This applications describes a video endoscope system with 3D and “look around capabilities”. The components include a multi-view light field endoscope, a standard stereo LCD monitor, eyewear, an eye and head position tracker, and control software.
We see the world in three dimensions. We have two eyes that see the world at slightly different horizontal positions. Our brains interpret this slight horizontal visual disparity (parallax) as three-dimensional depth. People have been interested in recreating this capability with art, photography, and video since at least the 16th century. All such attempts involve presenting two views, one to each eye. First attempts used two hand drawn pictures. Starting in the mid-19th century, Wheatstone, Brewster, and Holmes developed techniques and viewers using two photographs. A dual camera was used which recorded the two views. These systems used special viewers called stereoscopes which focused and presented each image, one to each eye. The viewer's brain then merges these two pictures giving depth perception. By the early to mid-20th century, stereo (3-D) movies were developed. The first of these used anaglyphic techniques. A special movie camera filmed two images side by side in synchronism. After film processing and editing, then they were projected onto a movie screen. In the projector, one of the views was passed through a cyan filter and the other view was passed through a red filter. The audience wore special glasses, the lens for one eye was cyan and the lens for the other eye was red. The viewer's brain then merged these cyan and red images, giving depth perception. Color rendition was fair at best.
By the latter part of the 20th century, video systems were developed. The first such systems used a standard CRT display and active eye wear. A special electronic switch arrangement alternated the right and left image frames at a rate faster than perceptible, typically the 60 Hz video frame rate. The switch also provided a signal to control special eyewear worn by each user. The eye wear had an optical shutter that alternately passed or blocked the right or left image in synchronism with the video frames. The viewer's brain then merges these two alternating images giving depth perception.
By the early 2000's projection displays and flat panel liquid crystal displays with passive eye wear were developed. The right and left images are displayed with alternating optical polarization. Users wear glasses that have one lens polarized in one direction and the other lens polarized at 90 degrees from the first. As a result, one eye only sees one view and the other eye only sees the other view. The user's brain merges these two views, giving depth perception. All commercial movies that are now being presented in “3-D” use this type of system. Many surgical endoscope systems also use this system. See
Other means of presenting depth involving several different but conceptually similar methods were developed by Lippmann, F. E. Ives, H. E. Ives, and others from the start of the 20th century into the 1930's. These systems used parallax barriers, multiple slit cameras, or lenticular sheets to capture multiple views of a scene at the same time. Recording and display systems were film based and primarily optical, but they provided multiple views out into the viewing area at the same time. More than one person could experience the display, and each had their own unique view. H. E. Ives developed several film projectors that could display as many as 39 images at the same time onto a lenticular screen. See, for example, U.S. Pat. No. 1,883,291. Due to the primitive nature of electronics at the time, these were very limited systems. Static, printed lenticular 3D pictures can still be seen today on things like novelty birthday cards, post cards, and advertising pieces.
Autostereoscopy is a method of displaying stereoscopic images. It does not require special headgear or glasses, etc., in order for the user to be able to perceive the images in 3D. See
See also Levoy and Hanrahan 1996, Light Field Rendering, Proceedings of SIGGRAPH '96. Jones et al 2014 describe a system that uses 72 projectors. Jones, Nagano, Liu, Busch, Yu, Bolas, and Debevec 2014, Interpolating vertical parallax for an autostereoscopic three-dimensional projector array, Journal of Electronic Imaging 23.
Modern day two-channel prior art endoscope systems are depicted in
The
As has been demonstrated, the bandwidth and storage requirements of autosteroscopic systems are severe.
A primary objective of this disclosure is therefore to preserve the look around capability of a minimal autostereoscopic system while having the bandwidth, simplicity, and lower cost of a simple two channel stereoscopic system.
The present application describes an autostereoscopic or light field endoscopic camera system that preserves the look around capability of prior autostereoscopic systems while having the bandwidth, simplicity, and lower cost of a simple two channel stereoscopic system. The described concept allows for a light field camera to be made in endoscopic form, meeting the reduced cabling requirements that are beneficial and practical to endoscope systems, where all signals need to pass through a small incision, natural orifice, or trocar port in the patient, which may be restricted to a diameter of 10 mm or less.
Referring to
In the embodiment shown in the drawing, the example multi-camera endoscope 10 is equipped with six image camera sensors 12, although other larger or smaller numbers of sensors may be suitable. For example, three or more, four or more, five or more, or six or more sensors are used.
The camera sensors may be the type of image sensors commonly used for endoscope or laparoscopic images, such as CCD sensors, CMOS sensors, or other images sensors known now or developed in the future.
The camera sensors are positioned side by side so as to product six views with horizontal disparity. A desirable spacing for the sensors is 4 to 5 mm center-to-center as depicted in
To facilitate introduction into a body cavity, the camera sensors are positioned on a camera head 14 that articulates relative to the fixed elongate shaft 16. Again, for an endoscope, this means that the sensor mounting must enter the patient's port sideways. After introduction into the patient, the head 14 articulates 90 degrees relative to the shaft 16 or associated trocar. In the embodiment shown in the drawings, the head 14 and shaft 16 are rigid members having a mechanical hinge, vertebrae section, or bendable structure between them. In other embodiments, one or both of the head 14 and shaft 16 (or the portion of the shaft just proximal to the head 14) may be made of flexible material or a vertebrae configuration.
While it may be preferable to position the camera sensors on the camera head, alternatives in which the camera sensors are positioned more proximally in the camera where they receive light captured via lenses at the camera head (e.g. in an arrangement similar to that shown for the distal sensors) from related optical components are considered within the scope of this disclosure.
Referring to
If the user moves their head about one eye to eye spacing to the left, the eye tracker transmits this change to the control software which then sends a signal out to the video switching selector system. This then selects image pair B and C instead. See
The system works similarly if the user moves their head to the right from center. Views D and E are selected as shown in
As can be appreciated from a review of
In a modification of the disclosed embodiment, the image data from the camera sensors is subjected to image processing that allow the in-between images of stereo pairs to be interpolated. In this embodiment, more than five stereo pairs could be presented based on the six camera sensors, allowing for a smooth transition effect as the user moves their head. In a further modification, a larger number of cameras is used with closer spacing. For example, placing the sensors 2.25 mm apart could result in each stereo pair being two cameras apart, again giving a smoother transition effect during user movements.
The tracking device is preferably both an eye and a head tracker. These may be integrated into a single unit as depicted in
Since the purpose of the image data selector is to reduce the number of cables, it would be optimal to place it as close to the camera image sensors as possible. Depending on the sensor data format, this selector could be implemented as a small FPGA or CPLD or analog switch integrated circuit and could be located either on the same board as the image sensors, or it could be located in the shaft of the endoscope or finally it could be located in the box shown at the proximal end of the endoscope. The image sensors should be synchronized with each other so that they all start capturing frames at the same time. The selection control information requires only a small amount of data and thus could easily share the same signal wire as the vertical sync signal. The intention is that the switching from one set of images to another would take place during the vertical scanning interval.
Note that the light source needed to provide illumination for endoscope usage is not shown in any of the figures. This was done for clarity. For this invention, it is assumed that some source of light is included in the light field endoscope system.
A number of advantages are provided by the concepts disclosed in this application. The light field endoscope provides a look around capability that is not provided by current two camera stereo endoscope setups by giving the user the perception of look around 3D capability with horizontal movements of the user's head position. This can allow the user to look around a body cavity without re-positioning the endoscope, adding efficiency to the surgical procedure. For typical robotic surgical applications, robotic manipulators hold and manipulate surgical instruments and endoscopes. Providing an endoscope with look around capability can reduce capital equipment costs by potentially eliminating the need to position the endoscope on a robotic manipulator. Instead, it could be positioned on a fixed support. it can allow the endoscope to be positioned on a stationary device.
The disclosed endoscope does not require a specialized display, but can be used with a standard commercially available stereo display system, eye wear, and an eye tracker device. Moreover, the endoscope does not require significant bandwidth or signal wires as was the case with prior art autostereoscopic systems, but instead offers bandwidth and cable requirements on par with standard endoscope systems.
This application claims the benefit of U.S. Provisional Application No. 63/295,703, filed Dec. 31, 2021.
Number | Date | Country | |
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63295703 | Dec 2021 | US |