Fluorescence Imaging Scope With Dual Mode Focusing Structures

Abstract

Improved fluoresced imaging (FI) and other sensor data imaging processes, devices, and systems are provided to enhance use of endoscopes with FI and visible light capabilities. A first optical device is provided for endoscopy imaging in a white light and a fluoresced light mode with an image sensor assembly including one or more image sensors. A mechanism in the first optical device to automatically adjust the focus of the first optical device wherein the automatic focus adjustment compensates for a chromatic focal difference between the white light image and the fluoresced light image caused by the dispersive or diffractive properties of the optical materials or optical design employed in the construction of the first or second optical devices, or both. Adjustment mechanisms are provided using liquid lenses or repositioning sensors. The design may be integrated with a scope or detachable.

1 . An endoscopic camera operable to image in white light and fluoresced light, where a fluoresced light spectrum is outside of a wavelength spectrum of the imaged white light, wherein the endoscopic camera can be removably attached to an endoscope comprising a plurality of relay lenses including rod lenses, comprising:
 a focusing lens group to receive and condition a relayed light from the endoscope;   a light splitter to split the conditioned, relayed light into a first beam and a second beam; and   an image sensor assembly including a first image sensor operable to capture white light images, a second image sensor operable to capture fluoresced light images, and a focus adjustment mechanism configured to automatically adjust the position of the second image sensor a distance D along a focal path orthogonal to an image sensitive surface thereof,   wherein the automatic focus adjustment compensates for a chromatic focal difference between the white light image and the fluoresced light image caused by dispersive or diffractive properties of optical materials or optical design employed in the attached endoscope.   
     
     
         2 . The endoscopic camera of  claim 1 , wherein there are no further focusing optics between the light splitter and the second image sensor. 
     
     
         3 . The endoscopic camera of  claim 1 , wherein the light splitter is a dichroic prism, directing the first beam to the first image sensor and the second beam to the second image sensor. 
     
     
         4 . The endoscopic camera of  claim 3 , wherein the first beam includes light spectra below a cutoff wavelength of about 650 nm. 
     
     
         5 . The endoscopic camera of  claim 1 , wherein the endoscopic camera is configured to automatically recognize the attached endoscope, and, in response, automatically move the second image sensor a known, prescribed distance D, such that images captured by the second image sensor are in focus. 
     
     
         6 . The endoscopic camera head of  claim 5 , further comprising a memory, wherein the memory contains focal settings for multiple endoscopes, each endoscope having different dispersive or diffractive properties of optical materials or optical design employed therein. 
     
     
         7 . The endoscopic camera of  claim 1 , wherein the focus adjustment mechanism comprises a motor. 
     
     
         8 . The endoscopic camera of  claim 7 , wherein the motor is a piezoelectric motor. 
     
     
         9 . The endoscopic camera of  claim 1 , wherein the position of the second image sensor toggles between two pre-determined positions when the endoscopic camera is switched from a white light mode to a fluoresced light mode. 
     
     
         10 . The endoscopic camera of  claim 1 , wherein the distance D is smaller than would be required to adjust for differing focal lengths between visible and infrared light. 
     
     
         11 . An endoscopic system, comprising
 The endoscopic camera of  claim 1 ;   a plurality of endoscopes that may be detachably attached to the endoscopic camera, each endoscope comprising relay lenses and an identifying means indicating a model of the endoscope, where each endoscope has a chromatic focal difference between white light with a first wavelength band and fluoresced emission light with a second wavelength band longer than that of the first wavelength band, where the chromatic focal difference is caused by the dispersive or diffractive properties of optical materials or optical design employed therein;   a light source able to provide white light illumination in a first mode and fluorescence excitation illumination in a second mode; and   a memory on which is stored focus settings for multiple endoscope models, including known, prescribed adjustments to provide desired focal settings required for each endoscope to provide in-focus images at the image sensors.   
     
     
         12 . The endoscopic system of  claim 11 , further comprising a camera control module and wherein the memory is an element of the camera control module. 
     
     
         13 . The endoscopic system of  claim 12 , wherein the camera control module further comprises image processing circuitry. 
     
     
         14 . A method for providing an automatic focus adjustment of an endoscopic camera, comprising the steps of
 providing an endoscope comprising relay lenses and an identifying means indicating a model of the endoscope, where the endoscope has a chromatic focal difference between white light with a first wavelength band and fluoresced emission light with a second wavelength band longer than that of the first wavelength band, where the chromatic focal difference is caused by the dispersive or diffractive properties of optical materials or optical design employed therein;   providing the endoscopic camera to which the endoscope may be removably attached, the endoscopic camera comprising a focusing lens group to receive and condition a relayed light from the endoscope and an image sensor assembly comprising a first image sensor and a focus adjustment mechanism;   providing a memory on which is stored focus settings for multiple endoscope models, including known, prescribed adjustments to provide desired focal settings required for each endoscope to provide in-focus images at the image sensor;   attaching the endoscope to the endoscopic camera;   recognizing, by means of the endoscope identifying means, the model of the endoscope; and   retrieving from the memory the focal settings for the attached endoscope.   
     
     
         15 . The method of  claim 14 , comprising the further step of collecting image light in a visible light mode by illuminating a subject scene with white light, collecting image light with an objective lens of the endoscope, relaying light by means of the relay lenses from the objective lens to the focusing lens group, focusing the relayed visible light, and collecting an in-focus white light image with the first image sensor. 
     
     
         16 . The method of  claim 15 , comprising the further step of subsequently collecting a fluoresced light image, comprising the steps of
 applying the automatic focus adjustment to the endoscopic camera;   illuminating the subject scene with a fluorescence excitation light;   collecting fluorescence emission image light with the objective lens of the endoscope, relaying light by means of the relay lenses, from the objective lens to the focusing lens group, focusing the relayed fluorescence emission light; and;   collecting an in-focus fluoresced light image with the first image sensor or a second image sensor.   
     
     
         17 . The method of  claim 16  wherein the automatic focus adjustment comprises the step of adjusting the position of image sensor collecting the fluoresced light image a distance D along a focal path orthogonal to an image sensitive surface thereof. 
     
     
         18 . The method of  claim 16 , wherein the automatic focus adjustment comprises the step of adjusting the curvature of a liquid-based deformable lens positioned along an optical path within the endoscopic camera. 
     
     
         19 . The method of  claim 14 , comprising the further steps of
 collecting image light by illuminating a subject scene, collecting image light with an objective lens of the endoscope, relaying light by means of the relay lenses from the objective lens to the focusing lens group, focusing the relayed visible light,   splitting the relayed light downstream from the focusing lens group such that the first image sensor receives light in the visible spectrum; and   providing a second image sensor that receives fluorescence image light.   
     
     
         20 . The method of  claim 19 , wherein the relayed light is split by a dichroic prism.