London: Scientists are developing a cheap microscopic "pinhead" camera which they claim could soon revolutionise a host of applications ranging from surgeries to robotics.

Researchers at Cornell University in New York produced a working prototype which is 100th of a millimetre thick and just half a millimetre across.

The device, which is small enough to fit on the head of a pin and contains no lenses or moving parts, is able to resolve 20 pixel images using a clever piece of mathematics and some fast computing, the researchers said.

It is created from pieces of silicon doped to make them sensitive to light at different angles, they said.

"It's not going to be a camera with which people take family portraits, but there are a lot of applications out there that require just a little bit of dim vision,"Dr Patrick Gill, who led the research team, said.

According to the researchers, the camera could be used to help brain surgeons image neurons, or be a component in any cheap electronic system.

For example, it could be fitted to devices that detect the angle of the sun, or micro-robots that require a simple visual system to navigate.

The camera was invented in the lab of Alyosha Molnar, assistant professor of electrical and computer engineering at Cornell, and developed by a group led by Gill, a postdoctoral associate.

The scientists, who detailed online in the journal Optics Letters, call their camera a Planar Fourier Capture Array (PFCA) because it uses the principles of the Fourier transform -- a mathematical tool that allows multiple ways of capturing the same information. Each pixel in the PFCA, according to the researchers, reports one component of the Fourier transform of the image being detected by being sensitive to a unique blend of incident angles.

While Fourier components themselves are sometimes directly useful, a bit of computation can also transform Fourier components into an image, they said.

The scientists will continue working to improve the camera's resolution and efficiency, but they think their concept can lead to a myriad of applications.

It could be a component in any cheap electronic system -- in devices that detect the angle of the sun or a micro-robot that requires a simple visual system to navigate.