DE102021214722A1 - Method and device for generating images of an object - Google Patents

Abstract

The invention relates to a method and a device for generating at least one image of an object, comprising the steps:
- generating radiation with a swept-source radiation source (2), wherein radiation with different wavelengths is generated at different times,
- Radiation of the radiation into the object (10) through at least one chromatic lens (3),
- receiving the radiation reflected from the object (10) with at least one detection device (4) and detecting a time-specific intensity (I) of the received radiation,
- Assigning the time-specific intensity (I) detected by the detection device (4) to a pixel of the image at least as a function of the wavelength (λ1, λ2, λn) of the radiation assigned to the reception time.

Description

The invention relates to a method and a device for generating images of an object, in particular a transparent or semi-transparent object, more particularly an eye or a partial area of the eye.

The integrity of the corneal surface of the human eye, especially the epithelium, is guaranteed by the functional interactions of the cornea, conjunctiva and limbus in interaction with the tear film and the lid apparatus. Disturbances of this balance can be summarized in the disease group of surface diseases of the eye (Ocular Surface Diseases, OSD) and can be caused by lubricating disorders, scarring processes as a result of inflammation or thermal/chemical noxae, but also by diabetes mellitus, limbal stem cell deficits or meibomian gland dysfunction. For the diagnosis of such diseases and the monitoring of possible therapeutic successes, examination methods with subcellular resolution are desirable. The microscopic examination of deeper layers of the cornea, for example to distinguish between fungi, acanthamoeba and keratitis, is of high clinical relevance. Diseases that are associated with endothelial dysfunction also require subcellular investigation of these structures.

Using the technology of so-called laser scanning, the combination of Heidelberg Retina Tomograph (HRT) and Rostock Cornea Module (RCM), both of which are distributed by Heidelberg Engineering GmbH (Heidelberg, Germany), has proven itself worldwide for in-vivo examinations of this type established, with the RCM underlying technology in the DE 20 2005 009 189 U1 is described. Both devices (HRT, RCM) together enable the generation of a two-dimensional en-face image, which ideally shows tissue sections parallel to the surface. The depth from which the image originates can be roughly adjusted manually, which is very impractical given the resolution in the micrometer range. There are approaches based on taking these en-face images sequentially from different depths and registering them in a downstream process, whereby motion-related artefacts are also removed using image processing methods. That's how she describes it DE 10 2017 203 995 A1 an objective for a confocal microscopy device for generating images of an eye or a partial area of the eye, the objective comprising at least one optical element for beam guidance and/or shaping, the objective further having at least one means for changing a focal point position at least along an optical axis of the lens. In principle, any sectional images can then be generated from the volume reconstructed in this way.
Since the pure recording time for such an en-face single image of the cornea is 0.03 s, eye movements can occur during the recording time, which in turn places the highest demands on both the registration algorithms and the mechanical fixation of the eye when a subcellular resolution is to be achieved in imaging.

Also from the prior art is the document "Jeong D., Park S.J., Jang H., Kim H., Kim J. and Kim C.S., Swept-Source-Based Chromatic Confocal Microscopy, Sensors 2020, 20(24): 7347 " known. It describes a method for generating surface profiles.

The technical problem arises of creating a method and a device for generating images, in particular of an eye or a partial area of the eye, which enable images to be generated quickly, with high quality and with high resolution.

A method is proposed for generating images, in particular of a transparent or semi-transparent object, further in particular of an eye or a partial area of the eye. The proposed method comprises generating radiation with a swept-source radiation source, with radiation having different wavelengths being generated at different points in time. In particular, the swept-source radiation source can be used to generate radiation from a predetermined wavelength range in a wavelength sweep in a time interval with a predetermined length of time, in particular starting at a predetermined minimum wavelength and ending at a predetermined maximum wavelength. The radiation generated at a certain point in time during the wavelength run, i.e. the point-in-time-specific radiation, can be radiation from a wavelength range with a central wavelength and a predetermined bandwidth, this bandwidth being smaller than the bandwidth of the entire wavelength range that is run through in the explained wavelength run. The time-specific wavelength can correspond to the central wavelength of the time-specific radiation.

In the wavelength sweep, for example, the point-in-time-specific central wavelength can then be changed, starting at the predetermined minimum wavelength to the predetermined maximum wavelength, in particular continuously or continuously. in predetermined wavelength increments. The bandwidth of one of the time-specific radiation can be less than or equal to 5 nm, for example, preferably less than or equal to 1 nm. The minimum wavelength can be, for example, a wavelength of 450 nm or 780 nm or 1060 nm. The maximum wavelength can be, for example, a wavelength of 1095 nm, 1500 nm or 2000 nm. The bandwidth of the wavelength range that can be traversed in one wavelength run can also be 70 nm, for example. Of course, however, other values are also conceivable, in particular application-dependent values.

1. a) erneut Strahlung aus dem vorbestimmten Wellenlängenbereich beginnend bei der vorbestimmten minimalen Wellenlänge und endend bei der vorbestimmten maximalen Wellenlänge oder
2. b) Strahlung aus dem vorbestimmten Wellenlängenbereich beginnend bei der vorbestimmten maximalen Wellenlänge und endend bei der vorbestimmten minimalen Wellenlänge

erzeugt wird.It is also possible for the swept-source radiation source to be operated at a predetermined frequency, for example a frequency of 100 kHz, this frequency indicating how often the wavelength range is passed through per second. It is possible here for radiation from the predetermined wavelength range to be generated in a first wavelength sweep, beginning at the predetermined minimum wavelength and ending at the predetermined maximum wavelength, with either

1. a) renewed radiation from the predetermined wavelength range beginning at the predetermined minimum wavelength and ending at the predetermined maximum wavelength or
2. b) Radiation from the predetermined wavelength range beginning at the predetermined maximum wavelength and ending at the predetermined minimum wavelength

is produced.

The method also includes radiating the radiation into an examination object through at least one chromatic lens. A chromatic lens refers to a lens or an optical element through which the light of different wavelengths is refracted to different degrees. In other words, the chromatic lens produces a so-called chromatic aberration, ie an imaging error that is wavelength-dependent. In particular, the irradiation takes place through at least one chromatic lens with longitudinal chromatic aberration, the lens having different focal lengths for different wavelengths due to the longitudinal chromatic aberration. In particular, the focal points for different wavelengths are at different positions along the optical axis of the chromatic lens. A magnitude of the angle (scanning angle) between the optical axis of the chromatic lens and a direction of irradiation of the radiation into the object may be smaller than a predetermined threshold value, e.g., 40°. The optical axis and the irradiation direction can preferably be oriented parallel to one another. The irradiation direction can correspond to the main propagation direction of the radiation directed towards the object.

The method also includes receiving the radiation reflected from the object with at least one detection device and detecting/determining a time-specific intensity of the received radiation, the time-specific intensity designating the intensity of the radiation detected at the time of reception. The detection device can be designed as a photodiode, photomultiplier or as a photon detector. Of course, other embodiments of the detection device are also conceivable. The detection device can generate a signal, in particular an electrical signal, with at least one property of the signal representing or encoding the intensity of the reflected radiation.

The method also includes assigning the time-specific intensity of the reflected radiation detected by the detection device to a pixel of an at least one-dimensional, but preferably an optional two- or three-dimensional image at least depending on the wavelength of the radiation assigned to the reception time. In other words, the time of reception and then the wavelength of the radiation assigned to the time of reception are determined, which in turn is then used to assign the intensity detected at the time of reception, ie time-specific, to a pixel. An image can thus be generated by assigning the intensity detected at a point in time to a pixel and in particular determining the pixel coordinates of this pixel at least as a function of the wavelength of the radiation assigned to the point in time of reception. The wavelength of the radiation associated with the time of reception can be, in particular, the previously explained central wavelength of the radiation that is generated by the swept-source radiation source at the time of reception. However, depending on the radiation propagation time, it is also possible for the wavelength of the radiation assigned to the reception time to be the central wavelength of the radiation that was generated with the swept-source radiation source at a point in time that is a predetermined, in particular propagation-dependent, time period before the reception time .

The pixel coordinates, which are determined at least as a function of the wavelength of the radiation assigned to the time of reception, can in particular be the coordinate along a (first) image direction, which corresponds to an axial direction, ie the direction of incidence. If the radiation is directed through the chromatic lens into the object, this first image direction can therefore correspond to a depth direction in the object. In particular, it is thus possible to image information from different depths of the tissue of the object, in particular in the form of intensities of the radiation reflected from these different depths, into different pixels.

In a further method step, the image generated from the pixels in this way can be transmitted to a higher-level system and/or displayed on a corresponding display device.

In cooperation with the chromatic lens, the radiation generated in a wavelength sweep is focused to different positions along the optical axis of the chromatic lens, so that the reflected light is mainly reflected from this position, whereby the intensity of the reflected light in turn provides information about the tissue or the tissue Tissue properties at this position of focus. Since the swept-source radiation source performs a wavelength sweep very quickly in terms of time, the image can be generated quickly in terms of time. In particular, the method enables an image to be generated in a time period that can be significantly less than a millisecond. This in turn allows movement artifacts, for example the artifacts generated by a movement of the eye (saccades and microsaccades), to be reduced or completely eliminated during image generation. A further technical advantage is that the generation of radiation with the swept-source radiation source with different wavelengths does not require any moving parts. Radiation can thus be focused onto different focal point positions without moving parts, which on the one hand enables a simple mechanical structure, low production costs, but also very reliable and low-maintenance image generation. Due to the lack of moving parts, the process also enables very energy-efficient generation of images. Particularly due to the fact that there is no electromechanical scanner near the patient, e.g. for changing the focus, with a comparatively high operating voltage, e.g. for a piezo actuator, the approval of a medical device through which the method is carried out can be simplified in a further advantageous manner, especially since no high operating voltages are required on actuators.

The proposed method can be used in particular to generate a microscopic recording of a (partial) volume of the cornea of the eye, in which case rapid image generation is made possible, the fixation of the eye during a corresponding optical examination is simplified or avoided altogether. In particular, the method advantageously enables the generation of distortion-free images, in particular images free of movement artifacts. Due to the rapid generation, the use of image processing methods, for example for so-called post-processing and/or registration, must not be used or to a much lesser extent than before. Rather, such a post-processing of the images can be completely or largely omitted, which in turn enables images to be generated and displayed in real time. The method also improves patient comfort and patient acceptance due to the convenient and rapid imaging.

Since it is also possible to set different wavelengths with very high resolution using swept-source radiation sources (in other words, set wavelengths that are very closely spaced from one another), a high resolution of the generated image can be achieved in a further advantageous manner, in particular subcellular imaging be made possible, which was previously not possible with the explained, conventional slit lamp microscopy. The method thus enables, in particular, a distortion-free real-time display of corneal structures.

However, the method is also suitable for generating images in other scientific areas in which high-resolution volumes have to be examined. The method reduces the recording time by around two orders of magnitude and thus enables, for example, the imaging of very rapid cell changes or cell damage, especially in real time . In combination with a change in the irradiation direction, which will be explained in more detail below, the method also makes it possible to generate two-dimensional images, in particular so-called cross-sectional images, or even three-dimensional images of the object, in particular cross-sectional images through the cornea, where - as explained - a subcellular resolution is achieved can be. These enable an analysis of individual cell layers, in particular of the epithelium, the subbasal nerve plexus, the stroma and the endothelium. From a three-dimensional image, two-dimensional cross-sectional images with any orientation can subsequently be generated, which further improves diagnostics.

In particular, a generated image can be used for in-vivo diagnostics at the cellular level. Furthermore, it is also possible to separate the examination, ie the image generation, and the diagnosis. It is thus possible for the images to be taken using the proposed method by appropriately trained personnel and for a diagnosis then to be made subsequently by a doctor by having the generated image data analyzed by the doctor. Furthermore, due to the high resolution that can be achieved, a histological diagnosis can also be made without a biopsy. Depending on the area of application, however, it can be advantageous for the swept-source radiation source to generate wavelengths greater than or equal to 1300 nm.

• - Verändern einer Lage und/oder Orientierung der in das Objekt eingestrahlten Strahlung und
• - Einstrahlen der Strahlung in das Objekt mit verschiedenen Lagen und/oder Orientierungen.

In a further embodiment, the method further comprises the steps:

• - changing a position and/or orientation of the radiation radiated into the object and
• - Irradiation of the radiation into the object with different positions and/or orientations.

The position of the radiation radiated into the object can indicate the spatial position of a central ray of the radiated radiation. The orientation of the radiation radiated into the object can indicate the spatial orientation of this central ray. For example, the central beam can be a beam that is oriented concentrically to the central axis of symmetry or central axis of the irradiated radiation. If the irradiated radiation is represented by a straight line in a reference coordinate system, an orientation of the straight line can represent the orientation of the radiation and the position of the straight line can represent the position of the radiation. Changing the position of the radiation then also results in a change in the position of the straight line explained, and changing the orientation results in a change in the orientation of the straight line explained. By changing the position and/or orientation of the radiation, a scan angle, i.e. the angle between the optical axis of the chromatic lens and the radiation, and/or an offset between the optical axis of the chromatic lens and the radiation can be changed, in particular if the optical axis and the radiation are oriented parallel to each other.

It is thus possible, for example, for radiation with a first position and/or orientation and radiation with a further position and/or orientation to be oriented parallel or not parallel to one another. This advantageously makes it possible to generate two-dimensional or three-dimensional images of the object or of the partial area of the object.

For example, it is possible that by changing the position and/or orientation, pixels can be generated along a further image direction that differs from the first image direction explained above. The intensities generated after changing the position and/or orientation can in particular be assigned to pixels whose pixel coordinates are changed at least in relation to this further image direction. In this case, the position and/or orientation can be changed in particular with a suitable means for changing the position and/or orientation. Exemplary means are explained in more detail below. In other words, it is therefore possible for the focal point positions, which change during a wavelength sweep, to be changed along the optical axis of the chromatic lens when the position and/or orientation changes.

It is possible, for example, for the position to be changed perpendicularly to the previous direction of irradiation, ie shifted parallel to the previous direction of irradiation, as a result of which a two-dimensional sectional image, for example a sagittal section or a transverse section through the eye, can be generated. The two-dimensional or three-dimensional images that can be generated by the change can also be generated very quickly in terms of time, which in turn—as explained above—enables the generation of images with as few movement artifacts as possible, without distortion and in real time.

In particular, the position and/or orientation of the radiation along a spatial direction can be changed to generate a two-dimensional image. This can be done by a scanner, in particular a galvo scanner, a resonant scanner, but also by a scanner designed differently from these scanners, e.g. a polygon scanner or an acousto-optical modulator.

In a further embodiment, the position and/or orientation is changed along at least two different spatial directions. For example, it is possible that by changing along a first spatial direction, pixels can be generated along a second image direction, which differs from the first image direction explained above. It is also possible that by changing along a second spatial direction, pixels can be generated along a further image direction, which is different from the first image direction explained above and also from the second image direction explained above. This advantageously enables the generation of three-dimensional images, i.e. volume images, of the object or a part of the object. These can also be generated quickly in terms of time and thus as free of artifacts and distortion as possible.

It is possible for the two different spatial directions to be linearly independent of one another, in particular oriented perpendicularly to one another. The spatial directions and the irradiation direction can also be linearly independent of one another. For example, the two different spatial directions can in turn be oriented at right angles to the irradiation direction for irradiation into the object.

In order to generate a three-dimensional image, the position and/or orientation can be changed along a first spatial direction by a first scanner and along the further spatial direction by a further scanner. One of the two scanners can be a galvo scanner, while the remaining scanner can also be a galvo scanner, but also a resonant scanner or a scanner designed differently from these scanners, e.g. a polygon scanner or an acousto-optical modulator.

In a further preferred embodiment, the position and/or orientation of the irradiated radiation is changed along a first spatial direction with a so-called galvo scanner and the position and/or orientation of the irradiated radiation is changed along a further spatial direction with a further scanner. This has been explained previously.

To generate a two-dimensional image, it is possible, for example, for the generation of pixels along a first image direction (depth direction) to assign the intensity generated by the detection device to these pixels at least as a function of the wavelength of the radiation assigned to the time of reception. The pixels along the first image direction can also be referred to as a pixel stack, such a stack comprising at least 2 pixels. Since light is reflected from different depths of the object in a wavelength sweep, depth information can be generated along the direction of incidence in a wavelength sweep and encoded as intensities of pixels of the pixel stack.

In order to generate pixels along a second image direction, the position and/or orientation of the irradiated radiation can then be changed, in particular after exactly one or after a number of wavelength runs. After each change, another pixel stack can then be generated, for example, as explained above. Thus, for example, a pixel stack can be assigned to each position along a line, whereby a two-dimensional image is generated.

In order to generate a three-dimensional image, additional image points can be generated along a third image direction by again changing the position and/or orientation of the irradiated radiation. In particular, by changing along the first spatial direction, pixel stacks can be generated and assigned to different positions along a row, and by changing along the second spatial direction, pixel stacks can be generated and assigned to different positions along a column. In this case, each image line and image column position can be assigned a pixel stack.

For example, the position and/or orientation for generating pixel stacks along an image line can be generated by the resonant scanner or a galvo scanner and the position and/or orientation for generating pixel stacks along an image column can be generated by changing the galvo scanner. It is also possible for the change to generate pixel stacks in different image columns to take place only when a pixel stack has been generated for each position in the image line. The position and/or orientation of the irradiated radiation along the further spatial direction can be changed with a constant position and/or orientation of the irradiated radiation along the first spatial direction until a pixel stack has been generated for each position of an image line. The position and/or orientation of the irradiated radiation can then be changed along the first spatial direction, with the position and/or orientation of the irradiated radiation along the further spatial direction having a constant position and/or orientation of the irradiated radiation along the first spatial direction can be changed until a pixel stack has been generated for each position of the image line. It is possible that the further spatial direction is changed so quickly by the resonant scanner, for example, that an image can be generated with a predetermined line frequency, for example a line frequency from a range of 4 kHz (inclusive) to 12 kHz (inclusive). The first spatial direction can be changed with the galvo scanner so quickly that a predetermined refresh rate, for example from a range from 0.1 Hz (inclusive) to 2 kHz (inclusive), can take place.

The use of a galvo scanner and a resonant scanner for changing the beam alignment advantageously results in a device being able to be manufactured at low cost for carrying out the method, but at the same time a desired refresh rate can be guaranteed.

In a further preferred embodiment, the position and/or orientation of the irradiated radiation is changed after the swept-source radiation source has carried out at least one wavelength run, radiation from a predetermined wavelength range being generated in one wavelength run. This has already been explained above. In particular, the position and/or orientation can be changed after the swept-source radiation source has carried out exactly one wavelength sweep. It is also conceivable that the beam alignment is only changed after the swept source radiation source has carried out several, ie at least two, wavelength sweeps with the same position and/or orientation. In this case, the intensities of the pixels of the pixel stack detected during the multiple passes can be averaged over the number of multiple passes, for example. This advantageously results in the rapid generation of a two-dimensional or three-dimensional, high-resolution image with the features already explained above.

In a further embodiment, the swept-source radiation source generates radiation from the predetermined wavelength range in a first wavelength run, beginning at a predetermined minimum wavelength and ending at a predetermined maximum wavelength, with the position and/or orientation of the irradiated radiation being changed after this first wavelength run and the swept-source radiation source generates radiation from the predetermined wavelength range starting at the predetermined maximum wavelength and ending at the predetermined minimum wavelength in an immediately following wavelength sweep. This advantageously results in a particularly rapid generation of images, since immediately consecutive wavelength sweeps are used to generate image information that is encoded in different pixel stacks.

By changing the position and/or orientation, depth information can be generated from other areas of the object and imaged in pixels of a further pixel stack. If the beam direction is changed along exactly one spatial direction, a two-dimensional image can be generated, with intensities detected in a wavelength sweep being assigned to different pixels of a pixel stack and after a change in the position and/or orientation of the irradiated radiation, the intensities detected during a wavelength sweep are assigned to the Pixels of a further pixel stack are assigned, the pixels of the further pixel stack being different from the pixels of the first pixel stack, in particular having other pixel coordinates. The same applies to changes along two independent spatial directions.

In a further embodiment, the detection device is in the form of a photodiode, a photomultiplier or a photon detector. For example, what is known as an avalanche photodiode (APD) can be used as a detector as a photoelectron multiplier, which advantageously has a sufficiently high upper limit frequency. This can then enable the necessary dynamic properties for detecting intensities in the MHz range. However, other detection devices, in particular those with single-photon resolution, can also be used, for example so-called nanowire single-photon detection devices, multi-pixel photon counters or superconducting single-photon detection devices. The use of such detection devices results in a cost-effective production of a device for carrying out the method, in particular since no two-dimensional sensor chip is required for two-dimensional image generation.

It is possible that the method further comprises the creation of an OCT image of the object, ie the creation of an image by optical coherence tomography. In particular, the OCT image can be used to image the same object area/object volume that is imaged in the SS image (swept source image) generated with the evaluation device, with the SS image depending on the wavelengths associated with the various reception times Radiation generated image called. The OCT image and the SS image can then be co-registered, i.e. arranged in the correct position relative to one another, e.g. in a reference coordinate system. Image fusion can then be performed to produce a fused image that advantageously has the high axial resolution provided by the OCT image and the high lateral resolution provided by the SS image. Methods of co-registration and image fusion can be methods known to those skilled in the art.

• - mindestens eine Swept-Source-Strahlungsquelle,
• - mindestens eine chromatische Linse,
• - mindestens eine Detektionseinrichtung,
• - mindestens eine Auswerteeinrichtung,

wobei die Vorrichtung konfiguriert ist, ein Verfahren gemäß einer der in dieser Offenbarung erläuterten Ausführungsformen durchzuführen. Insbesondere kann mit der Swept-Source-Strahlungsquelle also Strahlung erzeugt werden, wobei zu unterschiedlichen Zeitpunkten Strahlung mit unterschiedlicher Wellenlänge erzeugt wird. Weiter kann die Strahlung derart erzeugt und in Richtung des Objekts gerichtet werden, dass diese durch die mindestens eine chromatische Linse in das Objekt eingestrahlt wird. Weiter kann mit der Detektionseinrichtung die aus dem Objekt reflektierte Strahlung empfangen werden. Weiter kann mit der Auswerteeinrichtung die von der Detektionseinrichtung detektierte zeitpunktspezifische Intensität zu einem Bildpunkt eines Abbilds mindestens in Abhängigkeit der Wellenlänge der dem Empfangszeitpunkt zugeordneten Strahlung zugeordnet werden. Die Vorrichtung kann hierbei selbstverständlich noch weitere optische Elemente zur Strahlführung und/oder -formung, beispielsweise Linsen, umfassen. Ferner kann die Vorrichtung mindestens eine, vorzugsweise jedoch zwei, Blendenvorrichtung(en), insbesondere Lochblenden, umfassen.Also proposed is a device for generating images of an object, in particular a transparent or semi-transparent object, more particularly an eye or part of the eye, comprising:

• - at least one swept source radiation source,
• - at least one chromatic lens,
• - at least one detection device,
• - at least one evaluation device,

wherein the device is configured to perform a method according to any of the embodiments discussed in this disclosure. In particular, radiation can thus be generated with the swept source radiation source, with radiation having different wavelengths being generated at different points in time. Furthermore, the radiation can be generated and directed in the direction of the object in such a way that it is radiated into the object through the at least one chromatic lens. Furthermore, the radiation reflected from the object can be received with the detection device. The evaluation device can also be used to assign the time-specific intensity detected by the detection device to a pixel of an image at least as a function of the wavelength of the radiation assigned to the reception time. The device can, of course, also include other optical elements for beam guidance and/or beam shaping, for example lenses. Furthermore, the device can comprise at least one, but preferably two, diaphragm device(s), in particular pinhole diaphragms.

The device thus makes it possible in an advantageous manner to carry out the method explained and thus to provide the advantages already explained. In particular, therefore, the method can be carried out with this device. The device is used for confocal imaging of the object.

In a further embodiment, the device comprises at least one device for changing the position and/or orientation of the irradiated radiation. This and corresponding advantages have been explained above. Exemplary devices for changing the beam orientation have also been explained above.

In a further embodiment, the detection device is designed as a photodiode or photomultiplier or as a photon detector. This and corresponding advantages have likewise already been explained above.

Since the radiation signals scattered back or reflected back for different wavelengths arrive at/in the detection device one after the other, it is no longer necessary to use a spectrometer to identify the intensities of individual wavelengths, nor is it necessary to use a camera with a two-dimensional chip as a detector. The use of a swept-source radiation source, which can be designed as a swept-source laser device, for example, allows the replacement of a mechanical scanner for imaging in the axial direction and at the same time increases the sensitivity compared to a structure with a radiation grating, since there is no Light is lost due to unused diffraction orders.

The device can also include a device for generating an OCT image, which can be arranged and/or designed such that the same object area/the same object volume is imaged by the OCT image as by the SS image. A merged image can then be determined by the evaluation device, as explained above.

In a further embodiment, the device comprises a beam splitter. The beam splitter can be arranged in such a way that radiation generated by the swept-source radiation source or a part thereof is radiated through the beam splitter to the object and radiation reflected from the object or a part thereof is radiated through the beam splitter to the detector.

The beam splitter is also designed as a polarization beam splitter, with the polarization beam splitter only radiating to the object the radiation generated by the swept-source radiation source which has predetermined first polarization properties, in particular a predetermined first polarization angle. Furthermore, only the radiation reflected from the object is radiated to the detection device by the polarization beam splitter, which radiation has predetermined further polarization properties, in particular a predetermined further polarization angle, which can be different from the first polarization angle. In particular, the first polarization properties and the further polarization properties can therefore be different from one another. The part of the radiation that does not have the predetermined polarization properties is not radiated to the object or not to the detection device and is reflected, for example.

The device also includes at least one optical element for changing the polarization properties of the radiation radiated into the object and/or the radiation reflected from the object. This optical element can be designed, for example, as a retardation plate that changes the polarization of the radiation passing through. Such a retardation plate can in particular be designed as a λ/4 plate. For example, by the optical element, a linear polarization generated by the swept-source radiation source and radiation transmitted through the beam splitter can be changed into a circular polarization, which radiation is then radiated into the object. Furthermore, the optical element can be used to change a circular polarization of the radiation reflected from the object into a linear polarization, with this radiation then being radiated from the beam splitter to the detection device. The swept-source radiation source can, for example, generate linearly polarized radiation with a first polarization angle, or the device can have an optical element for linear polarization of the radiation generated by the swept-source radiation source. The reflected radiation can be changed by the optical element into linearly polarized radiation with a further polarization angle, in which case this further polarization angle can be different from the first polarization angle, in particular can be different by 90°.

The use of a polarization beam splitter and the optical element advantageously enables a high intensity yield of the radiation generated by the swept source radiation source, in particular because the beam splitter compares the intensity of the radiation radiated into the object and/or the radiation reflected from the object e.g. to a 50/50 beam splitter is not changed or is only changed to a reduced extent. This in turn results in a high quality image.

In a further embodiment, the device comprises an optical element for compensating for a spherical aberration of the radiation radiated into the object. This element can therefore be designed to correct aspherically. In particular, the element is arranged and/or designed in such a way that a spherical aberration of the radiation caused by the object is compensated. In particular, radiation irradiated into the object can be influenced by the optical element in such a way that the spherical aberration of the radiation in the object is reduced or even completely avoided in comparison to irradiation without the optical element. This advantageously results in improved imaging by the proposed device.

In a further embodiment, the device comprises a receiving element which has or forms a receiving volume for at least part of the object.

The receiving element can be a contact element of the device for contacting the object. However, it is possible, in particular for imaging the eye, for a contact or immersion gel to be arranged between an object-side surface of the recording element, in particular the object-side surface which delimits the recording volume, and the object. In particular, its refractive index can be the same as the refractive index of the material of the object into which the radiation is radiated, or it can differ by no more than a predetermined amount, e.g. 10%, in order to prevent reflections of the radiation at the interface between the contact gel and the object to reduce. The recording element can, for example, have a concavely curved surface on the object side, which delimits the recording volume and through which the radiation radiated into the object passes. A radius of curvature can be selected depending on object properties. If the object is an eye, the radius of curvature can be 7.8 mm in particular. The receiving element can be designed in particular as a contact cap. Furthermore, the receiving element can be attached, in particular detachably, to a housing of the device or to a housing of an objective which includes the chromatic lens. The receiving element can therefore be an exchangeable element.

Furthermore, the receiving element can form the previously explained optical element for compensating for a spherical aberration. In this case, it is possible for a lens-side surface of the recording element, ie a surface facing away from the object-side surface explained above, through which the radiation radiated into the object passes, to be convexly curved.

Alternatively or cumulatively, the receiving element can form the previously explained optical element for changing the polarization properties of the radiation radiated into the object and/or the radiation reflected from the object, or this element can be attached to the receiving element, in particular releasably attached.

Alternatively or cumulatively, an object-side surface of the receiving element, in particular a concavely curved surface, which delimits the receiving volume, has a recessed or recessed area. This depression can be arranged in particular in a central area of the object-side surface, with an optical axis of the chromatic lens extending through this central area. The central area can be completely surrounded or bordered by a non-recessed area of the object-side surface.

The recessed area can in particular be arranged and/or designed in such a way that in the recessed area a Distance between an object which rests on the surface in a non-recessed area is provided. In particular, the thickness of a gel layer between the object and the receiving element in the depressed area can be greater in comparison to the remaining, ie not depressed area, of the object-side surface.

If the object-side surface is a concavely curved surface corresponding to, for example, a portion of a surface of a sphere having a predetermined first radius, the recessed area may be recessed with respect to that surface. The recessed area may also have a concavely curved surface, for example also corresponding to a portion of a surface of a sphere having a predetermined further radius, which further radius may be the same as or different from the first radius.

This advantageously means that reflections at the boundary between the recording element and the immersion gel have less of an effect on the image generated by the device, which means that a high quality of the image generated can be ensured.

A recording element for arrangement on or as part of an apparatus for generating images of an object described in this disclosure is also described. This receiving element can be further developed according to one or more aspect(s) explained in this disclosure and can represent an independent invention.

The field of application of the invention lies in particular in the fields of medicine, in particular medical technology, here for diagnosis. In relation to this, the proposed method can be used in the field of ophthalmology, e.g. for diagnosing the cellular structures of the cornea or the retina. It is also conceivable to use the method in dermatology, e.g. for melanoma diagnostics. Different central wavelengths are preferably used for different applications, e.g. from a range of 450 nm to 1100 nm for imaging the cornea, from a range from 800 nm to 2000 nm for imaging the retina and from a range of 900 for imaging in dermatological applications nm to 3000 nm. The method can also be used for quality assurance in laser-based refractive surgery. In biology it can be used for non-invasive observations of cellular changes in real time and in three-dimensional methods.

• 1 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung,
• 2 eine schematische Darstellung eines Schemas der Bilderzeugung eines zweidimensionalen Abbilds,
• 3 eine schematische Darstellung eines Schemas der Bilderzeugung eines dreidimensionalen Abbilds,
• 4 ein schematisches Flussdiagramm eines erfindungsgemäßen Verfahrens,
• 5 ein schematisches Blockschaltbild einer erfindungsgemäßen Vorrichtung,
• 6. einen schematischen Querschnitt durch ein Aufnahmeelement und
• 7 einen schematischen Querschnitt durch ein Aufnahmeelement einer weiteren Ausführungsform.

The invention is explained in more detail using exemplary embodiments. The figures show:

• 1 a schematic representation of a device according to the invention,
• 2 a schematic representation of a scheme for generating a two-dimensional image,
• 3 a schematic representation of a scheme for imaging a three-dimensional image,
• 4 a schematic flow chart of a method according to the invention,
• 5 a schematic block diagram of a device according to the invention,
• 6 . a schematic cross section through a receiving element and
• 7 a schematic cross section through a receiving element of a further embodiment.

In the following, the same reference symbols designate elements with the same or similar technical features.

1 shows a schematic block diagram of a device 1 according to the invention for generating an image of an object. An exemplary embodiment of the device 1 for generating an image of an eye 10 is shown here, although the device 1 can also be used to generate images of other objects, in particular transparent or semi-transparent objects. The device 1 comprises a swept-source radiation source 2, a chromatic lens 3, a detection device 4 and an evaluation device 5. The evaluation device 5 can be designed, for example, as a computing device which can include a microcontroller or an integrated circuit or as such can be trained.

It is also shown that the device 1 includes lenses 6 . Also includes the device 1 pinhole 7. The device 1 is designed such that the radiation generated by the swept-source radiation source 2 through a first pinhole 7a and a first lens 6a, through a beam splitter 8 to a device 9 for changing the Position and / or orientation of the radiation radiated into an eye 10 is radiated. The radiation radiated into the eye, in particular its position and/or orientation, is 1 symbolized by an arrow 13, this arrow being oriented concentrically to the axis of symmetry of the beams radiated from the device 1 into the eye 10 and from the device 1 towards the eye 10. The beam splitter 8 and the device 9 for changing tion are also components of the proposed device 1. From the device 9 for changing, the radiation is radiated through the chromatic lens 3, a second lens 6b and through a third lens 6c designed as an objective into an eye 10. Radiation reflected from/out of the eye is reflected through the objective 6c, the second lens 6b and the chromatic lens 3 and the device 9 for changing the position and/or orientation to the beam splitter 8 and from this then through a further lens 6d and a further one Pinhole 7b directed to a detection device 4. Depending on the intensity of the radiation reflected from the eye, this generates an electrical signal which is transmitted to the evaluation device 5, which assigns the detected intensity to a pixel of an image to be generated, this assignment being at least dependent on the wavelength of the signal assigned at the time of reception radiation occurs. Furthermore, the assignment can also take place as a function of the position and/or orientation of the radiation radiated into the eye, which is set by the device 9, in particular at the time of reception.

In 1 is represented by different wavelengths λ1, λ2, ..., λn that the radiation radiated into the eye is focused at different focal points and is then also reflected by these different focal points. A dotted line represents radiation with a first wavelength λ1, a dash-dotted line represents radiation with a second wavelength λ2 and a broken line represents radiation with a further wavelength λn. Thus, in 1 the effect of the longitudinal chromatic aberration can also be seen.

The entirety of the first lens 6a and the first pinhole diaphragm 7a is used in a known manner to parallelize the radiation generated by the swept-source radiation source 2 . The entirety of the second pinhole diaphragm 7b and the additional lens 6d is used in a known manner to focus parallel radiation. The second lens 6b and the objective 6c are used in a known manner to adjust the position of a focal point, ie the position of a focal point along the direction of incidence, which can be oriented parallel to the optical axis of the lenses 3, 6b, 6c. The swept-source radiation source 2 can in particular be embodied as a swept-source laser.

It is of course also conceivable that the swept-source radiation source 2 is optically connected to the first lens 6a via a glass fiber, with radiation generated by the swept-source radiation source 2 being coupled into the glass fiber and the radiation coupled out of the glass fiber through the first lens 6a is parallelized. Furthermore, the detection device 4 can also be optically connected to the further lens 6d via a glass fiber, with radiation being coupled into the glass fiber through the further lens 6d and coupled out of the glass fiber to the detection device 4 . As a result, the pinholes 7a, 7b can be omitted.

It is also conceivable that the swept-source radiation source 2 and the detection device 4 are coupled to the device 9 for modification via a fiber-optic-based beam splitter, with radiation generated by the swept-source radiation source 2 being coupled into the fiber-optic-based beam splitter via a first interface and is coupled out to device 9 via a second interface of the glass fiber-based beam splitter. Reflected radiation can then be coupled back into the glass fiber-based beam splitter via the second interface and coupled out of it via a third interface towards the detection device 4 . The glass fiber-based beam splitter can in particular be designed as a polarization beam splitter, with the polarization beam splitter only radiating to the eye 10 the radiation generated by the swept-source radiation source 2 which has predetermined first polarization properties, in particular a predetermined first polarization angle. Furthermore, only the radiation reflected from the eye 10 is radiated to the detection device 4 by the polarization beam splitter, which radiation has predetermined further polarization properties, in particular a predetermined further polarization angle, which can be different from the first polarization angle. In particular, the first polarization properties and the further polarization properties can therefore be different from one another. The portion of the radiation that does not have the predetermined polarization properties is not radiated to the eye or not to the detection device 4 and is reflected, for example. It is also possible for the polarization beam splitter to be a beam splitter that changes the polarization properties of the radiation generated by the swept-source radiation source 2 and/or reflected from the eye 10 .

In particular if the beam splitter is designed as a polarization beam splitter, a retardation plate, e.g. a λ/4 plate, can be arranged along the beam direction from the swept source radiation source 2 to the eye 10, e.g. before or after the third lens 6c. It is also possible that along the beam direction from the swept-source radiation source 2 to the eye 10, an optical element for compensating for a spherical aberration, which can be configured as a phase plate, for example, is arranged in the radiation radiated into the eye 10, e.g. in front of the third lens 6c. This element can be achromatic.

It is also conceivable that a retardation plate, for example a λ/2 plate, is arranged between the swept source radiation source 2 and the beam splitter 8 in order to optimize the direction of polarization.

with the inside 1 For a set position and/or orientation of the radiation radiated into the eye, the device 1 shown can be directed to the detection device in a wavelength sweep of the swept-source radiation source 2 from different depths of the eye 10, whereby the latter can then detect a corresponding intensity. In this case, the depth is associated with a wavelength. Depending on the optical properties of the chromatic lens 3, radiation with increasing wavelength is focused in focal points which are deeper along the direction of incidence, ie further away from the device 1, in particular the objective 6c or the chromatic lens 3. In particular, the intensity of the radiation with the first wavelength λ1 is detected at a first reception time and assigned to a first pixel. Since the swept-source radiation source 2 generates radiation with different wavelengths at different times in a wavelength sweep, the intensity of the radiation with the second wavelength λ2 can be detected at a second reception time, which is after the first reception time, and assigned to a second pixel . Correspondingly, the intensity of the radiation with the additional wavelength λn can be detected and assigned to an nth pixel at an nth time of reception, which is chronologically after the second time of reception. Since radiation with different wavelengths is generated at different points in time, this assignment can therefore be based on time. The pixels generated in this way form pixels of a pixel stack 11 (see 2 and 3 ). Such a pixel stack 11 can be generated in at least one wavelength sweep.

Furthermore, the position and/or orientation of the irradiated radiation can be changed by the device 9 along at least one or at least two different spatial directions, preferably along exactly one or along exactly two spatial directions.

In 2 shows a schematic representation of a scheme of image generation. If the position and/or orientation of the irradiated radiation is changed, for example along a first spatial direction, at least one wavelength sweep can be carried out by the radiation source 2 for a set first position and/or orientation along this first spatial direction and the wavelength sweep detected at a first reception time point during the wavelength sweep Intensity of a first pixel coordinate x1, y1 are assigned, with the assignment to the pixel coordinate x1 along a first image axis x depending on the set position and / or orientation and the assignment to the pixel coordinate y1 along a second image axis y depending on the first wavelength λ1. Intensity detected at a second reception time point during the wavelength sweep can be assigned to a second pixel with the pixel coordinates x1, y2. Accordingly, the intensity detected at a further reception time in the wavelength sweep can be assigned to a further pixel with the pixel coordinates x1, yn. After exactly one or more wavelength runs with the set first position and/or orientation, this can then be changed to a second position and/or orientation, in which case exactly one wavelength run is then once again carried out by the radiation source 2 . In this, the intensity detected at a first reception time during a wavelength sweep can then be assigned to a pixel with the pixel coordinates x2, y1, the intensity detected at a second reception time during the wavelength sweep can be assigned to a second pixel with the pixel coordinates x2, y2 and the intensity detected at a further time of reception during the wavelength sweep can be assigned to a further pixel with the pixel coordinates x2, yn. A two-dimensional image of the eye or a partial area of the eye can thus be generated, with information from different depths being able to be generated as explained by changing the wavelength and being imaged in different pixel coordinates y1, y2, . . . yn along a second image axis y can. By changing the position and/or orientation, a second dimension of the image can be generated, whereby the pixels can be generated along the first image axis x.

3 shows a schematic representation of a scheme for generating a three-dimensional image. Corresponding to the generation of a two-dimensional image, such three-dimensional images of the eye 10 or a part thereof can be generated. At least one wavelength sweep of the swept-source radiation source 2 can be carried out for each set location and/or position of the irradiated radiation, which can be changed along two spatial directions, with intensities of different pixels of a pixel stack 11 being generated in each of these wavelength sweeps , With these - as explained - intensities of different focal points positions are assigned to radiation reflected along the direction of incidence. For example, the location and/or position of the irradiated radiation can be set to a second value along a first spatial direction and likewise to a second value along a second spatial direction, and a wavelength sweep can be carried out. The intensity detected at a first reception time during the wavelength sweep can then be assigned to a pixel with the pixel coordinates x2, y2, z1, radiation having a first wavelength λ1 being generated at the first reception time.

Correspondingly, pixels can be generated for this set position and/or orientation, the pixel coordinates of which do not change along a first and a second image axis x, y, but only along a third image axis z. Correspondingly, pixels with other pixel coordinates along the first and/or second image axis x, y can be generated in other adjusted positions and/or orientations of the irradiated radiation.

In the 2 and in 3 The images shown can be generated with a scan scheme. in the in 2 illustrated embodiment, pixels are generated along a first image axis x by changing the position and/or orientation of the incident radiation and along a second image axis y by changing the wavelength. in the in 3 illustrated embodiment, the pixels are generated along a first image axis x and a second image axis y by changing the position and / or orientation of the irradiated radiation and the pixels along a third image axis z by changing the wavelength.

The device 9 for changing the beam alignment can be designed, for example, as a two-dimensional scanning alignment. For example, this can include a galvo scanner and a resonant scanner or another galvo scanner. It is possible that the position and/or orientation of the irradiated radiation for generating pixels is changed along one of the image axes x, y of the set of first and second image axes x, y by the resonant scanner, with the change in position and/or or orientation of the irradiated radiation for generating image points along the remaining image axes y, x of this set takes place through the galvo scanner.

The change in the position and/or orientation of the irradiated radiation by the resonant scanner can be used in particular to generate pixels or pixel stacks 11 along an image line, with the change by the galvo scanner being used to generate pixels or pixel stacks 11 along an image column. In particular, the scanning speeds of these scanners, the detection rate or A/D conversion rate of the detection device 4 and the so-called sweep frequency of the swept source radiation source 2 can be adapted to one another in such a way that for each position and/or orientation of the irradiated Radiation carried out exactly one wavelength run and thus a pixel stack 11 is generated. Within the exposure time for a position and/or orientation of the irradiated radiation, the light is therefore focused into a different depth of the eye and reflected again from this depth due to the longitudinal chromatic aberration and due to the wavelength sweep at each point in time of the wavelength sweep. As a result, a three-dimensional image can be generated quickly in terms of time.

4 shows a schematic flow diagram of a method according to the invention, in which radiation is radiated into the eye 10 with a predetermined position and/or orientation and a wavelength sweep from the radiation source 2 (see FIG 1 ) is carried out. In a first step S1, radiation with a first wavelength λ1 is generated and radiated into the eye 10 through at least one chromatic lens 3 . In a second step S2, the radiation reflected from the eye 10 is received by a detection device 4 and assigned in a third step S3 by an evaluation device 5 to a pixel of the image to be generated as a function of the wavelength λ1. For this purpose, a reception time of the radiation can be determined and the wavelength λ associated with the reception time can be determined as the wavelength that was generated by the radiation source 2 (ie in the first step S1) at the reception time. Thereafter, ie at a later point in time, the method is continued with the first step S1, but a second wavelength λ2 of the radiation generated by the swept-source radiation source 2 is set. The method is continued until, for a last wavelength λn of a wavelength sweep, the detected intensity as a function of the wavelength λn has been assigned to a pixel of the image to be generated. After this wavelength run, the position and/or orientation of the irradiated radiation can then—as explained—be changed along at least one spatial direction and the method begins again with the first step S1, radiation with the first wavelength λ1 then being generated again. The corresponding, higher-level loop(s) are not shown in FIG.

Depending on the sweep frequency, laser power, sensitivity and detection frequency, the proposed device can record a volume in the time that would otherwise be required for a single image with purely mechanical scanners. Especially the in 2 The two-dimensional image shown can be generated at extremely high speed. In this way, a complete two-dimensional sectional image can already be generated when the beam alignment is changed along one spatial direction. The extremely short recording time for generating these sectional images, which can be well under a millisecond, significantly reduces the influence of movement artifacts or even eliminates them.

5 shows a schematic block diagram of a device 1 according to the invention. Shown is a housing 12, wherein in the housing 12 the swept source radiation source 2, the aperture 7a, 7b, the lenses 6a, 6d, the beam splitter 8 and device 9 for changing and the Detection device 4 (see 1 ) can be arranged. It is also shown that a lens 13 protrudes from the housing 12 and includes, for example, the chromatic lens 3 and the lenses 6b, 6c.

Also shown is a receiving element 14 for the object, which is designed in particular as a contact cap and is placed on the lens 13 . The receiving element 14 comprises a hollow-cylindrical section 15 and a hollow truncated-cone-shaped section 16, the object-side end of which has a receiving volume 17 (see FIG 6 ) for the object or a part thereof. A central axis of symmetry of the receiving element 14 can be arranged parallel, in particular concentrically, to the optical axis of the chromatic lens 3 in the attached state. The receiving element 14 is detachably fastened to the housing 12 or the lens 13, in particular by being clamped onto the lens 13. The lens 13 can be arranged in an inner volume of the receiving element 14 in the attached state.

6 shows a schematic cross section through a recording element 14, which has or forms a recording volume 17 for at least part of the object. It shows that the receiving element 14 has or forms a receiving section 18 at an object-side end, with an object-side surface 19 of the receiving section 18 or at least part of this surface 19 being concavely curved and thus forming the receiving volume 17 in which the object is arranged can. A first radius of curvature R1 of this surface can be, in particular, 7.8 mm if the object is an eye. The object-side surface 19 can correspond to a section of a spherical surface with this first radius of curvature. It is possible for immersion gel to be arranged in the receiving volume 17 . This has already been explained above. The viscosity of the immersion gel and the concave curvature of the surface 19 can further reduce the risk of eye movements, for example, since these eye movements are opposed by a resistance that is based on the displacement of the immersion gel.

Radiation exiting the lens 13 and radiation reflected by the object and entering the lens 13 can radiate through the curved surface 19 .

The receiving element 14 can form the previously explained optical element for compensating for a spherical aberration. For this purpose, a lens-side surface 20 of the receiving element 14 or at least part of this surface 20 is convexly curved. A second radius of curvature R2 of this surface can be selected depending on the application, in particular depending on the optical and/or geometric properties of the object, and can be 7.59 mm, for example. Radiation exiting the lens 13 and radiation reflected by the object and entering the lens 13 can radiate through the curved surface 20, the effects of a spherical aberration of this radiation in the object being reduced by this design of the recording element 14.

It is also conceivable for the receiving element 14 to form the previously explained optical element for changing the polarization properties of the radiation radiated into the object and/or the radiation reflected from the object, or for this element to be attached to the receiving element, in particular releasably attached. In this case, the optical element can be inserted into the receiving element 14, e.g.

7 shows a schematic cross section through a recording element 14 in a further embodiment, which has or forms a recording volume 17 for at least part of the object.

In contrast to the in 6 The embodiment shown has the concavely curved, object-side surface 19 of the receiving element 14, which delimits the receiving volume 17, a recessed or recessed area 21. This depression or bulge / recess can be in particular in a central area object-side surface 19, with an optical axis of the chromatic lens extending through this central area. The central area can be completely surrounded or bordered by a non-recessed area 21 of the object-side surface 19 . Radiation exiting the lens 13 and radiation reflected by the object and entering the lens 13 can radiate through the recessed area 21 . It is shown that the object-side surface 22 of the recessed area (and thus therefore the concavely curved surface 19 in the recessed area) is also (concavely) curved and in particular corresponds to a section of a surface of a sphere. A third radius of curvature R3 of the surface 21 of the recessed area 21 can correspond to the first radius of curvature R1 or be different from it.

If the object-side surface is a concavely curved surface corresponding to, for example, a portion of a surface of a sphere having a predetermined first radius, the recessed area may be recessed with respect to that surface. The recessed area may also have a concavely curved surface, for example also corresponding to a portion of a surface of a sphere having a predetermined further radius, which further radius may be the same as or different from the first radius.

The depressed area 21 allows the thickness of a gel layer between the object and the object-side surface 19 of the receiving element 14 to be greater in the depressed area 21 compared to the remaining, i.e. non-depressed area, of the object-side surface 19, thereby reducing the effect of reflections is reduced to the image at the boundary between object-side surface 19 or 22 and the gel.

Reference List

1

Device for generating at least one image

2

Swept source radiation source

3

chromatic lens

4

detection device

5

evaluation device

6, 6a, 6b, 6c, 6d

lens

7, 7a, 7b,

pinhole

8th

beam splitter

9

Device for changing position and/or orientation

10

Eye

11

pixel stack

12

Housing

13

lens

14

receiving element

15

hollow cylindrical section

16

frustoconical section

17

recording volume

18

recording section

19

object-side surface

20

lens-side surface

21

recessed area

22

object-side surface in the recessed area

x

first image axis

y

second image axis

e.g

third image axis

x1, x2, xn

image coordinate

y1, y2, yn

pixel coordinate

λ1, λ2, λn

wavelength

z1, z2, zn

pixel coordinate

S1

first step

S2

second step

S3

Third step

I

intensity

R1

first radius of curvature

R2

second radius of curvature

R3

third radius of curvature

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 202005009189 U1 [0003]
• DE 102017203995 A1 [0003]

Claims (13)

Method for generating at least one image of an object, comprising the steps: - Generating radiation with a swept-source radiation source (2), wherein radiation with different wavelengths is generated at different times, - irradiating the radiation into the object through at least one chromatic lens (3), - receiving the radiation reflected from the object (10) with at least one detection device (4) and detecting a time-specific intensity (I) of the received radiation, - Assigning the time-specific intensity (I) generated by the detection device (4) to a pixel of the image at least as a function of the wavelength (λ1, λ2, λn) of the radiation assigned to the reception time. procedure after claim 1 , further comprising the steps of: - changing a position and/or orientation of the irradiated radiation, - irradiating the radiation into the object (10) with different positions and/or orientations. procedure after claim 2 , characterized in that the position and/or orientation is changed along at least two mutually different spatial directions (x, y). procedure after claim 3 , characterized in that the position and/or orientation of the irradiated radiation along a first spatial direction (y) is changed with a galvo scanner and the position and/or orientation of the irradiated radiation is changed along a further spatial direction (x) with a further scanner. Procedure according to one of claims 2 until 4 , characterized in that the position and/or orientation of the irradiated radiation is changed after the swept-source radiation source (2) has carried out at least one wavelength sweep, with radiation from a predetermined wavelength range being generated in a wavelength sweep. procedure after claim 5 , characterized in that the swept-source radiation source (2) generates radiation from the predetermined wavelength range starting at a predetermined minimum wavelength and ending at a predetermined maximum wavelength in a first wavelength run, wherein after the first wavelength run the position and/or orientation of the irradiated radiation is changed and the swept-source radiation source generates radiation from the predetermined wavelength range starting at the predetermined maximum wavelength and ending at the predetermined minimum wavelength in an immediately following wavelength sweep. Method according to one of the preceding claims, characterized in that the detection device (4) is designed as a photodiode or photomultiplier or as a photon detector. Device for generating images of an object, comprising: - at least one swept-source radiation source (2), - at least one chromatic lens (3), - at least one detection device (4), - at least one evaluation device (5), the device (1) is configured, a method according to any one of Claims 1 until 7 to perform. device after claim 8 , characterized in that the device (1) comprises at least one device for changing the position and / or orientation of the irradiated radiation. device after claim 8 or 9 , characterized in that the detection device (4) is designed as a photodiode or photomultiplier or as a photon detector. Device according to one of Claims 8 until 10 , characterized in that the device (1) comprises a beam splitter (8), the beam splitter (8) being designed as a polarization beam splitter, the device having at least one further optical element for changing the polarization properties of the radiation radiated into the object and/or the radiation reflected from the object. Device according to one of Claims 8 until 11 , characterized in that the device (1) comprises an optical element for compensating for a spherical aberration of the radiation radiated into the object. Device according to one of Claims 8 until 12 , characterized in that the device (1) comprises a recording element (14) which has or forms a recording volume (17) for at least part of the object, the recording element (14) having an optical element for compensating for a spherical aberration of the Object forms radiation irradiated and / or wherein the receiving element (14) is an optical element for changing the polarization properties of the radiation radiated into the object and / or reflected from the object radiation or wherein an optical element for changing the polarization properties is attached to the recording element (14) and/or wherein a surface (19) of the recording element (14) on the object side, which delimits the recording volume (17), has a recessed region (21).

Images