To achieve an accurate evaluation of the effect of laser interference, this paper studies on the image simulation model of laser interference infrared detectors. According to different interference densities, the characteristics of the laser interference detector spots are investigated. First, based on the laser interference transmission link, a simulation model of the gray response of the detector image and the laser interference power is established. Then, a set of NEFD measurement methods for infrared detector response models are established based on the response characteristics of the detector. Finally, according to the different NEFD values at the entrance pupil optical system, theoretically simulation is carried on the relationship between the laser interference effect and the power density irradiated to the entrance pupil surface of the optical system. The results show that when the irradiance density at the entrance of the pupil optical system exceeds 1*106 of the NEFD value, the point target can be effectively interfered. Further, when the irradiance density at the entrance of the pupil optical system exceeds 1*107 of the NEFD value, the area target can be effectively interfered. The proposed model is verified by the ground test as the ground test results have the same trend and magnitude as the simulation results.
In this paper, the thermal resistance radiant heat flow sensor and the automatic balance thin film radiant heat flow sensor are calibrated according to the small-scale heat flow in the cold vacuum environment, and the stability time is analyzed, the calibration data is linearly fitted, and then the calibration process is analyzed. The errors that may occur in the It provides a method basis for the engineering use of the heat flow meter in a similar environment.
The solar stray light will seriously affect the imaging quality of the infrared detection system. The traditional point source transmittance (PSF) index is difficult to evaluate the image degradation of the detection system due to stray light. In this paper, a stray light simulation is performed firstly for a given infrared detection system, and the irradiance distribution of solar stray light on the surface of the detector with different incident angles are obtained. Then a simulation model of the detection system is established based on the physical conversion process of the infrared detection system. By combining this simulation model with the light distribution, the spatial noise of the detection system with solar stray light can be calculated quantitatively, and the image degradation due to solar stray light can be quantitatively evaluated.
The mechanism of the image degradation due to the opaque metallic wire grid is analyzed and a degradation mode is built based on the theory of Fourier optics. The effect of different opaque wire grid on the image quality is simulated. We define the manner of using wire grid that will meet system requirements for both optical and shielding efficiency. A gray non-uniformity correction model based on two-point correction method is built, and the way to estimate the degradation function and the restoration process are proposed. Both the experimental results and simulation show that the non-uniformity of the image after correction is less than 1/10 of that of before correction and the relative error between the original image and restored image is 0.56%.
In view of the lack of precision and small dynamic range in one or two-point temperature nonuniformity correction method which is applied in the Space Infrared Image, this paper will introduce the technique of discrete wavelet transform which is applied to the non-uniformity correction. In addition, it is used the real-time infrared image processing method of removing blind pixels, invalid pixels and additive noise with using ground calibration parameters and deep space images. It is designed the infrared image processing method applied to the flight that the multiplicative noise in infrared image is turned into additive noise using the logarithm aimed at the characteristic of noise distribution.
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