Scanning imaging system

Abstract

A scanning imaging system has a scanning component that receives light from a light source and generates a scanning beam that is directed by an optics train to a sample to be imaged. A camera captures light returning from the sample to construct an image. Reflection on a target lens within the optical system is prevented by one or more light stops. A first light stop imaged to the target lens is positioned in an optical path from the light source to the scanning component to create a first moving dark space on the target lens through which a scanning beam from the scanning component to the sample cannot pass. A second light stop, also imaged to the target lens, is positioned in the optical path from the sample to the collector to create a second moving dark space on the target lens through which light returning from the sample cannot pass. And the moving dark area keeps the scanning light beam separated from the return light on the target lens.

Description

[0001] This application is a divisional application of the Chinese national phase application, filed on September 24, 2019, with international application number PCT / EP2019 / 075769 and entitled "Enhanced Function of Slit Scan Fundus Imaging Analyzer". The Chinese national phase application entered the national phase on March 24, 2021, with application number 201980062815.3 and entitled "Enhanced Function of Slit Scan Fundus Imaging Analyzer". Technical Field

[0002] This invention generally relates to the field of scanning imagers. More specifically, this invention relates to reducing image artifacts caused by reflections from the internal optics of scanning imagers, particularly fundus scanning imagers. Background Technology

[0003] Various types of image capture devices are known for imaging samples in testing. Of particular interest are imaging systems capable of capturing close-up images of samples with sufficient detail (e.g., adequate focus, illumination, magnification, and signal-to-noise ratio (SNR)). One example of such an imaging system is a fundus imager, which is commonly used to image the fundus of the eye. The fundus is the inner surface of the eye opposite the lens and may include the retina, optic disc, macula, fovea, and posterior pole. Two classes of imaging systems used for fundus imaging are flood illumination imaging systems (or flood illumination imagers) and scanning illumination imaging systems (or scanning imagers).

[0004] A flood illumination imager simultaneously floods the entire field of interest (FOV) of the sample (e.g., by using a flash) and captures an image of the sample (e.g., the fundus) with a full-frame camera. Figure 1This is a conceptual diagram of a flood-illuminated fundus imager 10. A flash tube 15 is shown as the illumination source, its illumination light following an optical path along an illumination axis 17, which may include various system lenses 19, and is then folded by a mirror 23 onto an optical axis 25, which includes a system lens 11 to deliver the illumination light to the sample or specimen to be imaged (e.g., the retina 33 of the eye 13 in this example). The system lens 11 is the imager lens closest to the eye 13 and may be referred to herein as an eyepiece or ophthalmic lens. The optical axis 25 traverses the optical components of the eye 13 (including the cornea 27, iris 28, pupil 29, and lens (or ocular lens) 31) to reach the retina 33. Thus, illumination light traveling along the optical axis 25 enters the eye 13 through the cornea 27, passes through the pupil 29, and traverses the lens 31 to reach the retina 33 in the posterior part of the eye (e.g., the fundus region), and is scattered by the retina 33 (and other parts of the fundus). Scattered light returning from the fundus 33 exits through the lens 31, pupil 29, and cornea 27, and travels along the optical axis 25 to the observation axis 35. The observation axis 35 may include multiple system lenses 21 and guides the scattered light returning from the fundus to a full-frame camera 37, which captures a full-frame image 39 of the fundus of the eye 13. Since the observation axis 35 and the illumination axis 17 are aligned along the optical axis 25, the mirror 23 typically has a centrally located aperture 43 that allows scattered light returning from the eye 13 to pass through the mirror 23 onto the observation axis 35 for capture by the camera 37. The mirror 23 may be flat or annular (e.g., ring-shaped) with a central circular aperture 43. If the mirror 23 is used for pupillary segmentation, it can be further imaged onto the pupil 29.

[0005] Pupil segmentation allows illumination light (light entering eye 13) and returning light (scattered light leaving the eye) to enter and exit eye 13 via different paths within an optimally selected area of ​​pupil 29. These areas are selectable, for example, to avoid pupil shearing, cataract light scattering, and specular reflection (e.g., reflection) of illumination light, such as reflection of illumination light from cornea 27. To facilitate pupil segmentation, a mirror 23 can be imaged onto or near pupil 29, reflecting illumination light toward eye 13 and having an aperture 43 that allows returning light to pass through to camera 37. For example, when mirror 23 folds (e.g., reflects) illumination light from illumination axis 17 toward eye 13 onto optical axis 25, an annular illumination region can be created at eye 13. That is, the circular aperture 43 of mirror 23 can create a circular, non-illuminated region near cornea 27 at the center of the annular illumination region. Scattered light returning from retina 33 can exit eye 13 through this non-illuminated region, thus preventing illumination light from entering eye 13. Furthermore, specular artifacts from the optical surfaces of the flood illumination imager itself can be reduced by using so-called dark spots, which are fixed in the illumination path to prevent certain surface areas of the illumination system optics from being affected. Flood illumination imaging systems can rapidly image the fundus and have high signal levels and dynamic range, but may encounter low contrast issues. The need to eliminate reflections can also impose constraints on the system, which may limit its field of view (FOV). Examples of flood illumination imaging systems can be found in U.S. Patent No. 3,915,564, assigned to the same assignee as this invention, and are incorporated herein by reference in their entirety.

[0006] In contrast, scanning imagers illuminate and image only a portion of the sample at a time, collecting multiple image segments as they scan the illumination beam across the sample. These image segments are then stitched together to create a composite image that forms the full frame. One advantage of scanning imagers over flood illumination imagers is increased confocality, which allows for greater resolution of unwanted light scattered from surfaces other than the retina, resulting in a wider field of view (FOV) without artifacts. Like flood illumination imagers, fundus scanning imagers encounter, albeit to a lesser extent, reflection problems at various optical components of the eye and at various system lenses within the scanning imager itself. Techniques for reducing reflections at the eye's optical components, such as pupillary segmentation, can be applied to scanning imagers. Pupillary segmentation reduces reflections to some extent, but does not eliminate them; its advantage lies in minimizing unwanted light from the eye, rather than light from specific system lenses.

[0007] One object of the present invention is to provide a scanning imager having a mechanism for directly reducing or preventing reflections from a particular system lens.

[0008] Another object of the present invention is to provide a fundus scanning imager that reduces reflections at a given target optics / lens of a fundus scanning imager. Summary of the Invention

[0009] The aforementioned objectives can be achieved in systems, devices, and / or methods for directly reducing or eliminating reflection artifacts at a given target optics (e.g., system optics such as lenses, prisms, mirrors, etc.) within a scanning imager (or scanning illumination imaging system), particularly in a scanning imager configured as a fundus scanning imager. The scanning imager may include a radiation source (e.g., a light source) and a scanning component. The radiation source may be a coherent light source (e.g., a laser) or an incoherent light source (e.g., a lamp or light-emitting diode (LED)). The scanning component may be one or more galvanometers, a microelectromechanical system (MEMS) scanner, an electro-optic deflector, a rotating mirror, and / or a rotating polygon scanner, or other scanning mechanism. The scanning component receives a radiation stream (e.g., a laser beam or light beam) from the radiation source and defines a scanning beam (e.g., by rotating a deflector within the galvanometer). The scanning beam may scan across the sample to be imaged, thereby creating a moving illumination area on the sample. In the case of a fundus scanning imager, the sample will be the fundus (or retina) of the eye, and the scanning component can be imaged onto the pupil of the eye to facilitate pupillary segmentation, as described above.

[0010] System optics (e.g., scanning lenses and eyepieces or ophthalmic lenses) guide a scanning beam from the scanning member to the sample to be imaged. The system optics may form an optic train that defines a radiation path (e.g., an optical path) from the scanning member to the imaged sample. Optionally, a target optics from which reflections are to be eliminated may be selected. The scanning beam may scan across the target optics. A radiation blocking member (e.g., a first light block) may be positioned to partially block the radiation stream output from a radiation source and limit the radiation received by the scanning member. Therefore, the radiation blocking member may be positioned along the radiation path from the radiation source to the scanning member. The radiation blocking member may be imaged onto the target optics (e.g., positioned on the conjugate plane of the target optics) and create a moving non-radiative region (e.g., a first dark region) on the target optics through which the scanning beam of the scanning member cannot pass. The scanning beam may define a moving illumination area, and the non-radiative region may move along with the illumination area. Optionally, the non-radiative area can block (or partially block) the overlap between the illumination area and the collection area (through which scattered light returning from the sample can pass), particularly at the target optics.

[0011] A scanning imager may include a collector (e.g., a photodetector, a light sensor, a charge-coupled device (CCD) image sensor, or a complementary metal-oxide-semiconductor (CMOS) image sensor) for collecting scattered radiation (e.g., scattered light) returning from a sample through a collection region. The scanning imager may further include a collector blocking member (e.g., a second light block) positioned to partially block the collection region to reduce the amount of scattered radiation returning to the collector. The collector blocking member may be imaged onto a target optics (e.g., a target optics located on a conjugate plane of the target optics) to create a moving non-collecting region (e.g., a second dark region) on the target optics (or a second target optics) through which scattered radiation returning from a moving illumination region cannot pass. The non-collecting region may be moved by a scanning member and may overlap with the collection region. For example, the non-collecting region may move along with a non-radiative region and a scanning beam and may block (or partially block) the overlap between the illumination region and the collection region, particularly at one or more target optics. The overlap between the blocking illumination area and the collecting area can be achieved by making the non-collecting area and the non-radiating area adjacent to or overlapping each other, for example, when they move on one or more target optics (e.g., combined / aligned with each other).

[0012] The overlap between the illumination and collection areas on the target lens limits (or blocks) reflections from the target lens to the collector, thus helping to avoid reflection artifacts in the captured image. Therefore, for any given scanning position of the scanning component, it is desirable to minimize or eliminate the overlap between the illumination and collection areas on the target lens. However, system focusing, as part of a typical setup routine for image capture sequence, can defocus and / or change the positions of the non-radiative and / or non-collecting areas, resulting in increased overlap between the illumination and collection areas. Various steps to compensate for this defocusing effect are considered.

[0013] Although it is desirable to completely block the overlap between the illumination and collection areas, the adjustment of the system focus can alter (e.g., magnify) the size of the overlap between the illumination and collection areas. The size and position of the collector blocking component and the radiation blocking component can be selected such that the overlap between the moving non-radiative area and the moving non-collecting area on the target optics is sufficient to cover a predetermined increase in the overlap between the illumination and collection areas, such as defocusing effects caused by axial movement of the conjugate plane of the target lens relative to the collector blocking component and / or the radiation blocking component.

[0014] In the case of a fundus scanning imager that images a highly myopic eye, as a result of compensating for the myopia, the conjugate plane of the target lens may be moved (e.g., axially) relative to one or more blocking components. In some instances of severe myopia, because the positions of one or more blocking components are moved relative to the illumination and / or collection areas, the non-collection and / or non-illumination areas may restrict too much light (to or from the eye), resulting in a darker image or a slower image capture cycle. In these extreme cases, it is desirable to accept some degree of reflection in exchange for a brighter image. That is, the collector blocking component and / or radiation blocking component may be configured to be movable (or removable) to limit their obstruction of the radiation path (e.g., the optical path). For example, the radiation blocking component may be positioned to partially block radiation output from a radiation source, the collector blocking component may be positioned to partially block scattered radiation returning from the moved collection area, or the radiation blocking component may be positioned not to block radiation output from the radiation source, and / or the collector blocking component may be positioned not to block scattered radiation returning from the moved collection area.

[0015] Alternatively, if the scanning imager has a focusing mechanism that moves (e.g., axially) the conjugate plane of the target optics when the sample is focused on the collector, the collector blocking member and / or radiation blocking member can move together with the conjugate plane of the target optics to remain substantially on the conjugate plane of the target optics. This may be due, for example, to movement of the optics between the blocking member and the target lens (including the target lens) when focusing is adjusted for myopia. In other words, one or more blocking members can be moved when focusing is adjusted to remain on the conjugate plane of the target lens. Alternatively, the position of the radiation blocking member can remain stationary, independent of movement of the conjugate plane of the target optics.

[0016] Alternatively, the relative positions of the collector blocking component, the scanning component, and the target optics can be independent of the focusing mechanism. For example, the focusing optics can be positioned between the collector blocking component and the collector such that even when the focusing optics focus the sample onto the collector, the relative positions of the optics along the optical path of the reflected radiation from the target optics to the collector blocking component (including the scanning component) remain fixed.

[0017] Furthermore, changes in the position of the blocking component relative to the illumination plane and / or the collection plane can affect the amount of light captured. Such changes in position may be due to movement within the optical chain (e.g., movement between the radiation source and the radiation blocking component and / or between the collector and the collector blocking component), or it may be due to movement of the blocking component keeping it on the conjugate plane of the target lens, as described above. This change in position may result in increased light blocking when adjusting camera focus for greater myopia. Therefore, for more myopia, the amount of blocking provided by either blocking component can be adjusted to allow more light to pass through, even if this results in some increased reflections back to the collector.

[0018] In certain embodiments, the radiation blocking component may be coplanar with the collector blocking component. This simplifies the design and alignment of the scanning imager. Furthermore, an illumination aperture (e.g., the retina in the case of a fundus imager) on a conjugate plane of the surface of the sample to be imaged may be positioned in front of the radiation source to construct (e.g., shape) its output radiation beam. In this case, the illumination aperture may be located between the illumination source and the radiation blocking component. Similarly, the scanning imager may have a collection aperture on a conjugate plane of the surface of the sample to be imaged (e.g., the retina of the eye). In this case, the collection aperture may be positioned between the collector and the collector blocking component, and the illumination aperture may be coplanar with the collection aperture. The illumination aperture may be matched to the collection aperture diameter and may be on the conjugate plane of the collection aperture on the light sensor (e.g., the collector).

[0019] Optionally, the scanning imager may also include a pupil segmentation aperture that defines a segmentation region that separates the scanning beam of radiation emanating from the sample (e.g., the retina or fundus) from the scattered radiation returning from the sample. For example, in the case of pupil segmentation in a fundus imager, the pupil segmentation aperture may be positioned substantially immediately before the scanning component in the radiation path from the radiation source to the scanning component. The segmentation region may define a first sample opening through which the radiation beam from the radiation source reaches the scanning component, and may define a second sample opening through which the scattered radiation returning from the sample passes. The first and second sample openings may be coplanar. In this configuration, the scanning imager may also include a dual lens, embodied as two coplanar lenses molded into a single optical component, and including a first sub-lens aligned with the first sample opening and a second sub-lens aligned with the second sample opening. A structure (e.g., a wall) may maintain alignment between the first sample opening, the first sub-lens, the radiation blocking component, and the illumination aperture, and maintain alignment between the second sample opening, the second sub-lens, the collector blocking component, and the collector aperture. This structure can also be used to prevent light from leaking from the first sample aperture side to the second sample aperture side.

[0020] When the scanning imager is a fundus imager, the target lens can be a transmission lens. For example, the target lens may be the lens closest to the sample (e.g., the fundus) in the radiation path from the scanning element to the sample. Alternatively, the target optics may be, for example, a scanning lens between the scanning element and the sample, which functions to receive the scanning beam from the scanning element at an incident angle and output the scanning beam along a predetermined, generally collimated path.

[0021] The scanning imager can be a confocal point scanning imager or a line scanning imager. As understood, a line scanning imager (or line scanning ophthalmoscope) can include both line scanning laser scanner / ophthalmoscope (LSLO) and wide-line scanning (fundus) imager / ophthalmoscope (BLFI). When the scanning imager is a line scanning imager, the radiation beam can be substantially rectangular. The rectangular radiation beam can have a (optionally fixed) length dimension and can have a variable width dimension substantially perpendicular to the length dimension.

[0022] A scanning imaging system includes: a radiation source; a scanning component that receives radiation from the radiation source and defines a scanning beam of radiation; an optics component that guides the scanning beam of radiation to a sample to be imaged, the optics component including a target optical element, the scanning beam of radiation scanning across the target optical element; and a radiation blocking component positioned to partially block radiation output from the radiation source and limit the radiation received by the scanning component, the radiation blocking component being on a conjugate plane of the target optical element and creating a moving non-radiative region on the target optical element, the scanning beam of radiation being unable to pass through the moving non-radiative region, a portion of the scanning beam outside the moving non-radiative region scanning across the sample, thereby creating a moving illumination area on the sample. A collector for collecting radiation returning from a moving illumination area; and a collector blocking component positioned to partially block radiation returning from the moving illumination area, the collector blocking component being on a conjugate plane of the target optical element and creating a moving non-collecting area on the target optical element, wherein radiation returning from the moving illumination area cannot pass through the moving non-collecting area, wherein the radiation blocking component and the collector blocking component are coplanar; an illumination hole on a conjugate plane of the surface of the sample to be imaged, the illumination hole being between the illumination source and the radiation blocking component; and a collection hole on a conjugate plane of the surface of the sample to be imaged, the collection hole being between the collector and the collector blocking component; wherein the illumination hole and the collection hole are coplanar.

[0023] A scanning imaging system includes: a radiation source; a scanning component that receives radiation from the radiation source and defines a scanning beam of radiation; an optics component that guides the scanning beam of radiation to a sample to be imaged, the optics component including a target optical element, the scanning beam of radiation scanning across the target optical element; and a radiation blocking component positioned to partially block radiation output from the radiation source and limit the radiation received by the scanning component, the radiation blocking component being on a conjugate plane of the target optical element and creating a moving non-radiative region on the target optical element, the scanning beam of radiation being unable to pass through the moving non-radiative region, a portion of the scanning beam outside the moving non-radiative region scanning across the sample, thereby creating a moving illumination area on the sample. A collector for collecting radiation returning from a moving illumination area; wherein: the sample to be imaged is an eye with a pupil and a fundus; a scanning beam of radiation enters the eye through the pupil and creates a moving illumination area in the fundus; and radiation returning from the moving illumination area exits the eye through the pupil; the system further includes: a radiation aperture positioned in front of the radiation source, the radiation aperture substantially imaging onto the fundus; a pupil-splitting optics substantially imaging onto the pupil of the eye, the pupil-splitting optics separating the scanning beam of radiation entering the eye from the returning radiation exiting the eye, the pupil-splitting optics including a pupil aperture substantially imaging onto the pupil; wherein a radiation blocking component is positioned between the pupil aperture and the radiation aperture.

[0024] This scanning imager can be implemented in different types of scanning configurations. For example, the scanning imager can be a scan-non-scan system, a scan-scan system, or a scan-scan-re-scan system.

[0025] Other objects and objectives of the invention, as well as a more complete understanding, will become clear and readily apparent from the following specific embodiments and claims, taken in conjunction with the accompanying drawings.

[0026] The embodiments disclosed herein are merely examples, and the scope of the invention is not limited to these embodiments. Any embodiment feature mentioned in one claim class (e.g., method) may also be claimed in another claim class (e.g., system). Dependencies or references in the appended claims are chosen solely for formal reasons. However, any subject matter derived from careful reference to any prior claims may also be claimed, such that any combination of claims and their features may be disclosed and claimed, regardless of the dependency chosen in the appended claims. Attached Figure Description

[0027] In the accompanying drawings, the same reference numerals / figure marks refer to the same parts:

[0028] Figure 1 This is a conceptual diagram of a floodlight illumination fundus imaging system.

[0029] Figure 2This illustrates a generalized confocal point-scan fundus imager.

[0030] Figure 3 A simplified exemplary scanning pattern of a confocal point scanning fundus imager (or more generally, a point confocal scanning system) is shown.

[0031] Figure 4 A simplified exemplary scanning mode for a line (confocal) scanning system is shown.

[0032] Figure 5A , Figure 5B and Figure 5C Each example shows an illumination line (or slit) of different sizes and widths that can be used with a line-scan fundus imager.

[0033] Figure 6A An idealized scanning configuration of a so-called "scan-non-scan" system is shown, in which, when scanning a sample, a transverse line beam will cross the lines of the sample (e.g., see...). Figure 4 , Figure 5A , Figure 5B and Figure 5C The system provides illumination and allows the returned reflected / scattered light to be scanned similarly across a collector (e.g., a photodetector or camera). Optionally, the collector can be coupled to a CPU for further processing and a monitor for display, such as... Figure 2 As shown.

[0034] Figure 6B An idealized scanning configuration of a so-called "scan-to-scan" system is shown, in which the line beam is scanned across the sample, but the line of returned scattered light is held at a single predetermined position on the collector, rather than being scanned across the collector.

[0035] Figure 6C An example of a so-called "scan-de-scan-re-scan" system is shown, in which an auxiliary scanning mechanism is incorporated into the scan-de-scan system to rescan (e.g., re-scan) the returned scattered light generated by the scan-de-scan system before it reaches the collector, otherwise not scanned, thereby rescanning the returned scattered light across the collector. Optionally, this re-scanning capability can be provided by a second scanning element, or by different portions of a scanning element that scans the scan beam across the sample. For example, re-scanning can be accomplished by using the back side of a single scanning element or different locations on a single scanning element that also scans the scan beam across the sample.

[0036] Figure 6D It shows the integration of spherical mirrors into something similar Figure 6C The system involves scanning, descanning, and rescanning.

[0037] Figure 7 An example of an alternative scan-to-scan configuration for a line-scan fundus imager incorporating the present invention is shown.

[0038] Figure 8 Provided Figure 7 A simplified, non-scale, close-up view of the ophthalmic lens, including an illumination block (e.g., a non-illuminated area) after imaging, a collection block (e.g., a non-collection area) after imaging, an illumination window through which the scanning beam from the scanning element can pass to the eye, and a collection window through which the returning light from the eye can pass to the collector.

[0039] Figure 9 An example of an alternative scan-de-scan-re-scan configuration for a line-scan fundus imager incorporating the present invention is shown.

[0040] Figure 10 The conceptual design of a compound dual-lens system is shown.

[0041] Figure 11 An alternative structure is shown for adding a beam stop for imaging to an ophthalmic lens / eyepiece in a scan-de-scan-re-scan line scan system using a compound dual-lens system.

[0042] Figure 12 An example computer device (or CPU or computer system) is shown. Detailed Implementation

[0043] There are two types of scanning imagers: confocal point scanning imagers (which use a laser point beam to scan one point of the sample at a time) and line scanning imagers (which use a narrow line beam or a wide line beam (e.g., a linear slit of predetermined width) to scan a line of the sample at a time). In the field of fundus imaging, line scanning imagers may be referred to as line scanning ophthalmoscopy, and include line scanning laser imagers / ophthalmoscopy (LSLO) (which typically use a laser to generate a very narrow transverse line across the sample during its scanning) and wide-line scanning (fundus) imagers / ophthalmoscopy (BLFI) (which can generate a transverse wide line (or slit) of predetermined width across the sample during its scanning using an incoherent light source). In the following text, the term line scanning imager may be understood to refer to both laser line (or very narrow line) scanning imagers (e.g., LSLO) and wide-line scanning imagers (e.g., BLFI).

[0044] Scanning imagers typically capture scattered light returning from each scanned location of a sample (e.g., by using a collector, such as a photosensor or light sensor) and stitch the captured scanned locations together to produce a composite image of the sample that may define a full-frame (e.g., full field of view, FOV) image. For ease of discussion, embodiments of the invention describe the use of a scanning imager to image the fundus of the eye, which is the inner surface of the eye opposite the lens (e.g., the lens) and may include the retina, optic disc, macula, fovea, and posterior pole. That is, the present scanning imager is presented within the context of fundus scanning imagers; however, it is understood that the invention can also be used with scanning imagers optimized for other applications, such as imaging samples other than the eye.

[0045] Each type of scanning imager has its advantages and disadvantages and can be optimized for various applications. For example, confocal point scanning imagers inherently avoid defocused light, but because each imaged point (e.g., each captured scanned position) corresponds to one image pixel, scanning across the sample laterally and vertically is required to construct a synthetic, full-frame image. This can result in relatively long image capture times. Line scanning imagers typically achieve confocal measurements in their width direction (perpendicular to the length direction of the scan line or line beam) and can scan across the sample faster than point scanning imagers. However, at least in the case of wide-line scanning imagers, if the scanned line beam is too narrow, the captured image may not achieve the desired brightness. Nevertheless, wide-line scanning imagers avoid the need for a laser source, making them more cost-effective than the other two types of scanning imagers, and can further generate line beams of varying widths to increase the amount of light applied to the scanned sample during each capture sequence, resulting in a brighter image, but at the cost of reduced confocality.

[0046] When using a scanning imager to image the fundus, it is generally desirable to avoid collecting (e.g., capturing or imaging) incoming light, as well as reflections from the cornea and light scattering from the lens of the eye (e.g., due to cataracts). Sequential illumination and collection of the individual target locations of the retina / fundus, inherent to the scanning imager, reduces the collection of unwanted light from external (e.g., peripheral) areas of the fundus; however, eliminating / reducing unwanted reflections and light scattering from the eye may require a more direct approach. As the scanning beam enters the posterior part of the eye, it traverses the cornea and lens, causing corneal reflections and lens scattering. These problems can be addressed using a technique called pupillary segmentation, which blocks corneal reflections and lens scattering by providing different paths for the scanning beam entering the eye and the returning (scattered) light leaving the eye within an optimally selected area of ​​the pupil. For example, these areas can be selected to avoid pupil clipping (e.g., a portion of the beam being blocked by the iris, which defines the pupil at its center), light scattering from cataracts (e.g., cloudy areas of the eye's lens), and specular reflection of the illumination light (e.g., reflections, such as specular reflections caused when the scanning beam illuminates the cornea as the illumination light enters the eye). Essentially, pupil segmentation defines a pupil illumination area (or window) through which the scanning beam enters the eye to illuminate a specific scanning location on the fundus, and defines a pupil collection area (or window) that determines which portion of the scattered light leaving the eye should be collected (by the collector) to capture an image of the scanned location. Pupil segmentation can be used in in-line fundus imaging, but it is generally not considered necessary in confocal fundus imaging. Another advantage of pupil segmentation is that it tends to keep the illuminating scanning beam and the returning scattered light separated not only at the pupil but also in areas close to the pupil (e.g., at the cornea). Due to the defocusing of the pupil illumination area and the pupil collection area, the ability of pupil segmentation to separate the scanning beam from the returning scattered light is weakened when leaving the pupil.

[0047] The aforementioned scanning imagers can use different radiation sources (e.g., lasers for coherent point scanning imagers and laser line scanning imagers, and incoherent light sources, such as lamps or one or more light-emitting diodes (LEDs), for wide-line scanning imagers). However, each scanning imager typically generates a radiation stream or beam that is delivered (along a radiation path) to a scanning mechanism / component (e.g., one or more galvanometers, a MEMS scanner, an electro-optic deflector, and / or a rotating polygon scanner). The radiation beam (or illumination beam) output from the radiation source can be shaped by placing a slit (e.g., a specially configured aperture) in front of the radiation source. This slit aperture can be imaged onto the fundus (e.g., the conjugate plane of the fundus) or onto any surface to be imaged. The scanning component receives the radiation beam from the radiation source and generates a scanning beam that scans in a specific pattern. From the scanning component, the scanning beam exits the scanning imager along with the optical system (which defines the scanning path) and scans across the sample (e.g., the fundus). The optical components typically include a scanning lens in front of the scanning element (along the scanning path), followed by one or more optical components (e.g., lenses or lens structures) that guide the scanning beam to the object to be imaged. In the case of a fundus imager, the lens closest to the eye (along the scanning path) may be referred to as an ophthalmic lens or eyepiece.

[0048] One inherent problem with such scanning imagers is reflection (e.g., light reflection) at system lenses (or other optics) within the scanning imager along the illumination and / or collection paths. This invention provides methods, systems, or apparatus for eliminating (or reducing) reflections at one (or more) target optics (e.g., system optics) within a scanning imager. In the case of fundus imagers, reflections at the lens closest to the eye (e.g., the imaged sample) are often of concern, and some embodiments have been presented herein regarding the elimination of reflections at the lens closest to the eye (e.g., ophthalmic lenses); however, it will be understood that the invention can be applied to another target lens (or other target optics) within a scanning imager.

[0049] In an embodiment, a radiation block (e.g., an illumination block, radiation blocking component, or beam block) that images onto an ophthalmic lens (or other target optics of a system where reflections are eliminated / reduced) is placed between the radiation source and the scanning component to partially block the radiated beam received by the scanning component. The radiation block or beam block can be constructed using foil or metal plates with openings, filters, or other light-blocking mechanisms that selectively block a portion of the beam while allowing others to pass through. The radiation block may be located on the conjugate plane of the ophthalmic lens and create a non-radiating region (non-illuminating region) that is scanned (e.g., moved) across the ophthalmic lens as the scanning component scans the radiated beam from the radiation source. This non-illuminating region creates a moving area with no (or reduced) reflections on the ophthalmic lens adjacent to the scan beam generated by the scanning component. In an embodiment, the radiation block may be placed in front of the radiation source, for example, in front of a slit aperture of the radiation source. If a pupil-splitting optics device is positioned in front of the radiation source, the pupil-splitting optics device may be placed between the illumination block and the scanning component. As will be understood, an illumination blocking block can be substantially imaged to an ophthalmic lens, a pupil splitting optic can be substantially imaged to the pupil (or cornea), and a slit aperture can be substantially imaged to the fundus (or retina).

[0050] In embodiments, another radiation block (e.g., a collection block or collector blocking component) may also be imaged onto the ophthalmic lens (or a target optics of another system, where reflections are eliminated / reduced) and may be positioned in the optical path from the scanning component to the collector. The collection block may be located on the conjugate plane of the ophthalmic lens and create a non-collecting area on the ophthalmic lens, adjacent to which (scattered) return light from the eye toward the collector is scanned (e.g., moved) across the ophthalmic lens. Thus, a portion of the scattered radiation (e.g., light) returning from the fundus (e.g., a sample) may be blocked by the non-collecting area, thereby creating a second moving area with no (or reduced) reflections on the ophthalmic lens (or other target optics). In some embodiments, reflections on the ophthalmic lens may be further reduced by arranging the non-collecting areas to partially overlap with the non-illuminated areas as they move in series on the ophthalmic lens. The collection block may be positioned in front of the collector. If a collection aperture (e.g., a pinhole or slit through which light enters the collector) is positioned in front of the collector, the pinhole may be positioned between the collector and the collection block. In this configuration, the collection aperture can be imaged onto the fundus (or retina) of the eye, and the collection block can be imaged onto an ophthalmic lens (or other target optics). The collector can also be imaged onto the fundus, in which case the collection aperture may be slightly out of focus on the retina.

[0051] This invention can be implemented as part of a confocal point scanning imager or a line scanning imager. A point confocal scanning imager, such as a (fundus) confocal scanning laser ophthalmoscope (cSLO), can use a laser (or other bright, confocal light source) to illuminate and image a small point (or spot) on the retina at a time.

[0052] Figure 2A generalized confocal point-scan fundus imager 51 is illustrated. A laser or other light source, such as a superluminescent diode (SLD) (e.g., a radiation source) 53 emits a spatially coherent point beam, which passes through an optional aperture 55 and a collimating lens 57, through a beam splitter 59, to a scanning component. In this example, the scanning component includes two galvanometers 61 and 63 (e.g., servo-controlled rotating (or oscillating) mirrors). The first galvanometer 61 provides a vertical scan (e.g., a V-scan) of the point beam (e.g., a scan in the Y-axis direction, which defines a column of illumination points on the sample to be imaged), and the second galvanometer 63 provides a horizontal scan (e.g., an H-scan) of the point beam (e.g., a scan in the X-axis direction, which defines a row of illumination points on the sample). For example, the H-scan galvanometer 63 can rotate a mirror to horizontally scan the point beam in discrete steps (or continuous, definable steps) to define a row of points. Once a line of dots is completed, the V-scanning galvanometer 63 can vertically rotate its mirror to move the scanning beam to a new vertical offset position, preparing for scanning a new line. The scanning lens 67, in the optical path between the scanning component and the eye 75, functions essentially to receive the scanning beam from the H-scanning galvanometer 63 at any of a plurality of scanning angles (incident angles) and generate a scanning beam 69 using a substantially flat surface focusing plane (e.g., a collimated optical path). The scanning beam 69 can then be focused by the ophthalmic lens 71 onto the retina 73 of the eye 75 to image the fundus. The scattered light leaves the eye 75 and returns through the ophthalmic lens 71, the scanning lens 67, and the galvanometers 61 and 63 to the beam splitter 59. Because the return path of the scattered light from the eye 75 is similar to that of the scanning beam, the galvanometers 61 and 63 have the effect of “de-scanning” (or not scanning) the returning light, so that when it reaches the beam splitter 59, it is a stable beam (unscanned). At beam splitter 59, the returned light is directed to another focusing lens 77, which focuses the returned beam onto photodetector 79 through pinhole 81. Pinhole 81 is optically conjugate with retina 73 and helps eliminate defocus signals (light). Each illuminated point is individually imaged (e.g., captured or detected) by photodetector 79, and a series of imaged points are collected to construct a composite image of retina 73 as the point beam from the scanning element is scanned across the sample in a grating pattern. That is, the signals (e.g., light spots) detected by photodetector 79 can be processed by computer or CPU 83 to form a confocal (full-frame) image 84. The resulting confocal image 84 can be displayed on video display 85 or stored for further processing. An example of a point confocal scanning system integrated into an optical coherence tomography system is provided in U.S. Patent No. 8,783,868, which is assigned to the same assignee as this invention and is incorporated herein by reference in its entirety.

[0053] As described in further detail below, optionally, an illumination block 87 imaging onto the ophthalmic lens 71 may be positioned in front of the radiation source 53 to create a moving non-illuminated area on the ophthalmic lens 71 adjacent to the scanning beam output from the scanning element (e.g., the scanning beam output from the galvanometer 63). This non-illuminated area prevents (or reduces) reflections due to the scanning beam. Similarly, optionally, a collection block 89 may be positioned in front of the photodetector 79, and the position of the collection block 89 may be selected such that the optics in the system form an image of the collection block 89 at a surface location of the ophthalmic lens 71 (e.g., the collection block 89 is located on a conjugate plane of the surface of the ophthalmic lens 71) to create a moving non-collection area on the ophthalmic lens 71 that prevents (or reduces) reflections due to scattered light returning from the eye 75.

[0054] Figure 3 A simplified exemplary scanning mode of a confocal point-scan fundus imager (or more generally, a point confocal scanning system) is shown. It will be understood that other scanning modes may also be used. In this illustrative example, each point Sp_1 to Sp_n is captured separately and individually in the scanning mode. Since only one point of the sample is illuminated and captured at a time, imaging typically requires scanning over a regular grating (e.g., a rectangular pattern of parallel scan lines) on the sample (e.g., the retina or fundus). For example, a laser scanning beam is scanned across the sample in the XY plane (perpendicular to the principal axis direction of the scanning beam, e.g., the Z-axis) using scanning components (e.g., galvanometers 61 and 63). Individual rows of points (e.g., R1 to Rm) are captured one after another in corresponding individual horizontal scans (H-scans), and the scanning beam is scanned vertically in progressive steps with a one-row-offset (e.g., a vertical step after each horizontal scan) to define the vertical scan (V-scan). Generally, slower scans provide a better signal-to-noise ratio, resulting in better contrast and higher resolution.

[0055] Due to their point-confocal arrangement for illumination and detection, confocal scanning imagers can advantageously suppress stray and out-of-focus light, thus generating high-contrast images without requiring pupil segmentation. However, because they operate using point illumination, they may require high intensity, which can pose safety concerns when imaging the retina. Similarly, since most of the light from the sample is blocked at pinhole 81, the increased resolution often comes at the cost of reduced captured signal strength, potentially requiring longer exposure times. Furthermore, confocal point-scan fundus imagers typically require multiple scanning mechanisms for horizontal and vertical scanning (e.g., galvanometer 63 for horizontal scanning and galvanometer 61 for vertical scanning), which is expensive and complex, and slows down their image generation as many points need to be collected to construct a full-frame synthetic image. Eye-movement problems can also occur during image construction, potentially leading to image distortion.

[0056] The difference between a line scan imager and a confocal scan imager is that a line scan imager uses a line beam that spans a specific width across the sample, rather than a point beam. Therefore, a line scan imager can capture an entire row (or column) of image data at once and requires a simplified scanning assembly (e.g., one less galvanometer than the confocal point scan fundus imager described above). In some embodiments, a line scan imager may also include a second scanner to allow imaging over a wider field of view than a line. Alternatively, the entire optical head of the system may be manually rotatable to allow illumination over an even wider field of view.

[0057] Figure 4 A simplified exemplary scanning pattern for a line scan system is shown. In this example, the transverse line beam is generated by a radiation source (not shown) and scanned vertically (e.g., by using a vertical scanning galvanometer, such as...). Figure 2 The galvanometer 61 generates multiple scan lines L1 to Li in a vertical scanning mode (V-scan). As mentioned above, the two types of line scan imagers are laser line scan imagers and wide-line scan imagers. For ease of discussion, scan lines L1 to Li can represent line scans generated by either a laser line scan imager or a wide-line scan imager. It is understood that scan lines generated by a laser line scan imager are generally much narrower than those generated by a wide-line scan imager. In general, line scan imagers can maintain a perpendicular (e.g., along) direction to (e.g., along) the vertical direction of the imager. Figure 4 Some degree of confocal suppression of the defocused light along the Y-axis scan lines (L1 to Li), but lacking along the lines (e.g., along the Y-axis). Figure 4Confocal suppression (on the X-axis). Line scan systems have been combined with pupil segmentation (see, for example, U.S. Patent No. 8,488,895 to Muller et al., the entirety of which is incorporated herein by reference). Advantageously, line scan imagers can scan across the retina (or fundus) faster than confocal point scan imagers and are therefore less sensitive to motion artifacts, but at the cost of less defocus suppression. However, variations in line intensity or linear array sensitivity in a line scan system can lead to tailing in captured images.

[0058] Wide-line scan imagers strive to combine some of the advantages of laser line scan imagers with those of flood illumination imagers. Wide-line scan imagers use a much wider illumination line (or slit) than laser line scan imagers, thus allowing for a much greater optical extension. This enables the use of incoherent light sources (e.g., non-laser sources), such as one or more lamps or one or more LEDs, which are typically inexpensive and provide broadband illumination, helping to achieve more natural images.

[0059] Figure 5A , Figure 5B and Figure 5CExemplary wide lines (or illumination slits) 43A, 43B, and 43C of different sizes are shown for illuminating the corresponding fundus regions 41A, 41B, and 41C. In each figure, illumination slits 43A, 43B, and 43C are schematically shown as having different widths. Each illumination slit 43A, 43B, and 43C corresponds to the position of the scanning beam on the fundus at a specific scanning step or time. It should be noted that the scanning beam can scan smoothly across the retina or move step by step. Increasing the width of the illumination slit, such as slit 43C compared to strip 43A, increases the amount of light applied and can improve the dynamic range. In cases where the illumination does not move significantly during detector acquisition (typically when the scanning beam scans step by step and is relatively stationary during acquisition), the sharpness of the illumination strip edges can be used to find an optimized focus for the line scanning system. Various image processing techniques can be further used to improve the constructed image. For example, unilluminated areas on the retina (e.g., in captured images) can be detected to assess the background level, such as stray light level, from the out-of-focus area of ​​the eye. This background level can then be subtracted from the captured line image, for example, from illumination slits 43A, 43B, or 43C. Furthermore, the size of each vertical scanning step can be smaller than the width of the illumination slits, such that multiple consecutive illumination slits cover the same area of ​​the retina. In this way, multiple image captures will image the same area of ​​the retina. This allows for the use of various image processing techniques (e.g., averaging) to improve the image quality of individual areas. Alternatively, the optimal image quality of individual areas can be selected for stitching into the final composite image. Moreover, various pupil segmentation configurations can also be used with wide-line imaging systems. For example, pupil segmentation for illumination and detection can be implemented closer to the cornea than in a flood illumination fundus imager, and the slits can be illuminated instead of the illumination ring (as described above in the flood illumination fundus imager). Examples of wide-line (slit) scanning imagers are provided in U.S. Publication No. 2017 / 0049323 and U.S. Publication No. 2018 / 0014727, both of which are assigned to the same assignee as this invention, and the entire contents of which are incorporated herein by reference.

[0060] The aforementioned (fundus) scanning imager can use various scanning configurations. For illustrative purposes, some simplified scanning configurations are presented in the content of the line scanning imager (e.g., an imager using a scanning line beam), but these configurations can also be applied to point scanning imagers, as those skilled in the art will understand.

[0061] Figure 6A A scanning configuration (a so-called "scan-non-scan" system) is shown, wherein when the line beam 115 is scanned on another dimension (e.g., the Y dimension), such as in... Figure 4 , Figure 5A , Figure 5B and Figure 5C As shown, the transverse line beam 115 illuminates the lines L1 to Li across sample 109 in one dimension (e.g., the X-axis). Similarly, returned (e.g., reflected or scattered) light 116 is allowed to scan across collector 107 (e.g., a light detector or camera), optionally coupled to a CPU for further processing and a monitor for displaying the full-frame image, such as... Figure 2 As shown. In Figure 6A In this example, collector 107 can be a full-frame digital camera, and return light 116 can "draw" a full-frame image as the camera scans across a two-dimensional (2D) light sensor (e.g., a 2D array of light detectors). That is, each detected line of return light 16 can be captured at different locations on the camera, buffered, and processed to construct a synthetic full-frame image, either in a single acquisition or through multiple acquisitions that constitute the full frame (e.g., moving a series of line illuminations to additional horizontal positions on the sample). Radiation source 101 (e.g., a light source such as a laser, lamp, or LED) generates an illumination line beam 103 (an incoherent beam or laser beam). A radiation aperture 105, imaged onto a sample 109 (e.g., the surface to be imaged), can be positioned in front of radiation source 101 to help shape the illumination line beam 103. In the case of a fundus scanning imager, radiation aperture 105 can be imaged onto the retina of the eye. The illumination beam 103 may pass through one or more optics (e.g., lenses) 111 before reaching the scanning element (e.g., galvanometer) 113, which generates a scanning radiation beam (e.g., scan beam 115) defining illumination lines L1 to Li across the sample 109. It will be understood that, in more practical applications, the scan beam 115 output from the scanning element 113 may pass through scanning lens 117 and ophthalmic lens 119 before reaching the sample 109 (e.g., the retina or fundus of the eye), as referenced above. Figure 2 As described above. In this example, the line beam 115 output from the scanning unit 113 is perpendicular to the sample 109 in steps (e.g., as...). Figure 4 The V-scan shown is used. Scattered light 116 returning from sample 109 can pass through aperture 123 in scanning member 113 (or otherwise transmitted from sample 109) to collector 107, and can similarly be vertically scanned on collector 107 in the corresponding steps. More practical applications may include focusing lens 121 in front of collector 107. In the case of fundus scanning imagers, scanning member 113 may be substantially optically conjugate with the pupil of the eye.

[0062] As described in further detail below, an illumination block 125, which images onto a target optics device (e.g., ophthalmic lens 119), can be positioned in front of the radiation source 101 to create a movable non-illuminated area on the target optics device, which may be adjacent to the scanning beam 115 output from the scanning unit 113. This non-illuminated area prevents (or reduces) reflections caused by the scanning beam 115.

[0063] Figure 6B An idealized scanning configuration of a so-called “scan-to-scan” system is shown, in which the scan line beam 115 scans across sample 109, but the line of returned scattered light 139 is held at a single predetermined position on the collector, rather than scanning across the collector. Figure 6B Zhongyu Figure 6AAll identical elements have the same reference numerals and have been described above. Because the return line of the scattered light 139 is not scanned, this scanning configuration allows the use of a line scan camera 131 as a collector. Alternatively, a full-frame digital camera having a line, such as a row of pixels (or a predetermined number of rows of pixels to define a wide line), within its 2D array is designated as a region of interest (ROI), and the designated ROI is used to receive and capture the return light 139. In this example, the radiation source 101 generates an illumination line (or wide line / slit) (e.g., a line beam) 103, which passes through a beam splitter (beam separator) 133 onto an optical path 135, reaching a scanning element (e.g., a galvanometer) 137. The scanning element 137 converts the received illumination beam into a scanning beam that scans across the sample 109. As described above, in a more practical application, the light from the scanning element 137 may pass through a scanning lens 117 and an ophthalmic lens 119 before reaching the sample 109 (e.g., the retina or fundus of the eye). In this example, scanning component 137 can vertically scan the scan beam 115 along the sample in discrete scanning steps, but other scanning directions may also be used. In each scanning step, light is reflected / scattered back (during the capture phase) to scanning component 137. For the purposes of discussion, it can be assumed that scanning component 137 is substantially stationary during this capture phase and therefore reflects the returned light along the same optical path 135 as the incident light from radiation source 101. Thus, optical path 135 can be referred to as the shared path, as indicated by the double arrows. The returned, stationary scattered light is guided by beam splitter 133 onto collection path 139, which transmits it to a photodetector, such as line scan camera 131. As shown, the position of the returned scattered light on collection path 139 is substantially fixed and independent of the vertical scanning position of the line beams L1 to Li on sample 109; this is referred to herein as the “de-scan” operation. This allows the use of a line scan camera 131, which can contain a single row of pixels for very rapid data capture (e.g., using a fast CCD sensor or CMOS image sensor). The captured light from each discrete scan step can be captured and mapped into a buffer 141 at positions corresponding to the scan locations of the respective scan lines L1 to Li. The buffered line image can then be reconstructed (e.g., stitched or stitched) into a full-frame image, for example, by using a CPU (e.g., a computing system or device), and presented on a computer monitor, such as... Figure 2 As shown.

[0064] Optionally, an illumination block 125 can be used to reduce or eliminate reflections at the target optics. The illumination block 125 can be positioned in front of the radiation source 101 and can be placed on the conjugate plane of the target optics (e.g., scanning lens 119). Due to the scanning action of the scanning member 137, a moving non-illuminated area is generated on the target optics, which may be adjacent to the scanning beam 115 output from the scanning member 137. The non-illuminated area prevents (or reduces) reflections on the target optics caused by the scanning beam 115. Optionally, a collection block 143, imaged onto the same target optics, can be positioned in front of a collector (e.g., line scan camera 131). The use of the collection block 143 is facilitated because the returned scattered light on the collection path 139 is relatively stable (e.g., not scanning). Thus, a moving non-collection area can be generated on the target optics (e.g., ophthalmic lens 119), which prevents (or reduces) reflections caused by light returning from the sample 109. When the non-collecting region and the non-radiating region move on the conjugate plane of the target optical device or directly on the target optical device, they can be adjacent to or overlap each other.

[0065] Further reduction of reflections can be achieved by using cross-polarizers. That is, introducing two polarizers orthogonal to each other in a cross-polarizer configuration, for example, polarizers in each path of the illumination and detection (collection) paths, can further reduce reflections. For example, a first polarizer can be positioned in the illumination path, and a second polarizer, orthogonal to the first polarizer (e.g., rotated 90 degrees relative to the first polarizer), can be positioned in the detection path. The polarizers can be anywhere in these paths, but preferred embodiments may place them in the stationary portion of the path; for example, the first polarizer can be positioned before the scanning mirror 137 in the illumination path from the light source 101 to the sample 109 (e.g., the eye), and the second polarizer can be positioned in the collection path 139 after the scanner 137 (e.g., in the de-scanned portion of the optical (collection) path from the sample (e.g., the eye) to the collector).

[0066] Figure 6A Some advantages of scan-to-non-scan systems (such as simplified image capture structure) and Figure 6B Some advantages of the scan-to-de-scan system (such as the ability to collect unscanned, stable return light used by block 143) can be achieved in a third scan configuration, which is referred to herein as “scan-to-de-scan-re-scan”. Figure 6CA simplified scan-de-scan-re-scan system is shown, wherein an auxiliary scanning mechanism is incorporated into the scan-de-scan system to re-scan (e.g., re-scan) the returned, scattered light generated by the scan-de-scan system before it reaches the collector, or otherwise not scan (e.g., de-scan), thereby re-scanning the returned scattered light across the collector. Figure 6C Zhongyu Figure 6A and Figure 6B All identical elements have the same reference numerals and have been described above. As previously stated, a radiation source 101 with a selectable aperture 105 and a collimating lens 111 generates an illumination line beam 103, which passes through a beam splitter 133 onto an optical path 135 and reaches a scanning element (e.g., a galvanometer) 137. The scanning element 137 converts the received illumination beam into a scanning beam (e.g., a scanning line beam 115), which can pass through a scanning lens 117 and an ophthalmic lens 119 to scan across a sample 109 (e.g., the retina or fundus of the eye). Figure 6B In this case, the light returning from sample 109 is descanned by scanning member 137 to generate a substantially stable return line beam on optical path 135, which is guided onto collection path 139 by beam splitter 133. The descanned return light on collection path 139 is then guided to a second scanning mechanism, for example, by using one or more mirrors 151a / 151b along optical paths 153a and 153b. In this example, the back surface of the galvanometer (scanning member 137) is reflective and serves as the second scanning mechanism to rescan the return light and define the rescanned collection beam 116b on collector 107 via focusing lens 121. Since the scanning beam 115 and the rescanned collection beam 116b are defined together by scanning member 137, they correspond to each other.

[0067] As in Figure 6A In this case, the illumination block 125 can be used to reduce or eliminate reflections at the target optics (e.g., ophthalmic lens 119). That is, the illumination block 125 can be positioned in front of the aperture 105 and the radiation source 101, and can be imaged onto the target optics (e.g., the rear or front surface of the target optics). This creates a moving unilluminated area on the target optics, which may be adjacent to the scanning beam 115 output from the scanning unit 137. Furthermore, the collection block 143 can be used before rescanning the return light of the rescanned collection beam 116b. That is, optionally, the collection block 143 can be positioned along any of the optical paths 139, 153a, or 153b. Figure 6BIn this case, the collecting block 143 can be imaged onto the same target optics, at which it is desirable to reduce reflections due to returned scattered light. Since the returned light between the collecting block 143 and the beam splitter 133 is relatively stable (e.g., not scanning) along the collecting path (e.g., 139, 153a, and / or 153b), this facilitates the use of the collecting block 143. Therefore, a moving non-collecting region can be generated on the target optics (e.g., ophthalmic lens 119) that prevents (or reduces) reflections due to returned light from the sample 109. As previously described, when the non-collecting and non-radiating regions move on the conjugate plane of the target optics or directly on the target optics, they can be adjacent to or overlap each other.

[0068] U.S. Patent No. 9,549,672 provides additional examples of scanning configurations used in fundus scanning imagers, which has been assigned to the same assignee as this application and is incorporated herein by reference in its entirety.

[0069] Typically, lenses can introduce aberrations due to their imperfect focusing (e.g., light may be scattered over a region of space instead of being focused on a single point). For example, light from the outside / edge of the lens may appear blurry or distorted compared to the interior of the lens. This type of aberration may be due to field curvature or because the lens tends to focus the image at the edges, which appear too close to the center where the focus is best. Optionally, one or more spherical mirrors can be used to eliminate / cancel / reduce this type of aberration. The field curvatures on multiple lenses can be traced (e.g., combined) using the Petzvalsum. Typically, under the consistent radius convention assumed when deriving the Petzvalsum, converging lenses (e.g., as used in this exemplary embodiment) have a positive term in the sum. In contrast, converging mirrors have negative radii and negative field curvatures, and can be used herein to cancel the field curvature of converging lenses. Although multiple spherical mirrors may be used (e.g., one in the illumination path from the light source to the eye, and another in the return observation path from the eye to the collector (e.g., the collection path)), a single spherical mirror (e.g., one that compensates for the combined field curvature of the lenses according to the size of the petzwald) may be sufficient, and this single spherical mirror may be positioned anywhere along the observation path, or in a shared, scanned, or descanned segment.

[0070] The advantage of using spherical mirrors in shared paths (e.g., the portion of the optical path shared by the illumination and returning collection paths) is that a major challenge in fundus imaging is blocking back reflections from the cornea and optics in the portion of the optical system shared by the illumination and collection paths (e.g., between the beam splitter and the retina). Unlike transmission lenses, which allow light to pass through the interface between air and glass, mirrors do not exhibit significant back reflections, thus greatly reducing the problem of back reflections. The difficulty in replacing lenses in shared paths with mirrors lies in the fact that mirrors reflect light, thus folding the optical path back to the eye, which creates difficulties in terms of mechanical interference between the optical system and the face.

[0071] Spherical mirrors can be used with any scanning configuration discussed herein, but for illustrative purposes, Figure 6D It shows the integration of spherical mirrors into something similar Figure 6C The system involves scanning, descanning, and rescanning. Figure 6D Zhongyu Figure 2 , Figure 6A , Figure 6B and Figure 6C All identical elements have the same reference numerals and have been described above. (As in...) Figure 6C In the example, a radiation source 101 with a selectable aperture 105 and a collimating lens 111 produces an illumination line beam 103, but with... Figure 6C Unlike other examples, beam splitter 133 is not required. Instead, illumination beam 103 can directly reach the scanning element, which in this example is embodied as a set of mirrors (e.g., a polygon scanner) 138 that rotate back and forth to achieve scanning across a sample (e.g., eye 75). Thus, polygon scanner 138 converts the received illumination beam 103 into a scanning beam (e.g., path 115a) that passes through scanning lens 117 and ophthalmic lens 119 to scan across the retina 73 of eye 75. Scattered light returning from eye 75 (e.g., optical path 115b) is de-scanned by different surfaces of polygon scanner 138 to produce a substantially stable return line beam on optical path 139a, which is then guided to spherical mirror 151c.

[0072] The difficulty with using spherical mirrors lies in the fact that, to prevent a beam of light guided at the spherical mirror from reflecting directly back to itself, the beam needs to strike the mirror off-axis (e.g., not perpendicular to the mirror's surface). However, off-axis strikes can produce unwanted astigmatism. Several methods can address this problem. To minimize astigmatism, it is desirable to strike the mirror (e.g., spherical mirror 151c) as coaxially as possible. Astigmatism can be eliminated by adjusting the radius of curvature of the mirror along the plane of reflection of the incident beam. Astigmatism associated with the difference in mirror curvature between the reflecting plane and the orthogonal plane can cancel out astigmatism associated with off-axis illumination. Another method for eliminating astigmatism from the first spherical mirror (e.g., spherical mirror 151c) is to reflect the beam back from a second spherical mirror (not shown), whose reflecting plane is orthogonal to that of the first spherical mirror. The astigmatism from the two mirrors is then orthogonal and can therefore be eliminated. To avoid other aberrations, parabolic or other higher-order mirror shapes can also be used.

[0073] The advantage of using a spherical mirror in a de-scanned path is that it can be used to help redirect the de-scanned path back to scanner 138. For example... Figure 6C As shown by mirrors 151a and 151b, the de-scanned path is typically folded by multiple mirrors to return to scanner 137 and be re-scanned. Since spherical mirror 151c inherently folds the optical path (e.g., reflects light), its position in the de-scanned path allows it to serve two purposes. First, it compensates for aberrations caused by the field curvature of the lenses in the system (e.g., according to Petzwald and). Second, spherical mirror 151c acts as a fold, returning the de-scanned line beam along optical path 153c to another surface of polygon scanner 138, where the line beam is re-scanned to define a re-scanned collected beam 116c on collector 107 via focusing lens 121. Alternatively, a second spherical mirror can be added to the illumination path (e.g., the path from light source 101 to polygon scanner 138), introducing a second folded path, and the folding of the optical path allows for a more compact design, making it possible to reduce the size of the fundus camera.

[0074] As previously described, the illumination block 125 can be used to reduce or eliminate reflections at a target optics device (e.g., ophthalmic lens 119). That is, the illumination block 125 can be positioned in front of the aperture 105 and the radiation source 101, and can be imaged onto the target optics device (located on a conjugate plane of the target optics device's surface) (e.g., on a curved surface of the target optics device) to create a moving unilluminated area on the target optics device. The collection block 143 can be positioned on a de-scanned segment of the path returning from the eye 75. In this example, the collection block 143 is positioned before the spherical mirror 151c in the de-scanned path from the polygon scanner 138 to the spherical mirror 151c. Alternatively, the collection block 143 can be imaged onto the same target optics device (located on a conjugate plane of the same target optics device's surface) (e.g., ophthalmic lens 119), or onto another target optics device, where it is desirable to reduce reflections due to returned scattered light. Therefore, a moving non-collecting region can be generated on the target optics, which prevents / reduces reflections caused by light returning from the retina of the eye 75. When the non-collecting and non-radiating regions move on the target optics, or on the conjugate plane of the target optics, they can be adjacent to or overlap each other.

[0075] As described above, the present invention aims to reduce image artifacts, such as those caused by reflections from system optics in a scanning imager (e.g., a line scan imager or a point scan imager). This can be achieved by placing light blocks (e.g., radiation blocks, illumination blocks, or collector blocks) in the illumination path and / or collection path on the conjugate plane of the target optics (e.g., the plane to which the target optics are imaged), thereby minimizing or eliminating overlap between the illumination path and the collection path on a given optics (e.g., the target optics). As described above, this technique can be applied to different scanning configurations of scanning imagers. For illustrative purposes, some specific examples of scan-to-scan scanning imagers are provided below, and it is understood that this discussion can be applied to other scanning configurations unless otherwise stated. As described above, in a scan-to-scan configuration, scattered light returning from the sample is de-scanned, thereby causing the returned light to be fixed (e.g., not scanned) for at least a portion of the collection path. An illumination block can be inserted into the illumination path, and a collection block can be inserted into a fixed portion of the collection path. The images (e.g., darkened areas) from these two optical blocks can be generated on one or more target optics (e.g., ophthalmic lenses or scanning lenses). This eliminates the overlap between the illumination path and the collection path at the target optics, thereby eliminating reflections from the target lens. The examples below illustrate various design concepts to make this reflection-blocking effect more robust to changes in alignment, focus, etc.

[0076] As described above, scanning imagers minimize unwanted light returning to the detector (e.g., camera) by illuminating a limited area of ​​the sample to be imaged (e.g., the retina of the eye) at a time and collecting light only from that limited area, thereby blocking light that has already been reflected or scattered back to the camera from other illuminated areas of the sample. In line-scan imagers used for ophthalmic imaging, the separation between illumination and collection (pupil segmentation) on a plane near the pupil of the eye eliminates reflections from the cornea and reduces reflections from the ophthalmic lens (the imager lens closest to the cornea), but does not eliminate ophthalmic lens reflections.

[0077] In a scanning imager, such as a line scan imager, the scanning component can be imaged onto the pupillary plane. Therefore, by imaged onto the scanning component (e.g., by imaged separately on the scanning component, with an illumination window and a collection window), the illumination and collection light can be separated relatively easily at the pupil (or near the pupil, such as at the cornea), just before the scanning component (potentially close to the corneal plane). In other words, if the scanning component is essentially imaged onto the pupil, separating the illumination and collection windows before the scanning component will bring the pupil separation closer to the cornea.

[0078] However, at ophthalmic lenses (or other target optics in scanning imagers), separating the illumination and collection light is much more difficult. Typical methods for reducing reflections at ophthalmic lenses rely on a combination of pupillary segmentation at the pupillary plane and an (illumination) slit with highly limited optical spread (e.g., very narrow slit requirements), but even this yields limited results. Besides failing to completely eliminate ophthalmic lens reflections, relying solely on the narrowness of slit illumination results in very narrow slits (e.g., a width of 0.25 degrees in practical applications), and / or small scanning steps with overlapping slit illumination on the retina increase the number of scans required to complete a full scan across the retina (e.g., the object / sample being imaged). This very narrow slit width requirement also limits the amount of light reaching the retina and leads to long acquisition times or noisy images.

[0079] It should be noted that, due to differences in eye length (and pupil size), as understood by those skilled in the art, the linear distance along the retinal span (e.g., the width of the illumination slit) is conventionally defined in degrees, that is, the width of the field of view across the retina that results in a specific degree of focal length, assuming the focal length extends substantially from the pupil to the retina.

[0080] In this invention, instead of minimizing the narrowness of the slit illumination (e.g., the width of the illumination slit / line beam) to reduce reflections at the ophthalmic lens, the reflections caused by the overlap between the illumination path and the collection path at the ophthalmic lens (or another target optical component within the scanning imager) are addressed directly, regardless of pupil segmentation. This is achieved by placing a light block in the illumination path and / or collection path on a plane conjugate to the ophthalmic lens (e.g., the image plane to which the target optics are imaged), such that the light block is imaged (focused) onto the target optics.

[0081] Figure 7 An example of an alternative scan-to-scan configuration for a slit (or line) fundus imaging system incorporating the present invention is shown. Figure 7 Zhongyu Figure 2 The same elements in Figure 6 have the same reference numerals and have been discussed above. Illumination (e.g., a slit beam or line beam) from radiation (or illumination) source 101 passes through illumination slit 105 along illumination beam path (103a to 115a), which helps to shape the slit beam (or slit illumination), passes through first beam block (e.g., illumination block) 125, and reaches scanning member 137 through lens 111. At scanning member 137, it is scanned to generate a scanning beam along path 115a. The scanning beam can pass through scanning lens 117 and ophthalmic lens 119 into eye 75 and scan the light incident on retina 73. Light scattered from retina 73 returns along the collected beam path (e.g., 115b to 103b to 161) through ophthalmic lens 119 and scanning lens 117, is scanned by rotating scanning mirror 137, deflected onto optical path 161 by pickup mirror 163, passes through lens 121, and reaches camera 131, such as detector or collector, via second beam stop (e.g., collection stop) 143. In this example, scanning element 137 may be imaged onto the pupillary plane of eye 75, and pickup mirror 163 may be positioned close to scanning element 137 (e.g., just before scanning element 137) to more closely segment the illumination and collection paths (e.g., provide pupillary segmentation). And in this example, camera 131 may be a line scan camera, and time delay integration (TDI) may be used to generate the vertical dimension of the image (e.g., a full-frame image). As described above, the line image captured by camera 131 can be buffered, processed by the CPU, and stored for future processing and / or display on a monitor (e.g., see...). Figure 2In this example, the ophthalmic lens 119 is the target optics on which reflection artifacts are removed or reduced. Therefore, both beam blocks 125 and 143 can be imaged onto the ophthalmic lens 119. Specifically, beam blocks 125 and 143 can be imaged onto the rear surface 119a of the ophthalmic lens 119. Alternatively, beam blocks 125 and 143 can be imaged onto the front surface 119b of the ophthalmic lens 119, or one beam block (e.g., illumination block 125) can be imaged onto the rear surface (e.g., surface 119b) of the ophthalmic lens 119, while the other beam block (e.g., collection block 143) can be imaged onto the opposite side surface (e.g., front surface 119a) of the ophthalmic lens 119.

[0082] In this scan configuration ( Figure 7 In this configuration, the light returning from the sample (e.g., eye 75) is descanned, and portions of the illumination path and collection path can be substantially fixed. For example, the illumination beam output from the light source 105 can be fixed on the optical path 103a before being scanned by the scanning member 137, and the returned light (e.g., the collected beam) on the optical paths 103b and 161 can be fixed after being descanned by the scanning member 137. Although the illumination block 125 can be inserted anywhere in the illumination path (e.g., from 103a to 115a), and the collection block 143 can be inserted anywhere in the collection path (e.g., from 115b to 103b to 161), for the convenience of implementation, the illumination block 125 can be positioned on a fixed portion of the illumination path (e.g., 103a) before being scanned by the scanning member 137, and the collection block 143 can be positioned on a fixed portion of the collection path (103b and / or 161) after being descanned by the scanning member 137.

[0083] Figure 8 Provided Figure 7A simplified, non-scale, close-up view of the ophthalmic lens 119, including an imaged illumination block 125' (e.g., a non-illuminated area created by the illumination block 125), an imaged collection block 143' (e.g., a non-collection area created by the collection block 143), a scanning beam from the scanning member 137 that can pass through to reach the illumination window 165 of the eye 75, and a returning light from the eye 75 that can pass through to reach the scanning member 137 and the collection window 167 of the collector 131. That is, the illumination block 125 can create an imaged illumination block 125' that defines a non-illuminated area through which the scanning beam from the scanning member 137 cannot pass, and the collection block 143 can create an imaged collection block 143' that defines a non-collection area through which light returning from the eye 75 cannot pass. As shown, optionally, the imaged illumination block 125' may overlap (e.g., define an overlap area 169) with the imaged collection block 143' on the target optics (e.g., a lens or ophthalmic lens 119 near the eye 75). This eliminates any overlap between the illumination path 115a (e.g., illumination window 165) and the collection path 115b (e.g., collection window 167) at the optics, and thus eliminates reflections from the optics. As the scanning member 137 sweeps (e.g., rotates), the two imaged blocks 125' and 143' move together through the ophthalmic lens (e.g., as indicated by arrows 171a / 171b), maintaining their overlap 169, thereby blocking reflections. Alternatively, the illumination block 125' and the collection block 143' may be imaged to be adjacent to each other but not overlapping.

[0084] Figure 9 An example of an alternative scan-de-scan-re-scan configuration for a slit (or line) fundus imaging system incorporating the present invention is shown. Figure 9 Zhongyu Figures 2 to 8 The same elements have the same reference numerals and have been discussed above. The scan-descan section of this configuration is similar to... Figure 7 The scan-to-scan section, but this configuration is different from... Figure 7The difference lies in the inclusion of a rescanning mechanism between its collector (e.g., camera 189) and the collection stop 143. That is, slit illumination from light source 101 travels along the illumination beam path (103a to 115a) through illumination slit 105, past the first beam stop (e.g., illumination stop) 125, through lens 111, and reaches scanning element (e.g., galvanometer) 137, which generates a scanning beam on optical path 115a. The scanning beam on illumination path 115a passes through scanning lens 117 and ophthalmic lens 119 into eye 75, where it is scanned and incident on retina 73. Light scattered from retina 73 returns along the collected beam path (115b to 103b to 161 to 191) through ophthalmic lens 119 and scanning lens 117, is scanned by rotating scanning mirror 137, deflected onto optical path 161 by pickup mirror 163, passes through lens 121, passes through second beam block (e.g., collection block) 143, and passes through collection slit (or aperture) 181, which may be located corresponding to Figure 7 The camera 131 is positioned at the location of the retina 73. Optionally, the collecting (slit) aperture 181 may be located on the conjugate plane of the retina 73. The returning light passing through the collecting aperture 181 passes through the focusing lens 183 and is rescanned by a second scanning element (second galvanometer) 185, which may be synchronized with the scanning element 137. The rescanned returning light from the second galvanometer 185 passes through an optics 187 (which may be one or more lenses, such as a second scanning lens and a focusing lens) to scan across a camera 189, which may be a full-frame camera, to define the composite image.

[0085] In the scan-not-scan configuration (e.g., for example...) Figure 6A In the configuration shown, the illumination light is scanned, but the collected light is not de-scanned. Illumination blocks can still be placed in the illumination path leading to the ophthalmic lens (or other target optics) to reduce unwanted reflections, but there may not be a corresponding position in the collection path to place such a collection block. Placing a block only in the illumination path will reduce reflections, but it may not be as effective as placing blocks in both the illumination and collection paths to ensure that there is no overlap between the illumination and collection paths at the ophthalmic lens.

[0086] Variations in refractive errors across the population can also complicate matters. To effectively image patients with different refractive errors (degrees of myopia or hyperopia), fundus imagers typically have focusing mechanisms to focus the image of the retina onto a camera sensor (e.g., a collector or detector). If this focusing alters the position of the image (conjugate) plane of the ophthalmic lens (or other target optics) where the illumination and / or collection blocks are placed, it is desirable to move the block position with the focusing to maintain it on the ophthalmic lens image plane. Alternatively, since reflection problems are more severe in more myopic patients, the block may be placed (e.g., fixed) at a position corresponding to the ophthalmic lens image plane of a relatively myopic patient (e.g., -10 diopters).

[0087] Another method to keep the position of the illumination block / collection block substantially constant relative to the image plane of the ophthalmic lens is to keep the optics between the illumination block / collection block and the ophthalmic lens fixed, and to separately correct the camera focus between the illumination block / collection block and the illumination source / camera. For example, in Figure 9 In one embodiment, the position of the collecting block 143 is kept fixed on the conjugate plane of the ophthalmic lens 119, while one or more lenses (e.g., lens 183 and / or lens 187) between the camera 189 and the collecting block 143 are adjusted so that the image of the retina 73 is focused on the light sensor of the camera 189. It has been found that maintaining the focus of the illumination beam (e.g., in…) Figure 9 The light path 103a in the light block may not be critical, so the illumination focus can also be adjusted between the illumination block (e.g., 125) and the illumination source (e.g., 101 / 105), or the illumination block 125 can remain stationary when adjusting the camera focus.

[0088] While there is an optimal location for the illumination and collection blocks (e.g., on the conjugate plane of the target optics), some flexibility has been established regarding their placement. A blind zone is provided between the post-imaging blocking regions (e.g., 125' and 143'). Figure 8 The overlapping portion (169) can reduce the sensitivity of the positioning of the illumination block and the collection block relative to the image plane corresponding to the ophthalmic lens (or other target optics). Such overlapping portions or blind spots are also desirable for eliminating the overlap between illumination and collection at the ophthalmic lens in the presence of optical aberrations in the system. Because line-scan systems (e.g., wide-line-scan imagers) have low optical spread in the segmentation direction (e.g., perpendicular to the slit length direction), a relatively small amount of overlap allows for significant flexibility in the placement of the illumination block and the collection block.

[0089] It was also found that in patients with high myopia (e.g., -6 diopters), the cornea can image the retinal plane onto a plane close to the ophthalmic lens. Therefore, in patients with high myopia, obstructing the overlap between the illumination and collection paths at the ophthalmic lens may affect the overlap between the illumination and collection paths at the retina, potentially leading to reduced optical efficiency and lower image brightness. Therefore, it is desirable to have imaging modalities for some myopic patients (e.g., those with high myopia) where the illumination and collection blocks are removed, or pulled back slightly, to allow some overlap between the illumination and collection paths at the ophthalmic lens, accepting some reflections in the image to maintain acceptable overall brightness and image quality.

[0090] Although the illumination path and the collection path are separated by a reflector 163 positioned just before the scanning component 137, for example, Figure 7 and Figure 9 As shown, this provides a relatively flexible design, but it introduces additional alignment steps when the deflection angle of the mirror becomes a free parameter. Conceptually, an optical wedge (e.g., see...) can be used. Figure 6B To replace mirror 163, a fixed angle is deflected to the collection path, thus eliminating this free parameter. One problem with inserting a wedge optics or prism into the system is that reflections from the front and rear surfaces of the wedge can produce artifacts in the image. However, by modifying the focusing optics and adding a wedge to one side, a "double lens" as described herein can be obtained. Combining the double lenses into a single compound structure is what is referred to herein as a "compound double lens".

[0091] Figure 10 A conceptual design of a compound double lens 209 is shown. As illustrated, it is desirable to combine lens 201 with optical wedge 203. This can be achieved by combining lens 201 with prism 205 to obtain a conceptual double lens 207, which can be constructed (e.g., molded) as a single component to obtain a compound double lens 209 with a fixed spacing between the two centroids C1 and C2.

[0092] Figure 11 An alternative structure is shown for adding a beam stop (125 / 143) to the ophthalmic lens / eyepiece 119 in a scan-de-scan-re-scan line scan system using a compound dual lens 209. Using the compound dual lens 209 to separate the illumination and collection paths reduces both alignment steps and the number of components. Figure 11 Zhongyu Figures 2 to 10All identical elements have the same reference numerals and have been described above. In this example, the pupil segmentation aperture 211 (or segmentation region) may be positioned immediately before the scanning member 137 (e.g., in the path between the light source 101 and the scanning member 137) and close to the corneal imaging, for example, assuming the scanning member 137 images onto the pupil, as described above. Furthermore, the ophthalmic lens 119 may be adjusted for myopia, and the illumination block 125 and the collection block 143 may be on the conjugate plane of the ophthalmic lens 119 (e.g., corresponding to a myopic eye setting) to block reflections. And, the radiation slit (aperture) 105 and the collection slit (or aperture) 181 may be imaged onto the retina 73 and are further constructed on a common (same) membrane, thereby eliminating the need to align one with the other (e.g., displacement is determined by the separation between the bilenses 209). Furthermore, the beam stoppers 125 / 143 and the slits 105 / 181 can move together, for example, by means of a common (same) support wall W1, thereby maintaining alignment. The support wall W1 can further provide a light barrier to separate the illumination light on the side of the light source 101 from the collected light on the side of the second scanning member 185 and the collector 189.

[0093] In this example, the illumination stop 125 and the collecting stop 143 are substantially coplanar on the image plane of the ophthalmic lens (eyepiece) 119 and can be manufactured from a single foil, thus providing high alignment accuracy between them. Similarly, the illumination slit 105 and the collecting slit 181 are also coplanar and therefore can also be manufactured from a single foil. The alignment tolerance between the beam stops 125 / 143 and the slits 105 / 181 may not be as stringent as the relative alignment between the slits or between the beam stops, so this alignment can rely on precise mounting between the two components without requiring further alignment adjustments. The two centroids C1 and C2 of the compound double lens 209 (see...) Figure 10 The spacing between the two lenses is critical for alignment, so it is desirable to mold the compound dual lens 209 as a single component.

[0094] In the above description, the beam block (e.g., 143 / 125) has been imaged onto the ophthalmic lens, as the lens is a crucial component that generates reflections in an ophthalmic scanning imager. However, a similar method of placing a beam block (e.g., an additional or identical beam block) on the conjugate plane of a given target optics other than the ophthalmic lens can be used to block reflections from that other target optics in the system.

[0095] Figure 12An example computer device (or CPU or computer system) 83 is shown. The computer device 83 can take any suitable physical form. For example, the computer system 83 can be an embedded computer system, a system-on-a-chip (SOC), a single-board computer system (SBC) (e.g., a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, a computer system grid, a mobile phone, a personal digital assistant (PDA), a server, a tablet computer system, or a combination of two or more of these systems. Where appropriate, the computer device (or computer system) 83 can reside in a cloud, which may include one or more cloud components in one or more networks.

[0096] In some embodiments, the computer system 83 includes one or more processors 102, memory 104, storage 106, input / output (I / O) interface 108, communication interface 110, and bus 112. Optionally, the computer system 83 may also include a display 114, such as a computer monitor or screen (e.g., or...). Figure 2 The processor 102 includes hardware for executing instructions, such as instructions that constitute a computer program. For example, the processor 102 may be a general-purpose computing unit on a central processing unit (CPU) or a graphics processing unit (GPGPU). Memory 104 may include main memory for storing instructions that the processor 102 executes or saves temporary data during processing. For example, memory 104 may include random access memory (RAM), such as dynamic RAM (DRAM) or static RAM (SRAM). In some embodiments, memory 106 may include long-term or high-capacity memory for data or instructions. For example, memory 106 may include a hard disk drive (HDD or SSD), flash memory, ROM, EPROM, or other types of non-volatile memory. I / O interface 108 may include one or more interfaces for communicating with I / O devices, enabling communication with a person (user). Communication interface 110 provides a network interface for communicating with other systems or networks. For example, communication interface 110 may include a network interface controller (NIC) and / or a wireless NIC for communicating with another computer system on a network. Communication interface 110 may also include a Bluetooth interface or other types of packet-based communication. Bus 112 provides a communication link between the aforementioned components of computing system 83.

[0097] Although the invention has been described in conjunction with several specific embodiments, it will be apparent to those skilled in the art, based on the foregoing description, that many further alternatives, modifications, and variations will be apparent. Therefore, the invention described herein is intended to cover all such alternatives, modifications, applications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A scanning imaging system, comprising: Radiation source; A scanning component receives radiation from the radiation source and defines a scanning beam of radiation; An optical device that guides a scanning beam of radiation onto a sample to be imaged, the optical device comprising a target optical element on which the scanning beam of radiation scans; A radiation blocking component is positioned to partially block radiation output from the radiation source and limit radiation received by the scanning component. The radiation blocking component is located on the conjugate plane of the target optical element and creates a moving non-radiative zone on the target optical element. The scanning beam of the radiation cannot pass through the moving non-radiative zone. A portion of the scanning beam outside the moving non-radiative zone is scanned across the sample, thereby creating a moving illumination area on the sample. A collector for collecting radiation returned from the moving lighting area; as well as A collector blocking component is positioned to partially block radiation returning from the moving illumination area. The collector blocking component is on the conjugate plane of the target optical element and creates a moving non-collecting area on the target optical element. Radiation returning from the moving illumination area cannot pass through the moving non-collecting area, wherein the radiation blocking component and the collector blocking component are coplanar. An illumination hole is located on the conjugate plane of the surface of the sample to be imaged, between the illumination source and the radiation blocking component; A collection hole on the conjugate plane of the surface of the sample to be imaged, the collection hole being between the collector and the collector blocking component; The illumination hole and the collection hole are coplanar.

2. The scanning imaging system according to claim 1, further comprising: The segmented region is essentially imaged to a position immediately preceding the scanning component in the radiation path from the radiation source to the scanning component. The segmented region separates the scanning beam of the radiation at the sample from the radiation returning from the sample. The segmented region has a first sample opening and a second sample opening, through which the scanning beam of the radiation passes and through which the radiation returning from the sample passes. The first sample opening and the second sample opening are coplanar. A dual lens is formed by molding two coplanar lenses into a single optical component, and the dual lens includes a first sub-lens aligned with the opening of the first sample and a second sub-lens aligned with the opening of the second sample; The structural support maintains alignment between the first sample opening, the first sub-lens, the radiation blocking component, and the illumination hole, and also maintains alignment between the second sample opening, the second sub-lens, the collector blocking component, and the collection hole.

3. A scanning imaging system, comprising: Radiation source; A scanning component receives radiation from the radiation source and defines a scanning beam of radiation; An optical device that guides a scanning beam of radiation onto a sample to be imaged, the optical device comprising a target optical element on which the scanning beam of radiation scans; A radiation blocking component is positioned to partially block radiation output from the radiation source and limit radiation received by the scanning component. The radiation blocking component is located on the conjugate plane of the target optical element and creates a moving non-radiative zone on the target optical element. The scanning beam of the radiation cannot pass through the moving non-radiative zone. A portion of the scanning beam outside the moving non-radiative zone is scanned across the sample, thereby creating a moving illumination area on the sample. A collector for collecting radiation returned from the moving lighting area; in: The sample to be imaged is an eye with a pupil and a fundus; The scanning beam of radiation enters the eye through the pupil and generates the moving illumination area in the fundus; and Radiation returning from the moving illumination area leaves the eye through the pupil; The system also includes: A radiation aperture positioned in front of the radiation source, the radiation aperture substantially imaging the fundus; A pupil-splitting optics that substantially images onto the pupil of the eye, the pupil-splitting optics separating the scanning beam of radiation entering the eye from the returning radiation leaving the eye, the pupil-splitting optics including a pupil aperture substantially imaged onto the pupil; The radiation blocking component is positioned between the pupil and the radiation aperture.

4. The scanning imaging system according to claim 1 or 3, wherein, The target optical element is a system lens positioned in the radiation path from the scanning component to the sample to be imaged.

5. The scanning imaging system according to claim 4, wherein, The system lens is closest to the sample on the radiation path from the scanning component to the sample.

6. The scanning imaging system according to claim 1 or 3, wherein, The radiation source is one of a laser source and an incoherent radiation source.

7. The scanning imaging system according to claim 1 or 3, wherein, The radiation emitted from the radiation source is essentially a rectangular beam.

8. The scanning imaging system according to claim 7, wherein, The rectangular radiation beam has a length dimension and a variable width dimension that is substantially perpendicular to the length dimension.

9. The scanning imaging system according to claim 1 or 3, wherein, The scanning imaging system is one of a point scanning imager and a line scanning imager.

10. The scanning imaging system according to claim 1 or 3, wherein, The scanning imaging system is one of the following: a scan-non-scan system, a scan-non-scan system, and a scan-non-scan-re-scan system.

11. The scanning imaging system of claim 1 or 3 further includes a spherical mirror to counteract field curvature aberrations of one or more lenses of the scanning imaging system.

12. The scanning imaging system according to claim 11, wherein, The radius of curvature of the spherical mirror is adjusted along the reflection plane of the incident beam to reduce or eliminate astigmatism from the spherical mirror.

13. The scanning imaging system according to claim 1 or 3, further comprising: First spherical mirror; as well as The second spherical mirror is positioned to receive reflected signals from the first spherical mirror and has a reflecting plane orthogonal to the reflecting plane of the first spherical mirror to cancel the astigmatism of the first spherical mirror.

14. The scanning imaging system of claim 1 or 3 further includes a cross polarizer, the cross polarizer comprising a first polarizer positioned in the optical path from the radiation source to the sample, and a second polarizer orthogonal to the first polarizer and positioned in the optical path from the sample to the collector.

Images