Testing device, system, and testing method

Abstract

The present invention relates to a testing device (10) comprising: a light supply (12), which is designed to guide a first illumination light; a conversion element (14), which is designed to convert light from the first illumination light having a first wavelength (16) at least partially into second illumination light having a second wavelength (18) different from the first wavelength (16); and an optical target (20), which is arranged such that first illumination light and second illumination light can be supplied thereto for lighting the target (20) in order to detect a calibration image (22) of the optical target (20).

Description

[0001] Test device, system and test procedure

[0002] The present application relates to a test device, a system and a test method.

[0003] In medical imaging, exoscopes are state-of-the-art, allowing spatial (magnified) representations of an examination area to be generated. For example, such exoscopes can be used to visualize microsurgical and / or open procedures to assist a surgeon. The spatial representation allows the surgeon to assess and / or track their own actions more intuitively via a screen.

[0004] To generate the spatial representation, such exoscopes have at least two image capture devices, each capturing an image of the examination area. The image capture devices must have the most precise geometric calibration possible, which may mean, in particular, that they are aligned relative to each other in such a way as to capture images in a common coordinate system. Otherwise, the spatial representation would be generated with errors, and viewing the image, especially over a longer period of time, would lead to greater cognitive strain on the surgeon, even leading to headaches or other physical impairments.

[0005] Furthermore, the exoscopes can have image capture devices that are configured to capture images at least additionally in a wavelength range different from the visible light wavelength range. For example, the different wavelength range can be in the near-infrared range, and luminescence imaging, such as fluorescence imaging, can be performed using these image capture devices. Images based on luminescence imaging can be superimposed on other images to provide the surgeon with additional information about the examination area. Therefore, it is necessary that these image capture devices are also coordinated with the other image capture devices, i.e., that they have a common geometric calibration.

[0006] Typically, geometric calibration is performed at the factory, and a calibrated exoscope is delivered to the customer. The factory calibration is verified before delivery. Bulky test equipment is used for verification. These test equipment must be equipped with various illumination devices and / or light sources, each providing light in the wavelength range in which the image capture devices operate. For example, it is common for the test equipment to have a (near-)infrared light source and a white light source.

[0007] Based on the state of the art, the invention is based on the object of checking the geometric calibration in a simple and flexible manner.

[0008] This object is achieved according to the invention by a testing device, a system and a testing method as described herein and defined in the claims.

[0009] The present invention can provide a testing device comprising a light feed configured to guide first illumination light, a conversion element configured to at least partially convert light of the first illumination light having a first wavelength into second illumination light having a second wavelength different from the first wavelength, and an optical target arranged such that first illumination light and second illumination light can be supplied to it for illuminating the target to capture a calibration image of the optical target.

[0010] Furthermore, it can be provided a system comprising a testing device and a medical imaging device with an image acquisition unit. The image acquisition unit can comprise a first image acquisition device that is light-sensitive in a first spectral range comprising the first wavelength, and a second image acquisition device that is light-sensitive in a second spectral range different from the first spectral range and comprising the second wavelength. In this case, the image acquisition unit can have a geometric calibration of the first image acquisition device and the second image acquisition device with regard to their imaging ranges, and the image acquisition unit can be configured to record calibration images of the optical target. Furthermore, the geometric calibration of the image acquisition unit can be verifiable using the calibration images.

[0011] Furthermore, it may be provided to provide a testing method. The testing method may include the steps of generating first illumination light comprising light having a first wavelength, generating second illumination light comprising light having a second wavelength different from the first wavelength, supplying the first illumination light and the second illumination light to an optical target for illuminating it, recording calibration images of the target by means of a medical imaging device having an image acquisition unit, wherein the image acquisition unit comprises a first image acquisition device that is light-sensitive in a first spectral range, and a second image acquisition device that is light-sensitive in a second spectral range different from the first spectral range and comprising the second wavelength,wherein the image acquisition unit comprises a geometric calibration of the first image acquisition device and the second image acquisition device with respect to their imaging areas, and a verification of the geometric calibration of the image acquisition unit based on the calibration images of the optical target. Generating the second illumination light may comprise converting light of the first illumination light having the first wavelength at least partially into second illumination light having the second wavelength different from the first wavelength.

[0012] According to one aspect, the present invention can provide a testing method for checking a geometric calibration of an image capture unit based on a calibration image of an optical target. This can be a further development of the above-mentioned testing method or a testing method independent thereof. The image capture unit can comprise a first image capture device and a second image capture device, wherein the image capture unit has the geometric calibration of the first image capture device and the second image capture device with respect to their imaging areas. The image capture unit can be configured to record calibration images of the optical target, and the geometric calibration of the image capture unit can be verifiable based on the calibration images. In addition, the optical target can comprise at least one calibration pattern.Furthermore, the test method can comprise a verification sequence with the steps of recording a first calibration image by means of the first image acquisition device and a second calibration image by means of the second image acquisition device, so that these each image the calibration pattern, creating a calibration representation with an overlay representation based on the first calibration image and the second calibration image, wherein the overlay representation comprises an image of the calibration pattern at least in sections, and checking the geometric calibration based on the image of the calibration pattern in the overlay representation.

[0013] The test methods, systems, and / or test devices may be independent of one another. Some embodiments may also utilize features of different test methods, systems, and / or test devices and / or partially or completely combine multiple test methods, systems, and / or test devices.

[0014] Advantageously, the geometric calibration can be easily and flexibly verified. In particular, the geometric calibration can be verified after delivery of the exoscope to a customer and / or at regular test intervals. It can therefore be easily and flexibly verified whether the customer has received and / or is operating a sufficiently geometrically calibrated exoscope. Thus, with regard to calibration, it can be ensured that the exoscope can operate within the specified tolerance ranges and that images can be generated that are comfortable for an operator to view, especially over an extended period of time. Furthermore, it is advantageous that no heavy and / or cumbersome test equipment needs to be brought to the customer to verify the geometric calibration.Furthermore, the test method for verifying geometric calibration does not require a particularly powerful computing unit, but can be carried out using standard computing units. The test device can be compact and designed for transport to the customer. Nevertheless, the test device can be used to check image acquisition units for geometric calibration, which include image acquisition devices that are light-sensitive in different spectral ranges. This and / or the compactness can be achieved by the test device incorporating the conversion element. As a result, only the first illumination light from the light supply needs to be guided to provide the first and second illumination light. The simplicity of verifying the geometric calibration can be achieved in particular by making the calibration verifiable using the calibration images.Calibration images can, for example, be recorded in the same or at least similar way to how images would be recorded during normal operation. The image acquisition unit therefore does not have to be specially designed for checking the optical calibration. This also makes the testing device flexible to use, particularly for different image acquisition devices. Furthermore, the use of the calibration pattern can easily check the geometric calibration. The use of the optical target represents a cost-effective and quick way to check the calibration. By using the overlay display, the calibration can be checked efficiently on-site. The testing device can, in particular, be a calibration testing device for checking the geometric calibration.The testing device can be configured in particular to check the geometric calibration of medical imaging devices, wherein the imaging device comprises an image acquisition unit.

[0015] The light supply can be configured to provide illumination light such that the optical target can be illuminated and / or the conversion element can be at least partially illuminated. Guiding can mean that the light can be guided in a preferred direction. In general, guiding can mean that light is guided from a location where illumination light is coupled out from a light source to the target by means of one or more optical elements. This can comprise both beam guidance and diffuse, directed scattering. In particular, the light supply can be configured to guide light with high efficiency, for example with a power loss of at most 50%, at most 40%, at most 30%, or even at most 20%. Furthermore, light can be coupled into the light supply.

[0016] Illumination light can generally comprise wavelengths that can be assigned to the wavelength range of visible light. Illumination light can generally be understood as light that is intended for illuminating and / or illuminating a body and / or object. The first illuminating light can, for example, be intended for illuminating the conversion element and / or for illuminating the optical target. For this purpose, light, in particular illuminating light, can be guided in the test device. The first illuminating light can, in particular, be light that can be coupled into the light supply and / or generated therein. Furthermore, the first illuminating light can, in particular, be guided to the conversion element by means of the light supply.

[0017] In principle, light in a certain range can mean that a part of the entire spectral light intensity distribution of the light is located in this range. The spectral light intensity distribution can be defined as the distribution of the light intensity across the various light wavelengths of the entire spectrum. For example, the part can be 10% to 100%, in particular 40% to 100% and preferably 80% to 100%. Particularly preferably, a part can mean that the light intensity is distributed such that at least substantially the light intensity is in the said spectral range. If the spectral range is visible light, for example, the light intensity of the light is substantially distributed across the spectral range of visible light. This can be particularly relevant if features relate to the first illumination light and / or the first wavelength.The conversion element can be configured to convert light with the first wavelength, in particular light of the first illumination light, into light with the second wavelength, in particular light of the second illumination light. Furthermore, the conversion element can be partially transparent to light with the first wavelength. For example, the conversion element can be configured to convert 10%-100%, in particular 30%-80%, preferably 40%-60%, of the light quantity and / or the luminous flux of the light with the first wavelength into light with the second wavelength. Furthermore, the conversion element can be configured to convert light in narrow spectral bands in accordance with the other features. Narrow can mean that the converted spectral band is, for example, up to 200 nm, in particular 100 nm, preferably 50 nm, particularly preferably 20 nm wide. The conversion element can in particular be configured to emit light with the second wavelength.The emitted light can be used to illuminate the optical target. Alternatively or additionally, light with the first wavelength can be used to illuminate the optical target. For example, the conversion element can be configured to alternately convert and transmit light over time.

[0018] The conversion element can comprise filters configured for light conversion. The conversion element can, in particular, be configured to absorb light having the first wavelength and emit light having the second wavelength. Furthermore, in some embodiments, alternatively or additionally, the wavelength of the light having the first wavelength can be halved by means of the conversion, for example by frequency doubling (second harmonic generation, SHG) and / or frequency multiplication using nonlinear optical processes. For example, the second wavelength can be a wavelength from the ultraviolet range. Furthermore, quantum dots can be provided for light conversion, or the conversion element can comprise quantum dots.

[0019] The conversion element can comprise a light-transmissive or a partially light-transmissive plate. Alternatively or additionally, the conversion element can comprise a transluminescent plate. Furthermore, the conversion element can comprise a coating which acts such that a greater amount of light and / or a greater luminous flux can be emitted at the second wavelength. Alternatively or additionally, the conversion element can comprise a film, in particular a frosted film, and / or be film-coated. The optional plate of the conversion element can, for example, be covered with the film on one side and / or both sides. One-sided and / or two-sided can refer in particular to the sides to which the light at the first wavelength can be guided or from which light at the second wavelength can be emitted.

[0020] The optical target can serve as a target or target object to which an optical system, in particular the medical imaging system, can be aligned or calibrated. The optical target can comprise a structure which, when imaged, allows the acquisition of the calibration image. This can mean that optical calibration can be carried out based on an image of the structure of the optical target. The optical target can be illuminated with light having the first wavelength, in particular the first illumination light, and with light having the second wavelength, in particular the second illumination light, or this light can be supplied to it. For example, the optical target can comprise partially opaque regions and / or sections which can be used for optical calibration when they are imaged and / or acquired using the calibration image.For example, a target point can be defined using the optical target, and the geometric calibration can be verified with reference to the target point. Furthermore, multiple target points can also be provided. For example, the optical target can be used to verify the geometric calibration in multiple areas of the imaging areas of the image capture devices.

[0021] The calibration image can be an image that can be recorded at least primarily for carrying out the verification of the geometric calibration. The calibration image can in particular be acquired using predefined and / or standardized image acquisition settings. This can mean that the image acquisition devices, the image acquisition unit and / or the medical system can have defined settings during the acquisition of the calibration image. It can be provided that a temporal sequence of calibration images, in particular a calibration video, is / will be acquired. For example, calibration images can be acquired at least substantially in real time and / or transmitted to a display device, and / or a representation of the calibration images can be displayed on the display device at least substantially in real time. In particular, the calibration can be verified using a sequence of calibration images.

[0022] The medical imaging device can preferably be an exoscope. Alternatively or additionally, the imaging device can be an endoscope. The medical imaging device can be configured to record images of an examination area. In some embodiments, the imaging device can be configured to generate magnified images of the examination area. The image can be observed while performing a medical procedure and / or during a diagnostic action. The medical imaging device can be mobile and / or movable. It can be provided that the imaging device is movable, for example, in an operating room. If a user requires assistance through imaging, for example, the imaging device can be movable to the site of use, for example a patient. The imaging device can also be movable in itself.The image capture unit may, for example, comprise a movable support arm and / or the image capture unit may be arranged on the movable support arm.

[0023] The image acquisition unit can generally be configured to capture images. Furthermore, the image acquisition unit can comprise the imaging part of the imaging device. For example, the image acquisition unit can jointly house the components involved. The image acquisition unit can, in particular, be selectively attachable to the support arm and / or detachable therefrom. This can mean that the image acquisition unit is interchangeable with another image acquisition unit. Furthermore, the image acquisition unit can comprise connections by means of which image data, signals, and / or electrical supply energy can be exchanged with the medical imaging device, in particular with a control unit of the imaging device, and / or transferred between them.

[0024] The image capture unit can comprise several, for example, two, three, four, five, and / or six, image capture devices. Each image capture device can comprise an image sensor. The image sensor can comprise, for example, a CCD sensor and / or a CMOS sensor. Furthermore, each image capture device can comprise an optical device by means of which light can be guided onto the image sensor. The light can be coupled into the image capture unit by means of an input optical system. For example, each image capture device can comprise its own input optical system. Preferably, however, the image capture unit comprises an input optical system by means of which light can be coupled into all image capture devices. The coupled-in light can then be divided among the image capture devices, for example, by means of a beam splitter. The input optical system can comprise a converging lens. All image capture devices can have a common image plane.

[0025] The image capture devices can be at least substantially identical in construction. Preferably, all image capture devices can have at least substantially identical image capture characteristics. For example, the light can be guided to the image sensor in the same way and / or a distance to the input optics can be the same. The image capture devices can furthermore be configured to image the same imaging area. This is particularly true if the image capture devices have good geometric calibration relative to one another. The image capture devices can image the imaging area from slightly different imaging angles. This can, for example, enable a spatial representation of the imaging area to be created. This can mean that the image capture unit can be at least partially a stereo imaging unit.

[0026] Alternatively or additionally, the image capture unit can be configured to guide light in different spectral ranges and / or to image the imaging range in different spectral ranges. For this purpose, the first image capture device can be light-sensitive in the first spectral range and the second image capture device can be light-sensitive in the second spectral range. For example, the image sensor can be light-sensitive in the spectral range of visible light, in the spectral range of ultraviolet light, and / or in the near-infrared spectral range. “Light-sensitive” can be understood in particular to mean that the respective image sensor is configured to perceive light in the specified range of the electromagnetic spectrum, or the specified wavelength range, and / or to capture images.The image sensor can also be light-sensitive in the specified range and additionally in a wavelength range beyond that. For example, an image sensor can be light-sensitive in the near-infrared wavelength range and additionally in the visible light range.

[0027] The wavelength range of visible light can basically be understood as the wavelength range between approximately 380 nm and 780 nm, in particular between 400 nm and 700 nm.

[0028] The geometric calibration of an image acquisition unit can be understood as aligning the image acquisition unit such that images can be captured in a specific coordinate system. This can mean that the image acquisition unit is aligned to a specific point and / or a specific pattern. The imaging field of an image acquisition unit that has a geometric calibration is within a specific expected range, within the limit of expected and / or application-specific tolerances. The tolerances are determined, for example, by the need for precise geometric calibration. For some embodiments, a tolerance of, for example, 1 pixel to 100 pixels, in particular 3 pixels to 50 pixels, preferably 5 pixels to 25 pixels, may be sufficient.Two image acquisition units that share a common geometric calibration can, for example, be configured to image images of imaging regions in a common coordinate system. In particular, a spatial point imaged by one of the geometrically calibrated image acquisition units can be at a first location of the image of this image acquisition unit, and the same spatial point imaged by the other geometrically calibrated image acquisition unit can be at at least a second location of the image of this image acquisition unit, wherein the first location at least substantially corresponds to the second location with respect to the image boundaries.

[0029] Generally, the pixel size of different imaging devices can vary. A specification of the number of pixels should be understood in the context of common pixel sizes. For example, a pixel can be between 10 pm and 1 mm in size.

[0030] The geometric calibration can be verified using the calibration images from the image acquisition unit. This can mean, for example, that the relative position of an image of the optical target in two calibration images is comparable to each other in order to verify the geometric calibration. A deviation in the relative position in two calibration images can indicate insufficient geometric calibration. A deviation in the relative position can also indicate sufficient calibration, provided the deviation lies within a tolerance range. The calibration images can each be acquired using one of the image acquisition devices.

[0031] According to some embodiments, the second wavelength can comprise a wavelength from the infrared range, in particular from the near-infrared range. This can mean that, by means of the conversion element, light with the first wavelength can be converted into light with the second wavelength, wherein the second wavelength can be assigned to the near-infrared light. The conversion element can in particular be configured to emit and / or radiate infrared, in particular near-infrared, radiation. Near-infrared radiation can, for example, have a wavelength of approximately 780 nm to 3 pm. Infrared radiation can generally have a wavelength of approximately 780 nm to 1000 pm. Furthermore, in this context, the imaging range of an image capture unit can be imaged in infrared, in particular near-infrared, radiation. This can be the case for at least a partial range of the infrared range and / or the near-infrared range.Depending on the sensor technology used, infrared light can be detected in different spectral ranges. This can advantageously provide information about an object that goes beyond the information obtainable from imaging with visible light. For example, molecules present in the imaging range can emit near-infrared radiation. The presence of these molecules and / or a quantity of these molecules can be verified by imaging with near-infrared radiation. For example, certain tissue types and / or structures can be specifically labeled with these molecules. The molecules can specifically be dyes, particularly fluorescent dyes. In some embodiments, they can also be native molecules, for example, endogenous proteins. Detection can then be directed at autofluorescence.The tissue types can include, for example, cancerous tissue. By labeling cancerous tissue with molecules that emit light with near-infrared radiation, the presence of this tissue in the imaging area can be inferred. For example, a representation based on near-infrared radiation can be generated and made available to the user. For example, the near-infrared radiation can be color-coded. Furthermore, a representation based at least partially on near-infrared radiation can be superimposed on a representation based at least partially on visible light.Furthermore, it is advantageous that the second wavelength comprises a wavelength from the infrared range, in particular from the near-infrared range, since this means that for checking the geometric calibration of an image capture device that is light-sensitive in the second spectral range, the testing device and / or the system does not need to include an illumination device by means of which light with the second wavelength can be generated. This makes it possible to provide a particularly compact testing device. Furthermore, a cost-effective and / or less error-prone testing device can be provided. Advantageously, the testing device can be flexible and / or easily transportable to a customer in order to check the geometric calibration.In particular, it can be avoided that a bulky, expensive, complex and / or heavy test device is necessary for checking the geometric calibration and / or has to be transported to a customer.

[0032] Comprising, generating and / or converting can generally mean "at least predominantly" comprising, generating and / or converting. "At least predominantly" comprising, generating and / or converting can refer in particular to the spectral light intensity distribution. "At least predominantly" in this context can mean that a main component of the spectral intensity distribution is located in the specified spectral range. For example, at least over 80%, in particular at least 90%, preferably at least 95% of the light intensity can be located in the specified spectral range. If, for example, illumination light at least predominantly comprises light from the visible range, this can mean that at least 95% of the light intensity can be assigned to the spectral range of visible light.

[0033] Furthermore, the first illumination light can comprise at least predominantly light from the visible range. Such illumination light can be provided, in particular simply and / or efficiently, by available, common light sources.

[0034] Furthermore, the conversion element can be configured to at least partially convert light from the visible range into light from the infrared range. Easily available light can therefore be converted into less easily available light. Infrared light sources can be more expensive and / or less available than white light sources. This is particularly the case since a white light source is usually present in the operating room, but not an infrared light source. By configuring the conversion element in this way, a particularly simple, efficient, cost-effective, and / or compact testing device can be provided.

[0035] According to some embodiments, the conversion element can have luminescent properties, wherein the conversion element is configured to use the luminescent properties to at least partially convert light from the first illumination light having the first wavelength into the second illumination light having the second wavelength different from the first wavelength. For example, the conversion element can have fluorescent and / or phosphorescent properties. The conversion element can, for example, have a coating, be formed at least partially from a material alloy, or comprise a material that is luminescent, in particular fluorescent and / or phosphorescent. The conversion element can be configured to absorb light having one wavelength, in particular the first wavelength, and to emit light having a different wavelength, in particular the second wavelength.The conversion element can thus be manufactured inexpensively and / or compactly. Furthermore, various second wavelengths can be provided flexibly and / or efficiently, in particular selectively. For this purpose, various conversion elements with different optical properties can be provided, which can be quickly interchanged with one another.

[0036] Furthermore, the testing device can comprise a holder, wherein the holder is provided to enable the testing device to be coupled to a medical imaging device to be tested. The holder can be used to ensure that the geometric calibration can be checked reproducibly. Furthermore, the testing device can be easily operated, in particular by allowing the testing device to be aligned efficiently, easily, and / or simply with respect to the imaging device.

[0037] The holder can also comprise a spacer that defines a distance between the medical imaging device to be tested and the target. The distance can, for example, approximately correspond to the distance that the imaging device, in particular an image acquisition unit and / or input optics of the imaging device, can usually have during operation from an object to be examined. Furthermore, the distance can be specifically coordinated with the optical target and / or with the imaging device. The distance can at least substantially correspond to a focal length of the first image acquisition device and / or a focal length of the second image acquisition device. In some embodiments, the distance can be at least 5 cm, at least 10 cm, or at least 20 cm, and / or at most 100 cm, at most 80 cm, or at most 50 cm. The reproducibility of the test can be increased.Furthermore, the review can be standardized.

[0038] Furthermore, the mount can be configured to support the test device's own weight when coupled to the medical imaging device to be tested. This can mean that the test device can be coupled to the imaging device in such a way that the test device is not standing on the floor. This means that the test device does not need to include a support leg and / or the like. The system comprising the test device and the imaging device can thus be more easily coupled, in particular dynamically. Advantageously, fewer vibrations and / or less vibration energy can be transferred to the test device via the floor. The accuracy of the inspection can be improved. Furthermore, the test device can be designed to be more compact.The holder can also comprise a coupling section for coupling to the medical imaging device to be tested, wherein the coupling section comprises a projection configured to hold the testing device by engaging behind it. The imaging device can also comprise a holding section to which the holder can be coupled. For example, the projection can at least partially engage behind the holding section. Furthermore, the projection can be configured to hold the testing device during coupling by engaging behind it, in particular at least in sections of the holding section. The testing device can be rotated about the projection during coupling, in particular while the latter partially engages behind the holding section. The projection can be rotatably mounted in the holding section.The testing device, in particular the coupling section and / or the projection, and the imaging device, in particular the holding section, can jointly form a connection. The connection can, for example, comprise a dovetail joint. This makes it possible to provide a compact and / or efficient testing device.

[0039] The coupling section can further comprise a movable holding element configured to selectively fix the holder to the medical imaging device to be tested or to detach it from the latter. For example, the holder can be clamped to the imaging device by means of the holding element. Alternatively or additionally, the movable holding element can be configured to engage behind the imaging device, in particular the holding section, in sections. The movable holding element can comprise, for example, a tensionable holding element, in particular a clamping spring, an adjusting spring and / or the like, a screw and / or a locking lug. As a result, the testing device can be selectively fixed to the imaging device and / or detachable from it in a simple manner. Coupling can be carried out quickly and / or flexibly.

[0040] In addition, the light guide can comprise a reflective screen designed to guide the illuminating light to the conversion element, wherein the screen has a cross-sectional area that increases in the direction of the conversion element. The screen can be funnel-shaped and / or conical, for example. Reflective can mean that a large portion of the incident light is reflected. Reflective can also include diffusely reflecting. For example, the screen can comprise a reflective coating. The coating can be specular. Furthermore, the coating can comprise white paint designed to diffusely reflect light. "White" here refers in particular to the visible spectral range. Light can be guided to the conversion element efficiently and / or without significant light losses.

[0041] In addition, the testing device can comprise a fiber optic connection to which a fiber optic connection can be connected such that first illumination light guided in the fiber optic connection can be coupled into the testing device. Advantageously, the testing device does not have to comprise its own light source. In some embodiments, the system and / or the medical imaging device can comprise a light source. A fiber optic connection of this light source can be connectable to the testing device. The fiber optic connection can be any common fiber optic connection. If the geometric calibration of a medical imaging device is to be checked, no light source needs to be transported. It is sufficient to transport the testing device to the customer. A light source available there can be connected to the testing device. The fiber optic connection preferably guides first illumination light, which comprises at least predominantly white light and / or visible light.

[0042] Furthermore, the light guide termination can be arranged at a proximal end of the reflective screen, which has a first cross-sectional area, and the conversion element can be arranged at a distal end of the reflective screen, which has a second cross-sectional area, wherein the second cross-sectional area is larger than the first cross-sectional area. Consequently, an illuminable imaginary cross-sectional area can be enlarged with increasing distance from the light guide connection and / or a large area of ​​the conversion element relative to the light guide connection can be illuminated. Furthermore, the light can be guided efficiently and / or with minimal light loss, in particular to the conversion element.

[0043] In addition, the light supply can comprise a diffusion element configured to disperse and homogenize light from the first illumination light. The diffusion element can comprise a plate configured for diffusion. For this purpose, the plate can comprise a coating, for example. Alternatively or additionally, the plate can comprise a frosted glass plate and / or a frosted Plexiglas plate. The diffusion element can be arranged at the distal end of the reflective screen. The conversion element can be arranged distally from the diffusion element. In some embodiments, the conversion element can contact the diffusion element. For example, the conversion element can comprise a plate arranged lying on the diffusion element. The diffusion element and / or the conversion element can be fixed and / or fixable in this configuration.For example, the testing device can include a receiving slot into which the diffusion element and / or the conversion element can be inserted. The receiving slot can be closable. The diffusion element can achieve homogeneous illumination of the conversion element and / or the optical target. This can increase the accuracy of the test.

[0044] Furthermore, the optical target can be movably mounted. The testing device can comprise a bearing device in which the optical target is movable. The target can be movable, for example, in a plane that corresponds to a main plane of the conversion element and / or the diffusion element. In this case, it can be provided that the bearing device prevents the target from being movable perpendicular to the plane, i.e., the mobility is limited to the plane. The main plane can comprise the emission plane of the conversion element, from which radiation is emitted in the direction of the optical target. Furthermore, the plane can be at least substantially parallel to the plane that can be imaged by the imaging unit, in particular in a coupled state, or in which the calibration image is to be captured by the imaging unit. The optical target can therefore be movably mounted in the image plane of the imaging unit.The optical target can further comprise at least one handle by means of which the target can be moved. The handle can be removable. The target can be inserted into the storage device, in particular in a state in which the handle is removed. Furthermore, the storage device can be designed such that mobility of the target is reduced. For example, the target can be clamped. The testing device, in particular the storage device, can comprise, for example, a rubber coating that is compressed by the target when the target is inserted into the testing device. This can reduce the risk of the target moving unintentionally relative to the imaging device. Operating safety is increased. Because the target is movable, the target can be aligned relative to the imaging device.

[0045] Furthermore, the optical target can comprise at least one calibration pattern, and the calibration pattern can be imaged on the calibration image. The calibration pattern can be clearly recognizable in the calibration image and / or, for example, can be displayed and / or imaged with a sharp contrast and / or in a different color than the surroundings. The calibration pattern can be provided in such a way that the geometric calibration can be checked easily and / or quickly using the calibration pattern. In some embodiments, the calibration pattern comprises opaque, light-reflecting, and / or light-absorbing sections. The calibration pattern can, for example, comprise a black print on a film. Furthermore, the calibration pattern can be formed as a relief in a plate, wherein the relief can be filled with a black and / or light-absorbing material.A film enclosing the calibration pattern can, for example, be arranged between two translucent plates, particularly glass plates, or clamped and / or stretched. The plates can reduce the risk of damage to the calibration pattern.

[0046] The calibration pattern may further comprise at least one line and / or one cross. In some embodiments, the line and / or the cross may also comprise isolated elements such as dots, lines, or other objects arranged on a line and / or a cross, thereby forming the line and / or the cross. The line and / or the cross are easily recognizable in the calibration image. Furthermore, it is particularly well suited for checking the optical calibration. A cross may preferably be provided. Using the cross, the optical calibration can be easily checked in two spatial directions.

[0047] Furthermore, the calibration pattern can comprise a central rectangular cross with elongated arms, the center of which can be arranged in the center of the calibration image, and which divides the calibration image into four quadrants, wherein in each of the four quadrants there is another rectangular cross with elongated arms, the center of which is each arranged in a central region of the corresponding quadrant. Elongated arms can mean that the cross can have thin arms. When the cross is imaged, an arm can extend in width, for example, over 1 pixel to 20 pixels, in particular over 1 pixel to 10 pixels, preferably over 1 pixel to 5 pixels. The center of the central cross can be moved to the center of the calibration image by moving the optical target. This allows the geometric calibration to be checked in the center.The four additional right-angled crosses in the central regions of the quadrants of the calibration image make it possible to check the geometric calibration in edge regions of the calibration image. A central region can mean a region of the quadrant that encompasses the center of the quadrant. The center of the quadrant can at least substantially comprise the center of the central region. The central region can extend over, for example, up to 50%, in particular up to 30%, preferably up to 15%, of the area of ​​the quadrant. The central region can in particular be arranged centrally in the quadrant. This can mean that overall the geometric calibration can be checked in a region of the calibration image that encompasses at least substantially half of the side edge in both directions from the center.This ensures that the image acquisition unit has good geometric calibration over a large imaging area. This allows for particularly good imaging quality and particularly good spatial representation.

[0048] In addition, the optical target can be integrated with the conversion element. For example, the calibration pattern can be printed onto the conversion element and / or a film comprising the optical target can be clamped onto the conversion element. Advantageously, the test device can be made more compact and / or lighter. Furthermore, the complexity of the test device can be reduced.

[0049] The system may further comprise an illumination device that is connected and / or connectable to the light supply. The illumination device may comprise a light source, in particular a white light source. Advantageously, the illumination device can provide light comprising the first wavelength, in particular the first illumination light. The illumination device can be connected to the light supply, in particular, by means of a light guide.

[0050] Furthermore, in an imaging operating mode, the illumination device can be connectable to the imaging device for providing illumination light during image acquisition. In a calibration operating mode, the illumination device can be connectable to the test device for providing illumination light. Advantageously, an illumination device for providing illumination light for the imaging device and the test device can be provided. Imaging devices usually have an illumination device and / or an illumination device is provided anyway for operating the imaging device. This means that an illumination device is usually present when an imaging device is present. The test device can then be operated with this illumination device.This eliminates the need to provide a separate lighting device to check the geometric calibration.

[0051] Furthermore, the system can comprise a display device configured to display a calibration representation based on the calibration images for a user. In the imaging operating mode, a representation of images of an object can be displayed on the display device, wherein the images can be captured by the imaging device. The representation can, in particular, comprise the spatial representation and / or the overlay representation. Advantageously, a display device that is already available can therefore be used for the verification.

[0052] The calibration images can comprise at least one first calibration image recorded by the first image capture device and at least one second calibration image recorded by the second image capture device, and the calibration representation can comprise an overlay representation based on the first calibration image and the second calibration image. “Overlay representation” can mean that the representation is based on both calibration images. For example, an overlay representation can be understood as a cross-fade representation. The overlay representation can, for example, comprise the first calibration image and the second calibration image, with at least one of the calibration images being shown partially transparently. In the overlay representation, image regions of the respective calibration images can be compared and / or aligned with one another. For example, a spatial position of components of the calibration images can be compared.This allows the geometric calibration to be verified.

[0053] Furthermore, the overlay representation can comprise sections of the first calibration image and the second calibration image arranged spatially next to one another. The sections of the calibration images can be approximately 5 pixels to 500 pixels, in particular 20 pixels to 250 pixels, preferably 30 pixels to 100 pixels in size, in particular based on at least one side length. In some cases, the sections can be square and / or rectangular. The pixel specifications can then relate to the length of a side, in particular a longer side. The size can relate to the extension in a spatial direction. In this way, the geometric calibration can be checked by comparing the calibration images section by section. In this way, it is easy to check whether the calibration images image an object, for example the optical target, identically, in particular at the same location, in the sections.An offset of these images indicates the quality of the geometric calibration.

[0054] Furthermore, the overlay representation can comprise multiple, alternating sections of the first calibration image and the second calibration image arranged side by side in two different spatial directions. For example, the calibration representation can have a checkerboard pattern. The squares of the checkerboard can comprise sections of the first calibration image and the second calibration image arranged side by side. This makes it possible to verify the geometric calibration in both spatial directions.

[0055] The optical target can comprise the calibration pattern, and the sections of the respective calibration images used for the overlay display can at least partially depict the calibration pattern. This makes it possible to verify whether the calibration pattern is offset in the overlay display. The offset is an indicator of the quality of the geometric calibration. The geometric calibration can be easily verified.

[0056] The system may further comprise an input device by means of which control commands for checking the calibration of the image capture unit can be initiated by a user. The input device may comprise a laptop, a computer, a mobile device, for example a mobile phone and / or a tablet, in particular a mouse and / or a keyboard. For example, arrow keys on the keyboard may be used to initiate a control command for moving an overlay. Furthermore, during the check, the control commands may be used to navigate through a menu that may be intended to navigate through the check of the geometric calibration.

[0057] In addition, the display device can be configured to display an alignment aid for aligning the optical target relative to the image acquisition unit. The alignment aid can, for example, be provided to assist in moving the calibration pattern, in particular the central cross, into the center of the calibration image. For example, the alignment aid can mark the center and / or the middle of the calibration image and / or the overlay display, and the optical target can be aligned using the alignment aid. Advantageously, the optical target can be easily aligned within the testing device. In particular, the optical target can be provided specifically for the imaging device. In some embodiments, the alignment aid comprises a central cross with elongated arms.The optical target can be moved to align it so that as much of the target image as possible overlaps the alignment aid.

[0058] According to some embodiments, the image capture unit may comprise a third image capture device that is light-sensitive in the first spectral range and a fourth image capture device that is light-sensitive in the second spectral range. Stereo image capture in the first spectral range may be performed by means of the first image capture device and the third image capture device, and stereo image capture in the second spectral range may be performed by means of the second image capture device and the fourth image capture device. For example, stereo image capture may be performed in the spectral range of visible light and additionally in the near-infrared and / or ultraviolet spectral range. A stereo representation, in particular a spatial representation, may be generated based on the stereo images in the two spectral ranges.The stereo representation based on the stereo images in a spectral range at least predominantly outside of visible light can be displayed in a spectral range of visible light. The geometric calibration can include aligning the imaging areas of all image capture devices with respect to one another.

[0059] Alternatively or additionally, stereo image acquisition can be performed using the first image acquisition device and the second image acquisition device and / or using the third image acquisition device and / or the fourth image acquisition device. In general, image acquisition devices can be used in any combination for stereo image acquisition. For example, three, four, five, and / or six image acquisition devices can be used together for stereo image acquisition. This can mean that stereo image acquisition does not necessarily have to be performed in the first and / or second spectral range. For example, stereo image acquisition can be performed jointly in the first spectral range and the second spectral range.

[0060] The testing method may further comprise the step of coupling the testing device to the medical imaging device. The coupling may, in particular, comprise placing and / or hooking the projection of the testing device onto the imaging device and / or may further comprise operating the movable holding element. Furthermore, the testing device may be placed onto the imaging device at at least one point and pivoted about the point. After coupling, the testing device is in a coupled state. In this state, the image plane of the image acquisition unit, or of the image acquisition devices, may preferably lie at least substantially parallel to the plane in which the optical target, in particular the calibration pattern, extends.

[0061] It may further comprise the step of connecting a lighting device to the test device.

[0062] In addition, the illumination device can be configured to be connected to the imaging device in an imaging operating mode for providing illumination light during image acquisition.

[0063] Furthermore, the overlay display can comprise the spatially adjacent sections of the first calibration image and the second calibration image such that the image of the calibration pattern is displayed at least partially in the spatially adjacent sections of the first calibration image and the second calibration image. This makes it easy to verify the geometric calibration. Advantageously, for example, the geometric calibration can be verified more independently of the resolution of the display device. This is particularly true compared to, for example, a blended display.

[0064] The verification process may further comprise the steps of displaying a verification aid in the calibration representation, wherein the verification aid frames a verification area and thereby defines a tolerance range for the verification, moving the verification aid in the calibration representation such that a first section of the image of the calibration pattern lies within the verification area, wherein the first section originates from the first calibration image, and checking whether the verification aid is movable such that, in addition to the first section, a second section of the image of the calibration pattern lies within the verification area, wherein the second section originates from the second calibration image.

[0065] The verification aid can comprise a rectangular frame. “Rectangular” can mean the shape of a rectangle with rounded corners. The verification area can be defined by the section of the frame. The verification area can be viewable by a user. This can mean that a user views the verification area or the section of the frame to assess the geometric calibration. The larger the tolerance range, the larger the section of the frame can be, or the larger the verification aid can be. Since an image of the calibration pattern can be shown section by section in the calibration display, a section-by-section offset of the image of the calibration pattern can occur between the calibration images. The smaller the offset, the better the geometric calibration.The offset can be so large that two sections of the image of the calibration pattern cannot be framed by the verification aid, wherein the image of the calibration pattern is depicted in different calibration images. If, for example, the calibration pattern is a line, the line can be depicted in the calibration representation as two parallel, offset, broken lines, wherein the lines each run along the sections of the respective calibration image. In general, the image of the calibration pattern can be depicted as if it were depicted in only one calibration image, in particular depicted at least substantially offset-free if the geometric calibration is ideal. By means of the verification aid, the geometric calibration can be verifiable in at least two spatial directions.In particular, if the verification aid comprises the rectangular frame, the geometric calibration can be verifiable in each direction in which the sides of the frame extend. In particular, the overlay representation can be shown in a checkerboard pattern. This can mean that a periodic offset of the calibration pattern can occur between the individual fields of the chessboard, in particular in two directions of the chessboard. The calibration pattern can, for example, comprise a cross that extends in two directions. For the purpose of verification, the verification aid can be movable using control commands. A user can initiate the control commands. To check the geometric calibration, the user can, for example, use a control command to move or shift the verification aid pixel by pixel and / or two-pixel by pixel in one of the directions.The user can initiate the control command frequently until, for example, they either recognize that the two sections of the image of the calibration pattern are within the verification aid, in particular the tolerance range, and / or until they recognize, for example, that the verification aid, in particular the tolerance range, cannot be moved such that the two sections of the image of the calibration pattern are within the verification aid, in particular the tolerance range. The user can do this, for example, in all extension directions of the verification pattern, or of the image of the verification pattern. According to one embodiment, the verification pattern comprises a rectangular cross with elongated arms. By checking along the arms and / or at at least one position of each arm, the geometric calibration can be checked in two spatial directions.Advantageously, this allows the geometric calibration to be verified very easily, quickly, efficiently, cost-effectively, reliably, and / or effectively. This verification method is particularly suitable for verifying the geometric calibration after delivery of the image acquisition unit or imaging device to a customer. For example, the geometric calibration can be verified quickly and / or efficiently after delivery to ensure that the customer has received a sufficiently calibrated image acquisition unit. In particular, this does not require a particularly heavy, bulky, and / or difficult-to-transport test device.By creating the overlay representation and checking the representation of the image of the calibration pattern, a calibration check can be carried out in such a way that no particularly large computing power of a computing unit is required, whereby the computing unit is involved, for example, in the creation of the overlay representation.

[0066] The verification of the geometric calibration can be assessed as positive if the verification aid is movable in such a way that, in addition to the first section, a second section of the image of the calibration pattern lies within the verification area, which section originates from the second calibration image. Positive can mean that the image acquisition unit is geometrically calibrated in such a way that a sufficiently good spatial representation of an object can be created for an application and / or a sufficiently good overlay representation of images of the object can be created, whereby the images were acquired in different spectral ranges. In particular, the assessment can result from the application. According to some applications, a particularly good representation quality is necessary. In such cases, a smaller verification aid or a smaller tolerance range can be used for the verification.

[0067] Furthermore, the inspection aid can extend over at least 5, preferably at least 10 pixels in one spatial direction and over at least 5, preferably at least 18 pixels in a spatial direction perpendicular thereto. In general, the number of pixels can be closely related to the pixel size, the resolution of the display, the image sensor used, and / or the required size of the tolerance range and / or the inspection aid.

[0068] The test method can also include further verification sequences, for which the verification aid is moved into different image areas of the calibration display. Different image areas can mean areas between which several, for example, at least two, three, four, five, and / or six, of the verification aids would fit. The image areas can be spaced apart from one another. For example, the image areas can be moved to different edge areas of the calibration display. This allows, for example, an assessment of the homogeneity of the geometric calibration across the entire imaging range of the image capture devices. Furthermore, distortion of the images from the image capture devices can be verified.

[0069] In addition, at least one verification process can be carried out in a central area of ​​the calibration representation, and further verification processes can be carried out in a central area of ​​each of the quadrants of the calibration representation. In principle, the calibration representation can be rectangular. At least one rectangular calibration representation can be divisible into four areas of at least substantially equal size, in particular rectangular areas. These areas can be the quadrants. This makes it easy to carry out a reproducible check of the geometric calibration in several areas of the calibration representation. The calibration pattern can be designed such that it comprises at least one partial pattern which, when imaged, can be displayed in the central area of ​​the calibration representation.

[0070] Furthermore, the testing method can comprise a step of generating an enlarged view of a section of the calibration image, such that central regions of each of the quadrants of the calibration image are each represented in a region of a corner of the enlarged view. This can mean that the enlarged view can be generated by enlarging the calibration image twice. In the enlarged view, the geometric calibration in the center and / or in the corners of the enlarged view can be checked and / or verified. This makes it possible to locate the center of the quadrants quickly and easily and / or to verify the geometric calibration in the central regions of the quadrants of the calibration image. The testing method can be carried out more efficiently and reliably.

[0071] The testing method may further comprise a preparation process. The preparation process may include the steps of capturing an image of the optical target with one of the image capture devices, generating a representation of the target based on the captured image, displaying an alignment aid for aligning the optical target relative to the image capture unit, and aligning the optical target with the alignment aid by moving the target. The preparation process may be executable and / or performed before performing at least one inspection process. Furthermore, the preparation process may be executable and / or performed before at least substantially every inspection process. The alignment aid can simplify the positioning of the optical target.For example, the optical target can be more easily arranged at a target location where the target can be imaged such that it can be displayed at a desired location in the calibration image. The desired location can, in particular, be the center of the calibration image. This can mean that the alignment aid can mark and / or point to the center of the calibration image. This allows the inspection method to be quickly and / or easily applied to various image capture devices. Furthermore, for example, movement of the target during the execution of a verification procedure can be compensated for.

[0072] Furthermore, the calibration pattern can comprise a central rectangular cross with elongated arms, and the alignment aid can comprise a rectangular cross with elongated arms. Two patterns that are at least substantially similarly shaped and / or designed can be compared in a particularly simple manner. For example, a degree of overlap between representations of both patterns can be easily compared, and / or the quality of the alignment can be assessed based on the degree of overlap. A high degree of overlap can indicate good alignment. According to other embodiments, the alignment aid can, for example, comprise a frame, in the section of which the image of the optical target is to be arranged at least substantially.

[0073] The image capture unit can further comprise at least one further image capture device, and the image capture devices can have a common geometric calibration with respect to their imaging areas. The testing method can further comprise checking the calibration of the image capture devices in pairs. By checking the image capture devices in pairs, a high quality of the spatial representation and / or the superimposed representation can be achieved. For example, one pair of image capture devices can be configured for stereo image acquisition and / or another pair can be configured for stereo image fluorescence acquisition in the near-infrared spectral range. The geometric calibration of all of these image capture devices can be checked in pairs. The pair-wise checking can be performed sequentially. The geometric calibration of multiple image capture devices can be checked in a simple and efficient manner.

[0074] The present invention may further provide a system for performing a testing method. In some embodiments, the system may be able to perform the testing in an automated and / or semi-automated manner.

[0075] The present invention may further provide for the provision of program code comprising instructions which, when executed by a processor, cause a testing method according to the invention to be carried out.

[0076] The present invention may further provide for a computer program product comprising a machine-readable medium on which program code according to the invention is stored.

[0077] The invention is explained below using exemplary 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.

[0078] 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.

[0079] They show:

[0080] Fig. 1 is a schematic representation of a system;

[0081] Fig. 2A is a schematic representation of an image acquisition unit of the system in a

[0082] side view;

[0083] Fig. 2B is a schematic representation of the image acquisition unit in a plan view;

[0084] Fig. 20 is a schematic representation of the image acquisition unit in a view of the

[0085] Back of the image capture unit;

[0086] Fig. 3 is a perspective view of a test fixture of the system and the image acquisition unit;

[0087] Fig. 4 is a perspective sectional view of a portion of the testing device;

[0088] Fig. 5 is a view of a portion of the testing device at the distal end of a holder;

[0089] Fig. 6 is a perspective view of a portion of the testing device at the proximal end;

[0090] Fig. 7 is a schematic representation of the operating principle of the test device;

[0091] Fig. 8 is an exemplary schematic representation of an intensity distribution;

[0092] Fig. 9 is a schematic sectional view of an optical target;

[0093] Fig. 10 shows an embodiment of a calibration pattern;

[0094] Fig. 11 shows a calibration image comprising an image of a calibration pattern and an alignment aid;

[0095] Fig. 12 shows a calibration representation based on a first calibration image and a second calibration image;

[0096] Fig. 13 a verification aid;

[0097] Fig. 14 is a schematic representation of an enlarged view of the calibration representation comprising an overlay of the verification aid and the image of the calibration pattern;

[0098] Fig. 15 shows a section of the calibration representation, on the basis of which the geometric calibration is positively evaluated;

[0099] Fig. 16 shows a section of the calibration representation on the basis of which the geometric calibration is negatively evaluated;

[0100] Fig. 17 shows another embodiment of an overlay display;

[0101] Fig. 18 is a schematic flow diagram comprising several steps of a test method; Fig. 19 is a schematic flow diagram comprising several steps of a verification process; and

[0102] Fig. 20 is a schematic flow diagram comprising several steps of a preparation process.

[0103] Fig. 1 shows a schematic representation of system 100. System 100 includes an image capture unit 64, a test device 10, a lighting device 74, a display device 78, and an input device 86. Some of the components—in the illustrated case, the lighting device 74, the display device 78, and the input device 86—are arranged on a cart 124. The cart 124 includes casters, allowing it to be moved within the room. For example, a user can move the cart 124 to a location where the image capture unit 64 is being used.

[0104] The image capture unit 64 is detachably attached to a movable support arm 122. The image capture unit 64 can, for example, be exchangeable for another image capture unit (not shown). Furthermore, the image capture unit 64 can be positioned in all three spatial directions by means of the support arm 122. The user can, for example, position the image capture unit 64 such that an image of an object, for example, an examination area, can be captured to support an action. Furthermore, a sequence of images can be captured, for example, a video. A representation of the image and / or the video can be displayed on the display device 78. The user can therefore view the representation of the image and / or the video on the display device 78 while performing an action.

[0105] Furthermore, the image acquisition unit 64 is configured for stereo imaging. For this purpose, the image acquisition unit 64 comprises a plurality of image acquisition devices 66, 68, 88, 90, 114. A more detailed schematic representation of the image acquisition unit 64 is shown in Figs. 2A and 2B. Stereo imaging can mean that a spatial representation can be generated. This is based on at least two images from two image acquisition devices 66, 68, 88, 90, 114. The image acquisition unit 64 is fundamentally configured to capture images in a first spectral range 70, which is predominantly within the spectral range of visible light. In addition, the image acquisition unit 64 is configured to capture images in a second spectral range 72, which is at least predominantly outside the spectral range of visible light. The image acquisition unit 64 is also configured for stereo imaging in the second spectral range 72.A spatial representation of the images of both spectral ranges 70, 72 can be shown together in a spatial overlay representation (not shown). In particular, the second spectral range 72 can comprise a second wavelength 18, wherein the second wavelength 18 comprises a wavelength from the infrared range, in particular from the near-infrared range. This can enable, for example, luminescence imaging, in particular fluorescence imaging and / or phosphorescence imaging. A structure to be examined within the examination region can be colored, for example, using a fluorescent dye which absorbs first light, in particular first illumination light comprising a first wavelength 16, and emits light comprising the second wavelength 18.The first wavelength 16 is assigned to the spectral range of visible light, or the first light, in particular the first illumination light, comprises at least predominantly light from the visible range. Consequently, the spatial overlay representation allows the structure to be more precisely localized and / or visualized.

[0106] The image capture unit 64 further comprises a light supply connection 126. A light guide 44 of the illumination device 74 can be connected to the light supply connection 126. The illumination device 74 is configured to generate and / or provide the first illumination light. This means that the illumination device 74 is configured to generate predominantly light in the visible range. In particular, in an imaging operating mode, it is provided that the illumination device 74 is connected to the imaging device 26, in particular to the image capture unit 64, to provide illumination light during image capture. In a calibration mode, it is provided that the illumination device 74 is connected to the testing device 10. In the calibration mode, a geometric calibration of the image capture unit 64 is checked.Clearly, only one illumination device 74 is provided for operating the inspection device 10 and the imaging device 26. The imaging device 26 is typically operated with illumination devices such as the illumination device 74, so that such an illumination device is present anyway when the imaging device 26 is operated.

[0107] The light guide 44 can be connected to the inspection device 10, in particular to a light guide connection 42 of the inspection device 10. In the illustrated case, the light guide 44 is connected to the inspection device 10, so that the first illumination light, which is guided in the light guide 44, can be coupled and / or is coupled into the inspection device 10. The inspection device 10 is coupled to the imaging device 26, in particular the image acquisition unit 64, by means of a holder 24 of the inspection device 10. In particular, the inspection device 10 is coupled to an input optics (see Figs. 2A and 2B) of the image acquisition unit 64. As a result, at least one image of an object within the inspection device 10 can be and / or is captured by means of the image acquisition unit 64. According to the illustrated embodiment, at least one image of an optical target 20 is captured.The optical target 20 is at least partially illuminated by light provided by the illumination device 74. The image acquisition unit 64, in particular the image acquisition devices 66, 68, 88, 90, 114, have the geometric calibration with regard to their imaging areas. As described in more detail in the following figures, the image acquisition unit 64 is configured to record calibration images 22 of the optical target 20, and the geometric calibration of the image acquisition unit 64 can be checked using the calibration images 22. An exemplary embodiment of a testing device 10 is shown in more detail in the following figures. Furthermore, the following figures show how the testing device can be operated, for example.

[0108] Recorded images, such as calibration images 22, can be displayed on the display device 78. Or the representations are displayed on the display device 78. By way of example, in Fig. 1, the display device 78 presents the calibration representation 80 to a user, wherein the calibration representation 80 is based on the calibration images 22. The calibration representation 80 comprises an overlay representation 82 which comprises sections 84 of the calibration images 22 arranged spatially next to one another. The sections 84 originate alternately from one of the calibration images 22 in each case. More precisely, the overlay representation 82 comprises several sections of one of the calibration images 22 arranged alternately next to one another in two different spatial directions. The overlay representation 82 is shown in more detail at least in Fig. 11.In the imaging mode of operation, for example, spatial representations, in particular spatial overlay representations, are displayed on the display device 78.

[0109] Using the input device 86, the user can, for example, initiate control commands to check the calibration of the image acquisition unit 64. Furthermore, the medical imaging device 26, in particular the image acquisition unit 64, can be controlled using the input device 86. The input device 86 can, for example, be connected to the imaging device 26, in particular the image acquisition unit 64, as shown in Fig. 1.

[0110] 2A, 2B, and 2C show a schematic representation of the image acquisition unit 64 of the medical imaging device 26 of the system 100 in various views. Fig. 2A shows a schematic representation of the image acquisition unit in a side view, Fig. 2B shows a schematic representation of the image acquisition unit 64 in a top view, and Fig. 2C shows a schematic representation of the image acquisition unit 64 in a view of the rear of the image acquisition unit 64. The image acquisition unit 64 comprises a plurality of image acquisition devices 66, 68, 88, 90, 114. The image acquisition devices 66, 68, 88, 90, 114 are collectively housed by the housing 128. In addition, the image capture unit 64 comprises an input optics 130, by means of which light for the image capture devices 66, 68, 88, 90, 114 can be coupled into the image capture unit 64.The image capture devices 66, 68, 88, 90, 114 have at least substantially identical optical properties. This means, for example, that they at least substantially have a common imaging region. The image capture unit 64 has the geometric calibration of the first image capture devices 66, 68, 88, 90, 114 with regard to their imaging regions. This means that the imaging regions are at least substantially identical. Furthermore, the better the geometric calibration, the more congruent the imaging regions are. If, for example, an object is captured using images from different image capture devices 66, 68, 88, 90, 114, the object may have been captured at slightly different coordinates in the images depending on the geometric calibration.This means that an offset can occur between images of the object acquired using different image acquisition devices 66, 68, 88, 90, 114. The better the geometric calibration, the smaller the offset. This is particularly important because spatial representations of an examination area are to be acquired using the image acquisition unit 64 and / or the medical imaging device 26. The smallest possible offset is desirable so that the spatial representation has the highest possible quality. Furthermore, different spatial representations, wherein the spatial representations can be based on images of different spectral ranges, can also be displayed superimposed. The image acquisition devices 66, 68, 88, 90, 114 are thus configured for stereo image acquisition. Pairs of the image acquisition devices 66, 68, 88, 90, 114 are formed in this case.

[0111] The image capture unit 64 comprises a first image capture device 66 and a second image capture device 88, each of which is light-sensitive in the first spectral range 70. Furthermore, the capture unit 64 comprises a second image capture device 68 and a fourth image capture device 90, each of which is light-sensitive in the second spectral range 72. At least one of the third and fourth image capture devices 88, 90 can also be referred to as a further image capture device 114. Stereo image capture in the first spectral range 70 can be performed by means of the first image capture device 66 and the third image capture device 88. Stereo image capture in the second spectral range 72 can be performed by means of the second image capture device 68 and the fourth image capture device 90. In particular, the second spectral range 72 lies in the near-infrared range.As a result, fluorescence stereo image acquisition can be carried out by means of the second image acquisition device 68 and the fourth image acquisition device 90.

[0112] The image capture devices 66, 68, 88, 90, 114 each comprise an image sensor 132, 134, which are light-sensitive in different spectral ranges. The first image capture device 66 and the second image capture device 88 each comprise a first image sensor 132, which is light-sensitive at least predominantly in the first spectral range 70, wherein the first spectral range 70 is assigned to the spectral range of visible light. This means that image capture in the wavelength range of visible light can be performed using the first image sensor 132. This corresponds approximately to conventional image capture. Image capture in the wavelength range of near-infrared light can be performed using the second image sensor 134. This enables fluorescence imaging. The second image capture device 68 and the fourth image capture device 90 each comprise a second image sensor 134.Since the second image sensor 134 is at least predominantly light-sensitive in the second spectral range 72 and, in particular, is relatively light-insensitive in the wavelength range of visible light, light must be provided in both spectral ranges 70, 72 in order to be able to check the geometric calibration of the image acquisition unit 64. To check the geometric calibration, the image acquisition unit 64 records the calibration images 22 of the optical target 20. In particular, each of the image acquisition devices 66, 68, 88, 90, 114 records at least one calibration image 22 of the optical target 20. Using the calibration images 22, the user can, for example, check the geometric calibration of the image acquisition unit 64. In particular, it is provided that the geometric calibration of the image acquisition devices 66, 68, 88, 90, 114 is checked in pairs.This means that, in particular, the geometric calibration of an image acquisition unit 68, 90, which is light-sensitive in the second spectral range 72 (near-infrared), and an image acquisition unit 66, 88, which is light-sensitive in the first spectral range 70 (visible light), is provided. For this purpose, near-infrared light, comprising the second wavelength 18, and visible light, in particular white light, comprising the first wavelength 16, are provided and / or the optical target 20 is illuminated with this light. As a result, calibration images 22 are acquired in both spectral ranges 70, 72, and overlay representations 82 can be generated based on images acquired in both spectral ranges 70, 72.By means of the conversion element 14, light can be provided in both spectral ranges 70, 72, although the system comprises only one illumination device 74 which at least predominantly provides and / or generates light in the first spectral range 70 (visible light).

[0113] The test device 10 is shown in more detail in Figs. 3 and 4. Fig. 3 shows a perspective view of the test device 10 and the image acquisition unit 64. Fig. 4 shows a perspective sectional view of a portion of the test device 10.

[0114] The test device 10 comprises the optical fiber connection 42, a light feed 12, the optical target 20, a conversion element 14, and the holder 24. The optical fiber 44 of the illumination device 74 can be connected to the optical fiber connection 42 such that the first illumination light guided in the optical fiber 44 can be coupled into the test device 10, in particular into the light feed 12. The optical fiber connection 42 can be any standard optical fiber connection. In particular, the optical fiber connection 42 can comprise a clamping device 156, by means of which the optical fiber 44 can be clamped. See Fig. 6. Fig. 6 shows a perspective view of a section of the testing device 10 at the proximal end 46 comprising the light guide connection 42, the clamping device 156, the light guide 44 and the screen 38. The first illumination light is guided by means of the light guide 12.In particular, the first illumination light is guided to the conversion element 14. The light guide 12 comprises a reflective screen 38, which is configured to guide the first illumination light to the conversion element 14. The screen 38 comprises a reflective coating on at least a large part of its inner surface. Furthermore, the screen 38 has a cross-sectional area 40 that increases in size toward the conversion element 14. The screen is hollow funnel-shaped and has openings at its proximal end 46 and at its distal end 49. The optical fiber connector 42 is arranged at the proximal end 46, and a diffusion element 52 and the conversion element 14 are arranged at the distal end 49. At the proximal end 46, the shield 38 has a first cross-sectional area 48 and at the distal end 49 a second cross-sectional area 50, wherein the second cross-sectional area 50 is larger than the first cross-sectional area 48.As a result, light, in particular the first illumination light coupled to the proximal end 46, is guided to a larger cross-sectional area 40. This allows flat elements to be illuminated and / or illuminated. Light, in particular the first illumination light, strikes the diffusion element 52 at the distal end 49. The light is homogenized and dispersed by the diffusion element 52. This achieves more uniform illumination of the conversion element 14 and subsequently improves image recording quality. The diffusion element 52 is a milky Plexiglas plate that is at least as large as the second cross-sectional area 50.

[0115] The conversion element 14 is also plate-shaped and rests on the diffusion element 52. The function of the conversion element 14 is explained in more detail with reference to Fig. 7 and Fig. 8. Basically, the conversion element 14 is designed to at least partially convert light, in particular the first illumination light, with the first wavelength 16 into light, in particular second illumination light, with the second wavelength 18, wherein the first wavelength 16 and the second wavelength 18 are different. The second wavelength 18 comprises a wavelength from the near-infrared range. The first wavelength 16 comprises a wavelength from the visible range. The first illumination light at least predominantly comprises light from the visible range. The conversion element 14 is designed to at least partially convert light from the visible range into light from the infrared range.For this purpose, the conversion element 14 has fluorescent properties. The conversion element 14 is designed as a fluorescent Plexiglas plate and is covered with a matte film on both main sides, i.e., the sides that are illuminated and / or from which light is at least primarily emitted, particularly in the direction of the optical target 20. The matte film enables homogeneous radiation in the direction of the optical target 20 and couples out the infrared radiation more efficiently.

[0116] The conversion element 14 is approximately the same size as the diffusion element 52. Both elements 14, 52 are inserted together into a receiving slot 142 of the test device 10, in particular into the light path of the light with the first wavelength 16, in particular the first illumination light. If necessary, additional elements can be inserted into the receiving slot 142 and / or at least one of the elements 14, 52 can be replaced. For this purpose, the test device 10 comprises a detachably attachable closure plate 144, which can be fastened by means of screws. The closure plate 144 is arranged on a lateral side of the test device 10, in particular of the screen 38.

[0117] The optical target 20 is arranged at a distance from the conversion element 14 and is also plate-shaped. The distance can be, for example, 1 cm to 20 cm, in particular 2 cm to 10 cm, preferably 3 cm to 8 cm. In addition, the optical target 20 is movably mounted. For this purpose, the optical target 20 comprises two handles 138 on two opposite sides. The optical target 20 also has a smaller area than the conversion element 14, so that the main surface of the optical target 20, which is illuminated in particular by means of illumination light, can be moved parallel to the main surface of the conversion element 14, from which light comprising the first wavelength 16 and the second wavelength 18 is emitted. As a result, the calibration pattern 54 of the optical target 20 can be aligned with respect to the image acquisition unit 64, in particular the image acquisition devices 66, 68, 88, 90, 114.The optical target 20 is mounted in a bearing device 136. The bearing device 136 is a plain bearing device and has a slot-shaped design. A rubber coating 140 of the bearing device 136 is in contact with the optical target 20. The rubber coating 140 is provided on all side walls 148 into which the bearing device 136 is recessed in a slot-like manner. The side walls 148 define a cavity 150 into which the light of the first illumination light and the second illumination light and / or light comprising the first wavelength 16 and / or the second wavelength 18 is guided. The handles 138 are removable, so that when at least one of the handles 138 is removed, the optical target 20 can be inserted into the bearing device 136. The optical target 20 comprises two glass plates 152, in the center of which a film 154 is arranged, on which the calibration pattern 54 is provided and / or which comprises the calibration pattern 54. See also Fig. 9. Fig.9 shows a schematic sectional view of the optical target 20. The glass plates 152 serve to protect the film 154 from damage and / or to facilitate handling of the film 154, in particular of the calibration pattern 54. Alternatively or additionally, the calibration pattern 54 can be provided directly on the conversion element 14 and / or the optical target 20 can be provided integrated with the conversion element 14 (not shown).

[0118] The holder 24 extends distally from the side walls 148. The holder 24 is designed, in particular, to be reduced in mass and / or optimized in mass. The holder 24 comprises a spacer 28 and a coupling section 32. The spacer 28, in particular the holder 24, extends only on two sides and / or has recesses 146.

[0119] This allows weight to be saved. The recesses 146 can, for example, be sawn and / or milled out of aluminum plates. The coupling section 32 is arranged at a distal end of the spacer 28. At the distal end, in particular by means of the coupling section 32, the inspection device 10 is coupled to the image acquisition unit 64. The holder 24 is configured to bear the dead weight of the inspection device 10 in the coupled state shown. This means that the inspection device 10 is merely fastened to the image acquisition unit 64 and is held and / or supported by it. The spacer 28 defines a distance 30 between the imaging device 26, in particular the image acquisition unit 64, and the optical target 20. As a result, the distance 30 can be reliably and repeatedly predictable.

[0120] The coupling section 32 is shown in more detail in Fig. 5. Fig. 5 shows a representation of a section of the testing device 10 at the distal end of the holder 24. Furthermore, Fig. 5 shows a holding section 156 of the image acquisition unit 64. To couple the testing device 10, the testing device 10 is fastened to the holding section 156 by means of the coupling section 32. The testing device 10, in particular the coupling section 32, comprises a projection 34 configured to hold the testing device 10 by engaging behind it. The projection 34 engages behind a section of the holding section 156 of the image acquisition unit 64.

[0121] For this purpose, the holder section 156 can comprise, for example, a circumferential groove 158 that is rounded. Furthermore, the testing device 10, in particular the coupling section 32, comprises a movable holding element 36 that is configured to selectively fix the holder 24 to the medical imaging device 26 to be tested. In this case, the holding element 36 is designed as a rotatable fixing screw that can be rotated in a thread provided on the coupling section 32. By turning the screw, the testing device 10 is fixed and / or clamped to the imaging device 20. In particular, the holding section 156 is clamped between the projection 32 and the holding element 36.To couple, the user can first insert the projection 32 into the circumferential groove 158 so that the projection 32 partially engages behind the holding section, and then rotate the testing device 10 around the projection 32 while the projection remains in contact with the holding section. This allows the user to move the holding element 36 toward the holding section 156. In the correct position, which is adjustable as needed, the user can fix the testing device by operating the movable holding element 36. The projection 32 and the holding section 156 can form a dovetail-like connection.

[0122] In general, the testing device 10 is designed to be compact and easy to handle. It weighs, for example, between 0.1 kg and 20 kg, in particular between 1 kg and 10 kg, preferably between 2 kg and 5 kg. Furthermore, the length between the fiber optic connection 42 and the coupling section 32 is, for example, between 0.1 m and 2 m, in particular between 0.2 m and 1.3 m, preferably between 0.3 m and 0.8 m. In particular, the testing device 10 is shorter than the image acquisition unit 64. Furthermore, the testing device 10 is at least predominantly made of aluminum and / or a plastic, in particular a frame of the testing device 10. In particular, the material is easy to clean, disinfect, and / or autoclave.

[0123] Fig. 7 shows a schematic representation of the functional principle of the testing device 10. Light in the first spectral range 70 comprising the first wavelength 16, in particular first illumination light, is provided and guided to the conversion element 14. The conversion element 14 transmits this light at least partially. In addition, the conversion element 14 converts light with the first wavelength 16, in particular the first illumination light, into light in the second spectral range 72 comprising the second wavelength 18, in particular the second illumination light. This is shown in more detail in Fig. 8 using an exemplary schematic representation of an intensity distribution. This shows the intensity I plotted against the wavelength A. It is understood that the intensity distribution shown is not based on an actual measurement of an emission spectrum of the illumination device 74 and / or the conversion element 14.The distribution is to be understood as an example and merely serves to explain the functional principle in more detail. Actual emission spectra can sometimes deviate significantly from the intensity distribution shown. Fig. 8 shows a diagram with the wavelength plotted on the abscissa 160 and the light intensity plotted on the ordinate 162. A first distribution 168 of the first illumination light is shown as an example in a solid line and a second distribution 170 of the second illumination light is shown in a dashed line. The first distribution 168 is predominantly within the first spectral range 70 and includes the first wavelength 16, which is also within the first spectral range 70. The second distribution 170 is predominantly within the second spectral range 72 and includes the second wavelength 18, which is also within the second spectral range 72.The first spectral range 70 corresponds to the wavelength range of visible light 164, approximately between 380 nm wavelength and 780 nm wavelength. The second spectral range 72 corresponds to the wavelength range of near-infrared light 166, approximately between 780 nm wavelength and 3000 nm wavelength. The conversion element 14 converts the light with the first wavelength 16 at least partially into light with the second wavelength 18 through fluorescence and / or phosphorescence, in particular luminescence. Consequently, the conversion element 14 converts light in the visible range 164 into light in the near-infrared range 166. By providing the conversion element 14, there is no need to provide an illumination device that predominantly emits light in the wavelength range of the near-infrared light 166. The conversion element 14 can comprise multiple elements that convert light by means of luminescence.This allows a wider second distribution 170 comprising multiple wavelength peaks to be provided.

[0124] Returning to Fig. 7, it can be seen that after the light in the first spectral range 70 has passed through the conversion element 14, light in the first spectral range 70 and in the second spectral range 72 is present. This light is guided to the optical target 20, in particular for illuminating the latter. Consequently, at least one calibration image 22 can be acquired by means of the image acquisition unit 64. Preferably, at least one calibration image 22 is acquired by means of each of the image acquisition devices 66, 68, 88, 90. This means that calibration images 22 are acquired in the spectral range of visible light and near-infrared light. The geometric calibration of the image acquisition unit 64 can be checked using the calibration images 22. In particular, the optical target 20 comprises the calibration pattern 54, and at least one image of the calibration pattern 54 is acquired by means of the image acquisition unit 64.The image of the calibration pattern 54 can extend, for example, in sections across various calibration images 22, as will be shown below. The geometric calibration can be verified using the image of the calibration pattern 54 in the overlay representation 82.

[0125] Fig. 10 shows an embodiment of the calibration pattern 54. The calibration pattern 54 comprises a line 56 and / or a cross 58. The calibration pattern 54 comprises a central rectangular cross 59 with elongated arms 60, the center of which can be arranged in the center of the calibration image 22 and which divides the calibration image 22 into four quadrants 62. See Fig. 11 and Fig. 12. In each of the four quadrants 62, a further rectangular cross 58 with elongated arms 60 is arranged, the center of which is each arranged in a central region of the corresponding quadrant 62. Although the calibration image 22 is divided into four quadrants 62, the calibration pattern 54 can also be divided into the four quadrants 62 for the sake of simplicity. The calibration pattern 54 is arranged in a central region of the optical target 20. The calibration pattern 54 comprises elongated pattern sections (e.g., the line 56 and / or the elongated arms 60).This can be used to check for an offset of the image of the calibration pattern 54 in the overlay display 82. If the offset is too large, the geometric calibration is insufficient.

[0126] Before performing the geometric calibration check, the optical target 20, in particular the calibration pattern 54, can be aligned relative to the image acquisition unit 64, in particular the input optics 130. For this purpose, the optical target 20 is grasped by the user at the handles 138 and the calibration pattern 54 is aligned using an alignment aid 92. See Fig. 11. Fig. 11 shows a representation of a calibration image 22, comprising an image of the calibration pattern 172, and the alignment aid 92. The representation is shown on the display device 78 during the alignment. That is, the display device 78 is configured to display the alignment aid 92. The calibration image 22 is acquired by only one of the image acquisition devices 66, 68, 88, 90. In particular, a sequence of calibration images 22, in particular a video, is displayed during the alignment.When the user moves the calibration pattern 54, they can view the representation on the display device 78. This allows them to see how the calibration pattern 54 is arranged relative to the alignment aid 92. In a good alignment, the image of the central cross 59 and the alignment aid 92 are displayed at least predominantly overlapping. In this alignment, the image of the calibration pattern 172, in particular of the central cross 59, is arranged at least substantially in the center of the calibration images 22. Thus, the image of the cross 59 also passes through the center of the overlay representation 82. In the example shown, the alignment aid 92 comprises a central cross with elongated arms.

[0127] Fig. 12 shows the calibration representation 80, which is based on a first calibration image 180 and a second calibration image 182. The calibration representation 80 is divided into four quadrants 62. The display device 78 is configured to display the calibration representation 80 based on the calibration images 22, 180, 182 to the user. The first calibration image 180 was acquired by the first image acquisition unit 66, and the second calibration image 182 was acquired by the second image acquisition unit 68. The calibration images 180, 182 were thus acquired in different spectral ranges. The calibration representation 80 includes the overlay representation 82. The overlay representation 82 is designed like a chessboard 169. This means that the overlay representation 82 comprises sections 84 of the first calibration image 180 and the second calibration image 182 arranged alternately next to one another in two different spatial directions.The sections 84 of the first and second calibration images 180, 182 are each offset by a whole section 84 in successive rows of the checkerboard 169. The overlay representation 82 comprises image sections from various image capture devices 66, 68, which were combined to form the overlay representation 82. As can be seen in Fig. 14, an image of the calibration pattern 54 can also be combined from the sections 84. However, since the sections 84 originate from images of different image capture devices 66, 68, which can image the optical target 20, in particular the calibration pattern 54, slightly differently, an offset 184 can occur between sections of the image of the calibration pattern 54. The offset 184 is a measure of the quality of the geometric calibration. The offset 184 is smaller if the geometric calibration is better.The calibration representation 80 comprises different image areas 106 in which the geometric calibration check is performed. For this purpose, a check aid 94 (see Figs. 13, 14, 15, 16) can be moved into the image areas 106. A check sequence for checking the geometric calibration is then performed in each of the image areas 106. First, a check sequence is performed in a central area 108 of the calibration representation 80. Subsequently, further check sequences are performed in a central area 110 of each of the quadrants 62 of the calibration representation 80.

[0128] To carry out a test method, in particular the verification process, an enlarged view 112 (see Fig. 14) can be generated. The enlarged view 112 is based on a section 113 of the calibration view 80. Using the enlarged view 112, the user can more easily carry out the verification process, in particular, better estimate the size of the offset 184. In the enlarged view 112, central regions 110 of the quadrants 62 of the calibration view 80 are each shown in a region of a corner of the enlarged view 112. This means that the enlarged view 112 includes an image of the cross 58 of the calibration pattern 54 in each corner region. This allows the geometric calibration to be checked in five regions in the enlarged view 112.

[0129] Fig. 13 shows an example of the verification aid 94. The verification aid 94 frames a verification area 94 and thereby defines a tolerance range 98 for checking the geometric calibration. The verification aid 94 comprises a verification frame 99 that defines an edge area of ​​the verification aid 94. The section 101 of the frame 99 defines the tolerance range 98. Tiles can be seen in Fig. 13. Each of the tiles corresponds to a pixel 174. The tiles are not to be confused with the squares of the chessboard 169. Each square of the chessboard 169 comprises several pixels 174. The frame is 4 pixels wide. The width can be changed depending on the pixel size and / or resolution of the display device 78. The frame should be clearly visible to the user in a representation.The verification aid 94, in particular the tolerance range 98, extends in one spatial direction over at least 5, preferably at least 10 pixels and in a spatial direction perpendicular thereto over at least 5, preferably at least 18 pixels.

[0130] Fig. 14 shows a schematic representation of the enlarged representation 112 of the calibration representation 80, in particular of the overlay representation 82 and / or the checkerboard 169, comprising an overlay of the verification aid 94 and the image of the calibration pattern 172. The sections 84 of the respective calibration images 22 used for the overlay representation 82, in particular of the first calibration image 180 and the second calibration image 182, at least partially depict the calibration pattern 54. This may mean that the representation includes the overlay representation 82 and the image 172 of the calibration pattern 54. The spatially adjacent sections 84 of the first calibration image 180 and the second calibration image 182 are included such that the image 172 of the calibration pattern 54 is shown section by section in the spatially adjacent sections 84 of the first calibration image 180 and the second calibration image 182.As a result, the offset 184 of the image 172 of the calibration pattern 54 occurs between the sections 84. In a theoretically ideal geometric calibration, the offset 184 is no longer recognizable and / or at least substantially no offset 184 is present. In the example shown, the calibration pattern 54 comprises the central cross 59, and the magnified representation 112 comprises an image of the cross 59 depicted with a section-wise offset 184. Furthermore, offset images of the crosses 58 can be seen in the corner regions of the magnified representation 112. The geometric calibration can be checked wherever an offset 184 is visible in the representation 112.

[0131] For this purpose, the verification aid 94 is displayed in the calibration representation 80. The verification aid 94 is then moved in the calibration representation 80 such that a first section 102 of the image of the calibration pattern 54 lies within the verification area 96, wherein the first section 102 originates from the first calibration image 180. A check is then carried out to determine whether the verification aid 94 can be moved such that, in addition to the first section 102, a second section 104 of the image of the calibration pattern 54 lies within the verification area 96, wherein the second section 104 originates from the second calibration image 182. The verification of the geometric calibration is assessed as positive if the verification aid 94 can be moved such that, in addition to the first section 102, the second section 104 of the image of the calibration pattern 54 lies within the verification area 96, which originates from the second calibration image 182.The user can perform the inspection using control commands initiated via input device 86. They can move the inspection aid, for example, pixel by pixel to the right or left, up or down, to perform the inspection. Alternatively or additionally, a system 120 can be provided (see Fig. 1) by means of which the inspection and / or a test procedure can be carried out semi-automatically and / or automatically. A positive evaluation of the geometric calibration means that a spatial representation by means of the image capture devices 66, 68, 88, 90 is of sufficiently good quality. Furthermore, a fluorescence image representation can be sufficiently well superimposed on the spatial representation.

[0132] Fig. 15 shows an example in which the geometric calibration is evaluated positively, based on a section of the calibration representation 80. Fig. 16 shows an example in which the geometric calibration is evaluated negatively, based on a section of the calibration representation 80. According to Fig. 15, the verification aid 94 can be moved such that, in addition to the first section 102, the second section 104 of the image 172 of the calibration pattern 54 lies within the verification area 96, wherein the first section 102 originates from the first calibration image 180 and the second section 104 originates from the second calibration image 182. The sections 102, 104 are therefore within the tolerance range 98.

[0133] According to Fig. 16, the verification aid 94 cannot be moved such that, in addition to the first section 102, the second section 104 of the image 172 of the calibration pattern 54 lies within the verification area 96, wherein the first section 102 originates from the first calibration image 180 and the second section 104 originates from the second calibration image 182. Sections 102, 104 are therefore outside the tolerance range 98.

[0134] Fig. 17 shows a schematic representation of another embodiment of an overlay representation 82' of a calibration representation 80'. The majority of the features correspond to the explanations for the calibration representation 80. Therefore, differences will be discussed primarily. The overlay representation 82' comprises a blend representation 225. The calibration representation 80', in particular the overlay representation 82' and / or the blend representation 225, is based on the first calibration image 180 and the second calibration image (182). The first calibration image 180 and the second calibration image 182 each comprise an image 172 of the calibration pattern 54. The second calibration image 182 is shown partially transparent and superimposed on the first calibration image. An offset 184 can therefore be seen along a line of the images 172 of the calibration pattern 54. The geometric calibration can be checked using the offset 184.Furthermore, the displayed verification aid 94 can be seen in the calibration representation 80'. The verification aid 94 is movable in the calibration representation 80 such that a first section 102' of the image of the calibration pattern 54 lies within the verification area 96, wherein the first section 102' originates from the first calibration image 180. By means of the verification aid, it can be verified whether, in addition to the first section 102', a second section 104' of the image 172 of the calibration pattern 54 can be arranged within the verification area 96, wherein the second section 104' originates from the second calibration image 182.

[0135] Fig. 18 shows a schematic flow diagram comprising several steps of a testing method. The testing method can be carried out using the testing device 10 and / or the system 100 and comprises the following steps: a step 201 of generating the first illumination light, which comprises light with the first wavelength 16; a step 202 of generating the second illumination light, which comprises light with the second wavelength 18 different from the first wavelength 16; a step 203 of supplying the first illumination light and the second illumination light to the optical target 20 for its illumination;a step 204 of recording the calibration images 22 of the target 20 by means of the medical imaging device 26 with the image acquisition unit 64, wherein the image acquisition unit 64 comprises the first image acquisition device 66, which is light-sensitive in the first spectral range 70, which includes the first wavelength 16, and the second image acquisition device 68, which is light-sensitive in the second spectral range 72, which is different from the first spectral range 70 and includes the second wavelength 18, wherein the image acquisition unit 64 has the geometric calibration of the first image acquisition device 66 and the second image acquisition device 68 with respect to their imaging ranges;and a step 205 of checking 205 the geometric calibration of the image acquisition unit 64 based on the calibration images 22 of the optical target 20. The generation 202 of the second illumination light comprises converting light of the first illumination light with the first wavelength 16 at least partially into second illumination light with the second wavelength 18 different from the first wavelength 16. The testing method can comprise at least one further step 206.;

[0136] Fig. 19 shows a schematic flow diagram comprising several steps of a verification process. The verification process comprises the following steps: a step 210 of capturing the first calibration image 180 by means of the first image capture device 66 and the second calibration image 182 by means of the second image capture device 68, so that they each image the calibration pattern 54; a step of creating the calibration representation 80 with the overlay representation 82, which comprises the spatially adjacent sections 84 of the first calibration image 180 and the second calibration image 182 such that the image of the calibration pattern 54 is represented in sections in the spatially adjacent sections 84 of the first calibration image 180 and the second calibration image 182; and a step of checking the geometric calibration based on the image of the calibration pattern 54 in the overlay representation 82.According to one embodiment, the verification process further comprises the following steps: a step 213 of displaying the verification aid 94 in the calibration representation 80, wherein the verification aid 94 frames the verification area 96 and thereby defines the tolerance range 98 for the verification; a step 214 of moving the verification aid 94 in the calibration representation 80 such that the first section 102 of the image of the calibration pattern 54 lies within the verification area 96, wherein the first section 102 originates from the first calibration image 180; and a step 215 of checking whether the verification aid 94 is movable such that, in addition to the first section 102, the second section 104 of the image of the calibration pattern 54 lies within the verification area 96, wherein the second section 104 originates from the second calibration image 182. The verification process may comprise at least one further step 216.

[0137] Fig. 20 shows a schematic flow diagram comprising several steps of a preparation process. The preparation process includes the following steps: a step 220 of capturing the image of the optical target 20 with one of the image capture devices 66, 68, 88, 90; a step 221 of generating the representation of the target 20 based on the captured image; a step of displaying the alignment aid 92 for aligning the optical target 20 relative to the image capture unit 64; and a step of aligning the optical target 20 with the alignment aid 92 by moving the target 20. The preparation process can include at least one further step 224. List of Reference Symbols

[0138] 10 Test device

[0139] 12 Light supply

[0140] 14 Conversion element

[0141] 16 first wavelength

[0142] 18 second wavelength

[0143] 20 optical target

[0144] 22 Calibration image

[0145] 24 bracket

[0146] 26 medical imaging device

[0147] 28 spacers

[0148] 30 distance

[0149] 32 coupling section

[0150] 34 lead

[0151] 36 Holding element

[0152] 38 reflective screen

[0153] 40 cross-sectional area

[0154] 42 Fiber optic connection

[0155] 44 light guides

[0156] 46 proximal end

[0157] 48 first cross-sectional area

[0158] 49 distal end

[0159] 50 second cross-sectional area

[0160] 52 Diffusion element

[0161] 54 calibration samples

[0162] 56 Line

[0163] 58 Cross

[0164] 59 central cross

[0165] 60 arms

[0166] 62 quadrants

[0167] 64 image acquisition unit

[0168] 66 first image capture device

[0169] 68 second image capture device

[0170] 70 first spectral range

[0171] 72 second spectral range

[0172] 74 Lighting device

[0173] 78 Display device Calibration display Overlay display Section

[0174] Input device third image capture device fourth image capture device alignment aid

[0175] Verification aid Verification range Tolerance range

[0176] Review framework system

[0177] Excerpt first section second section

[0178] Image area central area central area of ​​a quadrant magnification section of the calibration image further image acquisition device system holding arm

[0179] Equipment trolley

[0180] Light supply connection housing

[0181] Entrance optics first image sensor second image sensor bearing device handle

[0182] Rubberized receiving slot

[0183] Closing plate recess side wall cavity glass plates

[0184] film

[0185] holding section

[0186] Circumferential groove

[0187] abscissa

[0188] ordinate

[0189] Wavelength range of visible light

[0190] Wavelength range of near-infrared light first distribution

[0191] Chessboard second distribution

[0192] Image of the calibration pattern

[0193] Pixel first calibration image second calibration image

[0194] Offset

[0195] Step

[0196] Step

[0197] Step

[0198] Step

[0199] Step further step

[0200] Step

[0201] Step

[0202] Step

[0203] Step

[0204] Step

[0205] Step further step

[0206] Step

[0207] Step

[0208] Step

[0209] Step further step

[0210] Transition display

Claims

Claims 1. A testing device (10), comprising: a light feed (12) configured to guide first illumination light; a conversion element (14) configured to at least partially convert light of the first illumination light having a first wavelength (16) into second illumination light having a second wavelength (18) different from the first wavelength (16); and an optical target (20) arranged such that first illumination light and second illumination light can be fed to it to illuminate the target (20) for capturing a calibration image (22) of the optical target (20).

2. Test device (10) according to claim 1, wherein the second wavelength (18) comprises a wavelength from the infrared range, in particular from the near-infrared range.

3. Test device (10) according to claim 1 or 2, wherein the first illumination light comprises at least predominantly light from the visible range.

4. Test device (10) according to one of the preceding claims, wherein the conversion element (14) is configured to convert light from the visible range at least partially into light from the infrared range.

5. Test device (10) according to one of the preceding claims, wherein the conversion element (14) has luminescent properties, wherein the conversion element (14) is configured to convert, by means of the luminescent properties, light of the first illumination light having the first wavelength (16) at least partially into the second illumination light having the second wavelength (18) different from the first wavelength (16).

6. Test device (10) according to one of the preceding claims, further comprising a holder (24), wherein the holder (24) is provided to make the test device (10) coupleable to a medical imaging device (26) to be tested.

7. The test device (10) of claim 6, wherein the holder (24) comprises a spacer (28) defining a distance (30) between the medical imaging device (26) to be tested and the target (20).

8. Test device (10) according to claim 7, wherein the holder (24) is configured to support the dead weight of the test device (10) when coupled to the medical imaging device (26) to be tested.

9. Test device (10) according to claim 7 or 8, wherein the holder (24) comprises a coupling portion (32) for coupling to the medical imaging device (26) to be tested, wherein the coupling portion (32) comprises a projection (34) which is configured to hold the test device (10) by engaging behind it.

10. The test device (10) according to claim 9, wherein the coupling portion (32) further comprises a movable holding element (36) configured to selectively fix the holder (24) to the medical imaging device (26) to be tested.

11. Test device (10) according to one of the preceding claims, wherein the light supply (12) comprises a reflective screen (38) which is designed to guide the illuminating light to the conversion element (14), wherein the screen (38) has a cross-sectional area (40) which increases in the direction of the conversion element (14).

12. Test device (10) according to one of the preceding claims, further comprising a light guide connection (42) to which a light guide (44) can be connected in such a way that first illumination light guided in the light guide (44) can be coupled into the test device (10).

13. Test device (10) according to one of claims 11 or 12, wherein the optical fiber connection (42) is arranged at a proximal end (46) of the reflective screen (38) having a first cross-sectional area (48), and wherein the conversion element (14) is arranged at a distal end (49) of the reflective screen (38) having a second cross-sectional area (50), wherein the second cross-sectional area (50) is larger than the first cross-sectional area (48).

14. Test device (10) according to one of the preceding claims, wherein the light supply (12) comprises a diffusion element (52) which is configured to scatter and homogenize light of the first illumination light.

15. Test device (10) according to one of the preceding claims, wherein the optical target (20) is movably mounted.

16. Test device (10) according to one of the preceding claims, wherein the optical target (20) comprises at least one calibration pattern (54), and wherein the calibration pattern (54) can be imaged on the calibration image (22).

17. Test device (10) according to claim 16, wherein the calibration pattern (54) comprises at least one line (56) and / or a cross (58).

18. Test device (10) according to claim 16 or 17, wherein the calibration pattern comprises a central rectangular cross (59) with elongated arms (60), the center of which can be arranged in the center of the calibration image (22), and which divides the calibration image (22) into four quadrants (62), wherein in each of the four quadrants (62) there is arranged a further rectangular cross (58) with elongated arms (60), the center of which is arranged in a central region of the corresponding quadrant (62).

19. Test device (10) according to one of the preceding claims, wherein the optical target (20) is integrated with the conversion element (14).

20. A system (100) comprising a testing device (10) according to any one of the preceding claims; and a medical imaging device (26) having an image acquisition unit (64), wherein the image acquisition unit (64) comprises: a first image acquisition device (66) that is light-sensitive in a first spectral range (70) that includes the first wavelength (16); and a second image acquisition device (68) that is light-sensitive in a second spectral range (72) that is different from the first spectral range (70) and includes the second wavelength (18); wherein the image acquisition unit (64) has a geometric calibration of the first image acquisition device (66) and the second image acquisition device (68) with respect to their imaging ranges;wherein the image acquisition unit (64) is configured to record calibration images (22) of an optical target (20), and wherein the geometric calibration of the image acquisition unit (64) can be checked using the calibration images (22); 21. System (100) according to claim 20, further comprising a lighting device (74) which is connected and / or connectable to the light supply (12).

22. The system (100) of claim 21, wherein the illumination device (74) is connectable to the imaging device (26) in an imaging mode of operation for providing illumination light during image acquisition.

23. The system (100) of any one of claims 20 to 22, further comprising a display device (78) configured to display a calibration representation (80) based on the calibration images (22) for a user.

24. The system (100) of claim 23, wherein the calibration images (22) comprise at least one first calibration image (180) acquired by the first image acquisition device (66) and at least one second calibration image (182) acquired by the second image acquisition device (68); and wherein the calibration representation (80) comprises an overlay representation (82) based on the first calibration image (180) and the second calibration image (182).

25. The system (100) of claim 24, wherein the overlay representation (82) comprises spatially juxtaposed portions (84) of the first calibration image (180) and the second calibration image (182).

26. System (100) according to claim 24 or 25, wherein the overlay representation (82) comprises sections (84) of the first calibration image (180) and the second calibration image (182) arranged alternately next to one another in two different spatial directions.

27. System (100) according to one of claims 24 to 26, wherein the optical target (20) comprises a calibration pattern (54), and wherein the portions (84) of the respective calibration images (22) used for the overlay display (82) at least partially depict the calibration pattern (54).

28. System (100) according to one of claims 20 to 27, further comprising an input device (86) by means of which control commands for checking the calibration of the image acquisition unit (64) can be initiated by a user.

29. System (100) according to one of claims 23 to 28, wherein the display device (78) is configured to display an alignment aid (92) for aligning the optical target (20) relative to the image acquisition unit (64).

30. The system (100) according to any one of claims 20 to 29, wherein the image capture unit (64) further comprises: a third image capture device (88) that is light-sensitive in the first spectral range (70); and a fourth image capture device (90) that is light-sensitive in the second spectral range (72); and wherein a stereo image capture in the first spectral range (70) can be carried out by means of the first image capture device (66) and the third image capture device (88), and wherein a stereo image capture in the second spectral range (72) can be carried out by means of the second image capture device (68) and the fourth image capture device (90).

31. Testing method, in particular by means of a testing device (10) according to one of claims 1 to 19 and / or by means of a system (100) according to one of claims 20 to 30, comprising: generating first illuminating light, which comprises light with a first wavelength (16); generating second illuminating light, which comprises light with a second wavelength (18) different from the first wavelength (16); supplying the first illuminating light and the second illuminating light to an optical target (20) for illuminating it; recording calibration images (22) of the target (20) by means of a medical imaging device (26) with an image acquisition unit (64), wherein the image acquisition unit (64) has a first Image capture device (66) which is light-sensitive in a first spectral range (70) comprising the first wavelength (16), and a second image capture device (68) which is light-sensitive in a second spectral range (72) different from the first spectral range (70) and comprising the second wavelength (18), wherein the image capture unit (64) has a geometric calibration of the first image capture device (66) and the second image capture device (68) with respect to their imaging ranges; and checking the geometric calibration of the image capture unit (64) based on the calibration images (22) of the optical target (20); wherein generating the second illumination light comprises converting light of the first illumination light having the first wavelength (16) at least partially into second illumination light having the second wavelength (18) different from the first wavelength (16).

32. The testing method of claim 31, further comprising coupling the testing device (10) to the medical imaging device (26).

33. Testing method according to claim 31 or 32, further comprising connecting a lighting device (74) to the test device (10).

34. The testing method of claim 33, wherein the illumination device (74) is configured to be connected to the imaging device (26) in an imaging mode of operation for providing illumination light during image acquisition.

35. Test method for checking a geometric calibration of an image acquisition unit (64) based on a calibration image (22) of an optical target (20), in particular by means of a test device (10) according to one of claims 1 to 19 and / or by means of a system (100) according to one of claims 20 to 30, in particular a test method according to one of claims 31 to 34, wherein the image acquisition unit (64) comprises: a first image acquisition device (66); and a second image acquisition device (68); wherein the image acquisition unit (64) has the geometric calibration of the first image acquisition device (66) and the second image acquisition device (68) with respect to their imaging areas; wherein the image acquisition unit (64) is configured to record calibration images (22) of the optical target (20), and wherein the geometric calibration of the image acquisition unit (64) can be checked based on the calibration images (22);wherein the optical target (20) comprises at least one calibration pattern (54); and wherein the testing method comprises a verification sequence with the following steps: capturing a first calibration image (180) by means of the first image capture device (66) and a second calibration image (182) by means of the second image capture device (68) such that they each image the calibration pattern (54); creating a; Calibration representation (80) with an overlay representation (82) based on the first calibration image (180) and the second calibration image (182), wherein the overlay representation (82) comprises an image of the calibration pattern (54) at least in sections; and checking the geometric calibration based on the image of the calibration pattern (54) in the overlay representation (82).

36. Test method according to claim 35, wherein the overlay representation (82) comprises spatially adjacent sections (84) of the first calibration image (180) and the second calibration image (182) such that the image (172) of the calibration pattern (54) is represented at least in sections in spatially adjacent sections (84) of the first calibration image (180) and the second calibration image (182).

37. The test method according to claim 35 or 36, wherein the verification sequence further comprises: displaying a verification aid (94) in the calibration representation (80), wherein the verification aid (94) frames a verification area (96) and thereby defines a tolerance range (98) for the verification; moving the verification aid (94) in the calibration representation (80) such that a first section (102) of the image of the calibration pattern (54) lies within the verification area (96), wherein the first section (102) originates from the first calibration image (180); checking whether the verification aid (94) is movable such that, in addition to the first section (102), a second section (104) of the image of the calibration pattern (54) lies within the verification area (96), wherein the second section (104) originates from the second calibration image (182).

38. Test method according to claim 37, wherein the verification of the geometric calibration is evaluated as positive if the verification aid (94) is movable such that, in addition to the first portion (102), the second portion (104) of the image of the calibration pattern (54) lies within the verification area (96) originating from the second calibration image (182).

39. Testing method according to claim 37 or 38, wherein the checking aid (94) extends in one spatial direction over at least 5, preferably at least 10 pixels and in a spatial direction perpendicular thereto over at least 5, preferably at least 18 pixels.

40. Testing method according to one of claims 37 to 39, comprising further checking sequences for which the checking aid (94) is moved into different image areas (106) of the calibration display (80).

41. Testing method according to claim 40, wherein at least one verification sequence is performed in a central region (108) of the calibration representation (80); and wherein further verification sequences are performed in a central region (110) of each of the quadrants (62) of the calibration representation (80).

42. Testing method according to one of claims 35 to 41, generating an enlarged representation (112) of a section (113) of the calibration representation (80), so that central regions (110) of one of the quadrants (62) of the calibration representation (80) are each represented in a region of a corner of the enlarged representation (112).

43. The testing method according to any one of claims 35 to 42, further comprising a preparatory sequence comprising: capturing an image of the optical target (20) with one of the image capturing devices; generating a representation of the target (20) based on the captured image; displaying an alignment aid (92) for aligning the optical target (20) relative to the image capturing unit (64); and aligning the optical target (20) with the alignment aid (92) by moving the target (20).

44. The test method of claim 43, wherein the calibration pattern (54) comprises a central rectangular cross (58) with elongated arms (60), and wherein the alignment aid (92) comprises a rectangular cross (58) with elongated arms (60).

45. The testing method according to any one of claims 35 to 44, wherein the image capture unit (64) further comprises at least one further image capture device (114); and wherein the image capture devices (66, 68, 114) have a common geometric calibration with respect to their imaging areas; further comprising: checking the calibration of the image capture devices (66, 68, 114) in pairs.

46. ​​System (120) for performing a test method according to one of claims 31 to 45.

47. Program code comprising instructions which, when executed by a processor, cause a testing method according to any one of claims 31 to 45 to be carried out.

48. A computer program product comprising a machine-readable medium on which program code according to claim 47 is stored.

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