Superresolution Optical Fluctuation Imaging (SOFI)
AssigneeSofast GmbH
InventorJoerg ENDERLEIN
Life of this patent
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Abstract
Statistical analysis techniques based on auto- and cross-correlations/cumulants, of image stacks of fluctuating objects are used to improve resolution beyond the classical diffraction limit and to reduce the background. The time trajectory of every pixel in the image frame is correlated with itself and/or with the time trajectory of an adjacent pixel. The amplitude of these auto- or cross-correlations/cumulants of each pixel, at a given time lag or averaged or integrated over an interval of time lags, is used as the intensity value of that pixel in the generated superresolved optical fluctuation image.
Claims9
A method for analyzing a field-of-view of independently blinking objects, comprising the steps of:
- i) selecting a sample or an observation image comprised of objects from the class of optically signaling objects that stochastically and independently fluctuate;
- ii) acquiring a sequence of repeated optical images of the object as a function of time, producing an x, y, t image stack of pixels;
- iii) extracting a time trajectory for each pixel from said image stack;
- iv) calculating an autocorrelation or autocummulant of each pixel's time trajectory to at least the second order, and
- v) generating a superresolved and background-reduced image from the calculated functions comprising pixels whose intensity value is the amplitude, with a chosen time lag, of the autocorrelation or autocummulant function, or the value of a finite integral of the autocorrelation or autocummulant function over a range of time lags.
A method for imaging the field-of-view of objects whose resolution is below the diffraction limit, in a system in which optical emitters in the field-of-view could be spaced apart by distances shorter than the diffraction limit-resolved distance of the imaging system used and fluctuate independently with time, the method comprising the steps of:
- (i) optically imaging the field-of-view with an optical system of a given point spread function as a function of time to produce x, y, t stacks, each stack comprising the variant pixel sequences whose intensities are superposition of signals emanating from the independent emitters of sub-diffraction size;
- (ii) extracting a time trajectory from said image stacks for each pixel therein;
- (iii) calculating a correlation or cumulant function of the time trajectory of each pixel to at least a second order;
- (iv) generating a new image comprising pixels, and wherein pixels'intensity values are related to the correlation or cumulant function in accordance with a chosen time lag, or a finite integral of said functions over a range of time lags, to derive a superresolution, background-reduced optical image.
Dependencies are inferred from the claim text.