In the process of using infrared radiation measuring equipment, it is generally required to calibrate the linear response of the linear response range of the infrared focal plane detector. The calibration process generally calculates the grayscale output value of the device by measuring the standard blackbody radiation source with different known temperatures, and calculates the linear response of the device by the fitting method. In the actual calibration process of the external field, since the calibration temperature of the blackbody radiation source cannot be set lower than the ambient temperature, the equipment cannot perform measurement calibration on the black body below the ambient temperature, resulting in the lower limit of the linear response interval of the device cannot be confirmed, lower than the environment. The extrapolation calibration of the temperature may have a large error and the error cannot be evaluated. In this paper, a calibration method for low temperature section of external field equipment is proposed. The experiment proves that the method has high calibration accuracy.
Because there is no practical method to validate the precision of atmospheric transmittance for earth based infrared optical system measuring flying aircraft, this paper applies multiple linear regression to analyze the measured meteorological parameters and atmospheric transmittance, and points out that: 1) the effects of air pressure and visibility on atmospheric transmittance are contrary with physical laws; 2) among all the meteorological parameters, the angle of elevation has the greatest impact on atmospheric transmittance. By comparing with practical result of the experiment, it is found there is big difference. At last, conclusion is drawn that the accuracy of atmospheric transmittance provided by one infrared optical system is not high.
Infrared character of aircraft is one important factor to estimate the ability of breaching the defense of enemy, this paper firstly analyzed the method of infrared calibration with collimator and energy factors composing the sky background, propose one method of deleting energy of background within current image; furthermore, the paper points out that the parameters of calibration with collimator can’t be directly applied to computing Infrared character of flying target, and based on that propose the method of deleting energy of background with another background image measured before mission.
The apparent temperature of high-speed flying target is an important parameter when checking the design of heat
protection system. This paper analyzes the characteristics of high-speed flying target measured by earth-based staring
infrared imaging system, and found out three facts made the measured image blur, the first is energy spread described by
Point Spread Function, the second is the phenomenon of target smearing, and the third is atmospheric agitation and
turbulence. Also the energy reflected by the target from sun and earth to infrared measuring system should be considered.
Thus the method dealt with static or low-speed target isn’t adapt to high-speed target, this paper proposed an effective
method dealing with High-speed flying target in infrared image. The first step is computing the luminance reflected by
target with information of target’s pose and surface structure, the second step is extracting the target from the infrared
image then computing the emission intensity with parameters of calibration, the third step is computing the luminance of
target by subtract the energy of background and energy reflected from the target, after computing the atmospheric trans,
the apparent temperature is finally found.