LOW CONTRAST MIDWAVE FLIR IMPLEMENTATION
An infrared camera system for low contrast employs a focal plane array (FPA) of a plurality of detector diodes. A read out integrated circuit (ROIC) including a plurality of integration switches is connected to the plurality of detector diodes. A frame mean calculator receives raw data from the FPA and an integration time servo receives a frame mean from the frame mean calculator and a preprogrammed target mean. The integration time servo compares the frame mean and target mean and provides an integration time output to the ROIC responsive to the comparison for control of the integration switches.
1 . An infrared camera system comprising:
a focal plane array (FPA) of a plurality of detector diodes;
a read out integrated circuit (ROIC) including a plurality of integration switches connected to the plurality of detector diodes;
a frame mean calculator receiving raw data from the FPA;
an integration time servo receiving a frame mean from the frame mean calculator and a preprogrammed target mean, said integration time servo comparing the frame mean and target mean and providing an integration time output to the ROIC responsive to the comparison for control of the integration switches.
2 . An infrared camera system as defined in claim 1 further comprising a nonuniformity correction arithmetic unit receiving raw data from the FPA.
3 . An infrared camera system as defined in claim 1 further comprising a bad pixel replacement unit.
4 . An infrared camera system as defined in claim 2 further comprising a memory storing predetermined nonuniformity correction tables, said memory addressed by the nonuniformity correction arithmetic unit based on raw data from the FPA and providing selected ones of said nonuniformity correction tables to the nonuniformity correction arithmetic unit responsive to said address.
5 . An infrared camera system as defined in claim 4 wherein the nonuniformity correction tables are stored in the memory by a host computer prior to operation of the camera system.
6 . A method for operation of an infrared camera system comprising:
reading data from a focal plane array of a plurality of detectors;
calculating a frame mean;
comparing the frame mean to a target mean; and,
adjusting an integration time for the plurality of detectors responsive to the comparison.
7 . The method for operation of an infrared camera system as defined in claim 6 further comprising applying nonuniformity correction to the raw data.
8 . The method for operation of an infrared camera system as defined in claim 7 wherein the nonuniformity correction is determined based on the FPA data.
9 . The method for operation of an infrared camera system as defined in claim 8 wherein the nonuniformity correction is applied by
addressing a memory based on FPA data and
reading a nonuniformity correction table into an arithmetic correction unit from the memory based on the address.