Abstract:Currently, composites have been widely used in the field of aviation. The inner defects of composites are usually detected by infrared thermal wave detection technologies. By processing the infrared thermal wave image sequences acquired, the defect information of composites can be obtained accurately and quantitatively. According to the demands of infrared thermal wave testing technologies, several processing technologies for thermal wave image sequences of composites at home and abroad are analyzed and compared with each other. The research and applications of these image processing technologies are reviewed. The future development trend in this field is forecasted. Thus, a certain basis is provided for the selection of infrared thermal wave image sequence processing technologies.

Abstract:InSb crystal is an important material for medium wave infrared detector fabrication. To satisfy the development needs of a new generation of ultra-large-scale array infrared focal plane detectors, the growth of large size InSb crystals is studied. The key technologies for large size crystal growth are solved, 4 inch high-quality InSb single crystals are grown successfully and high-quality 4 inch polished InSb wafers are fabricated. The test results show that the length of the crystal with a diameter greater than 120 mm is longer than 100 mm. The dislocation density of the crystal is less than 100 cm^-2. Its electric parameters, carrier concentration and carrier mobility are conformed to the requirements for producing high performance large format infrared focal plane detectors. This lays a good material foundation for the development of a new generation of ultra-large-scale array infrared focal plane detectors.

Abstract:A grating-type ultra-broad band far infrared absorber based on three kinds of semiconductor materials: indium phosphide (InP), indium arsenide (InAs) and indium antimonide (InSb) is designed. The groove depth of the absorber is changed gradually. Its absorption mechanism is surface plasma resonance and dielectric cavity resonance. They are calculated by a finite-difference frequency-domain (FDFD) method. The calculation results show that the change of the number of the groove has a relatively great influence on the absorptivity of the absorber while the changes of groove depth, groove width, coating thickness and grating period has a less influence on the absorptivity of the absorber. Under the condition of optimized structural parameters, the average absorptivity of the absorber is greater than 92% in the incident wavelength range from 28 to 75 m at the incident angle from 0 to 80 degree. The absorber designed is expected to find applications in far infrared detection, etc.

Abstract:To study a rapid and effective pork quality inspection method which could solve the problems of timeconsuming and high cost in traditional inspection methods, 109 groups of pork samples were collected from markets and farms. The samples were divided into healthy pork and diseased or dead pork by physical and chemical methods. A FT-NIR spectrometer was used to acquire the spectra of the samples. The spectra acquired were processed in noise reduction and dimensionality reduction. The results showed that after processing, a prediction model based on support vector machine algorithm was established. The accuracy of 5-fold cross validation was up to 94.5%. The results showed that the method could be used to classify the pork of different quality and provide the basis for the application of nearinfrared spectroscopy in pork quality detection.

Abstract:Because of the obvious affection of moisture from fog drops on longwave and middlewave infrared radiation, the channel radiation information in both bands is simulated respectively by using a Community Radiative Transfer Model (CRTM) according to the characteristics of the Atmospheric Infrared Sounder (AIRS). After analyzing the underlying surface radiation and upwelling radiation from the model, it is found that 1) to exclude the distraction from the underlying surface, the underlying surface radiation can be subtracted from the bottom layer radiation in CRTM. At this time, the ground layer radiation presents the same distribution as the sea fog. Therefore, this method can be used to monitor the horizontal distribution of sea fog; 2) the upwelling radiation and its gradient variation with altitude can reflect the intensity variation of sea fog in the vertical direction, which can be used to monitor the vertical structure of sea fog; 3) After analyzing the simulated radiation in longwave and middlewave infrared bands, it is found that the channel radiation in both infrared bands can mirror the 3D spatial characteristics of sea fog.

Abstract:A human body image gender identification algorithm was proposed for active millimeter-wave imaging security systems. The procedure of the algorithm includes imaging preprocessing, human body image segmentation, gender feature extraction, selection of weight of different characteristics, formation of gender feature maps, image classification identification and algorithm optimization verification based on map database. A kind of local histogram algorithm based on gray value extraction was proposed and an intuitive map for identifying gender of the figure was given. On the basis of the map, a multi-weight, multi-characteristic gender identification method was proposed. The identification rate of the method is above 80%, which would be helpful to the fast identification of huge number of pictures and the taking of corresponding measures to protect human privacy. The algorithm had been used in millimeter wave body security checkpoints. Because of high portability, fast running speed and high recognition rate, it would have great application potential in similar security equipment.

Abstract:To implement the detection of infrared ship targets in the complex shore island background, an infrared ship target detection and recognition method based on multi-spectral fusion is proposed. Firstly, Nonsubsampled Contourlet Transform (NSCT) multi-level multi-spectral image fusion is performed according to the relationship between different spectral segments. Then, in combination with LSD line segment detection and clustering, shoreline is detected in the fusion image. A selective search algorithm is used to generate the initial target candidate region. The spatial location of the shoreline, the ship target geometric feature and the gray feature constraint are used to eliminate some false target regions. Finally, the feature descriptors in the Histogram of Oriented Gradient (HOG) are extracted in the candidate region. The linear Support Vector Machine (SVM) classifier is used to classify and identify the real ship targets. The experimental results show that compared with the single spectral band infrared ship target detection method, the proposed method has a better detection accuracy.