> His code reconstructed the full image of the office from the "traveling slit".
This method is commonly used in vision systems employing line scan cameras. They are useful in situations where the objects are moving, e.g. along conveyors.
Even today most cameras have some amount of rolling shutter—the readout on a high-megapixel sensor is too slow/can't hold the entire sensor in memory instantaneously, so you get a vertical shift to the lines as they're read from top to bottom.
Global shutter sensors of similar resolution are usually a bit more expensive.
With my old film cameras, at higher shutter speeds, instead of opening the entire frame, it would pass a slit of the front/rear shutter curtain over the film to just expose in a thousandth of a second or less time.
This method is commonly used in vision systems employing line scan cameras. They are useful in situations where the objects are moving, e.g. along conveyors.