HK1196986A - Stereoscopic optics - Google Patents

Abstract

An adapter system for displaying and recording stereoscopic images from a single lens optic device and methods of producing stereoscopic images using such an adapter are provided herein. The adapter system utilizes an active stereoscopic shutter mounted along the optical path of the single lens optic device, such as, for example, a microscope or an endoscope, to provide a stereoscopic image to a video or still camera mounted along the same optical path.

Description

Three-dimensional optical system

Technical Field

The present invention relates generally to stereoscopic optical apparatus and more particularly to a stereoscopic optical assembly suitable for mounting stereoscopic imaging apparatus to conventional single lens optics, such as medical microscopes and endoscopes.

Background

Many stereoscopic imaging and/or viewing arrangements are known. For example GB606,065, which dates back to 1948, discloses an arrangement for viewing large models in a stereoscopic manner in which a viewing tube containing an objective lens and an add lens is combined with two mutually orthogonal mirrors which divert light exiting from left and right regions of the add lens to respective eyepieces of a binocular viewing arrangement. Us patent No. 2639653, which dates back to 1949, discloses a camera arrangement for taking micrographs using a microscope, the picture being viewed stereoscopically to obtain the stereoscopic impression of an object. Thus, the basic optical systems involved in producing stereoscopic images are well known. However, the application of these stereoscopic techniques to conventional optical devices such as microscopes and endoscopes in a manner that allows easy capture of both still and motion images is significantly more complex and has not achieved predictable success in view of the time and effort involved in these techniques.

For example, modern research microscopes often employ a light splitting assembly to allow for more viewing, video, and camera accessory ports. Available beamsplitters have a variety of configurations and may provide one or more optical connection ports in addition to the main viewing eyepiece. In addition, to provide greater flexibility, some adapters are designed to allow multiple cameras to be mounted to a single optical port on the microscope beam splitter. An adapter for simultaneously mounting a video camera and a 35-mm camera on one side of a surgical microscope beamsplitter is shown, for example, in U.S. patent nos. 4272161 and 4143938, the disclosures of which are incorporated herein by reference. These adapters are commercially available from Carl Zeiss, Inc., manufactured by Burbank Urban engineering, Calif.

Other prior art references describe other optical adapters that allow for the integration of cameras, the use of automatic iris control, integration of zoom, and magnification changes into these optical accessories. For example, a beam splitter with an integrated camera is shown in U.S. patent nos. 4805027 and 4344667, and a beam splitter with three identical optical trains and 4 viewing stations is shown in U.S. patent No. 4688907; an automatic iris control system for a surgical microscope adapter is shown in U.S. Pat. Nos. 3820882 and 4300167, a zoom lens adapter for an endoscopic camera is shown in U.S. Pat. No. 4781448; a universal adapter that allows for the use of different focal length magnifications is shown in U.S. patent No. 5264928, the disclosure of each of which is incorporated herein by reference.

Although having multiple functions and uses, such microscope adapters generally allow only the recording or projection of non-stereoscopic images. Recent progress in microscopes is the addition of stereoscopic imaging devices that allow projection recording of stereoscopic images. A typical microscope contains a single objective lens whose function is to produce a magnified image of the object to be viewed, and an entrance aperture for recording the magnified image using a single eyepiece for viewing with one eye, or using binoculars for viewing with the right and left eyes, or using a camera or video camera. Most of these conventional adapters allow observation through only one optical path of the objective lens, so that the viewer has no sense of depth. To address this limitation, certain adapters, particularly those used in surgical applications, have been modified to allow stereoscopic viewing. However, most of these adapters require the use of multiple objectives on different optical axes, as in the device disclosed in U.S. patent publication No. 2002/0080481, or the use of a single camera designed to acquire images from multiple optical axes, as in U.S. patent No. 3574295, the disclosure of each of which is incorporated herein by reference. Unfortunately, any such multiple-phase machine device is extremely complex and costly to produce.

Single lens stereo microscope eyepiece adapters have been proposed, however, to date, these devices have had serious drawbacks. One type of such single lens stereomicroscope adapter requires the use of polarizers or filters, however, such devices are known to degrade the optical quality of the image and often require the viewer to maintain a particular viewing angle with respect to the image. The required polarizers or filters, both of which have significant disadvantages. Examples of such devices are provided in U.S. patent nos. 3712199, 4716066, 5835264, 5867312, and 6275335, the disclosures of which are incorporated herein by reference. Other alternatives require the use of an active shutter, which is more expensive to install, more difficult to maintain, and significantly degrades the optical characteristics of the lens when it fails. Such methods have been disclosed, for example, in U.S. patent nos. 5471237, 5617007, and 5828487, the disclosures of which are incorporated herein by reference.

Also, stereoscopic endoscopes have recently been developed. In view of the size limitations of endoscopes, it is highly desirable to minimize the lateral dimensions of the optical system, and for this reason, many designs use a single objective lens and beam splitting arrangement in their optical path that separates the light that will form the left and right images. For example, U.S. patent No. 5222477 discloses a stereoscopic endoscope arrangement in which an aperture plate is located near the objective lens of a camera assembly at the distal end of the endoscope. The apertures on the left and right sides of the barrier are alternately opened by shutters coupled to a video switching arrangement. In this way, the left and right images are detected in rapid succession and can be alternately displayed on the monitor screen so that they can be viewed stereoscopically through a pair of glasses, with the left and right eyepieces alternately occluded in rapid succession in synchronism with the display. Such display systems are commercially available. However, the shutter arrangement has the disadvantage that it cannot be easily retrofitted to existing monocular endoscopes. Furthermore, adding a shutter member to the end of the endoscope tends to increase its bulk, which is undesirable.

The beam splitting arrangement at the exit pupil of the endoscope provided according to GB-a-2268,283 avoids the problems of the arrangement of us patent No. 5222477 mentioned above, but requires precise arrangement of the optical axis of the beam splitter and the optical axis of the endoscope, and also requires that the light rays exiting the eyepiece of the endoscope are parallel. Furthermore, the provision of a beam splitting arrangement undesirably increases the number of reflective surfaces and increases the cost of the apparatus.

One solution to the continuing problem of producing stereoscopic images from a single lens in these devices is proposed in U.S. patent No. 5914810 by watts, which is a single simple shutter element that divides the lens into three offset segments. Although watts technology appears to provide a viable solution for single lens stereoscopic imaging, there has been no attempt to integrate this technology into surgical microscopes or endoscopes to date.

It would therefore be advantageous to develop an optical adapter that can allow stereoscopic images to be projected or recorded from single lens standard optical devices such as microscopes and endoscopes using simple passive "optical shutters" that allow the full functionality of the base optical device including variable magnification to be used.

Disclosure of Invention

The present invention is directed to adapters for connecting video and/or still cameras to conventional or specially modified single lens optical devices such as, for example, microscopes and endoscopes via beam splitters or via eyepieces to provide stereoscopic images.

In one embodiment, an optical adapter for a microscope includes a body housing having an internal beam splitter oriented to receive light from a conventional microscope beam splitter along an axial beam path. The adapter beam splitter reflects a portion of the axial light along the transverse beam path. The adapter also includes a nose piece assembly removably mounted to the body housing and having a solid shutter disposed along the axial beam. In such embodiments, the stereoscopic shutter may be positioned within the beam splitter, with the camera mount or nose piece before or after the aperture, so that the image projected to the camera/cameras is stereoscopic.

In another embodiment, the optical adapter comprises a shutter element incorporated into a single lens endoscope or endoscope-like device in the vicinity of a pupil plane and/or pupil plane of the endoscope system.

In a further embodiment, the stereoscopic shutter comprises means arranged to selectively block light emerging from left and right regions of the further lens means to form right and left images at the image plane, and having means for combining the right and left images to form a stereoscopic representation of the field of view of the object. In such an embodiment, the means for combining the right and left images may comprise, for example, a video processing circuit that generates a video signal representing alternating left and right images. Such a video signal may be considered as a stereoscopic representation in electronic form.

In yet another embodiment, the shutter device comprises an array of more than two shutter elements distributed from left to right, and means for controlling the light transmission of the optical shutter elements to vary the stereoscopic base width between the right and left images. These elements may take any shape suitable for producing a change in position between the left and right images.

In a further embodiment the shutter means comprises control means for varying the size of the left and right unobstructed regions of the further lens means to vary the field width and/or illumination at the image plane. Preferably, the shutter device comprises multi-sensitive shutter elements arranged to form vertical cells having controllable width and/or height and spacing. In such an embodiment, the width of the field is integrated with the distance detector, which may optimize the parallax of the image.

In yet another embodiment, the shutter and camera are positioned relative to each other to optimize stereoscopic imaging. In such embodiments, the shutter and camera may be interconnected such that rotation of one causes an equivalently relevant rotation of the other element, such that the camera and shutter remain properly aligned at all times.

In a further embodiment, the shutter is electronically controlled, so that the shutter element can be manually controlled. In one such embodiment, the shutter may be closed to allow 2D viewing without modification of the device. In another such embodiment, the shutter and camera are controlled to allow triggering of a stereoscopic still image.

In yet another embodiment, the present invention is directed to a method of projecting, recording and viewing stereoscopic images using a stereoscopic optical adapter.

In yet another embodiment, the present invention is directed to a stereoscopic optical adapter comprising an optical adapter body configured to optically interconnect a single lens optical device defining an area to be imaged with an image capture device, the optical adapter body comprising at least a stereoscopic shutter and an optical relay, wherein the stereoscopic shutter is configured to generate a stereoscopic image from the imaging area of the single lens optical device, wherein the optical relay comprises one or more optical elements configured to transmit light from the single lens optical device through the stereoscopic shutter to the image capture device, and wherein a rotational alignment between the stereoscopic shutter and the camera is fixed to ensure that a stereoscopic image is captured by the image capture device.

In one such embodiment, the stereoscopic shutter is configured to alternately block light exiting a predetermined area of the single-lens optical device. In another such embodiment, the predetermined regions are left and right regions of the imaging region.

In yet another such embodiment, the shutter includes a plurality of individually controllable obscurable regions. In another such embodiment, the obscurable region is formed by a device selected from the group consisting of mechanical, electromechanical, chemical and material. In yet another such embodiment, the obscurable region is formed into a shape selected from the group consisting of curvilinear, circular, hexagonal and rectangular. In yet another such embodiment, at least one of the occludable regions is fixed.

In yet another such embodiment, the stereoscopic shutter is disposed between the optical relay and the single lens optical device. In one such embodiment, the stereoscopic shutter is disposed between the optical relay and the image capture device. In another such embodiment, the stereoscopic shutter is provided with an optical relay. In yet another such embodiment, the optical relay includes an aperture. In yet another such embodiment, the stereoscopic shutter is disposed within one of the single lens optical device or the image capture device. In yet another such embodiment, the stereoscopic shutter functions as an aperture.

In yet another such embodiment, the stereoscopic shutter is contained within a zoom lens. In one such embodiment, the zoom lens includes a series of converging lenses configured to be removably placed in optical alignment with the stereoscopic shutter to adjust the focal length of the adapter.

In yet another such embodiment, the adapter is removably interconnected between the image capture device and the single-lens optical device. In one such embodiment, the adapter is integrated within the image capture device. In another such embodiment, the adapter is integrated within the single-lens optical device.

In yet another such embodiment, the light entering the stereoscopic shutter has a conjugate approaching infinity. In one such embodiment, the optical relay is located near the exit pupil of the single lens optical device.

In yet another such embodiment, the single lens optical device is one of a microscope or an endoscope.

In yet another such embodiment, the image capture device is selected from the group consisting of: mechanical cameras, digital cameras, CCDs, CMOSs, digital video cameras, and light field capture systems.

In yet another such embodiment, the adapter utilizes the entire area of the lens of the single lens optic.

In yet another such embodiment, at least one of the stereoscopic shutter and the image capture device is mounted on an adjustment stage configured to allow rotational alignment of the stereoscopic shutter with respect to the image capture device. In one such embodiment, the stereoscopic shutter and image capture device are mounted on a rotatable adjustment stage configured to allow rotational alignment of the stereoscopic shutter with respect to the image capture device, and wherein the adjustment stages are interconnected such that rotation of one of the stereoscopic shutter or the image capture device results in equivalent rotation of its counterpart.

In yet another such embodiment, the adapter includes a programmable controller circuit that controls operation of the stereoscopic shutter. In one such embodiment, the shutter comprises a plurality of individually controllable obscurable regions configured to alternately obscure light exiting a predetermined region of the single lens optical device, and wherein the programmable controller circuit controls operation of each of the obscurable regions. In another such embodiment, the programmable controller circuit is further in signal communication with the image capture device and is configured to synchronize the opening and closing of the image capture device with the stereoscopic shutter to ensure stereoscopic viewing. In yet another such embodiment, the programmable controller circuit is configured to disable the stereoscopic shutter so that the adapter can be reconfigured as a non-stereoscopic device. In yet another such embodiment, the programmable controller circuit is configured to examine shadows formed in stereoscopic images and optimize operation of the stereoscopic shutter for optimal stereoscopic imaging. In yet another such embodiment, the image capture device has a rolling shutter, and wherein the programmable controller circuit is configured to synchronize the stereoscopic shutter with the rolling shutter. In yet another such embodiment, the adapter further comprises at least two image capture devices, and the programmable controller circuit is configured to synchronize the two image capture devices to capture a single static stereoscopic image. In yet another such embodiment, the programmable controller circuit is configured to allow data from the image capture device to be converted to stereoscopic video output in a format selected from the group consisting of: frames are continuous, progressive, interlaced, side-by-side, checkerboard, and horizontally interlaced/progressive. In yet another such embodiment, the adapter further comprises pulsed light, and wherein the programmable controller circuit is configured to synchronize the stereoscopic shutter with the pulsed light to allow high speed motion to be captured by the image capture device. In yet another such embodiment, the programmable controller circuit is configured to center the position of the stereoscopic shutter with the optical axis of the single-lens optical device. In yet another such embodiment, the programmable controller circuit is configured to determine a disparity of an image captured by the image capture device.

In yet another such embodiment, the stereoscopic shutter is electronic and the stereoscopic effect is produced by image signal processing.

Brief description of the drawings

These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view showing a pair of conventional camera mounting adapter systems according to the prior art;

FIG. 2 is a perspective view of a conventional camera mounting adapter system according to the prior art;

FIG. 3 is an exploded view of a conventional camera mounting adapter system according to the prior art;

FIG. 4 is a cross-sectional view of a conventional camera mounting adapter system according to the prior art;

FIG. 5 is a cross-sectional view of a conventional endoscope according to the prior art;

fig. 6A and 6B are schematic views of a stereoscopic shutter according to the related art;

FIGS. 7A to 7C are schematic views of another embodiment of a stereoscopic shutter according to the prior art;

8A-8D are schematic diagrams of a series of embodiments of a stereoscopic camera mounting adapter system according to the current invention;

FIG. 9 is a schematic illustration of a ray diagram of one embodiment of a stereoscopic camera mount adapter system according to the present invention;

FIG. 10 is a schematic illustration of a ray diagram of another embodiment of a stereoscopic camera mounting adapter system according to the present invention;

FIG. 11 is a schematic view of one embodiment of a stereoscopic endoscope in accordance with the present invention.

FIG. 12 is a schematic diagram of synchronization between a camera and a stereoscopic shutter according to the current invention;

FIG. 13 is a schematic diagram of a parallax phenomenon, an

Fig. 14A to 14C are schematic views of another embodiment of a stereoscopic shutter according to the current invention.

Detailed description of the invention

The present invention is directed to a stereoscopic adapter for connecting a video camera and/or a camera to a conventional single lens optical device, such as a microscope or endoscope, to provide stereoscopic image recording or projection of an image being viewed. In particular, the current invention improves upon stereoscopic optical adapters to allow incorporation of the stereoscopic image capture technique of the watts patent (U.S. patent No. 5914810) into conventional single lens optical devices such as microscopes and endoscopes. While the present invention can be applied to any number of optical devices, the following discussion will focus on two implementations of the present invention, a microscope and an endoscope.

Overview of Camera/Camera adapters for traditional microscopes

A conventional camera/camera microscope adapter system is shown in fig. 1. As shown, the conventional video adapter system allows a pair of cameras or other optical devices 10 to be mounted on a single microscope beam splitter assembly (BS). The video adapter may be mounted to any conventional microscope and beamsplitter assembly commercially available from a commercial supplier such as, for example, Carl Zeiss corporation. In fig. 1, a first video adapter system 10A has a video camera VC (shown in phantom) mounted thereon, while a second video adapter system 10B has a video camera VC (shown in phantom) and a camera C (also shown in phantom) mounted thereon. As will be discussed in detail below, these conventional video adapter systems 10 include a number of components that allow for the selection of various functions to allow for the installation of different video and/or still cameras, provide different focal length magnifications, and allow for the interconnection of various devices from different manufacturers with microscopes and beam splitters.

Referring now to fig. 2-4, the basic structure of a conventional video adapter system 10 will be described. The basic components of any video adapter system include: a body housing 12 defining an axial passage 14 that retains a beam splitter 16. Although the beam splitter shown includes a pair of opposing prisms, it should be understood that any means for reflecting and/or partially reflecting the axial beam of light 18 from a microscope objective moving along beam path 20 may be used in these devices, including a single prism, a partial mirror, a rotatable mirror, or any equivalent structure.

Although not necessary for operation of the video adapter, most conventional designs also include a nose piece assembly 24 that is removably secured to the proximal end of the body housing 12 by a mechanism such as a conventional locking ring 26. The nose piece assembly 24 also includes an axial passage 27, the axial passage 27 being aligned with the axial passage 14 in the main body housing 12 when the nose piece assembly is secured to the main body housing. As shown in these figures, the nose piece assembly 24 may also include an adjustable iris 36 mounted at the end of the nose piece. The aperture may be adjusted using an adjustment ring 38, the adjustment ring 38 being connectable to the aperture by any conventional connection assembly including a barrel (element 40 as shown in fig. 4). Alternatively, the video adapter system may further include an electrically powered iris control mechanism to automatically control the iris 36 in accordance with commands received from an external device such as, for example, a remote light sensor (not shown) that may be mounted within the camera.

The video adapter may also include a lens box 28 for focusing or otherwise altering the optical characteristics of the light 18 before the light 18 reaches the video or camera. The lens box 28 (fig. 4) is essentially a hollow tube with a single lens or a compound lens or series of lenses mounted therein. The optical and axial positions of the lens 34 within the cassette 28 may be varied to obtain different focal length magnifications for the attached video or still camera. To this end, in the illustrated embodiment, the lens cartridge is removably mounted to the body housing 12 by a threaded connector 30 received in a threaded socket 32 of the housing, however, it should be understood that the lens may be attached to the housing in any suitable manner and may be fixed in place if it is not necessary to change the lens.

Turning now to the camera mounting socket, as shown in fig. 1 to 4, in these conventional designs a video mounting socket 42 is formed in the body housing 12 and houses a video mounting and focusing assembly comprising a base 44 and a locking ring 46, as shown in particular in fig. 3 and 4. The locking ring 46 may be adapted to receive any suitable camera connector, including C-mount rings and bayonet mount rings.

As shown in fig. 2-4, the video adapter system 10 terminates in a receptacle 56, which in fig. 1 and 4 is shown with a dust cap 52 in place. To attach the camera, the dust cap 52 is removed and replaced with a lens holder assembly 54 (FIG. 4A), which lens holder assembly 54 may be threaded into a receptacle 56 formed in the body housing 12. Any suitable single or compound lens may be interchangeably mounted in the lens holder assembly 54 such that it is in the axial beam path 18 on the side of the beam splitter remote from the nose piece assembly 24. The lens holder assembly 54 may also include means at its proximal end for securing another camera body, typically by a threaded socket. Of course, the nature of the receptacle will depend on the type of camera mount, and the adapter system 10 may include any number of lens holder assemblies 54 to accommodate different cameras.

Regardless of the interconnection method, the lens will be selected to be optically compatible with the lens case 28 disposed in the nose piece 24, as previously described. In short, the lenses associated with the video camera VC and the camera C may be independently selected to provide different focal length magnifications for each camera.

Overview of conventional endoscope optics

A conventional optical arrangement of an endoscope is provided in fig. 5. As shown, in a conventional single lens endoscope, the optical system includes an objective lens 57 for forming an image at a first image plane 57A, an optional relay system 58 for transferring the image in plane 57A to a second image plane 57B, and an eyepiece 59 for viewing the transferred image. The objective lens 57 and the transmission system 58 occupy a relatively small diameter cylinder, typically surrounded by an annular fiber optic bundle. A typical diameter of the lens is about 2.5 mm.

In use, an endoscope is inserted within a body cavity or the like by a physician to view the interior body region. The objective 57 forms an image of the area to be viewed at a first image plane 57A, which is transmitted by the relay system 58 to a second image plane 57B near the eyepiece 59 for direct viewing by the doctor or communication to a television camera. In various embodiments to be discussed below, the optional relay system 58 may include a plurality of glued five-element assemblies 58A. The assemblies 58A are arranged in pairs, each pair providing a transfer module (i.e., a module that transfers an image from one plane in front of the module to a second plane behind the module). With such an optical scheme, the scene at the distal end of the endoscope can be transmitted to the proximal end of the endoscope at the viewer position.

General description of Watt's stereoscopic technology

While the above discussion has focused on the structure and function of a conventional single lens optical device including a microscope adapter and an endoscope, the present invention is directed to a stereoscopic optical adapter that modifies the prior art adapter structure to include the stereoscopic imaging technique set forth in U.S. patent No. 5914810, which is disclosed above. Before the novel microscope mount can be described in detail, the watt stereo imaging method needs to be explained.

The heart of the watt method is to provide a new stereoscopic shutter 61, as schematically shown in fig. 6A, 6B and 7A to 7C. The shutters are arranged to alternately block light emerging from the left and right regions of the eyepiece, preferably at a very fast rate (e.g. 60 times per second for video, although it will be appreciated that any suitable rate may be used, higher rates will provide superior performance), under control of signals from dedicated video processing circuitry. Shutters are made up of individually controllable regions made up of mechanical, electromechanical, chemical, or material devices capable of rapid switching such as, for example, liquid crystal materials. In the present embodiment, as shown in fig. 6 and 7, these regions are constituted by vertical bars 62a to 62h that can be controlled individually by signals from the control circuit. For example, in fig. 6A, when a left-hand side image is formed, the elements 62a and 62b are opened. At the instant the shutter switch signal is generated, these shutter elements are closed, and then shutter elements 62e and 62g are opened, as shown in fig. 6b, allowing the right hand side image to be formed.

The above sequence repeats at an extremely fast rate, such as, for example, 24 image pairs per second. Although vertical bars are used in the above examples, it should be understood that the shutter may be divided into cells of any shape, size or dimension, so long as the cells are capable of selectively occluding different vertical regions of the shutter. For example, instead of being straight, the various elements of the stereoscopic shutter may be curved, circular, hexagonal, etc. Further, while all of the individual elements of the shutter described above are formed of similar electromechanical or mechanical elements, it should be understood that the shutter may be made of a mixture of these elements. For example, in one embodiment, the middle shutter element may be fixed or mechanical, while the two side elements are electrically controllable elements, e.g., liquid crystal elements.

By controlling the number of shutter elements that are open at each exposure, the illumination and/or depth of field can be controlled and the conventional aperture 36 (FIG. 2) can be omitted. For example, if only shutter element 62c is open to form a left image and only shutter element 62f is open to form a right image, the f-number of the aperture will increase relative to that shown in fig. 6, so that the illumination will decrease and the depth of field will increase.

The stereoscopic spacing between the left and right images can also be varied by adjusting the spacing between the shutter elements that are open to form the left image and the shutter elements that are open to form the right image. For example, the spacing may be increased by opening elements 62a and 62b to form a left image and opening elements 62g and 62h to form a right image. In this way, the exposure and stereoscopic spacing can be varied independently. In addition, the shutter element may also be divided in the vertical direction, so that the size and position of the aperture to be obtained can be further controlled.

In operation, the video processing circuit generates video signals representing alternating left and right images generated from the left and right portions of the field of view and sends the video signals to a stereoscopic monitor or other stereoscopic viewing device, which alternately displays the left and right images at the same speed. The user may then view the image on the screen using glasses designed for the selected viewing device.

Fig. 7 shows another operation mode of the above-described stereoscopic shutter element 61. In this embodiment, the video circuit will be programmed to generate three-state switching signals that will, in turn, cause shutter elements 62a and 62b to open to form a left image (see FIG. 7 a), shutter elements 62d and 62e to open to form a center image (FIG. 7 b), and shutter elements 62g and 62h to open to form a right image (FIG. 7 c). A corresponding tri-state switching signal to the viewing device synchronizes the device to the received image. While this mode of operation slightly compromises the stereoscopic effect, it increases the average illumination and reduces flicker, thereby, in some cases, improving the overall quality of the image.

Stereoscopic optical adapter

The present invention provides a system for integrating a stereoscopic shutter such as described above with a conventional camera/camera adapter for any conventional single lens optical device such as, for example, a microscope or endoscope. Several alternative configurations of the adapter of the present invention configured for use with a microscope (fig. 8A through 8D) and an endoscope (fig. 9) are discussed below.

As shown in fig. 8A through 89C, the shutter of the present invention can be integrated into the microscope 64 in a number of different configurations. For example, the stereo shutter 66 may be positioned within the camera adapter lens assembly 68, either in front of the lens 70 and the aperture 72 (FIG. 8A), or behind the aperture and between different lens elements of the multi-element lens (FIG. 8B). Additionally, the shutter may be placed within the camera/video port 74 of the microscope 64 itself, prior to the microscope adapter lens assembly 68 (fig. 8C).

It should be understood that these are only some exemplary configurations and that the number of lenses in the lens adapter may be varied to accommodate the particular arrangement of the optical device. For example, the stereoscopic shutter may be integrated with a zoom lens. In such an embodiment, as schematically illustrated in fig. 8D, the converging lens 76 would be connected to the further converging lens 78 by a standard mechanical/electromechanical connection (not shown) so that the focal length can be adjusted. An intermediate diverging lens 80 is provided and a shutter 82 (which may be as shown and described with reference to any of figures 6 and 7) is mounted, for example, behind a further converging lens 84, where the aperture is typically located. The image is then focused on the camera/cameras 86 as is conventional. In a preferred embodiment, the shutter assembly is disposed between the rod lenses for optimal placement.

In addition, unnecessary aspects of the apparatus may also be omitted. For example, as described above, the stereoscopic shutter may operate as an aperture, thereby eliminating the need for a second aperture.

These different configurations each have different advantages. For example, holding the shutter within the adapter allows for alignment or misalignment with an endoscope that functions as a standard endoscope or a stereoscopic endoscope by simply moving the adapter. Furthermore, by connecting the adapter and the camera, the scope can be rotated while holding the camera, which is very important especially for angled scopes (i.e., 30 degrees DOV). Furthermore, in such embodiments, the scope may be replaced with a standard eyepiece connector, which is important if the angle of the scope needs to be switched in the middle of the procedure (i.e., from 0 degrees scope to 70 degrees scope), or if the scope fails during the procedure. Finally, when the shutter is not located within the scope but is located in the camera coupler, costs are reduced because standard instrumentation can also be used, which allows the scope to be rotated independently of the shutter, which allows the scope to be disinfected without fear of damaging the shutter, and which keeps all electronics and cables within the coupler. Similar advantages can be obtained by permanently integrating the shutter into the camera head. In such a case, the shutter and coupler may be aligned during manufacture and permanently attached/integrated, although clearly this requires a special purpose camera.

Regardless of the position of the stereo shutter or specific optics integrated into the adapter and microscope, it is important that the optics of the adapter and camera mount are aligned and selected to ensure that the stereo image reaches the video/camera without distortion and in the correct configuration. Fig. 9 and 10 show schematic diagrams of ray traces showing the operation of two different lens/shutter configurations. The light rays 86 that are preferably blocked by the shutter 88 are shown as parallel, but may alternatively be converging or diverging. This is particularly important if the shutter is incorporated into the camera coupler optics/adapter. Parallel rays are ideal positions for the shutter because the pupil plane contains the complete image information. Thus, in a preferred embodiment, the eyepiece is designed to provide light from the endoscope with a conjugate approaching infinity. In such an almost infinite conjugate system, the lens system may be placed at the exit surface or pupil of the endoscope so that the light is as close to the shutter as possible. Systems with infinite or near infinite conjugates allow the distance between the endoscope and the coupler to be varied and the optical system alignment can be more easily maintained. Conversely, if the light is converging, the shutter is preferably positioned adjacent to the lens.

Additionally, such an embodiment would be an ideal way to eliminate the endoscope and have a conventional endoscope that includes new technology. For example, an adapter for an existing endoscope may be provided to collimate the exiting light for the eyepiece. Various adapters may be constructed for use with various brands and models of endoscopes having various exit angles or eyepiece magnifications. For example, if an endoscope with 10 degrees of divergence of the light is provided and placed behind the adapter lens to ensure that the conjugate of the system is almost infinite, it is possible to use the coupler of the present invention regardless of that angle. It should be understood that such an adapter may be separate or designed into the endoscope.

More specifically, in fig. 9, a non-continuous model of a Zeiss microscope is provided. In this model, the objective lens is 175mm by 50mm in diameter, the CCD lens is 55mm FL by 20mm in diameter, and the turret is 12mm off-axis. The axial field point (blue) angle is adjusted to pass through the center of the shutter and CCD lens. The marginal field points (red and yellow) are switched to fill the l/3in CCD. The long dimension of the CCD is on the same axis as the stereo channel (y-axis). The angles of all field points are adjusted to pass through the center of the shutter. For a 100% effective top, the maximum shutter diameter is 5.5 mm. In fig. 10, the position of the entrance pupil is 486mm from the object. The spacing of the channels at the turntable is 24mm and the channel spacing at the entrance of the pupil is 66 mm. The image of the shutter at the entrance pupil is 15.4mm in diameter. (MS =15.4/5.5=2.8 times).

Simulation results of these optics show that although stereoscopic images can be obtained from any conventional microscope using the adapter of the present invention, the larger the diameter of the objective or pass-through used in the microscope, the better the stereoscopic effect will be. In particular, conventional endoscope designs do not maximize stereoscopic viewing. For example, in a conventional endoscope, a lens having a diameter of 6.5mm may only use a lens portion having a diameter of 4.5 mm. A disadvantage is that vignetting may result if the light rays are bent (the brightness or saturation of the image at the periphery is reduced compared to the center of the image). Simulations have shown, however, that the entrance pupil of the system is important for maximizing the stereoscopic effect. The reason for this difference in implementation between conventional and stereoscopic endoscopes is based on their purpose. In conventional endoscopes, the use of a smaller incident diameter allows for a better depth of focus. However, using a larger entrance diameter provides a larger area that provides an improved apparent inner pupil diameter, which greatly improves the stereoscopic effect and light transmission (brightness), but neither is critical for non-stereoscopic endoscopes. Thus, in a preferred embodiment, the objective lens of the stereoscopic endoscope system is designed to maximize the use of the lens.

In addition, the optical design of conventional endoscopes is optimized for the center of the optical system. Also, conventional single lens stereoscopic systems utilize shutters to block the center so that better optical performance can be achieved when they are designed to be optimized at 70% of the optical path edge. In the current invention, the shutter always blocks a part of the central portion of the image. By increasing this obscuration, more and more can be seen at the edges, enlarging the apparent inner pupil diameter. With the multi-part shutter of the present invention, the blocking portion can be moved back and forth, so that by using such a weighted design, the best image quality can be achieved at 70% of the center.

The optical adapter of the present invention is now integrated into an endoscope, a schematic illustration of an exemplary embodiment being provided in fig. 11. As shown, in this embodiment of the invention, a conventional monocular rigid endoscope 89 having an objective lens 90 at its distal end and an eyepiece 94 at its proximal end is optically coupled to a camera (shown schematically) that focuses light exiting the lens arrangement slightly farther away, i.e., focuses light exiting eyepiece 94 through a focusing lens 98 to camera optics 99. Those skilled in the art will appreciate that in practice, lens 98 will typically be a multi-element lens and exposure will typically be controlled by an aperture (not shown in the figures). As described so far, this arrangement is conventional. Additionally, the camera may be a video camera or a still camera, in which case light from the lens 98 is focused to a sensitive image plane of the video camera or film camera.

According to the present invention, shutters 96 are provided which are arranged to alternately block light exiting from the left and right regions of the eyepiece 94, preferably at an extremely fast rate such as 60 times per second or higher (for video), under control of signals from the video processing circuitry. The shutter 96 may be disposed in front of the lens 98, between different lens elements of the multi-element lens 98 (not shown), as shown, or may be located between the lens 98 and the camera, for example. In particular, the shutter may be mechanical or electronic, such as an LCD shutter printed on the surface of the lens 98. The light rays blocked by the shutter 96 are preferably conjugate to infinity as shown, but may alternatively be converging or diverging. The shutter should preferably be located close to the lens, especially when the light rays are converging.

It will be appreciated that although the above embodiments are described in relation to an endoscope, the optical adapter may also be applied to, for example, a laparoscope, a borescope, a cystoscope or an arthroscope. Furthermore, as will be discussed later, the user can drag focus or zoom (assuming the lens has such facilities) without affecting the stereoscopic imaging.

Regardless of the actual type of single lens optical device into which the stereoscopic optical adapter of the present invention is incorporated, it should be understood that specific structural limitations need to be considered. For example, in a typical single lens device, the position of the projected image on the screen can be changed by simply rotating the camera or camera adapter. Obviously, any such rotation of the camera or camera adapter is translated onto the viewing screen, allowing the viewer to modify their viewing angle without having to move or rotate the sample (which may be the patient's body in the case of surgery). However, in the current invention, such a way of manipulating the viewing angle of the observation target is complicated. In particular, because it is necessary to synchronize the video display with the shutter so that it can switch between left and right views to produce a stereoscopic effect, the orientation of the shutter and camera relative to each other must remain fixed. If the orientation of the camera or shutter changes relative to each other, the video display will not "know" whether the image sent to it is from the right or left portion of the shutter, and the stereoscopic effect will be destroyed or degraded. Fig. 12 provides a schematic diagram showing how changes in the relative orientation of the camera and shutter affect the stereoscopic image on the screen. In view a, the camera 100 and shutter 102 are properly aligned so when the shutter switches between left and right views, the camera transmits the images to the screen 104 in the proper orientation. However, in view B, the shutter is rotated 90 degrees, so there is a "top" view and a "bottom" view. However, the camera is not rotated, so the display still shows the top direction as the left direction. As a result, the stereoscopic effect is impaired for the observer.

Thus, in one embodiment of the invention, the stereoscopic shutter and camera are disposed on an adapter, on independently rotatable connections, such as any suitable type of manual or automatic adjustment ring that allows for the proper orientation of the shutter and camera. Once the shutter and camera are properly oriented, they are then interconnected by a mechanical or electromechanical connection such that rotation of one of the shutter or camera causes an equivalent rotation of the other of the shutter or camera in the same direction and with the same angle of rotation. With such a synchronous interconnection, the user is provided with the possibility to change the direction of the observed object without deteriorating or destroying the stereoscopic effect and without moving the observed object. For example, using such an interconnect allows the shutter and optics to be moved while the optics in the coupler are moved to focus the image. It is important to focus correctly without disturbing the orientation of the camera and shutter, since otherwise the stereo correspondence will be destroyed. Configuring such focus synchronization requires additional engineering due to the seals on the endoscope. In particular, conventional endoscopes have two windows on the outside that tightly seal the lens inside, and then have a cam mechanism with a handle that drives the lens forward and backward to adjust the focus. On more complex zoom mechanisms, there is an adjustment zoom mechanism that moves a set of optics to the appropriate position to increase magnification and another ring that adjusts focus. There will be an optimal position where the shutter should be positioned with respect to the optics. Therefore, it is necessary to fix the position so that it is at the proper point when the optics are focused. For simple focusing it is possible to simply fix the position between the shutter and the lens and move the whole system as a whole, but in a device with zoom it is also necessary to cam the (cam) shutter so that it moves into and out of position together with the zoom lens. An exemplary high temperature and pressure resistant system, in which movement occurs outside of a tight seal arrangement, may be found in U.S. patent application nos. 68/55106 and 63/98724, the disclosures of which are incorporated herein by reference.

It should be understood that programmable circuitry (not shown) that controls the operation of the stereoscopic shutter is also provided with the optical adapter. The circuit arrangement controls the transition of the shutter elements from the transmissive to the opaque state and controls the transition of the shutter elements from the opaque to the transmissive state. This circuitry may also be interconnected with the camera and/or video display device to synchronize the visible video portion of each video frame with the shutter.

The presence of such controllable electronics in combination with the active stereoscopic shutter of the present invention allows great flexibility in the operation of the stereoscopic optics. For example, using the shutter control circuitry, the user may perform some unique functions:

stereoscopic shutter control techniques allow the shutter to be opened and closed instantaneously. This allows for instantaneous switching between 3D and 2D views without any modification of the lenses, shutters or adapters.

Synchronization circuits can also be embedded so that the user can control the left and right fields to align with the correct odd and even frames of the camera. This circuitry may allow for manual control of this synchronization or automatic synchronization of the L/R view with specific camera requirements.

Using stereoscopic shutter control techniques, it is also possible to synchronize the processing/timing of the video with the shutter and the shutter with the camera, which ensures that all three elements (shutter/camera/video display) are synchronized to display the same L/R view, and to switch these elements at any time if they become unsynchronized.

The alignment function can be built into the shutter driver to verify the correct position and orientation of the shutter to optimize image quality and stereoscopic effect. In such an embodiment, the driver checks the shadows to determine if the shutters are in the correct position, and the driver opens and closes the segments to maximize the stereoscopic effect or alignment.

Shutter drivers can also be configured above or below the sample, left and/or right side of the optics, to accommodate rolling shutters in modern CMOS/MOS chip technology. In summary, some new camera systems do not have a global shutter that opens and closes all at once, but rather a rolling shutter that acts row-by-row. In these rolling or progressive shutters, the result will be an intermittent stereoscopic effect. Therefore, it is necessary to ensure shutter compensation for this and rolling shutters by frequency matching.

The controller can also be used to trigger the camera to take two pictures at a time that are to be synchronized to the right and left, allowing high quality stereo images to be taken without mechanically moving any elements of the adapter.

In another embodiment, additional video processor circuitry may be included in the shutter controller that will allow for conversion of frame sequential stereoscopic images to stereoscopic video output in any desired format, including frame sequential, progressive, interlaced, side-by-side, checkerboard, and horizontally interlaced/line-by-line, etc.

The shutter driver may also be synchronized with the pulsed light, so that the shutter driver and the pulsed light system can be used together to capture high speed motion in 3D. For example, using such a system, 3D strobing can be performed to study vocal cords or other rapidly moving parts of the body.

Finally, because multi-element/multi-pixel shutters are being used, the left and right sides (i.e., the position of the center pixel with respect to the optical axis or the center of the image) can be selectively placed to help center the shutter position automatically using a feedback mechanism, or manually without mechanically adjusting the shutter position.

The use of a stereoscopic shutter controller also allows image analysis. In one embodiment, the left and right images of the sample are examined to determine the appropriate image disparity. Parallax is a significant displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle of inclination or half-angle between the two lines, as shown schematically in fig. 13. As shown in the schematic diagram, the observer (M) views the object (O) from two different positions (P1 and P2). O is closer to the viewer than the background (B), so the change in position from P1 to P2 forces the change in projection of O to the respective positions S1 and S2. Since B is much further away than O, the projected position changes more with respect to O than with respect to B. Thus, the observer perceives a visible change in the position of O relative to B. To take this into account in the current system, the width of the shutter may be adjusted, as shown in fig. 14A to 14C, to adjust the parallax of the system, thereby improving the image quality. As shown in these diagrams, as the parallax increases (from fig. 14A to 14B to 14C), the number of right (110) and left (108) elements activated in the shutter (106) increases. This stereoscopic shutter width adjustment may be done manually by a shutter controller, or may alternatively be incorporated into a feedback loop system, such that upon zooming or enlarging the subject, the shutter parallax will be automatically adjusted. In such systems, the parallax adjustment may be performed according to some preset based on the level of magnification or reduction of the single-lens optical device, or by a distance measuring device such as, for example, a short-range sonar.

While the above discussion focuses on a shutter system, it should be understood that the shutter may be electronically designed, where the effect of a stereoscopic shutter is logical, or software driven through image signal processing. For example, a new technique called light field capture does not capture an image that is in focus, but rather an image that the usual aperture would be in. Thus, the process takes obfuscated data, which is then processed to form a 3-D image. One example of such a device is a light field detector produced by Lytro corporation. In this device, the sensor detects the entire light field, rather than a single bit of information.

In any of the above embodiments, it should be understood that the means to capture the light image may comprise any suitable recording/image/camera capture system, such as, for example, a CCD, CMOS or light field capture system, and that such a capture system may be placed at the pupil and spacing using electronic shutters or stereo may be accomplished by image processing as described above.

Principle of equivalence

The description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the above teaching. For example, while the above discussion of the adapter optics and circuits has been described with respect to a microscope beamsplitter or an endoscope, it should be understood that the adapter may be equally applicable to a microscope through its eyepiece, or may be applied to other single lens optics. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to the particular use contemplated. The scope of the invention is defined by the appended claims.

Claims (37)

1. A stereoscopic optic adapter, comprising:

an optical adapter body configured to optically interconnect a single lens optical device defining an area to be imaged with an image capture device, the optical adapter body including at least a stereoscopic shutter and an optical relay;

wherein the stereoscopic shutter is configured to generate a stereoscopic image from an imaging region of the single lens optical device;

wherein the optical relay includes one or more optical elements configured to transmit light from the single lens optical device through the stereoscopic shutter to the image capture device, and

wherein a relative rotational alignment between the stereoscopic shutter and the camera is adjustable such that the rotational alignment is configurable to ensure that the stereoscopic image is captured by the image capture device.

2. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is configured to alternately block light exiting a predetermined region of the single-lens optic device.

3. The stereoscopic optic adapter of claim 2, wherein the predetermined regions are left and right regions of the imaging region.

4. The stereoscopic optic adapter of claim 1, wherein the shutter comprises a plurality of individually controllable obscurable regions.

5. The stereoscopic optic adapter of claim 4, wherein the obscurable region is formed by a device selected from the group consisting of mechanical, electromechanical, chemical and material.

6. The stereoscopic optic adapter of claim 4, wherein the obscurable region is formed into a shape selected from the group consisting of curvilinear, circular, hexagonal and rectangular.

7. The stereoscopic optic adapter of claim 4, wherein at least one of the obscurable regions is fixed.

8. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is disposed between the optical relay and the single lens optical device.

9. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is disposed between the optical relay and the image capture device.

10. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is provided with an optical relay.

11. The stereoscopic optic adapter of claim 1, wherein the optical relay comprises an iris.

12. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is disposed within one of the single lens optical device or the image capture device.

13. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter functions as an iris.

14. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is contained within a zoom lens.

15. The stereoscopic optic adapter of claim 14, wherein the zoom lens comprises a series of converging lenses configured to be removably placed in optical alignment with the stereoscopic shutter to adjust a focal length of the adapter.

16. The stereoscopic optic adapter of claim 1, wherein the adapter is removably interconnected between the image capture device and the single lens optic device.

17. The stereoscopic optic adapter of claim 1, wherein the adapter is integrated within the image capture device.

18. The stereoscopic optic adapter of claim 1, wherein the adapter is integrated within the single lens optic.

19. The stereoscopic optic adapter of claim 1, wherein light entering the stereoscopic shutter has a conjugate configured to be nearly collimated.

20. The stereoscopic optic adapter of claim 1, wherein the optical relay is located near an exit of the single-lens optic device.

21. The stereoscopic optic adapter of claim 1, wherein the single lens optical device is one of a microscope or an endoscope.

22. The stereoscopic optic adapter of claim 1, wherein the image capture device is selected from the group consisting of: mechanical cameras, digital cameras, CCDs, CMOSs, digital video cameras, and light field capture systems.

23. The stereoscopic optic adapter of claim 1, wherein the adapter utilizes the entire area of an objective lens of the single lens optical device.

24. The stereoscopic optic adapter of claim 1, wherein at least one of the stereoscopic shutter and the image capture device is mounted on an adjustment stage configured to allow rotational alignment of the stereoscopic shutter with respect to the image capture device.

25. The stereoscopic optic adapter of claim 24, wherein the stereoscopic shutter and the image capture device are mounted on rotatable adjustment stages configured to allow rotational alignment of the stereoscopic shutter with respect to the image capture device, wherein the adjustment stages are interconnected such that rotation of one of the stereoscopic shutter or the image capture device results in equivalent rotation of its counterpart.

26. The stereoscopic optic adapter of claim 1, further comprising a programmable controller circuit that controls operation of the stereoscopic shutter.

27. The stereoscopic optic adapter of claim 26, wherein the shutter comprises a plurality of individually controllable obscurable regions configured to alternately obscure light exiting a predetermined region of the single lens optic device, and wherein the programmable controller circuit controls operation of each of the obscurable regions.

28. The stereoscopic optic adapter of claim 26, wherein the programmable controller circuit is further in signal communication with the image capture device and is configured to synchronize the image capture device with the opening and closing of the stereoscopic shutter to ensure stereoscopic viewing.

29. The stereoscopic optic adapter of claim 26, wherein the programmable controller circuit is configured to disable the stereoscopic shutter such that the adapter can be reconfigured into a non-stereoscopic device.

30. The stereoscopic optic adapter of claim 26, wherein the programmable controller circuit is configured to examine shadows formed in the stereoscopic images and optimize operation of the stereoscopic shutter for optimal stereoscopic imaging.

31. The stereoscopic optic adapter of claim 26, wherein the image capture device has a rolling shutter, and wherein the programmable controller circuit is configured to synchronize the stereoscopic shutter with the rolling shutter.

32. The stereoscopic optic adapter of claim 26, wherein the image capture device comprises a camera, and wherein the programmable controller circuit is configured to synchronize the camera with a stereoscopic lens to capture a single still stereoscopic image.

33. The stereoscopic optic adapter of claim 26, wherein the programmable controller circuit is configured to allow data from the image capture device to be converted to a stereoscopic video output in a format selected from the group consisting of: frames are continuous, progressive, interlaced, side-by-side, checkerboard, and horizontally interlaced/progressive.

34. The stereoscopic optic adapter of claim 26, further comprising pulsed light, and wherein the programmable controller circuit is configured to synchronize the stereoscopic shutter with the pulsed light to allow high speed motion to be captured by the image capture device.

35. The stereoscopic optic adapter of claim 26, wherein the programmable controller circuit is configured to center the position of the stereoscopic shutter with an optical axis of the single lens optic.

36. The stereoscopic optic adapter of claim 26, wherein the programmable controller circuit is configured to determine a disparity of images captured by the image capture device.

37. The stereoscopic optic adapter of claim 1, wherein the stereoscopic shutter is electronic and a stereoscopic effect is produced by image signal processing.