| 摘要 |
<p>A thermal imager including a cryogenically cooled detector element array and a scanning element has an optical system with a field of view limited by a field stop (2). A retroreflective region (6) is provided on part of the field stop to act as a temperature reference by allowing the detector array to "look at" itself. A second, different temperature reference (5) is provided on another part of the field stop and the two references are used to equalise and adjust the output characteristics of the elements in the detector array.</p> |
