Eliminating illumination crosstalk while using multiple imaging devices with plural scanning devices, each coupled to an optical fiber

• US 7,791,009 B2
• Filed: 11/27/2007
• Issued: 09/07/2010
• Est. Priority Date: 11/27/2007
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Johnston, Richard, Seibel, Eric, Melville, Charles David
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US11/945,901
• Publication Number:
  US 20090135280A1
• Time in Patent Office: 1,015 Days
• Field of Search: 250/208.1, 250234-236, 250/216, 250/227.11, 250/227.2, 250/227.21, 250/227.26, 250/461.1, 600/407, 600/425, 600/473, 600/310, 348/262, 348/335, 348/281
• US Class Current: 250/208.1
• CPC Class Codes: A61B 1/0005 combining images e.g. side-by-side, superimposed or tiled
• CPC Class Codes: A61B 1/00087 Tools A61B17/00234 takes precedence
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/00105 characterised by modular construction
• CPC Class Codes: A61B 1/00167 Details of optical fibre bundles, e.g. shape or fibre distribution
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/00179 for off-axis viewing
• CPC Class Codes: A61B 1/00183 for variable viewing angles
• CPC Class Codes: A61B 1/04 combined with photographic or television appliances
• CPC Class Codes: A61B 1/0607 for annular illumination
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 1/3132 for laparoscopy
• CPC Class Codes: A61B 17/068 Surgical staplers , e.g. containing multiple staples or clampsstaplers containing only one staple A61B17/10; magazines or containers for staples A61B17/105; for performing anastomosis A61B17/115; staplers in general B25C5/00
• CPC Class Codes: A61B 17/29 Forceps for use in minimally invasive surgery
• CPC Class Codes: A61B 2017/00137 Details of operation mode
• CPC Class Codes: A61B 2017/00278 Transorgan operations, e.g. transgastric
• CPC Class Codes: A61B 2090/306 using optical fibres
• CPC Class Codes: A61B 2090/3614 using optical fibre
• CPC Class Codes: G02B 23/2407 Optical details
• CPC Class Codes: G02B 26/103 having movable or deformable optical fibres, light guides or waveguides as scanning elements light guides per se G02B6/00
• CPC Class Codes: G02B 6/06 : the relative position of the fibres being the same at both ends, e.g. for transporting images
• CPC Class Codes: H04N 13/243 : using three or more 2D image sensors
• CPC Class Codes: H04N 13/254 : in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 23/56 : provided with illuminating means
• CPC Class Codes: H04N 25/41 : Extracting pixel data from a plurality of image sensors simultaneously picking up an image, e.g. for increasing the field of view by combining the outputs of a plurality of sensors

Abstract

A system includes a plurality of scanning devices and light receivers, enabling a plurality of images of a site to be displayed using output signals produced in response to light from the light receivers. To avoid crosstalk caused by light receivers receiving light emitted by a plurality of scanning devices, different wavebands of light can be applied to different scanning devices, the received light can be filtered, or the light can be supplied to one scanning device at a time to multiplex either frame-by-frame, or pixel-by-pixel, or the light supplied to each scanning device can be modulated and the received light demodulated so that an image is produced in response to light from a single scanning device. Expensive components such as laser light sources, optical detectors, a controller, and processor can be shared by multiple imaging devices to minimize the cost of the imaging system.

Claims

1. A system that produces a plurality of different images of a site produced by a plurality of imaging devices, while avoiding crosstalk in the images, comprising:

(a) a plurality of imaging devices, the plurality of imaging devices including a plurality of scanning devices and a plurality of light receivers, each light receiver being associated with one of the plurality of scanning devices to receive light from an area of the site illuminated by said one of the plurality of scanning devices, each scanning device being coupled to a distal end of an optical fiber used to convey light to the scanning device so that the light is emitted by the scanning device to illuminate the site, the light receiver receiving light from the site for use in producing an image of the site;

(b) at least one light source for supplying light to the scanning devices through a plurality of optical fibers; and

(c) means for imaging the site so as to prevent crosstalk between the plurality of images, by preventing light emitted by one of the plurality of scanning devices from interfering with light emitted by any other of the plurality of scanning devices, when light that is received from the site by the plurality of light receivers is used to produce a plurality of images of the site.

2. The system of claim 1, further comprising an optical switch that is controlled to direct light from the at least one light source through an optical fiber to a selected one of the plurality of scanning devices at a time.

3. The system of claim 2, wherein the means for imaging so as to prevent crosstalk comprises a controller that is coupled to the optical switch, the controller controlling the optical switch so that only one image of the site is permitted to be captured at a time by the plurality of imaging devices, whereby images of the site are time multiplexed on a frame-by-frame basis.

4. The system of claim 3, wherein the plurality of scanning devices scan the site with light emitted in a desired scanning pattern, followed by a retrace interval to restart another scan, and wherein the controller causes the optical switch to selectively enable light to be supplied to a first scanning device scanning an area of the site while a second scanning device is in the retrace interval, and then causes the optical switch to selectively enable light to be supplied to the second scanning device scanning the area of the site while the first scanning device is in the retrace interval.

5. The system of claim 2, wherein the means for imaging so as to prevent crosstalk comprises a controller that controls the optical switch so that light from the at least one light source is supplied to only one scanning device of a plurality of scanning devices that are scanning an area of the site at a time and only sufficiently long to scan a spot corresponding to a single pixel of an image of the site that is then being captured, whereby images of the site are pixel multiplexed so that the images are captured on a pixel-by-pixel basis, with only one pixel of each of the images being captured at a time.

6. The system of claim 1, wherein the at least one light source comprises a plurality of light sources, and wherein one or more of the plurality of light sources are used only by one of the plurality of scanning devices and produce light at one or more wavebands that are different than the waveband of light produced by any other light source of the plurality of light sources that is used by any other of the plurality of scanning devices to illuminate a common portion of the site.

7. The system of claim 6, wherein the means for imaging so as to prevent crosstalk comprises a plurality of optical filters used to filter the light received by a plurality of light receivers that are receiving light from the common portion of the site illuminated by the plurality of the scanning devices, specific optical filters of the plurality of optical filters passing light in one or more wavebands emitted by the scanning device associated with a specific light receiver, while blocking light in other wavebands emitted by any other scanning device.

8. The system of claim 7, wherein the plurality of optical filters have different polarizations, and wherein the light emitted by each scanning device has a specific polarization corresponding to the polarization of an optical filter used to filter light received by the light receiver associated with the scanning device, so that only the light received from the site that was emitted by the scanning device associated with a specific light receiver is used for producing an image of the site based on the output signal produced in response to the light.

9. The system of claim 1, wherein the means for imaging so as to prevent crosstalk comprises:

(a) a light modulator that modulates light provided to each scanning device differently; and

(b) a demodulator that demodulates output signals produced in response to the light received by the plurality of light receivers to separate the output signals based on each different scanning device that produced the light that was reflected from the site and received by the plurality of light receivers, so that only light emitted by the scanning device with which a specific light receiver is associated is used to produce an image.

10. The system of claim 9, wherein the light modulator modulates light using a type of modulation selected from a group consisting of:

(a) an amplitude modulation; and

(b) a frequency modulation.

11. A method for avoiding crosstalk in images produced by a plurality of imaging devices used for imaging a site to produce a plurality of images, comprising the steps of:

(a) conveying light from at least one light source to the plurality of imaging devices, wherein the plurality of imaging devices include a plurality of scanning devices and a plurality of light receivers, each scanning device being coupled to an optical fiber that conveys light from the at least one light source for use in illuminating the site, and each light receiver being associated with a specific scanning device and receiving light from the site;

(b) emitting the light from each scanning device to illuminate at least a portion of the site;

(c) responding to the light received from the site by the plurality of light receivers, to produce output signals indicative of the light that was received, for use in producing the plurality of images;

(d) controlling imaging of the site so as to prevent crosstalk between the plurality of images of the site produced using the light received by the plurality of light receivers, by preventing light emitted by one of the plurality of scanning devices from interfering with light emitted by any other of the plurality of scanning devices, when the light received by each light receiver associated with the one scanning device is used to produce an image of the site.

12. The method of claim 11, wherein the step of controlling the imaging of the site comprises the step of selectively supplying light to only one of the scanning devices at a time, enabling only one image at a time to be captured by the plurality of the imaging devices, so that the images of the site are time multiplexed on a frame-by-frame basis.

13. The method of claim 12, wherein the step of emitting the light from each scanning device comprises the steps of:

(a) using each scanning device to scan a portion of the site with light emitted in a desired scanning pattern; and

(b) after completing the scanning by each scanning device in the desired scanning pattern, returning to a start position during a retrace interval to restart another scan with the scanning device.

14. The method of claim 13, wherein the step of imaging includes the step of supplying light to only one imaging device at a time and only sufficiently long to scan a spot corresponding to a single pixel of an image of the site that is being captured, thereby pixel multiplexing images of the site on a pixel-by-pixel basis, by capturing only one pixel of one of the images at a time.

15. The method of claim 11, further comprising the step of supplying light from one or more light sources to only one of the plurality of scanning devices, wherein the one or more light sources operates at one or more wavebands, each of which is different than the waveband of any other light source supplying light to any other of the plurality of scanning devices.

16. The method of claim 15, wherein the step of controlling imaging so as to avoid crosstalk comprises the step of filtering light reaching the light receivers so that only light produced by a scanning device associated with a specific light receiver is used by the specific light receiver for producing one of the plurality of images of the site.

17. The method of claim 11, wherein the step of controlling imaging so as to avoid crosstalk comprises the steps of:

(a) modulating light provided to each scanning device at different modulation frequencies; and

(b) demodulating output signals produced in response to light received by the plurality of light receivers, to separate the output signals based on each different scanning device that emitted the light reflected from the site and received by the plurality of light receivers, so that only light from a desired scanning device that was received by a light receiver associated with the desired scanning device is used to produce one of the plurality of images.

18. The method of claim 17, wherein the step of modulating comprises the step of modulating the light with a type of modulation selected from the group consisting of:

(a) an amplitude modulation; and

(b) a frequency modulation.