Apparatus and methods relating to expanded dynamic range imaging endoscope systems

• US 20050228231A1
• Filed: 09/27/2004
• Published: 10/13/2005
• Est. Priority Date: 09/26/2003
• Status: Active Grant

• Current Assignee: Tidal Photonics Incorporated
• Original Assignee: Tidal Photonics Incorporated
• Inventors: Stange, Ulrich, MacKinnon, Nicholas B.
• Granted Patent: US 7,544,163 B2
• Time in Patent Office: Days
• US Class Current: 600/180
• 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 light sources and 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 endoscopes that have dynamic range limited because of small image sensors and small pixel electron well capacity, and other optical systems.

Claims

1. An optical imaging system having good dynamic range comprising:

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

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

,

c) a controller operably connected to the light source, the image sensor and the processor, the controller containing computer-implemented programming that is configured to coordinate the light source, image sensor and processor such that the programming varies the selected spectral output and wavelength dependent intensity distribution of the illumination light to provide a compensatory illumination light configured to compensate for at least one of saturation, overexposure or underexposure in a specific wavelength distribution in the image without substantially changing acceptable wavelength distributions, and the computer-implemented programming is configured to combine data about the variation of the light source with the data in the image to provide an enhance dynamic range for the system compared to the image sensor alone.

2. The optical imaging system of claim 1 wherein the system further comprises an endoscope body including a proximal end and a distal end, the body configured to position the distal end proximate to a target and to emit illumination light from the distal end.

3. The optical imaging system of claim 1 wherein the tunable light source comprises:

a) a source of light,

b) a tunable filter comprising;

a spectrum former able to provide a spectrum from a light beam traveling along a light path from the source of light,

a pixelated spatial light modulator (SLM) located downstream from and optically connected to the spectrum former, the pixelated SLM configured to pass substantially only the selected spectral output and wavelength dependent intensity distribution of the compensatory illumination light to compensate for oversaturation or underexposure in the specific wavelength distribution in the signal without substantially changing acceptable wavelength distributions, the pixelated SLM operably connected to the controller, which contains computer-implemented programming that controls an on/off pattern of pixels in the pixelated SLM to pass substantially only the desired wavelength distributions of illumination light.

5. The optical imaging system of claim 3 wherein the pixelated SLM is a reflective pixelated SLM, and wherein the reflective surface of the reflective pixelated SLM is configured to provide first and second pixelated SLM regions disposed substantially side-by-side with a light blocking barrier therebetween, and the system further comprises at least one optical element located and configured to transmit light from the first pixelated SLM region to the second pixelated SLM region.

6. The optical imaging system of claim 1 or wherein the tunable light source comprises:

a) a source of light, and, b) a tunable filter comprising an acousto-optic tunable filter (AOTF) operable configured to pass substantially only the selected spectral output and wavelength dependent intensity distribution of the compensatory illumination light to compensate for oversaturation or underexposure in the specific wavelength distribution in the signal without substantially changing acceptable wavelength distributions, the AOTF operably connected to the controller, which contains computer-implemented programming that controls transmission characteristics of the AOTF to pass substantially only the compensatory illumination light.

8. The optical imaging system of claim 2 wherein the image sensor is disposed at the distal end.

9. The optical imaging system of claim 2 wherein the image sensor is disposed at the proximal end.

10. The optical imaging system of claim 1 wherein the image sensor is a monochromatic image sensor.

11. The optical imaging system of claim 1 wherein the image sensor is a color image sensor.

12. The optical imaging system of claim 11 wherein the system further comprises 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 bands 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 of the bands with a selected color suitable for display on a display device.

13. The optical imaging system of claim 1 wherein the system is configured such that the compensatory illumination light is attenuated in substantially only a single wavelength band compared to the illumination light.

14. The optical imaging system of claim 13 wherein the single wavelength band is one of red, green, blue, cyan, yellow or magenta.

15. The optical imaging system of claim 1 wherein the system is configured such that the compensatory illumination light is attenuated in a plurality of wavelength bands compared to the illumination light.

16. The optical imaging system of claim 1 wherein the illumination light comprises at least one band of fluorescence excitation illumination light and the system further comprises at least one long pass filter configured to block substantially all of the fluorescence excitation illumination band that reflects back to the image sensor.

19. The optical imaging system of claim 1 wherein the system further comprises a display device operably connected to display the high dynamic range image.

20. The optical imaging system of any one of claim 1 wherein the body of the endoscope is non-flexible.

25. The optical imaging system of claim 1 wherein the system is configured to provide different intensities for at least one wavelength band of illumination light by varying the amount of time the different desired wavelength bands are emitted from the endoscope.

26. The optical imaging system of claim 1 wherein the system is configured to provide different intensities for at least one wavelength band of illumination light by attenuating the amount of light emitted for the different desired wavelength bands.

27. The optical imaging system of claim 1 wherein the computer implemented programming is configured to selectively also provide 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.

28. The optical imaging system of claim 1 wherein the computer implemented programming is configured to selectively also provide 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.

29. The optical imaging system of claim 1 wherein the computer implemented programming is configured to selectively also provide 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.

30. The optical imaging system of claim 1 wherein the computer implemented programming is configured to selectively also provide 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 .

4. (canceled)

7. (canceled)

17. (canceled)

18. (canceled)

21-24. -24. (canceled)

31-62. -62. (canceled)