Video system for three dimensional imaging and photogrammetry

• US 6,414,708 B1
• Filed: 02/03/1998
• Issued: 07/02/2002
• Est. Priority Date: 02/03/1997
• Status: Expired due to Fees

• Current Assignee: Dentop Systems Limited
• Original Assignee: Dentop Systems Limited
• Inventors: Carmeli, Ran, Dadi, Michel
• Primary Examiner(s): BRITTON, HOWARD W
• Application Number:
  US09/017,771
• Time in Patent Office: 1,610 Days
• Field of Search: 348/42, 348/45, 348/47, 348/49, 348/66, 348/56, 433/29, 433/30, 433/31
• US Class Current: 348/42
• CPC Class Codes: A61B 1/00045 Display arrangement
• CPC Class Codes: A61B 1/00048 Constructional features of the display
• CPC Class Codes: A61B 1/00193 adapted for stereoscopic vision
• CPC Class Codes: A61B 1/00194 adapted for three-dimensional imaging
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: A61B 1/06 with illuminating arrangements
• CPC Class Codes: A61B 1/24 for the mouth, i.e. stomatoscopes, e.g. with tongue depressors tongue depressors per se A61B13/00; Instruments for opening or keeping open the mouth combined with saliva removers A61C17/00; mouth openers for animals A61D15/00
• CPC Class Codes: G02B 30/24 involving temporal multiplexing, e.g. using sequentially activated left and right shutters
• CPC Class Codes: H04N 13/161 Encoding, multiplexing or demultiplexing different image signal components for multi-view video sequence encoding H04N19/597
• CPC Class Codes: H04N 13/167 Synchronising or controlling image signals
• CPC Class Codes: H04N 13/189 Recording image signals; Reproducing recorded image signals
• CPC Class Codes: H04N 13/211 using temporal multiplexing
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/246 Calibration of cameras
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof

Abstract

A video system for providing an operator with a three dimensional stereoscopic image of the oral cavity of a patient is provided. The system includes an imaging unit for providing at least two stereoscopic images of the oral cavity, a pair of switchable shutters for alternatingly blocking the view of the left eye and the right eye of the operator, a synchronizing unit for synchronizing the switching of the pair of switchable shutters with the rate of generation of the two stereoscopic video images by the imaging unit and a video display for displaying the two stereoscopic images.

Claims

1. A video system for providing an operator with a three dimensional stereoscopic image of the oral cavity of a patient, the system comprising:

an imaging unit for providing at least two stereoscopic images of said oral cavity;

a pair of switchable shutters for alternatingly blocking the view of the left eye and the right eye of said operator;

a synchronizing unit for synchronizing the switching of said pair of switchable shutters with the rate of generation of said at least two stereoscopic video images by said imaging unit; and

a video display for displaying said at least two stereoscopic images.

2. A video system according to claim 1 wherein said imaging unit comprises:

a video camera; and

an optical assembly disposed between said video camera and said oral cavity for alternatingly providing said video camera with at least two different stereoscopic images of said oral cavity in synchrony with the field rate of said video camera.

3. A video system according to claim 2 wherein said optical assembly is also operative to simultaneously provide a first image of said oral cavity along a first optical axis of said optical assembly, and a pair of second and third stereoscopic images of said oral cavity along a second and third optical axes of said optical assembly, respectively, wherein said second and said third optical axes are inclined at an angle to said first optical axis, and wherein said three different images are superimposed upon the imager of said video camera to provide a composite video image.

4. A video system according to claim 3 wherein said synchronizing unit also digitizes said composite video image and provides a host computer with a digitized composite video image for performing photogrammetric measurements thereon.

5. A video system according to claim 1 wherein said imaging unit comprises two video cameras providing a pair of stereoscopic images of said oral cavity, and wherein said synchronizing unit synchronizes said two video cameras with the switching rate of said switchable shutters.

6. A video system according to claim 1 wherein said imaging unit is attached to a harness worn on the head of said operator.

7. A video system according to claim 1 wherein said video system also comprises a folding mirror for folding the light reflected from said oral cavity towards said imaging unit.

8. A video system according to claim 5 wherein said imaging unit also comprises two folding mirrors for folding the light reflected from said oral cavity towards said two video cameras.

9. A video system according to claim 2 wherein said synchronizing unit provides multiplexed left and right video image signals to said video display at a rate which is double the field rate of said video camera for providing said operator with a flicker-free image of said oral cavity on said video display.

10. A video system according to claim 1 wherein said switchable shutters are liquid-crystal shutters.

11. A video system according to claim 2 wherein said video camera further comprises a zoom lens controllable by said operator for providing said three dimensional stereoscopic images at a selectable magnification.

12. A video system according to claim 2 wherein said video camera further comprises a zoom lens controllable by said operator for providing said composite video image at a selectable magnification.