No shutter required

Since the dawn of focal plane array (FPA) based thermal imaging, shutterless operation has been considered the holy grail of the industry and a seemingly technically impossible goal for all those involved in the thermal imaging world.

Until now, the current generation of FPA based cameras have required frequent shuttered calibration (NUC or Wink) blanking off the incoming image with a “shutter” or “flag” and rendering the observer “blind” to the scene for several seconds at a time.

In critical situations such as target tracking, on-line machine vision or weapon based applications, this complete obstruction to vision can be at least inconvenient and at worst, fatal.

Each element in the FPA detector possesses a different gain and offset value which require continuous adjustment to present a uniform image. Many factors including external ambient temperature, drift and the temperature of the detector itself lead to a fundamental fixed pattern noise in the detector output. This leads to steady deterioration of image quality over time.

Traditional cameras address this issue by regularly interposing a uniform surface in front of the detector – typically a mechanically driven shutter or flag which blocks all radiation from the scene and performs a Non-Uniformity Correction (NUC).

This ‘shuttered’ or ‘blinkered’ approach although being quite effective, has several obvious and major problems associated with it. Vision is interrupted while the detector is calibrated which can take several seconds, and acoustic noise generated by the shutter opening and closing. Additional power is required to operate the shutter and there is the added design complexity of extra moving parts and susceptibility to wear, or jamming.

Now, Cambridge-UK based Thermoteknix have cracked the problem with their new MIRICLE 110KS camera. Based on a 384 x 288 7-14 micron Alpha Silicon microbolometer, the miniature lightweight thermal imaging device is Instant-On and provides continuous, uncooled, solid state, perfect digital thermal imaging – all of the time.

Thermoteknix Systems was established in 1982 and has been a  developer of infrared systems for applications from aerospace to industrial process monitoring.