Boffins focus on distortion-free wide angle lens

South Korean researchers have developed a relatively cheap lens that produces a virtually distortion-free wide-angle image.

In contrast to commonly known 'fisheye' lenses which produce significant amounts of visual distortion, low-distortion wide-angle lenses can potentially improve image-based applications such as security camera systems and robot navigation.

The new wide-angle lens is lighter, smaller and more affordable than commercially available 'rectilinear' lenses, which also produce low-distortion views.

The researchers presented their new feat of optical technology in the 1 December issue of Applied Optics, a publication of the Optical Society of America.

Made of inexpensive components and available for little more than $100, the new wide-angle lens has been designed specifically to improve indoor security.

"For spacious places with high ceilings such as factories, hotels, theatres, resorts and auditoriums, the lens can capture the entire floor and will help security personnel to easily monitor those places," said lead author Gyeong-il Kweon of Homan University in South Korea.

In these situations, the lens would be attached to inexpensive commercially available bullet cameras.

An elegant piece of optics technology, the new lens looks like a snow globe in the shape of the dome of St Paul's Cathedral. Light from a large area enters the dome of the lens and encounters a V-shaped mirror.

This reflective lens then redirects the light rays to a second lens that resembles the slender statue atop the dome.

This 'refractive' lens produces a sharp image of the large area at the exact location of the image sensor within the bullet camera.