Single lens stereoscopic video camera

#The present invention relates generally to stereoscopic video cameras and more particularly to a stereoscopic video camera, system, and method which uses only a single objective lens.

#Cameras which can produce images having left and fight perspectives which, when viewed concurrently or sequentially, provide depth perception or a "3-D" representation of the object, are conventionally referred to as "stereoscopic" cameras. There are two general types of stereoscopic video camera systems used in the prior art. One type uses dual (left and fight) objective lenses, the images from which are directed to and focused on two separate video detectors. The outputs of each of these detectors are then processed and alternately displayed on a video monitor. However, to create the desired three dimensional stereoscopic video effect, the video monitor must be viewed with special glasses. These special glasses have left and right lenses which are alternately switched between light transmissive and opaque states, in synchronization with the alternating switched images displayed on the monitor. Thus, the viewer sees left and right hand perspective views of the object, resulting in a composite image on the screen capable of providing depth perceptive information to the viewer using the special glasses. The full image is seen concurrently because of the persistence of the monitor and of the viewer's eyes.

#The second type of prior art stereoscopic video camera is a variation of the dual lens/detector system described above. In this second system, the images from each of the lenses are superimposed on a single detector. However, the images are separated in time by dual shutters that alternate between the images produced by the left and right lenses. Consequently, the output of the single detector alternates between the two perspectives given by the left and right lenses. Again, special glasses synchronized with the lens shutters are necessary to view the image on the monitor in such a way that depth perception is obtained.

#FIG. 1 is a block diagram of the stereoscopic video camera system of a first embodiment of the present invention, using a conventional white light source, or any color sequential light source, and a color video camera, and including stereoscopic viewing glasses connected to a viewing lens drive signal by wireless remote.

#FIG. 2 is a block diagram of the video head-transmitter unit of a second embodiment of the present invention which uses a single sensor and sequential color object illumination.

#FIG. 3 is a block diagram representation of the receiver processor unit of the second embodiment of the present invention.

#FIG. 1 is a block diagram representation of a first embodiment of the system of the present invention adapted for use with a standard sequential or non-sequential illumination source 70 and a conventional prior art color video camera/sensor unit 15. Illumination source 70 directs light through optical fiber cables at an object which is proximate to the distal end of an optical tube, in this embodiment endoscope 40 which includes a single lens system 43 and an electronic shutter 45, mounted within a protective sheath 71. Light reflected from the object is focused by lens system 43 onto the sensor of camera 15, preferably a charge coupled device (CCD). The analog electrical video signal from camera 15 is then digitized in A/D converter 72 and communicated to digital signal processor (DSP) 75 by a hardwired or wireless radio link.

#DSP 75 also contains video buffer and timer circuitry which generates timing signals for the system. Accordingly, DSP 75 is used to generate a synchronous shutter drive signal which is sent to both shutter 45 of endoscope 40 as well as to left and right viewing lenses 61 and 62 of viewing glasses 60. The signal is transmitted either by a hardwire link or, as shown in FIG. 1, by means of wireless transmitter 50 and receiver 51.

#When using conventional camera/sensor 15 to provide a color right and left perspective image, each of the three primary colors can be sensed simultaneously to create an odd field video image and then again to create an even field image. Subsequently, a change in the shutter drive signal from DSP 75 to a "low" state causes shutter 45 to switch from a left to a right eye perspective, as shown in FIG. 7 and as described in greater detail below. This process repeats continuously as camera/sensor 15 supplies right and left perspective video images to display 29. The frequency of the shutter drive signal, preferably 120 HZ, is chosen to exceed the rate at which the eye perceives flicker.