Standard scanners might be a little boring, collecting dust next to your printer rarely getting use now that everyone with a phone has a decent digital camera, and most workplaces allow a PDF signature rather than a handwritten one. Instead of allowing that scanner to sit around hogging a valuable power brick outlet, a team of Japanese engineers have turned it into a gigapixel holographic camera.
The reason why you don’t see holograms everywhere is not because we don’t know how to make them, but because the technology required to do so is currently quite expensive. A standard megapixel-based digital camera simply doesn’t have a high enough resolution to construct a hologram, so the photos have to run through an arduous post-production process that creates the hologram. However, cameras able to reach a gigapixel — which are expensive — are capable of creating the hologram with comparative ease. So, rather than figure out how to significantly decrease the cost of digital cameras capable of gigapixel resolution — or bite the bullet and pony up the cash for one — an engineering team from Japan’s Chiba University grabbed a standard digital scanner and combined it with a laser to create a holographic gigapixel camera.
The scanner used by the team — a regular 4800 dpi A4 paper scanner you could buy on the cheap from any office supply store — is capable of creating images with a resolution of over two gigapixels.
To generate a hologram from an object, a recording device and laser must be aligned with that object. The laser aims at the object, and the light (diffracted and not) is recorded by the scanner. That’s what the gigapixel resolution is for, as lower-res recording devices have trouble capturing the result. A standard scanner works similarly to this method, shining a light down the length of an object, with a line of CCDs scanning down the document and capturing the reflected light, but without the laser.
So far, the team used the rig to create 0.43-gigapixel holograms of tiny insects — a flea and an ant. Using a process the team called “band-limited double-step Fresnel refraction,” they were able to build the hologram in only 177 seconds, down from an original 350.
Though the team has managed to create gigapixel holograms using cheap equipment, the end result can’t be displayed on a standard monitor, because a 1920×1080 resolution isn’t high enough for the image. So, the team removed the need for expensive capture equipment, but still hasn’t broken through the expensive display barrier. At the moment, the team doesn’t seem to have a solution for this problem, but at least they’ve already solved the issue of creating a hologram with cheap equipment.
Research paper: arXiv:1305.6084 – “Gigapixel inline digital holographic microscopy using a consumer scanner”