1. A method for detecting a white blood cell (WBC) event from in vivo capillary data associated with a subject, the method comprising: non-invasively obtaining the capillary data, the capillary data comprising a plurality of images captured over a first time period; specifying a first set of two-dimensional (2D) coordinates associated with the plurality of images, the first set of 2D coordinates corresponding to a plurality of internal contour points of a capillary visible in the plurality of images; specifying a second set of 2D coordinates associated with the plurality of images, the second set of 2D coordinates corresponding to a plurality of external contour points of the capillary; interpolating the first set of 2D coordinates to generate a first set of resampled coordinates; interpolating the second set of 2D coordinates to generate a second set of resampled coordinates; generating a plurality of intermediate curves based on the first set of resampled coordinates and the second set of resampled coordinates, the plurality of intermediate curves including a middle curve; defining a plurality of curvilinear distances based on the middle curve; extracting a plurality of intensity values from the plurality of images, each extracted intensity value corresponding to one of the plurality of images, one of the plurality of intermediate curves, and one of the plurality of curvilinear distances; transforming the plurality of extracted intensity values to a Radon domain; identifying a plurality of maxima locations corresponding to a flow trajectory inside the capillary; and detecting at least one visual gap in the flow trajectory inside the capillary, the at least one visual gap indicating the WBC event.