Method and System for Measuring and Compensating for the Case Temperature Variations in a Bolometer Based System

A bolometer type focal plan array system having means for compensating for the case temperature in a pixel level, the system comprises:

• a. an array of i×j differential measurement pixel detectors of the bolometer type, each comprises a sensing element for sensing scenery radiation;
• b. a case which accommodates said array of detectors, said case having a front window that provides exposure of said sensing elements of all the i×j pixel detectors to radiation coming from the scenery;
• c. a case offset correction matrix COi,j which comprises i×j pre-measurement values for discretely compensating each sensed output signal from each of said i×j pixel detectors respectively;
• d. at least one differential measurement blind detector of the bolometer type within the case in a column j+1 for sensing case radiation, each sensing element of said at least one blind detector is masked from the scenery and is irradiated by a baffle which extends from the case to close proximity with said sensing element of said at least one blind detector, and whose radiation is proportional to the case radiation;
• e. reading circuitry for reading indication for the scenery radiation as sensed by each of the i×j detectors of the array, and for reading indication for the case radiation as sensed by said at least one blind detector;
• and
• f. a case-temperature compensation circuitry for multiplying a signal as read from said at least one blind detector by each of the values of said case offset correction matrix, thereby to obtain plurality of case compensation values, each relating to each pixel, and compensation accordingly each of said scenery radiation indications of each detector by the corresponding result of said multiplication.