Ancient’s Scanning Light Field Display Spins an 1884 Nipkow Drum Into Multi-Viewer 3D DOOM

James Brown, the New Zealand maker better known as Ancient, has a habit of pulling forgotten display ideas out of history and making them do things their inventors never saw coming. His newest machine takes the Nipkow scanning drum that Paul Gottlieb Nipkow patented in 1884 for an “electric telescope” and turns it into a glasses-free light field display that several people can walk around at once. Each viewer gets a perspective-correct 3D image of the same scene, whether they stand close or far, left or right. Brown even ported DOOM to it.

Nikow’s original disk included a spiral pattern of holes that scanned a single light source line by line. Early mechanical televisions mimicked him, but electronic scanning eventually rendered the entire system obsolete. Peter Brown maintained the helical perforations and spinning drum, but removed the solitary light source. Behind the drum, he has stacks of high-speed LED panels. Every time a hole sweeps past, a complete 2D view of the 3D scene is displayed on those panels, perfectly timed to the angle of that hole and refreshed 512 times each frame. Light from each hole travels in a specific direction, so your left and right eyes receive distinct information, and your brain combines it all to create depth. People standing next to you can see the 3D quite fine because they have their own view from the same rotating piece of equipment.

That flexibility comes with a significant cost in terms of resolution. One eye only sees 100 by 48 pixels at a time. To achieve those pixels, the system generates roughly 5 million rays per frame, the most of which will be wasted in space. Vertical sharpness is all about the number of holes. Brown managed to squeeze into the drum, and horizontal sharpness is determined by how quickly the interior screens change. He used 32-by-64 LED modules, which can update at 22,500 frames per second in one-bit color. When you switch to 3 bit color, the frame rate decreases to 7,500 frames per second, and stretching the image among five active panels reduces it to one-fifth that. There are also diffusers in there to make sure each pixel is spread out just enough so the holes dont produce strong lines.

Building it all was difficult because he needed to keep the drum spinning at a high enough speed to keep the image stable while also keeping the motor and screen refresh in sync so the views did not smudge. Brown’s video walks you through the entire process, including diffuser trials, glacial-speed close-ups of the holes flying past the LEDs, and ultimately the first respectable results: a rampaging T-Rex, an angler fish, a mantis shrimp, and Slimer all floating around with what appears to be fairly nice parallax. Then, of course, there is Doom. The DOOMVOX port, which is licensed under the GNU GPL, converts the game into a light field, allowing passageways and demons to enter 3D space.
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