The camera in your smartphone is amazingly small already, but now imagine one even smaller still, microscopic in fact at about 200 microns in diameter (diameter of a pencil-point) that can be used in objects too small to incorporate current camera technology.
While a traditional camera requires a lens, this tiny camera is in fact an image sensor with a grating on top etched with a spiral pattern. Light enters from every orientation and the sensor captures a jumble of spirals that are then translated by software into a recognizable B&W image.
Technically, now anything could incorporate this lens-free camera from Rambus: medical devices, toys, even articles of clothing.
Smile, you are [always and sureptitiously] on camera.