Apparatus and methods relating to expanded dynamic range imaging endoscope systems

• US 8,100,826 B2
• Filed: 04/30/2009
• Issued: 01/24/2012
• Est. Priority Date: 09/26/2003
• Status: Expired due to Fees

• Current Assignee: Tidal Photonics Incorporated
• Original Assignee: Tidal Photonics Incorporated
• Inventors: MacKinnon, Nicholas B., Stange, Ulrich
• Primary Examiner(s): Leubecker, John P
• Application Number:
  US12/433,733
• Publication Number:
  US 20100004513A1
• Time in Patent Office: 999 Days
• Field of Search: 600/160, 600/178, 600/109, 362/574, 356/326, 356/328
• US Class Current: 600/178
• CPC Class Codes: A61B 1/00186 with imaging filters
• CPC Class Codes: A61B 1/05 characterised by the image sensor, e.g. camera, being in the distal end portion
• CPC Class Codes: A61B 1/0638 providing two or more wavelengths
• CPC Class Codes: A61B 1/0655 Control therefor
• CPC Class Codes: A61B 1/227 for ears, i.e. otoscopes
• CPC Class Codes: G01J 1/32 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00
• CPC Class Codes: G01J 3/0216 using light concentrators or collectors or condensers
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0286 Constructional arrangements for compensating for fluctuations caused by temperature, humidity or pressure, or using cooling or temperature stabilization of parts of the device; Controlling the atmosphere inside a spectrometer, e.g. vacuum
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01N 2021/6471 Special filters, filter wheel
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 21/6456 Spatial resolved fluorescence measurements; Imaging
• CPC Class Codes: G02B 23/2461 Illumination
• CPC Class Codes: G02B 23/2469 using optical fibres
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/84 : for processing colour signals

Abstract

The apparatus and methods herein provide quantitatively controllable light sources and expanded dynamic range endoscopy systems that can improve the quality of images and the ability of users to distinguish desired features when viewing tissues by providing methods and apparatus that improve the dynamic range of images from endoscopes, in particular for example with endoscopes that have dynamic range limited because of small image sensors and small pixel electron well capacity, and other optical system constraints. The apparatus and methods herein, for example, combine light sources with quantitatively variable spectral output and quantitatively variable wavelength dependent intensity distribution with image sensors and controllers to create an expanded dynamic range endoscopy system. By digitally combining illumination data from the digitally controllable light source with the digital image data from the image sensor the system synthesizes expanded dynamic range images whose dynamic range exceeds the dynamic range of the image sensor alone thus providing greatly enhanced information content in the acquired images.

Claims

1. A method of obtaining an image of a target having good dynamic range comprising:

a) emitting illumination light from a tunable light source configured to emit illumination light comprising a variable selected spectral output and a variable wavelength dependent intensity distribution, wherein the light source is configured to independently increase or decrease the variable selected spectral output and the variable wavelength dependent intensity distribution as desired, to illuminate a target;

b) sensing emanating light from the target via an image sensor configured to detect light emanating from a target and transmit an image of the target to a processor; and

,

c) determining whether the emanating light saturates, overexposes or underexposes sensing elements of the image sensor;

d) where the emanating light saturates, overexposes or underexposes sensing elements of the image sensor, selectively adjusting the selected spectral output and wavelength dependent intensity distribution of the illumination light to provide a compensatory illumination light configured to compensate for the oversaturation or underexposure in a specific wavelength distribution in the image without substantially changing acceptable wavelengths; and

,

e) combining data about the adjusting of the light source with data from the image to provide an enhanced dynamic range compared to the image sensor alone.

2. The method of claim 1 wherein the target is a target tissue and the method is implemented via an endoscope.

3. The method of claim 2 wherein the image sensor is disposed at a distal end of the endoscope.

4. The method of claim 2 wherein the image sensor is a monochromatic image sensor.

5. The method of claim 4 wherein the method further comprises using computer-implemented programming configured to coordinate the light source, image sensor and processor such that the light source provides over time a plurality of different desired wavelength distributions of illumination light each having a selected, substantially pure, variable distribution and intensity, the monochromatic image sensor detects light intensity emanating from the target to provide a detected light intensity for each of the desired wavelength distributions, and the processor associates the detected light intensity for each band with a selected color suitable for display on a display device.

6. The method of claim 2 wherein the compensatory illumination light is attenuated in a plurality of wavelength bands compared to the illumination light.

7. The method of claim 2 wherein the illumination light comprises at least one band of fluorescence excitation illumination light and at least one long pass filter blocks substantially all of the fluorescence excitation illumination band that reflects back to the image sensor.

8. The method of claim 2 wherein the endoscope is a surgical microscope or an otoscope.

9. The method of claim 2 wherein the method further comprises a displaying a high dynamic range image on a display device.

10. The method of claim 2 wherein a body of the endoscope is non-flexible.

11. The method of claim 2 wherein a body of the endoscope is flexible.

12. The method of claim 2 further comprising providing different intensities for at least one wavelength distribution of illumination light by varying the amount of time the different desired wavelength distributions are emitted from the endoscope.

13. The method of claim 2 further comprising providing different intensities for at least one wavelength distribution of illumination light by attenuating the amount of light emitted for the different desired wavelength distributions.

14. The method of claim 2 wherein computer implemented programming selectively also provides a spectral output and a wavelength dependent intensity distribution that substantially mimics a spectral output and a wavelength dependent intensity distribution of output energy for disease treatment.

15. The method of claim 2 wherein the computer implemented programming selectively also provides a spectral output and a wavelength dependent intensity distribution that substantially mimics a spectral output and a wavelength dependent intensity distribution of output energy for photodynamic therapy.

16. The method of claim 2 wherein the computer implemented programming selectively also provides a spectral output and a wavelength dependent intensity distribution that substantially mimics a spectral output and a wavelength dependent intensity distribution of output energy for disease diagnosis.

17. The method of claim 2 wherein the computer implemented programming selectively also provides a spectral output and a wavelength dependent intensity distribution that substantially mimics a spectral output and a wavelength dependent intensity distribution of output energy to enhance contrast for detection or discrimination of a desired object in the target.