Microbolometer unit cell signal processing circuit

A night vision camera comprising:

• an array of microbolometer unit cells;
• a plurality of unit cell signal processing circuits, one for each unit cell, each circuit including:
• a current source,
• a first switch for coupling said current source to a first terminal of an associated unit cell to generate first and second signals at the first terminal thereof during first and second time intervals,
• sampling means for sampling the first signal during the first time interval and for sampling the second signal during the second time interval to provide first and second sampled signals respectively, said sampling means including a second switch having a first terminal connected to the first terminal of the unit cell,
• means providing a third signal which is directly proportional to a difference between the first sampled signal and the second sampled signal, said means including a capacitor having a first terminal connected to a second terminal of the second switch, and
• amplifying means for amplifying the difference between the first sampled signal and the second sampled signal;
• and
• means for displaying the amplified difference signals.