motion blur (and its PSF)

A uniform streak-shaped PSF produced by a point of light moving during a single exposure.

Motion blur along one direction is modeled by a box (moving-average) PSF, $h(y)=1/L$ for $y=0,\ldots,L-1$ and $0$ otherwise, where $L$ is the streak length in pixels -- mechanically exact, since a point of light moving at constant velocity deposits equal brightness at every position it crosses. Its frequency response is a discrete sinc, comfortably nonzero across most of the spectrum for a short streak but capable of coming close to zero for a longer one.