1. A depth-imaging method comprising: with an infrared emitter of a depth-imaging time-of-flight (ToF) camera, irradiating a subject with temporally modulated light of spatially alternating bright and dark features; receiving the modulated light reflected back from the subject onto an array of pixels of the ToF camera; for each pixel of the array, outputting a ToF signal varying in response to a time of flight of the modulated light from the infrared emitter to a subject locus imaged at that pixel, and then back to the pixel; and mapping the subject in three dimensions based on the ToF signal associated with subject loci directly irradiated by the bright features, while omitting or weighting negatively the ToF signal associated with subject loci under the dark features, the mapping exhibiting an improved signal-to-noise ratio relative to mapping under uniform subject illumination, due to exclusion of indirect reflection from subject loci under the dark features.