Single Pixel Camera Takes Images Through Breast Tissue

KentuckyFC writes Single pixel cameras are currently turning photography on its head. They work by recording lots of exposures of a scene through a randomising media such as frosted glass. Although seemingly random, these exposures are correlated because the light all comes from the same scene. So its possible to number crunch the image data looking for this correlation and then use it to reassemble the original image. Physicists have been using this technique, called ghost imaging, for several years to make high resolution images, 3D photos and even 3D movies. Now one group has replaced the randomising medium with breast tissue from a chicken. They've then used the single pixel technique to take clear pictures of an object hidden inside the breast tissue. The potential for medical imaging is clear. Curiously, this technique has a long history dating back to the 19th century when Victorian doctors would look for testicular cancer by holding a candle behind the scrotum and looking for suspicious shadows. The new technique should be more comfortable.

Comments

Not a camera

[graphius]

Not really a single pixel camera, more of a single pixel light absorption meter taken over an area...

Dual Photography

[Required Snark]

Researchers from Stanford demonstrated in 2005 how to generate an image of a scene from the point of view of the light source instead of the camera. It's called dual photography, and has some similarities to the single pixel technique.

We present a novel photographic technique called dual photography, which exploits Helmholtz reciprocity to interchange the lights and cameras in a scene. With a video projector providing structured illumination, reciprocity permits us to generate pictures from the viewpoint of the projector, even though no camera was present at that location. The technique is completely image-based, requiring no knowledge of scene geometry or surface properties, and by its nature automatically includes all transport paths, including shadows, interreflections and caustics. In its simplest form, the technique can be used to take photographs without a camera; we demonstrate this by capturing a photograph using a projector and a photo-resistor. If the photo-resistor is replaced by a camera, we can produce a 4D dataset that allows for relighting with 2D incident illumination.

It exploits Helmholtz reciprocity to swap the camera view with the light view. If light is modeled as rays/photons, the path between the light source and a camera pixel is the same going from the light to the pixel, or the pixel to the light. Hence reciprocity.