A new multi-flash camera — using computational photography — can detect “depth discontinuities” in a scene and then render it as a line drawing. Think of A-ha’s famous “Take on Me” video from the 1980s, only produced in real time. From a review of multi-flash imaging with the non-photorealistic camera:
The multi-flash camera uses four strategically placed flashes that cast shadows along the depth discontinuities of a scene. The flashbulbs illuminate the scene during image capture creating thin slivers of shadow along the depth discontinuities. The position of the shadows is of course determined by the position of the camera and flashbulb: when the flashbulb is on the right, the shadows are created on the left, and so on.The shadows of an image are detected by first computing a shadow-free image, which is approximated with the MAX composite image. The MAX composite image is assembled by choosing from each pixel the maximum intensity value from the image set. Then the shadow free image is compared with the individual shadowed images identifying the shadow regions. The correspondence between the position of light and shadow region boundaries produce the depth edges.