Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N5/00—Details of television systems
  • H04N5/30—Transforming light or analogous information into electric information
  • H04N5/33—Transforming infrared radiation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/20—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from infrared radiation only
  • H04N23/23—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from infrared radiation only from thermal infrared radiation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
  • H04N25/67—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to fixed-pattern noise, e.g. non-uniformity of response
  • H04N25/671—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to fixed-pattern noise, e.g. non-uniformity of response for non-uniformity detection or correction

Definitions

• the invention relates to a thermographic camera with at least one infrared radiation detector, such as a thermal detector or a pyrodetector, and with at least one adjustment device that provides control and/or supply voltages necessary for the operation of the thermographic camera.
• the invention further relates to a method for operating a thermographic camera.
• Thermographic cameras are known for determining temperature profiles of objects and are frequently used in environments with varying temperatures.
• the adjustment devices of the thermographic camera which must provide various supply and/or control voltages, are also subject to corresponding temperature fluctuations, which can certainly amount to as much as 70° C. Because of this, the voltages generated by the associated electronics are also subject to fluctuations.
• thermographic camera in which the temperature-induced drift of electronics can be compensated for with simultaneously reduced component costs.
• thermographic camera of the type mentioned above on which a storage means is provided, in which at least one temperature-dependent characteristic is stored, and in which the thermographic camera automatically compensates for a temperature-induced drift of the at least one adjustment device based on the characteristic curve.
• thermographic camera There are various possibilities for re-regulating the detector gain by analog or digital means in the thermographic camera. These adjustment possibilities permit a compensation for the drift in the electronics.
• the slopes of the detector characteristic, as well as the temperature of the at least one adjustment device are determined for various ambient temperatures in a calibration step, and are then described by a mathematical model. From the latter, at least one characteristic curve is obtained which, once stored in the camera, can compensate for the temperature-induced drift of the system and is used in the measurement. In a temperature measurement range between 0° C. and 100° C., the measurement error component caused by the electronics drift can be reduced in this manner to fractions of a degree.
• thermographic camera in which the infrared radiation detector is formed by a bolometer, in particular a bolometer with a focal plane array (FPA) having a plurality of individual sensors (pixels).
• FPA focal plane array
• the compensation of measurement values based on a characteristic stored in memory can be realized especially expediently in a thermographic camera in which the detector amplification is accomplished by analog variation of the control voltage, the control current or the integration time of the adjustment device, or digitally by a coding processable by a processor.
• a more precise compensation of the electronics drift that also takes the temperature over smaller intervals into account can be achieved by the use of several characteristic curves associated with individual components or groups thereof, so that in an advantageous configuration of the thermographic camera, the storage means can hold one or more characteristic curves, each associated with one or more adjustment devices.
• At least one temperature sensor is provided to determine the ambient temperature of the adjustment devices, in particular one temperature sensor for each adjustment device.
• thermographic camera for example the thermographic camera as described above.
• the camera is first subjected to a calibration to be performed one time, in which the following steps are carried out.
• the camera is housed inside a temperature-stabilized environment, such as a thermal testing cabinet, after which the control and/or supply voltages provided by the electronic components at different temperatures are determined.
• a characteristic curve is derived from these voltages that are subsequently stored in a storage means of the thermographic camera for compensation of the electronics drift.
• the drift of the electronics is compensated for by specifying the correct control voltage based on the characteristic curve, so that the slope of the detector characteristic does not change.
• the above-mentioned compensation can also be accomplished in a different manner than via the control voltage, namely by an analog change of the control current or the integration time, or digitally by an appropriate coding to be processed by a processor and which is implemented in a chip.
• thermographic camera in which the temperature-induced drift of electronic components of the camera can be minimized or compensated for with reduced component expense.

Landscapes

• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)
• Radiation Pyrometers (AREA)
• Transforming Light Signals Into Electric Signals (AREA)
• Studio Devices (AREA)

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Publications (1)

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Citations (5)

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• 2008
  • 2008-01-19 DE DE102008005167A patent/DE102008005167A1/de not_active Withdrawn
  • 2008-08-21 EP EP08801648.0A patent/EP2245848B1/de active Active
  • 2008-08-21 CN CN200880125123.0A patent/CN101919237A/zh active Pending
  • 2008-08-21 US US12/863,466 patent/US20100289901A1/en not_active Abandoned
  • 2008-08-21 JP JP2010542519A patent/JP2011510274A/ja active Pending
  • 2008-08-21 WO PCT/EP2008/006871 patent/WO2009089852A1/de active Application Filing
  • 2008-12-22 JP JP2010542533A patent/JP5535085B2/ja active Active
  • 2008-12-22 US US12/863,452 patent/US8872110B2/en active Active
  • 2008-12-22 EP EP08870935.7A patent/EP2245849B1/de active Active
  • 2008-12-22 CN CN200880125121.1A patent/CN101919236B/zh active Active
  • 2008-12-22 WO PCT/EP2008/011032 patent/WO2009089897A2/de active Application Filing

Patent Citations (5)

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