of the imaging device to be tested. A minimum radiant power can be determined at which an image of the reflection target can be distinguished from an image of the surroundings of the reflection target. This can mean that a perception threshold can be determined. Furthermore, a shutter speed, a control limit, a sensitivity, an exposure time, and / or the like can be determined for certain brightness and / or intensity values. The illumination device can be dimmable. The irradiation parameter can be continuously adjustable.

[0045] Alternatively or additionally, the lighting device can comprise at least one light source and an attenuation filter, wherein the attenuation filter is arranged and / or can be arranged in front of the light source such that light generated by the light source can be provided in an attenuated form as test light. The attenuation filter can be used to reduce the light output and / or radiant output of the light emitted by the light source. The use of the attenuation filter can make it possible to reduce the light output and / or radiant output below a lower limit, wherein the lower limit is defined by a minimum stable operation of the light source.

[0046] The inventors have recognized that an imaging device configured for fluorescence imaging can be safely and reliably tested if the light intensity of the test light incident on the reflection target is at least substantially distributed over a spectral interval with a width of a maximum of 50 nm, in particular a maximum of 20 nm. The reflection target can be used to simulate an object region that emits light in a spectral range of a fluorophore.Such a check can prevent the user from mistakenly assessing, when using the imaging device to be tested, that no fluorophore is present in the object region, even though the object region actually emits light in the spectral range specific for the fluorophore. This misjudgement is due to the imaging device having too low a sensitivity, particularly in the specific spectral range, too high a perception threshold, and / or the like. The test light can be used to mimic an emission spectral range of a fluorophore. For example, the test light can be configured to mimic the light emission of a fluorescent dye, particularly at least one of fluorescein, indocyanine green, 5-aminolevulinic acid, acridine orange, and / or the like, with the test light being distributed across the spectral interval.The spectral interval may include a specific wavelength depending on the fluorescent dye to be imitated, for example, approximately 518 nm, 840 nm, 850 nm, 800 nm, 440 nm, 525 nm, and / or the like. The specific wavelength may define an emission maximum of the fluorescent dye to be imitated. Test light whose light intensity is at least substantially distributed over a spectral interval with a maximum width of 50 nm, in particular a maximum of 20 nm, may also be referred to as narrowband test light. The term "narrowband" may mean that the referenced light, in particular test light, is at least substantially distributed over a spectral interval with a maximum width of 50 nm, in particular a maximum of 20 nm.

[0047] Furthermore, the illumination device can comprise at least one light source, wherein the light source is configured to emit the test light. Advantageously, the test light, in particular the narrowband test light, can thereby be provided in a stable, reliable, and / or safe manner. The light source can comprise, for example, a light-emitting element such as a light-emitting diode configured to emit the test light, in particular the narrowband test light. The illumination device can be a special illumination device for simulating the emission of a fluorophore.

[0048] A cost-effective and widely and / or flexibly usable test bench can be provided if the illumination device comprises at least one spectral filter configured to at least substantially transmit light in the spectral interval and at least substantially block light outside the spectral interval. The spectral filter allows the test light simulating the fluorophore to pass through, while at least substantially blocking light outside this spectral range. The spectral filter can be selectively arranged in a light path of the illumination device, for example, by means of a filter turret and / or the like. This allows, for example, test light in various narrow-band spectral ranges to be selectively provided, in particular by means of a light source.

[0049] According to some embodiments, the light source can be configured to emit white light, pseudo-white light, infrared light, preferably near-infrared light, and / or a combination thereof. The light source can comprise a plurality of light-emitting elements, such as light-emitting diodes, each configured to emit light in a different spectral range. The light emitted by the plurality of light-emitting elements can be mixable and can be provided as light and / or test light. This light can be filtered by at least one of the filters described above. For example, a red LED, a green LED, a blue LED, and / or a near-infrared light-emitting LED can be provided, the emitted light of which is mixable.

[0050] In addition, the illumination device can comprise at least one structural filter configured to attenuate light to varying degrees in sections such that the test light incident on the reflection target has a spatially different intensity distribution on the reflection target. As a result, for example, a first section of the reflection target, in particular the reflection surface, can be illuminated such that the first section appears tissue-like, and a second section such that the second section appears like tissue stained with a fluorescent dye. In this way, a color contrast can also be measurable, and this can be compared with specifications in order to draw conclusions about the imaging quality. Alternatively or additionally, a line and / or bar pattern can be projected onto the reflection surface and / or the reflection target, with which the resolution of the imaging device under test can be checked.It is also conceivable to use a stencil as a structural filter that is partially colored super-black and / or has a fabric-like configuration. The stencil may comprise a pattern that can be used to determine the resolution of the imaging device under test and / or to determine image defects of the imaging device. The resolving power of the imaging device under test can be assessed either visually and / or computer-aided. According to some embodiments, the target holder may be coated such that it absorbs at least substantially a majority of the light rays incident on it. The target holder may, for example, be painted. The coating may be super-black. A majority may mean at least substantially 95%, 97%, 99%, and / or an even greater proportion of the incident light.

[0051] In general, the sensitivity of the imaging device under test can be assessed by imaging a standard object, the reflection target, using the imaging device and by determining the imaging device's response to the imaging. By using the reflection target and / or the sensor, the light emission of the reflection target can be at least substantially precisely specified with regard to at least the spectrum and / or the radiance (or spectral emissivity) and / or traceable to basic units of the SI system.

[0052] According to some embodiments, the illumination device, the diffusion target, and the device holder are arranged axially one behind the other. A simple, compact, and handy test bench can be provided.

[0053] The method for operating the test bench and / or the system may comprise a step of arranging a sensor in a target position on a base, illuminating the sensor with test light, determining at least one parameter related to the test light, and exchanging the sensor for a reflection target in the target position.

[0054] 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.

[0055] 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.

[0056] They show:

[0057] Fig. 1 is a schematic representation of a system with a test bench;

[0058] Fig. 2 is a schematic representation of another embodiment of a

[0059] Systems comprising a test bench;

[0060] Fig. 3 is a schematic perspective view of another embodiment of a system comprising a test bench;

[0061] Fig. 4 is a schematic representation of the system of Fig. 3 in a view from above;

[0062] Fig. 5 is a schematic representation of a diagram of a reflectance curve of a reflection target over a wavelength range;

[0063] Fig. 6 is a schematic representation of a verification image;

[0064] Fig. 7 is a schematic representation of a verification image;

[0065] Fig. 8 is a schematic representation of a verification image;

[0066] Fig. 9 is a schematic flow diagram of a method; and

[0067] Fig. 10 is a schematic flow diagram of a method.

[0068] Figure 1 shows a schematic representation of a system 52 and a test bench 10. The system 52 comprises the test bench 10 and an imaging device 18 to be tested, in this case an exoscope 19. The exoscope 19 does not have its own illumination device and is configured for fluorescence imaging. The test bench 10 comprises a base 12, an illumination device 14 for generating test light, a device holder 16, a reflection target 20, and a sensor 26.

[0069] Using the test bench 10, the imaging device 18 can be tested with regard to its imaging quality. For example, a sensitivity, a perception threshold, and / or the like can be determined. It can be verified, for example, whether the imaging device 18 under test is suitable for performing fluorescence imaging. Furthermore, a threshold value can be determined that indicates a brightness value and / or intensity value above which the imaging device is overdriven, and / or operating points can be determined that relate to the exposure system of an image sensor of the imaging device 18 under test. The operating point can include, for example, a shutter speed, in particular the longest, before electronic amplification is activated, and / or a point in time from which increasing image brightness changes to a constant image brightness.

[0070] Using the test bench 10, image sharpness, image aberration, illumination, and / or the like of the imaging device 18 under test can be checked. In general, a camera function of the imaging device 18 can be checked using the test bench 10 and / or the system 52.

[0071] The imaging device 18 and / or the exoscope 19 is configured to image an object region 70. The imaging device 18 defines an image cone 68 with an imaging axis 66. The image cone 68 can define a region in an image plane 74 that can be imaged by the imaging device 18. For testing, the imaging device can be arranged in the device holder 16 or on the test bench 10 such that the reflection target 20 is arranged in the object region 70. More precisely, a reflection surface 24 of the reflection target 20 is located in the image plane 74, which can be sharply imaged by the imaging device 18. The device holder 16 and the reflection target 20 are arranged at a distance from one another on the base 12, with the reflection target 20 located in the target position 22.The base 12 is designed as a threaded hole plate, and the elements arranged on the base 12 are screwed to the base 12, in particular by means of corresponding holders. The device holder 16 defines a receiving space 17 into which the exoscope 19 can be inserted along a receiving axis 30. In an inserted state, the exoscope 19 can be fixed by means of a clamping mechanism 64 (not shown in detail). The receiving axis 30 coincides with the imaging axis 66. In this position, the imaging device 18 can be adjusted such that the image plane 74 coincides with the object area 70 such that the reflection surface 24 can be sharply imaged and / or a sharp image of the reflection surface 24 can be generated. In such a state, the imaging device 18 can be inspected, in particular by generating an inspection image of the reflection surface 24.

[0072] The reflection target 20 may also be axially displaceable along the recording axis 30 and / or the imaging axis 66, for example by being mounted in a different axial target position (not shown).

[0073] The reflection target 20 is a diffuse reflection standard, is disk-shaped, and has a reflection surface 24 on one side of the disk. The reflection surface 24 is coated with Spectralon. The reflection surface 24 exhibits at least nearly Lambertian reflection behavior. Main backscattering by the reflection surface 24 occurs at least substantially perpendicular to the reflection surface, at least substantially and / or to a first approximation independent of the direction of irradiation.

[0074] The reflection target 20, in particular the reflection surface 24, defines a main backscattering axis 72, which is arranged perpendicular to the reflection target 20, in particular the reflection surface 24. In the arrangement shown, the main backscattering axis 72 coincides with the imaging axis 66. It is also conceivable that the two axes 66, 72 can run at least substantially parallel to each other. At least the main backscattering axis 72 runs in the direction of the imaging device 18.

[0075] It is also conceivable that the reflection target 20 has an at least approximately Lambertian surface.

[0076] In a verification image, the reflection surface 24 appears as a circular surface

[0077] 25 next to a background 27, as schematically illustrated in Fig. 6. Fig. 6 shows a test image 71 of the object region 70, comprising the image of the reflective surface 24. Based on the test image 71, it can be determined, determined, and / or the like whether the imaging quality of the imaging device 18 under test is sufficient. This can be done by evaluating the representation of the reflective surface 24 in relation to the representation of the background 27. If the imaging quality is too poor, for example, the reflective surface 24 is represented with insufficient contrast and / or the like.

[0078] Furthermore, at least one parameter of the imaging device 18 may exceed a limit value, for example with regard to an exposure time, above which a representation of the reflection surface 24 with a sufficiently high contrast is only possible.

[0079] Referring again to Fig. 1, a target holder 62 can be seen, by means of which the reflection target 20 can be attached to the base 12. Basically, it can be seen that a normal, in particular the main backscattering axis 72, of the reflection surface 24 intersects the imaging device 18 in a state in which the imaging device 18 is arranged in the device holder 16. The reflection target 20 is detachably attached to the target holder 62.

[0080] Instead of the reflection target 20, the sensor 26 can be arranged in the target position 20. The sensor 26 comprises an active surface 29, by means of which incident light can be measured. The active surface 29 can be designed to be similar in size to the reflection surface 24. The sensor 26 can be arranged interchangeably with the reflection target 20 such that the active surface 29 can be arranged at the position relative to the device holder 16 and / or the illumination device 14 at which the reflection surface 24 is arranged in a state in which the reflection target 20 is arranged at the target position 22.

[0081] In simple terms, the sensor 26 can be arranged in the target position 22. The sensor 26 comprises a lux meter and is and / or is configured to determine the light intensity, in particular specified in the SI unit lux (Ix). In addition, the sensor 26 is configured to measure the irradiance, specified in the unit W / m 2set up. Knowing the spatial extent of the reflection surface 24, the total power of the incoming electromagnetic energy striking the reflection surface 24 when the reflection target 20 is arranged in the target position 22 can be calculated.

[0082] Therefore, the radiation energy striking the reflection target 20, in particular the reflection surface 24, can be objectively determined. It is also conceivable that the sensor 26 is configured to determine at least one further parameter relating to the test light in the target position 22.

[0083] A reflectance of the reflection target 20, in particular of the reflection surface 24, is known and profiled in such a way that the luminance of the reflection target 20 in the target position 22 can be determined by determining the at least one parameter of the test light.

[0084] The brightness of Reflection Target 20 can be objectively determined depending on the incident light. Since Reflection Target 20 is a diffuse reflectance standard, it is available with a pre-defined and profiled reflectance. The reflectance has been determined under repeatable (laboratory) conditions by a certified facility.

[0085] Figure 5 shows, by way of example, a schematic representation of a diagram 84 showing the reflectance curve 82 versus wavelength. The reflectance R is plotted on the ordinate 78, and the wavelength X is plotted on the abscissa 80. It can be seen that the reflection target 20 has a reflectance R of at least 98% in a wavelength range from 350 nm to 1250 nm, indicated by the dashed horizontal line. This can mean that the reflection target 20 reflects over 98% of the incident luminous flux and / or radiant flux.

[0086] Because the luminous flux and / or radiant flux incident on the reflection surface 24 is known through the use of the sensor 26 in the target position 22, the reflected luminous flux and / or radiant flux can be calculated at least approximately. This makes it possible, for example, to determine reference values ​​with respect to at least one parameter of the imaging device 18 that are traceable to measured values ​​of the sensor 26. The testing of the imaging device 18 can be objectified. For example, an exposure time of the imaging device 18 can be determined as a function of the luminous flux and / or radiant flux. The light incident on the reflection target 20, also called test light, is provided by the illumination device 14.The illumination device 14 is arranged on the base 12 and comprises a light source 36, a light guide 54, an optical element 56, a holding device 58, an attenuation filter 38, a spectral filter 40, and a structural filter 42. It is understood that the representation of the test bench 10, in particular of the illumination device 14, is greatly simplified. The filters 38, 40, 42 can optionally be arranged between the optical element 56 and the reflection target 20, in particular in an optical axis 32 of the illumination device 14, in particular of the optical element 56, on the holding device 58. For example, they can be inserted laterally into the holding device 58 such that they intersect the optical axis 32 and filter light emitted by the optical element 56.

[0087] Light can be generated by means of the light source 36. In this case, narrowband light with a mean wavelength of 850 nm and a spectral width of 30 nm can be generated. Using such light, the emission wavelength of indocyanine green can be mimicked. This allows the imaging device 18 to be tested for its imaging quality during fluorescence imaging using indocyanine green.

[0088] It is also conceivable that the light source 36 is configured to generate white light and / or near-infrared light. For example, white light could be filtered using the spectral filter 40 such that narrowband test light with a mean wavelength of 850 nm can be provided. Other mean wavelengths are also conceivable, for example, depending on which fluorescence emission wavelength is to be simulated. The light generated by the light source 36 is guided by the light guide 54 to the optical element 56, which is configured to couple out the light. The optical element 56 is designed as a glass block, but it is also conceivable that it is designed as a lens.

[0089] The imaging device 14, in particular the optical element 56, defines the optical axis 32 along which the test light can be provided. The optical axis 32 defines a central line of a light cone 76 of the test light or of the imaging device 14. The light coupled out by the optical element 56 can optionally be modified by means of at least one of the filters 38, 40, 42. At least one irradiation parameter, in particular a radiant power, of the illumination device 14 is adjustable at the light source 36. The radiant power can be reduced, for example, so that only weak test light falls on the reflection target 20. This allows a limit value to be determined that indicates the minimum brightness the reflection target 20 must have in order to achieve a sufficiently high imaging quality of the imaging device 18. For example, a limit value for fluorescence imaging can be determined and / or ascertained.Using the attenuation filter 38, the light generated by the light source 36 can be optionally further attenuated by sliding it in front of the optical element 56. This allows the test light to be further attenuated while still allowing the light source 36 to operate stably.

[0090] By means of the holding device 58, the illumination device 14 is arranged at least partially at an illumination position 60. In this position, the test light is coupled out and / or provided along the optical axis 32. The illumination position 60 is arranged next to the device holder 16. The illumination position 60 is arranged approximately as far away from the target position 22 as the device holder 16.

[0091] The distance of the illumination position 60 from the target position 22 can be at least 70% to a maximum of 130% of the distance of the device holder 16 from the target position 22. According to a preferred embodiment, the illumination device 14 is arranged closer to the target position 22 than the device receptacle 16 (see Fig. 3 and Fig. 4). This ensures that light emitted by the illumination device 14 does not fall directly onto the device receptacle 16 and / or the imaging device 18 under test.

[0092] The illumination device 14, in particular the light-coupling element 56, is arranged next to the device holder 16 with respect to a connecting line 28 between the device holder 16 and the target position 22. The connecting line 28 coincides coaxially with the recording axis 32, the imaging axis 66, and the main backscattering axis 72. The recording axis 30, the connecting line 28, the main backscattering axis 72, and the imaging axis 66 are arranged at an angle to the optical axis 32. The illumination device 14, in particular the optical element 56, is arranged next to the device holder 16 such that the recording axis 30 (and / or one of the axes 28, 72, 66) and the optical axis 32 enclose an angle 34 of 40 degrees. A smaller angle, approximately 30°, is also conceivable.

[0093] The illumination device 14 is arranged such that test light coupled out of the illumination device 14 does not fall directly onto the imaging device 18 to be tested. The light falls onto the imaging device 18 only through the reflection of the reflection target 20. In other words, the device holder 16 is arranged outside the light cone 76. The imaging device 18 is arranged such that, in particular next to the device holder 16, the imaging device 18 to be tested can be indirectly illuminated by means of the reflection target 20. The test bench 10 is designed such that stray light from the illumination device 18 is minimized. The inspection image 71 generated by the imaging device 18 to be tested (see Fig. 6) therefore has a black background 27.

[0094] The structure filter 42 is configured to attenuate light to varying degrees in sections such that the test light incident on the reflection target 20 has a spatially different intensity distribution on the reflection target 20. If it is arranged in front of the optical element 56, for example, a test image 71 'as shown in Fig. 7 or a test image 71 "as shown in Fig. 8 can be generated. The reflection surface 24 is illuminated in a structured manner in each case.

[0095] In the schematic representation of the inspection image 71' (Fig. 7), it can be seen that the reflective surface 24 appears tissue-like in the inspection image 71'. The hatched areas reflect light with an average fluorescence emission wavelength of 850 nm due to the structured illumination. The dotted area reflects light with a lower intensity than the white area. This type of reflection is achieved by the structured illumination, which can be implemented using the structured filter 42. The structured filter 42 can be configured, for example, in sections for different light attenuation and / or spectral filtering.

[0096] It is also conceivable that a striped pattern can be projected onto the reflection surface 24 by means of the structure filter 42, as shown in the schematic representation of the inspection image 71". The hatched stripes correspond to sections that have a lower light intensity than the white stripes. Fig. 2 shows a schematic representation of a further embodiment of a system 52' comprising a test bench 100 and the imaging device 18 or the exoscope 19. Due to the great similarity to the test bench 10, differences will be discussed primarily and the same reference numerals will be used in some cases. The test bench 100 can have at least some of the same features as the test bench 10.

[0097] In contrast, the test bench 100 comprises a diffusion target 44, which is arranged on the base 12 in a target position 22 and is configured to transmit incident test light on a first side 46 and to diffusely emit it from a radiation surface 48 on a second side 50. The imaging device 18 to be tested, the exoscope 19, can be arranged in the device holder 16 for testing in such a way that the radiation surface 48 can be imaged by the imaging device 18.

[0098] The illumination device 14, the diffusion target 44, and the device holder 16 are arranged axially one behind the other. The illumination device 14 comprises at least one light source 36, wherein the light source 36 is configured to emit the test light. The illumination device 14 defines an optical axis 32 that coaxially coincides with a holder axis 30 of the device holder 16.

[0099] The diffusion target 44 is arranged between the device holder 16 and the illumination device 14 such that the holder axis 30 and / or the optical axis 32 intersects the emission surface 48. The diffusion target 44 comprises a diffuser 45, which emits test light incident on the first side 46 homogeneously and diffusely from the emission surface 48. Alternatively, a frosted glass pane can be provided instead of the diffuser 45. The brightness of the emission surface 48 can be determined similarly to the brightness of the reflection target 20, for example, by using a sensor (not shown) and / or at least one previously known diffusion property of the diffusion target 44.

[0100] Fig. 3 shows a schematic perspective view of another embodiment of a system 52" ​​comprising a test bench 10' and the imaging device 18 or the exoscope 19. Fig. 4 shows a schematic view of the system 52" ​​and the test bench 10' in a top view. Due to the great similarity to the test bench 10, differences will be discussed primarily, and the same reference numerals will be used in some cases. The test bench 10' can have at least some of the same features as the test bench 10.

[0101] In contrast, the base 12 comprises a rail 13 made of aluminum. The target holder 62 and the device mount 16 are removably attached to the rail 13. A clamping screw 63 is provided for each removably attaching them. The clamping screw can be tightened once the target holder 62 and the device mount 16 are arranged in the desired position.

[0102] The target holder 62 and the device holder 16 can be slid along the rail 13 when the clamping screw 63 is loosened. The exoscope 19 can be suspended from the device holder 16. The reflection target 20 is attached to the target holder 62. A spacer 59 of a holding device 58 of an illumination device 14 extends from the target holder 62 along an optical axis 32 of the illumination device 14.

[0103] The spacer 59 extends at an angle to a connecting line 28 between the reflection target 20 and the device holder 16. A base 61 of the holding device 58 is arranged on the spacer 59. A light guide 54 is connected to the base 61, by means of which light can be guided to the base 61.

[0104] The base 61 comprises an optical element (not shown) by means of which the light can be coupled out as test light. The base 61 is arranged diagonally next to the device holder 16. The test bench 10 can be enclosed (not shown). The target holder 62 and / or the reflection target can be at least partially painted with a super-black paint.

[0105] The holding device 58 and the target holder 62 are formed jointly and / or are jointly displaceable along the base 12. In other words, the reflection target 20 and the illumination device are at least partially jointly displaceable axially along the base 12. This allows a target position to be adjusted relative to the device holder. A distance between the illumination device 14 and the reflection target 20 remains constant during the adjustment of the target position 22 relative to the device holder 16. Fig. 9 shows a schematic flow diagram of a method for testing an imaging device 18 using a test bench 10, 10', 100 and / or a system 52, 52', 52".The method comprises step 110 of illuminating a reflection surface 24 of a reflection target 20 by means of an illumination device 14, step 112 of imaging the reflection surface 24 by means of the imaging device 18 and generating image data, and step 114 of checking the imaging device (18) based on the image data.

[0106] Fig. 10 shows a schematic flow diagram of a method for operating a test bench 10, 10', 100 and / or a system 52, 52', 52". The method comprises step 116 of arranging a sensor 26 in a target position 22 on a base 12, step 118 of illuminating the sensor 26 with test light, step 120 of determining at least one parameter relating to the test light, and step 122 of exchanging the sensor 26 with a reflection target 20 in the target position 22.

[0107] List of reference symbols

[0108] 10 Test bench

[0109] 12 Base

[0110] 13 Rail

[0111] 14 Lighting device

[0112] 16 Device holder

[0113] 17 Recording room

[0114] 18 Imaging device

[0115] 19 Exoscope

[0116] 20 reflection target

[0117] 22 Target position

[0118] 24 reflection surface

[0119] 25 area

[0120] 26 Sensor

[0121] 27 Background

[0122] 28 connecting line

[0123] 29 active area

[0124] 30 mounting axis

[0125] 32 optical axis

[0126] 34 angles

[0127] 36 light source

[0128] 38 attenuation filters

[0129] 40 spectral filters

[0130] 42 structural filters

[0131] 44 Diffusion target

[0132] 45 Diffuser

[0133] 46 first page

[0134] 48 radiating surface

[0135] 50 second page

[0136] 52 systems

[0137] 54 light guides

[0138] 56 optical element

[0139] 58 Holding device

[0140] 59 spacers

[0141] 60 Lighting position 61 Base of the holding device

[0142] 62 Target holder

[0143] 63 clamping screw

[0144] 64 clamping mechanism

[0145] 66 Image axis

[0146] 68 image cones

[0147] 70 Object area

[0148] 71 Review image

[0149] 72 Main backscattering axis

[0150] 74 Image plane

[0151] 76 light cones

[0152] 78 Ordinates

[0153] 80 abscissa

[0154] 82 History

[0155] 84 Diagram

[0156] 100 test bench

[0157] R reflectance

[0158] 110 steps

[0159] 112 steps

[0160] 114 steps

[0161] 116 steps

[0162] 118 steps

[0163] 120 steps

[0164] 122 steps

Claims

Claims 1. A test bench (10), comprising: a base (12), an illumination device (14) which is at least partially arranged on the base (12) and which is configured to provide test light, and a device holder (16) which is arranged on the base (12) and is configured to receive an imaging device (18) to be tested, characterized by a reflection target (20) which can be and / or is arranged on the base (12) in a target position (22) and which comprises a reflection surface (24) which is configured to diffusely reflect incident test light, wherein the imaging device (18) to be tested can be arranged in the device holder (16) for a test in such a way that the reflection surface (24) can be imaged by the imaging device (18).

2. Test bench (10) according to claim 1, further comprising a sensor (26) which can be arranged interchangeably with the reflection target (20) in the target position (22), wherein the sensor (26) is configured to determine at least one parameter relating to the test light, in particular the irradiance, in the target position (22).

3. Test bench (10) according to claim 2, wherein a reflectance of the reflection target (20) is known and / or profiled such that a luminance of the reflection target (20) in the target position (22) can be determined by determining the at least one parameter of the test light.

4. Test bench (10) according to one of the preceding claims, wherein the reflection target (20) has a reflectance of at least 95%, in particular at least 98%, in a wavelength range from 350 nm to 1250 nm.

5. Test bench (10) according to one of the preceding claims, wherein the reflection target (20) has an at least approximately Lambertian surface.

6. Test stand (10) according to one of the preceding claims, wherein the target position (22) is adjustable relative to the device holder (16).

7. Test stand (10) according to one of the preceding claims, wherein the illumination device (14) is arranged next to the device holder (16) with respect to a connecting line (28) between the device holder (16) and the target position (22).

8. Test stand (10) according to one of the preceding claims, wherein the device holder (16) defines a receiving axis (30) in the course of which the target position (22) is arranged, wherein the illumination device (14) defines an optical axis (32) along which the test light can be provided, wherein the receiving axis (30) and the optical axis (32) are arranged at an angle to one another.

9. Test bench (10) according to claim 8, wherein the lighting device (14) is arranged next to the device holder (16) in such a way that the holder axis (30) and the optical axis (32) enclose an angle (34) of a maximum of 45°, in particular a maximum of 30°.

10. Test bench (10) according to one of the preceding claims, wherein the lighting device (14) comprises at least one light source (36) and an attenuation filter (38), wherein the attenuation filter (38) is arranged and / or can be arranged in front of the light source (36) in such a way that light generated by the light source (36) can be provided in an attenuated form as test light.

11. Test bench (10) according to one of the preceding claims, wherein a light intensity of the test light striking the reflection target (20) is at least substantially distributed over a spectral interval with a width of a maximum of 50 nm, in particular a maximum of 20 nm.

12. Test bench (10) according to claim 1 1, wherein the illumination device (14) comprises at least one spectral filter (40) which is configured to at least substantially transmit light in the spectral interval and to at least substantially block light outside the spectral interval.

13. Test bench (10) according to one of the preceding claims, wherein the illumination device (14) comprises at least one structural filter (42) which is configured to attenuate light in sections to different degrees such that the test light incident on the reflection target (20) has a spatially different intensity distribution on the reflection target (20).

14. Test bench (100) at least according to the preamble of claim 1 and in particular according to one of claims 1 to 13, characterized by a diffusion target (44) which can be arranged and / or is arranged on the base (12) in a target position (22) and is designed to transmit test light incident on a first side (46) and to emit it diffusively from a radiation surface (48) on a second side (50), wherein the imaging device (18) to be tested can be arranged in the device holder (16) for a test in such a way that the radiation surface (48) can be imaged by the imaging device (18).

15. Test bench (100) according to claim 14, wherein the illumination device (14), the diffusion target (44) and the device holder (16) are arranged axially one behind the other.

16. System (52) comprising: a test bench (10, 100) according to one of the preceding claims, and the imaging device (18), which is designed in particular as an exoscope (19).

17. The system (52) of claim 16, wherein the imaging device (18) is configured for fluorescence imaging.

18. A method for testing an imaging device (18) using a test bench (10, 100) according to one of claims 1 to 15 and / or a system (52) according to one of claims 16 or 17, comprising the steps: Illuminating a reflection surface (24) of a reflection target (20) by means of a lighting device (14), imaging the reflection surface (24) by means of the imaging device (18) and generating image data, and Checking the imaging device (18) based on the image data.

19. A method for operating a test bench (10, 100) according to one of claims 1 to 15 and / or a system (52) according to one of claims 16 or 17.

20. A method for operating a test bench (10, 100) and / or a system (52) according to claim 19, comprising the steps: Arranging a sensor (26) in a target position (22) on a base (12), illuminating the sensor (26) with test light, Determining at least one parameter relating to the test light, and exchanging the sensor (26) for a reflection target (20) in the target position (22).

Images