capturing, by one or more thermal cameras, a plurality of frames from thermal data streams and visual data streams related to a same scene to define thermal data frames and visual data frames, wherein adaptive alignment is performed for thermal data frames and the visual data frames at different depths and different positions in a same image plane;

detecting and tracking, by a person tracker, a plurality of individuals moving in a free-flow setting within the visual data frames, wherein feature points are matched across the thermal data frames and the visual data frames to determine a homography matrix used for aligning thermal/visual object pairs;

generating a tracking identification (id) for each individual of the plurality of individuals present in a field-of-view of the one or more cameras across several frames of the plurality of frames;

fusing, by a frame fuser, the thermal data frames and the visual data frames temporally and spatially, the fusing comprising detecting each individual of the plurality of individuals in the visual data frames and determining the temperature of the each individual from the thermal data frames by estimating an alignment function ƒ_align by mapping from the visual data frames to the thermal data frames by (x_v, y_v)=ƒ_align(x_t, y_t), where (x_v, y_v) represents a given point in the visual data frames and (x_t, y_t) represents a corresponding point in the thermal data frames;

measuring, by a fever screener, a temperature of the each individual of the plurality of individuals within and across the plurality of frames derived from the thermal data streams and the visual data streams;

generating a notification when a temperature of a particular individual of the plurality of individuals exceeds a predetermined threshold temperature; and

automatically correcting for variation in measured temperatures of the plurality of individuals by dynamically adjusting parameters of the thermal camera based on detected environmental changes, and performing error correction by comparing the measured temperatures of the plurality of individuals to a reference temperature source responsive to detecting deviations from expected temperature readings.