Readout system and process for IR detector arrays

A method of detecting the intensity of radiation emanating from an object relative to a background level at a pixel detector, comprising the steps of:

• providing a resistive element with a resistance dependent upon the intensity of radiation impinging said detector and having first and second terminals;
• providing an integration element coupled to the first terminal of said resistive element;
• setting said first terminal to a reference voltage;
• defocusing said radiation such that the radiation impinging said detector is proportional to said background radiation level and applying a first voltage to the second terminal of said resistive element such that said integration element discharges to a background voltage level;
• focusing said radiation such that the radiation impinging said detector is proportional to the radiation emanating from said object and applying a second voltage to the second terminal of said resistive element such that said integration element charges to an output voltage level;
• and
• sensing said output voltage level.

A pixel detector for detecting radiation emanating from an object comprising:

• a resistive detector element with a resistance dependent upon said radiation, said resistive detector element having first and second terminals;
• a capacitor coupled directly to said first terminal of said resistive detector element;
• circuitry for applying a reference voltage to the first terminal of said resistive detector element;
• a shutter for focusing and defocusing said radiation;
• bias circuitry for applying a first voltage to the second terminal of said resistive element when said radiation is defocused and for applying a second voltage to the second terminal of said resistive element when said radiation is focused;
• and
• circuitry for sensing an output voltage on the first terminal of said resistive detector element.