Abstract:For the case that it is difficult to acquire hyperspectral image data, a hyperspectral image simulation method based on the radiation transfer model PROSAIL is proposed. Firstly, the sensitivity analysis of the input parameters of the PROSAIL model is carried out. On this basis, a parameter calculation model based on a support vector machine is established for five typical biochemical parameters (leaf structure parameter N, chlorophyll content Cab, leaf dry matter content Cm, carotenoid content Car and leaf area index LAI). Secondly, simulated hyperspectral images are obtained through pixel by pixel calculation by using the PROSAIL model according to the typical biochemical parameters. The multispectral image data from CCD1 onboard the environmental satellite HJ1A are used to realize the simulation of hyperspectral image data. After the equivalent simulation results are compared with the multispectral image data, it is found that the average structure similarity of the corresponding bands of two different images is greater than 95%. Except the blue color band, the total relative error is less than 10%. This shows that the proposed method can be used to realize the simulation of hyperspectral images based on multispectral data.

Abstract:A real-time image acquisition and display system based on a HgCdTe short-wave infrared staring camera is presented. The short-wave infrared staring camera uses a HgCdTe short-wave infrared detector and a FPGA DSP hardware. It has several functions including manual focusing, adjustable integral time and increasable attenuators. Taking a Camera Link connection line as the transfer channel, the real-time and fast acquisition and display of infrared images are realized by using a acquisition card compatible with the PCI Express x4 technology. In the experiment, an image acquisition and display interface is designed for the real-time control of the camera and the adjustment of the acquired images. Also, an image storage software is designed for the checkout and post processing of stored images. The experimental results show that the system is stable in performance. It has several functions such as real-time image acquisition, display and storage. It is of great value to engineering projects.

Abstract:The probe layout and attitude formula of an infrared earth sensor are presented. Then, a method for establishing the simulation model of the horizon sensor by using the Satellite Tool Kit (STK) is put forward. The established model is used for the dynamic simulation of the horizon sensor. The detection images are acquired. Finally, the satellite attitude is calculated by using the obtained images and the simulation results under different conditions are given. The method is helpful to the determination of the horizon sensor plan in the early phase of project development so that unnecessary repetition can be avoided.

Abstract:To effectively segment the targets of interest with blurred boundaries and low contrast in infrared images, an infrared image segmentation model based on region competition is proposed. For the Geodesic Active Contour (GAC) model sensitive to noise, assuming that the object and background in an image obey Gaussian distribution. Then, according to the probability of pixels belonging to the infrared object, a region energy term is constructed so as to improve the robustness of the model. Finally, a signed distance function is introduced to avoid the re-initialization of the curve in the process of evolution and improve the efficiency of the model. The experimental results show that the proposed method can segment the targets of interest in an infrared image effectively.

Abstract:Because the gray level and contrast of infrared images are lower than those of visible images, it is not effective for an edge detection method based on gray level to detect infrared images. For this reason, an infrared image edge detection method based on phase consistency is proposed according to the invariant principle of phase consistency for gray scale and contrast. First, the phase consistency value of an infrared image is calculated. Then, the regions containing edges are segmented by K-mean's method. Finally, the edge curves are generated by a morphological method. The experimental results show that the proposed method is more effective than the Canny algorithm in infrared image edge detection.

Abstract:In the observation of multi-angle polarized reflective spectra of objects, in addition to the physical and chemical properties of soil self, the angle factors such as polarization angle, detection zenith angle and so on will have significant impact on the spectra of objects too. Through the introduction of structural equation model (SEM), the multi-source spectral analysis including polarization, multi-angle and hyperspectral technologies is made for the saline alkali soil in western Jilin under the influence of multiple factors. It is found that the impact strength of the geometry factor is greater than that of the nature (salinity) of soil self. The orthogonal tests of three factors and two levels are designed and analyzed. The results also show that the impact of the angle factor is more significant. That is, in the analysis of single factor, the impact of polarization angle and detection zenith angle on the measured spectra is greater than that of the salinity of soil self. Furthermore, the interaction of different factors will have a certain impact on the spectral characteristics too. The SEM is compared with the orthogonal test. The difference and advantages of these two methods in spectral analysis are obtained.

Abstract:The reflectance-based calibration is the most common and effective in-orbit radiometric calibration method for visible and near infrared channels at present. In the method, accurate field reflectivity measurement is one of the important prerequisites for obtaining high precision calibration results. The time series measurement of field surface reflectance is performed by using a two-spectrometer method. The inconsistency of radiation conditions which may occur in traditional measurement methods is avoided. The reflectivity measurement values both in the central area and in the high reflectivity area are used to simulate the apparent reflectance of the VIIRS sensor. The apparent reflectance values observed by nine visible and near infrared channels (I1, I2, M1 to M7) of the VIIRS sensor are compared with the simulation values of a 6S radiation transmission model. The relative deviation of all channels except M6 (water vapor absorption) is less than 3%, which verifies the accuracy of the proposed surface reflectance measurement method.

Abstract:A portable on-line infrared, ultrasonic and ultraviolet synthetic partial discharge measurement system is realized by using image registration and fusion technologies. Firstly, the measurement principles and modular structures of infrared, ultrasonic and ultraviolet technologies are presented respectively. Then, a computer is used to fuse the three kinds of partial discharge measurement signals. The fused signals are put into the equipment image acquired by a camera. Thus, their corresponding relations with the equipment image are established. The proposed system not only can display the location imaging videos of infrared, ultrasonic and ultraviolet signals respectively, but also can fuse the above three kinds of signals into one video interface, so as to display the partial discharge location and its variation in three measurement methods directly. The results show that the system has the advantages of portability and fast measurement. It can find the faults in power equipment in time. Therefore, it has wide applications.