Institut National D'optique

Loïc Le Noc

Bruno Tremblay

Jean François Viens

A method detects a loss of calibration of a thermal imaging radiometer including an array of imaging microbolometers and a gauge microbolometer. The detection method includes applying a first and a second electrical stimulation to the gauge microbolometer to bring it to a first and a second predetermined temperature, followed by measuring an ohmic responsivity of the gauge microbolometer that is representative of a difference between the first and second electrical stimulations. The measured ohmic responsivity is compared with a reference ohmic responsivity, such that a loss of calibration is signaled whenever the measured and reference ohmic responsivities differ by more than a predetermined threshold. A correction method includes steps of the detection method, to yield a corrected voltage response function for each imaging microbolometer. Advantageously, the methods involve probing the electrical response of the gauge microbolometer without requiring thermoregulated blackbody calibrations sources.

Detection and correction of a loss of calibration of microbolometer thermal imaging radiometers

An apparatus and method precisely measure gas pressure over a large dynamic range and with good immunity to temperature fluctuations, encompassing applications such as gas sensing, bolometer imaging and industrial process monitoring. The micro-thermistor gas pressure sensor assembly includes a suspended platform micro-thermistor sensor device exposed to the gas pressure of a given atmospheric environment, an electrical readout circuit connected to the suspended platform micro-thermistor sensor device, wherein the suspended platform micro-thermistor sensor device acts as a variable electrical resistance in the readout electrical circuit, a binary-wave voltage source connected to the suspended platform micro-thermistor sensor device, and an ohmmeter.

Micro-thermistor gas pressure sensor

A method for sensing gas composition and gas pressure, based on the thermal constants of a variable electrical resistor, is presented. The method for sensing gas composition and pressure includes monitoring a variable electrical resistor whose dynamic thermal response is determined by the thermal conductivity and thermal capacity of the surrounding gas of a given atmospheric environment. In the thermal domain, the sensor has a low-pass characteristic, whose phase delay is determined by the thermodynamic characteristics of the surrounding gas such as composition and pressure. The method can be used for sensing gas composition and can also be used for sensing gas pressure.

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Québec, Canada

Loïc Le Noc