Variable resolution optical coherence tomography scanner and method for using same

Abstract

The invention relates generally to optical tomographic imaging and in particular to systems and methods for adapting the resolution of imaging. One embodiment of the present invention is an apparatus for optical coherence tomography imaging, characterized by its ability to vary the axial resolution and scanning speed during imaging.

1 . (canceled) 
     
     
         2 . A swept-source optical coherence tomography (SS-OCT) system generating images of a sample comprising:
 a light source for generating a probe beam designed to sweep over a range of optical frequencies;   optics for scanning the beam across multiple transverse locations on the sample and for combining light returning from the sample with reference light;   a detector for measuring the combined light; and,   a processor for generating images of the sample based on the output of the detector over a sampling of frequencies;   said SS-OCT system having a first mode and a second mode, wherein the range of optical frequencies over which the probe beam is swept is less in the first mode than in the second mode such that the images in the first mode have a lower axial resolution than the images in the second mode, and the time required for measuring at a single transverse location on the sample is less in the first mode than in the second mode.   
     
     
         3 . A system as recited in  claim 2 , wherein the rate of the sweep (THz/μsec) is the same in the two modes. 
     
     
         4 . A system as recited in  claim 2 , wherein the sampling densities in optical frequencies of the first mode and the second mode are the same. 
     
     
         5 . A system as recited in  claim 2 , wherein the data of the second mode are obtained at a higher density of optical frequencies than the second mode. 
     
     
         6 . A system as recited in  claim 2 , wherein the range of sampled frequencies is generated by opto-mechanical means. 
     
     
         7 . A system as recited in  claim 2 , wherein the first mode is a set-up mode and the second mode is a diagnostic mode. 
     
     
         8 . A system as recited in  claim 2 , wherein the image generated in the first mode is an en face image. 
     
     
         9 . A system as recited in  claim 2 , wherein the sweep range of the light source used to generate the image of the sample during the first mode is one half or less than the extent of the sweep of light source used to generate the image of the sample during the first mode. 
     
     
         10 . A system as recited in  claim 2 , wherein the sample is an eye. 
     
     
         11 . A swept-source optical coherence tomography (SS-OCT) system generating images of a sample comprising:
 a light source for generating a probe beam designed to sweep a range of wavelengths;   optics for scanning the beam across the sample at multiple transverse locations and for combining light returning from the sample and reference light;   a detector for measuring the combined light; and,   a processor for generating images of the sample based on the output of the detector over a sampling of wavelengths;   said processor being operable to change both the number of sweeps per second and the range of wavelengths over which the source is swept, and wherein in a first mode the number of sweeps per second is higher than the number of sweeps per second in the second mode and wherein the range of wavelengths over which the source is swept in the first mode is less than in the second mode.   
     
     
         12 . A system as recited in  claim 11 , wherein the range of wavelengths is generated by opto-mechanical means. 
     
     
         13 . A system as recited in  claim 11 , wherein in the first mode the processor generates an en-face image. 
     
     
         14 . A system as recited in  claim 13 , wherein the en face image is formed by summing two or more data points in the axial dimension. 
     
     
         15 . A system as recited in  claim 11 , wherein the first mode is a set-up mode and the second mode is a diagnostic mode. 
     
     
         16 . A system as recited in  claim 11 , wherein the sample is an eye.