Shutter functions, motion blur, and spatio-temporal aliases. Upper row: An object moving at speed s relative to the camera is captured with a box-filter shutter function as depicted in the upper left panel. The duration of each exposure is tc/2, half the time between exposures. The left panel schematizes the stimulus motion and the capture. The second, third, and fourth panels show the amplitude spectra that result from a box-filter shutter with stroboscopic presentation, single-flash presentation, and triple-flash presentation, respectively. As before, the circle represents the window of visibility. Lower row: The moving object is captured with a tent-filter shutter function. The duration of each exposure is tc. The three panels on the right show the spectra that result from a tent-filter shutter.