26 Apr 2007
A new thermal imaging camera from Thermoteknix needs no shutter mechanism.
Freed from the weight, noise and interrupted vision imposed by a shutter, the MIRICLE 110KS with XTi shutterless technology is uncooled, compact, silent and always on. "Shutterless technology has long been the goal for focal plane array (FPA) based thermal imaging, but one that posed daunting technical challenges," Jeremy Ford of Thermoteknix told optics.org.
"The camera is essentially a night-vision camera, suited for surveillance, border security and military applications," said Ford. "Losing vision for any length of time behind a closed shutter would be critical in these situations."
No shutter means the camera has no moving parts, resulting in a simpler design, improved reliability and no jamming. Less power is needed to drive it, and Ford points out that no moving parts ensure that the camera is completely silent in operation.
The camera's vision and IR detector systems are based on an alpha silicon uncooled micro-bolometer with an array of 384 x 288 pixels, and it operates in the 7-14 µm infrared band. But the camera footprint and weight are much reduced by the simplified mechanism.
"The small size and low power requirements make it ideal for use on unmanned aerial vehicles, which will more easily be able to carry the camera into the air," Ford commented.
Until now, shuttering has been an unavoidable requirement of camera design. This is because external ambient temperature, drift, and the temperature of the detector itself all lead to a fixed pattern of noise in the detector output and a steady deterioration of image quality.
The traditional solution has been to regularly interpose a mechanical shutter in front of the detector, which blocks all incoming radiation for a period of time. This allows a non-uniformity correction (NUC) to be carried out, but renders the camera blind for several seconds at a time.
The details of Thermoteknix' shutterless solution are being kept confidential, but Ford states that it involves a broad development of technologies across several aspects of the camera.