Abstract: Techniques for reducing a likelihood of detection of an imaging system by another imaging system are provided. For example, the techniques may include controlling read-out such that the timings between frames of an image are non-uniform. For example, a processor may be configured to generate a plurality of frame synchronization signals from a main clock and transmit the plurality of frame synchronization signals to readout circuitry. Each frame synchronization signal is an instruction to start the biasing and reading for a respective frame. The plurality of frame synchronization signals may be generated such that a timing between pulse biasing the same thermal sensor is not uniform. The techniques may also include controlling the read-out such that the timings between lines within a frame are non-uniform which also results in the timing between pulse biasing of the same thermal sensor not being uniform.

Abstract: Systems for detecting a presence of a microbolometer are provided. The systems may also discriminate a type of the microbolometer. The systems may comprise analog filtering and processing or digital filtering and processing. In some examples, both analog and digital filtering may be used. For example, a system may comprises a photodiode, an analog to digital converter (ADC) having a frequency sampling rate of at least two times an expected frequency range of known microbolometers and a processor. The ADC may receive an amplified output from the photodiode and produce a sampled sequence using the frequency sampling rate. The processor converts the sampled sequence into a frequency profile, examines the frequency profile to identity at least a fundamental frequency and determines whether a microbolometer is detected in a line of sight of the photodiode based on the fundamental frequency.