A procedure for the detection and removal of haze from dense hazy images has been proposed. It involves the analysis on the content of low-spatial-frequency information of a scene. The image contaminated by haze is decomposed into different spatial frequency layers by the wavelet transform, by which the hazy parts of the image are focused on the low-frequency components. A dehazing method combining both the airlight and direct transmission is employed to specially dehaze the low-frequency parts. The high-frequency parts are processed by a transfer function to enhance the clarity of the hazy image. Finally, a dehazed image with high clarity is obtained by image construction which employs the low- and high-frequency components. Experiments and analyses demonstrate the good performance of the scheme in terms of improving the contrast and clarity of hazy images. Particularly, it works well in improving the visual range of images captured in hazy weather conditions.

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A novel Nd(3+)-doped lead fluorosilicate glass (NPS glass) is prepared by a two-step melting process. Based on the absorption spectrum a Judd-Ofelt theory analysis is made. The emission line width of NPS glass is 44.2 nm. The fluorescence decay lifetime of the (4)F(3/2) level is 586+/-20 microsec, and the stimulated emission cross-section is 0.87x10(-20)cm(2)at 1056 nm. A laser oscillation is occurred at 1062 nm when pumped by 808 nm Diode Laser. The slope efficiency is 23.7% with a 415 mJ threshold. It is supposed that NPS glass is a good candidate for using in ultra-short pulse generation and amplification by the broad emission bandwidth and long fluorescence lifetime.

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A wide-field-of-view polarization interference imaging spectrometer (WPIIS) based on a modified Savart polariscope, without moving parts, and with a narrow slit has been designed. The primary feature of this device is for use with a large angle of incidence, and the target image as well as the interferogram can be obtained at the same time in the spatial domain and are recorded by a two-dimensional CCD camera. Under compensation, the field of view of the WPIIS will extend 3-5 times as large as a common interference imaging spectrometer, and throughput will raise 1-2 orders of magnitude. The developed optics is 20 x 8 cm ø in size. The spectral resolution of the prototype system is 86.8 cm(-1) between 22222.2 and 11111.1 cm(-1). This system has the advantages of being static and ultracompact with wide field of view and a very high throughput. The optics system and especially the wide-field-of-view compensation principle are described, and the experimental result of the interference imaging spectrum is shown.

High dynamic range, phase ambiguity and radiation limited resolution are three challenging issues in coherent X-ray diffraction imaging (CXDI), which limit the achievable imaging resolution. This paper proposes a spread spectrum phase modulation (SSPM) method to address the aforementioned problems in a single strobe. The requirements on phase modulator parameters are presented, and a practical implementation of SSPM is discussed via ray optics analysis. Numerical experiments demonstrate the performance of SSPM under the constraint of available X-ray optics fabrication accuracy, showing its potential to real CXDI applications.