Imaging apparatus
First Claim
1. Thermal imaging apparatus comprising:
- an array of parallel thermal detectors, which detectors exhibit a range of different responsivities, which range is significantly diverse at wavelengths greater than a predetermined long wavelength;
optical means for directing thermal energy radiation to said array of parallel detectors;
inhibiting means effective to inhibit passage to said detector array of radiation of at least a range of wavelengths greater than said predetermined long wavelength; and
electronic means operable to apply differing preset gain to each signal derived from a respective one of said parallel detectors, which preset gain differs according to the different detector responsivities thereof, and compensates at least partly for said different detector responsivities.
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Accused Products
Abstract
A thermal imager having an array of sprite detectors is provided with a novel means for reducing or eliminating lininess in the reproduced image. This means comprises a low pass optical filter which cuts out wavelengths above 11.5 microns and adjustable gain buffer amplifiers in the respective channels. It is found that with the use of the optical filter the gains of the buffer amplifiers may be preset, when setting up the apparatus, to eliminate lininess and it is not necessary to include complex and noisy circuitry for continuously monitoring the signals output by the detectors and then applying appropriate corrections to the individual channels during operation of the apparatus, as in the prior art.
17 Citations
17 Claims
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1. Thermal imaging apparatus comprising:
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an array of parallel thermal detectors, which detectors exhibit a range of different responsivities, which range is significantly diverse at wavelengths greater than a predetermined long wavelength; optical means for directing thermal energy radiation to said array of parallel detectors; inhibiting means effective to inhibit passage to said detector array of radiation of at least a range of wavelengths greater than said predetermined long wavelength; and electronic means operable to apply differing preset gain to each signal derived from a respective one of said parallel detectors, which preset gain differs according to the different detector responsivities thereof, and compensates at least partly for said different detector responsivities. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Optical apparatus, for use in a thermal imager, comprising:
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optical means for forming a thermal image of a scene to be detected by an array of parallel detectors; and inhibiting means which is effective to inhibit passage to said detector array of radiation of at least a range of wavelengths above a pre-determined long wavelength in the range 11 to 11.5 microns and also is effective to allow passage to said detector array of radiation at all wavelengths above 9 microns up to said predetermined long wavelength. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification