A novel fast method for pixel random mapping is proposed.Combining with the technology of information hiding of Least Significant Bit(LSB)，the RGB colour image used as a carrier image to hide real colour image，gray image，binary image and holography information are discussed.The experimental results show that this method has a high efficiency of encryption and decryption,and is robust to resist the attack of interference and image cutting.While the technology of LSB is applied properly according to the property of information hiding，the multiple information can be hidden well in carrier image while the quality of image is almost not influenced.

A noisy image enhancement method is proposed based on the three-state hidden Markov tree model in wavelet domain.It is not need to confirm thresholds accurately,the three-state Gaussian mixture model is adopted to estimate the distribution of wavelets coefficients,according to the states posterior probability of each coefficient belongs to achieving by the training of expectation maximization algorithm,coefficients are distinguished into noise,weak edge and strong edge coefficients respectively.Then the enhanced noisy image is obtained by restraining noise coefficients and enhancing detail feature coefficients.Cycle spinning strategy is introduced to avoid visual artifacts.By experimenting on noisy standard images and brain magnetic resonance images,compared with several classical image enhancement methods in visual effects and quantitative analysis,experiments show that the enhancement method proposed bears better robustness,can emerge more detail information and restrain noise effectively at the same time.

In order to solve the problem that the image registration method based on the classical mutual information may suffer from local maxima and these improved methods combing with gradient can not align the multimodal images because of the great difference on gradient amplitude,a novel multimodal image registration method is proposed.During the optimization of transform parameters,a hybrid optimization algorithm based on genetic algorithm (GA) and Powell is carried out to efficiently restrain local maxima of this new similarity measure function.The former provides the latter with effective initialization parameter,which will increase the algorithm’s robustness.Multi-resolution data structure based on wavelet transform is used to expedite the registration process.Experimental results demonstrate that this new algorithm can efficiently speed up the registration process with a good registration result.

In order to improve the accuracy of the fiber Bragg grating demodulation system,a denoising processing and filtering analysis method based on empirical mode decomposition is proposed.The intrinsic mode functions obtained by EMD are derived into signal component dominanting modes and noise component dominanting modes. Denoising can be achieved by reconstructing the signal using the modes reflecting the main structures of the signal. The experimental results show that the output signal of demodulation system can achieve identitfying the location of central wavelength and the Bragg wavelength shift accurately. The output spectrum has the features of less distortion and higher SNR.The curve fitting of temperature shows that the fitting linearity is 0.998, and the accuracy of demodulation system is greatly improved.

In order to slove the low contrast and image blur in X-ray fluorography caused by noise and low illumination conditions, a new noise detection composed of region detection and degree detection is presented to distinguish between noisy pixels and noise-free pixels in the original image. Then the similarity degrees are calculated between each pixel and median value in the region of neighborhood and considered as the weighted value. Eventually, the noisy pixels are improved by the fuzzy weighted median filter while the noise-free pixels are not modified. The experiment results show that the proposed method can suppress the noise and preserve the edge and detail information.

A novel reversible watermarking scheme is proposed,which is robust against high-quality JPEG compression.By computing the difference between the means of two adjacent image blocks,employing it to embed the watermark,and using block histogram shifting to avoid overflow/underflow,this technique receives both losslessness and robustness.If the watermarked image does not change at all,the watermark can be extracted out correctly and the original image can be recovered losslessly.If the watermarked image is compressed to some extent,the watermark can still be correctly extracted for semi-fragile authentication.The scheme is successfully applied to three kinds of medical images and commonly used images.Experimental results show that the high visual quality of images,the pure payload,and the robustness of the proposed scheme against compression are acceptable for many applications,including semi-fragile image authentication.

A novel image fusion method based on Contourlet domain hidden Markov tree models is proposed.Contourlet transform provides a flexible multiresolution,local and directional image expansion,and also a sparse representation for two-dimensional piecewise smooth signals building images.Contourlet HMT can capture all inter-scale,inter-direction,and inter-location dependencies of the Contourlet coefficients.Aiming at the different frequency bands of Contourlet decomposition with different characteristics,different fusion rules are applied to different subbands.In the low-frequency information,the weighted average mean is used to obtain the fused low-frequency information.Contourlet HMT is applied to design low-frequency information rule,the fusion method has the ability to strengthen the relationship among the Contourlet coefficients,extract more detailed and exact information from the original images.The fused images by the proposed algorithm exhibit good performance both in subjective and objective standards.Experimental results also show the simplicity and effectiveness of the method and its advantages over the conventional approaches.

As an important problem in the course of image fusion,the extraction of useful information from source images affects the fusion result directly,and it is all along one of the research focuses and difficult ponits of image fusion.A novel image fusion method for infrared and visible images based on nonsubsampled contourlet transform and fractal dimension is proposed.The regional properties,size of regions,intensity of edges and the strength of texture are all described by the regional fractal dimensions in different scales.Through selecting coefficients from two source images based on regional fractal dimension,the low frequency subband coefficients of the source images are fused.The bandpass directional coefficients are fused using different strategies based on the matching operator proposed.Compared with other methods,experimental results show that the proposed algorithm is effective and feasible.

This paper proposes an algorithm of affine-invariant starting-point matching of object contours,which leads to a new idea for fast object recognition.In the method,two affine-invariant arc-lengths based on curvature and enclosed area are employed to construct a characteristic function.Then,by utilizing extrema information of the characteristic function on amplitudes and positions,the amplitude error and relative-position error are derived based on which an estimation function is generated.According to cyclic-comparison and the rule of neighbouring position correspondence,the position variable which minimizes the estimation function is found,corresponding to the final resolved starting point of object.The experimental results show that the proposed method possesses high matching rate,high ability of anti-noise and low time-complexity.

Inspired by the directional and phase characteristics of textures，a novel texture image segmentation approach based on dual tree contourlet transform is proposed.Dual tree contourlet is constructed by the pyramidal dual-tree directional filter bank,it not only maintains the flexibility direction selectivity of the contourlet transform,overcomes the limitation of traditional contourlet which namely lack of shift invariance but also provides complex subband coefficients．The proposed scheme using the energy of each directional subbands as the directional features,and defining the mean phase angle of complex coefficents as the phase features for segmentaion.Finally,the fuzzy C-means clustering method is used to complete the texture image segmentation．Experiment results demonstrated,the phase features are complementary to the directional features; compared with a typical traditional method，the present approach shows visible improvements both in diminishing segmentation error，and in increasing boundary precision and region harmony.

Compared with traditional global threshold algorithms,which can not extract the pavement crack exactly under non-uniform illumination,an improved image segmentation and classification method is proposed to overcome the drawbacks.Firstly,a new image segmentation method combining sobel and maximum entropy is presented and the solitary noise is reduced based on the pixel geometrical shape of the image.Secondly,a pattern classifier based on RBF neural network is designed to recognize different cracks according to the geometrical shape differences of different cracks.The experimental result indicates that compared with other image segmentation algorithms,the method proposed in this paper has a good ability to extract the image edge,and a strong ability to suppress the noise in the image.Moreover,it can achieve classification accuracy.

Based on device simulation, an epitaxy structure with silicon doped base of a PNP InGaAsP-InP MQW transistor laser (HBTL) at 1 550 nm is designed and realized by MOCVD. Due to its much smaller diffusion coefficient and shorter diffusion length compared to the P dopant in the NPN HBTL, silicon as N dopant in the base perform with higher stability. Therefore, the active material with higher optical quality of PNP HBTL can be obtained easier than that of NPN HBTL. In addition, B type Ohmic contact can be realized easier than P type. The N doping density can be reduced compared to NPN HBTL benefiting to reducing both the optical loss and carrier recombination in the base. And therefore, both the lower threshold and higher stimulation power of the HBTL can be obtained. The result of PL spectrum measurement of the epitaxied material shows high peak intensity and as narrow as 65.1 nm FWHM which demonstrates good optical quality of the material.

A gas refractive index sensor with subwavelength-diameter fiber (SDF) based on intermodal interference is designed and its sensitivity is analyzed.The sensor head is formed by splicing a standard single-mode fiber with a stub of SDF without cladding,which only supports the fundamental mode and the 2nd-order mode.The sensor′s sensitivity is analyzed according to the peaks shift of the interference spectrum,which is caused by the refractive index change of the gas outside the sensor head.It is found that the sensitivity of this sensor is higher than the one based on intermodal interference using index-guided photonic crystal fiber (PCF).Since there is no process of gas diffusing into the micro-holes compared with the PCF,therefore this sensor can be used for real-time detecting.

A design of ratio turbidity sensor fabricated by laser refractive index modulation is proposed and tested. Both waveguide theory and detecting knowledge are combined. The turbidity sensing structure is made from UV curable optical polymer and a special “airing dry method” is used to dispose the unexposed part. The whole progress only takes 7~8 minutes and thus this method can greatly promote fabrication efficiency. Experimental test is conducted by using standard turbidity solutions, and the related data are processed with a SISO algorithm neural network system. The results curves are obtained for scattering coefficient and turbidity of the standards,which proves that the sensor system has a relative error rate of 5%.

In order to increase the transfer capacity and ultraviolet light stability of rare earth complexes, a series of doping complexes Sm1-xTbx(TTA)3phen are synthesized by chemical precipitation method as light conversion agent, where HTTA stands for 2-thenoyltrifluoroacetone, phen denotes 1,10-phenanthroline, x is the mole fraction of doping elements, then coated by SiO2. The characteristics of the complexes are analyzed using IR spectrum, UV-visible absorption and fluorescence spectroscopy. The results show that the structure of Sm1-xTbx(TTA)3phen are similar to Sm(TTA)3phen, and the UV absorption peaks of Sm1-xTbx(TTA)3phen are depended on organic ligands. Photoluminescence measurements indicate that the complexes emit strong luminescence, which is determined by the transitions of center samarium ion under UV radiation. The strongest luminescence of Sm0.5Tb0.5(TTA)3phen is at 647 nm, up to 8.0×106 cps. The luminescence of Sm1-xTbx(TTA)3 is enhanced with the addition of sensitized elements Tb3+. Parceled by SiO2, anti-decay is significantly enhanced.

In order to solve the difficulties in testing surface of long focal length mirror using interferometer,a novel optical metrology using phase retrieval is developed. In this method, tested mirrors is illuminated by a coherent point light source, a series of diffraction intensity patterns near focus are collected, then phase retrieval algorithm reconstructs the surface error of tested mirror. Compared with interferometer, it simplifies the metrology setup and requires no special environment. Mathematic model of phase retrieval measurement is found according to diffraction theory, and is solved by iterative algorithm which derives from Gerchberg-Saxton algorithm. Validity of this method is tested by simulations and an experiment. A spherical mirror with curvature radius of 8 700 mm and diameter of 145 mm is tested using phase retrieval. The position of intensity patterns are corrected and appropriate patterns are chosen to be computed. The reconstructed result is correlated well with that tested by simultaneous phase-measurement interferometer.

Various factors affecting boiling state are analyzed when water flow and exponent-decadence of laser by water characteristic are considered. By using unit difference methods surplus temperature of the coverage by laser is studied. According to the relationship of surplus temperature and boiling state, forced Convective Boiling modal of water by laser is founded. Annular beam is regarded as the main research object, concerned data was simulated and experiments are carride out. As a result they have good coherence.

A new method of fast on-line 3D measurement is proposed. A modulation delamination method is used to extract a token from object modulation distributions. With the token delamination information transformed into integer as the mask, the equivalent phase-shift deformed patterns at the same pixel coordinate can be realized by the pixels matching, which puts the fast on-line 3D measurement into practice. To verify its feasibility and validity, a contrast experiment on this method and a method based on a particular region of modulation distributions are carried on. Experiments show that the high-veracity of the algorithm and the speed of on-line inspection can be effectively improved.

In order to study the dynamic characteristics of ultra-weak photon emission in cell and its biological significance,soybean callus are radiated by UV-B radiation with 20μW/cm2 for 2 hours.Delayed luminescence of soybean callus induced by light within 4 days after the UV-B radiation is determined.Delayed luminescence integral intensity,the initial photon number,attenuation parameters and the spontaneous luminescence in ultra-weak photon emission of soybean callus are obtained through the establishment of delayed luminescence dynamics equation and mathematical fitting.The biological significance of these dynamic parameters of ultra-weak photon emission is discussed.The results show that delayed luminescence induced by light of soybean callus within 4 days after UV-B radiation to obey the laws of hyperbolic relaxation.Dynamic analysis shows that the changes of the delayed luminescence integral intensity and initial photon number with the time after UV-B treatment are volatility.The intensity of spontaneous luminescence and the content of malondialdehyde(MDA) are increased after the cessation of UV-B radiation.The peaks of them appear nearly two days after UV-B radiation.Using the ratio of delayed luminescence integral intensity and spontaneous luminescence to define the state parameter Q and the order parameter R of cell,it is found that the changes of Q value or R value of soybean callus cells after UV-B radiation reflect the damage of UV-B radiation on soybean callus and cell recovery process.

A single channel 16×10 Gb/s OTDM transmission over 100 km fiber is experimentally demonstrated. In the receiver, an opto-electric feedback loop is proposed for simultaneous 10 Gb/s clock recovery and 160 Gb/s to 10 Gb/s demultiplexing. The loop consists of a pair of electro-absorption modulators and a 10 Gb/s clock recovery module. By cascading electro-absorption modulators, the switching window is decreased from 25 ps to 5 ps and the synchronous problem in demultiplexing between clock and data is eliminated using the recovered clock as the feedback in the close loop, the jitter of recovered clock is less than 450 fs. Based on the loop, without using optical filters and eliminating PMD in the transimission line, error free 16×10 Gb/s OTDM 100 km transmission is successfully realized with power penalty less than 3 dB.

In order to study the capability of fitting Zernike polynomial aberration of the deformation mirror, two finite element models for deformation mirrors in different arrangements are established. Analysis is proceeded by giving theoretic displacements to actuators. The result indicates that the relationship between the different actuator arrangements and capability of fitting aberration, and shows that the arrangement of 57 actuators can fit the aberration to λ/20 or smaller and the print-through effects of actuators acted on the deformation mirror are verified.

In order to output the ideal infrared fluorescence matrix glass, a serial of chalcogenide glasses based on Ge-Ga-S-KBr system doped with different Er3+ concentrations are synthesized by a melt-quenching technique. The refractive indexes, absorption spectra, mid-infrared emission spectra of samples are measured. The oscillator strengths of absorption lines of Er3+ ions are calculated using the absorption spectra. The intensity parameters (Ωi,i=2,4,6), transition probabilities (A), branching ratios (β) are predicted for Er3+ ions in the samples using the Judd-Ofelt theory. The mid-infrared emission properties are investigated for the samples with the different Er3+ concentrations under 808 nm laser excitation. The 2.8 μm-emission cross-section is calculated using the theory of the Futchbauer- Ladenburg. The results indicate that the fluorescence under 808 nm excitation with peak wavelength at 2.8 μm is due to the Er3+∶4I11/2→4I13/2 transition. The intensity of the mid-infrared fluorescence is enhanced by increasing the concentration of the Er3+ from 0.4 wt% to 1.0 wt%. Multiphonon relaxation rate is estimated to be 37 s-1 for the Er3+∶4I11/2 level.

To improve ground infrared detection, the infrared detecting simulation model of ballistic missile in re-entry is established, considering the aerodynamic heating of missile in the re-entry, the infrared radiance attenuation in atmosphere, and background radiation noise. The SNR system is analyzed with different conditions. The results indicate that by selecting working band, increasing the system aperture and exposing time, improving the optical design, and selecting the cloudless weather for observation will improve the effect of system.

The directivity of the sound fields excited by laser-induced liquid breakdown is studied through theory by using fundamental theories of acoustics. So a conclusion is drawn that directivity calculated by theory. The directivity of the laser-induced sound field is related to energy range and radiation area of the laser beam.

Based on the phenomena of double refraction and double reflection in crystals,phase characteristics of p-polarized light reflecting and refracting at the boundary between an isotropic and a uniaxial crystal are studied by numerical evaluation.Results show that the direction of optical axis has important influence on phase properties.When light is incident from an optically thinner isotropic medium upon a crystal,the direction of optical axis affects the phase shift of reflected p-polarization light but has no effect on the phase of refracted light.When light is incident from an optically denser isotropic medium upon a crystal with the incident angle less than angle of total reflection,the direction of optic axis affects both the phase shift of reflected and refracted p-polarization light.If the incident angle is larger than critical angle,the optical axis has influence on the curve of phase change of reflected p-polarization light.For the case of light enters into an optically thinner isotropic medium from a crystal with the incident angle less than angle of total reflection,the direction of optical axis will change the way of phase shift of reflected p-polarization light.And the refracted p-polarization light undergoes a phase shift near the Brewster’s angle when the angle between the optical axis and crystal boundary is small.After the incident light is reflected totally,the curve of phase change of reflected p-polarization light varies with the direction of optical axis.

Based on the principle of hollow ring achieved by conical refraction effect in biaxial crystal, the formula of phase difference distribution between every point and the minimal point in the hollow ring are deduced, and the regularity of phase difference distribution is obtained by means of simulations. The continuity in the circumference of polarization direction variation of each point in the hollow ring is proved. In the experiment, un-polarized He-Ne laser is adopted to perpendicular radiate KNbO3 crystal, then polarization characteristic of hollow beams achieved by conical refraction effect in biaxial crystal is tested. The result of theoretical analysis agrees well with experiment.

Using Nd∶YAG laser pump intra-cavity optical parametric oscillator, dual wavelength near 2 μm can be generated.Through collinear difference-frequency-generation, widely tunable and continuous Mid-infrared- radiation in the range of 8~19 μm is obtained under the condition of type I phase matching. The maximum output power of 7.4 kW (pulse energy of 33.66 μJ) is achieved at 8.76 μm, corresponding to photon conversion efficiency about 4.43%. The reasons that affecting conversion efficiency are analyzed and new measures are proposed to compensate walk off angle.

Using the model of multi-photon nonlinear Compton scattering between an electron and a photon-groups, the longitudinal wave dispersion characteristic of the laser-plasma under Compton scattering is studied.The results show that the dispersion curvatures of the long longitudinal wave are formed by the analytic long wave, numerical computing result and short wave. The dispersions of longitudinal wave of the long and short waves are increased with the increase of the characteristic temperatures of the positive and negative relativity electrons, and these dispersions are reduced along with the increase of the frequency increasing number taken place by Compton scattering. The dispersion curvature of the one temperature laser-plasma and the dispersion curvature of the two temperature laser-plasma are similar.

By utilizing the 3D finite-difference time-domain technique, the influence of the photonic crystals with various structure parameters on the light extraction efficiency of light-emitting diode (LED) are studied. Based on the near to far field transformation, the far field radiation characteristics of PhC LEDs for two types of defect with different hole size are investigated. It is found that the light extraction efficiency and energy directionality in the far field radiation can be improved by incorporating defect into the PhCs and decreasing the hole size near to the defect.

Spherical silver nanoparticles are prepared by chemical reduction of sodium citrate,and photoinduced conversion of spherical Ag nanoparticles is conducted by the irradiation of high pressure spherical Xe lamp. The spectra property and morphologies of silver nanoparticles prepared under different irradiation time are studied by UV-visible absorption spectroscopy and Transmission Electron Microscope(TEM). Using crystal violet as a molecular probe, SERS spectra of crystal violet on Ag nanoparticles are studied. Experimental results indicate that the color of Ag colloid changes observably and the number of absorption peak of Ag colloid gradually manifold with the increase of irradiation time. TEM pictures show that morphology of Ag nanoparticles is evolved from sphericity to triangular plate, finally truncated triangular plate. As the irradiation time increasing, the SERS signal intensity increases first, and then decreases.

The effect of upconversion fluorescence properties in red laser pumping Tm3+ ions doped nanocrystals is studied with laser specroscopy. The upconversion efficiency caused by phonon energy is invesgated by changing the matrix and environment temperature of samples. The results show that suitable photon energy can improve the upconversion efficiency. Since the phonon energy depends on the sample temperature, the variation of the temperature can also influence the population rate of 3H4 level in Tm3+ doped low-phonon-energy crystal, resulting in the change of the fluorescence upconversion efficiency.

The interface and confined phonon modes of the wurtzite quantum cascade laser are investigated using the transfer-matrix method.One group of interface modes and two groups of confined modes are presented in the longitudinal optical frequency domain,and the interface modes can be transited into the confined modes for two lowest frequency modes.The dispersions and electronic potentials of the interface and confined modes are obviously different,and the scattering rate induced by the confined mode is comparable to that induced by the interface mode.

A dual-order Raman fiber laser (RFL) with stabilized output power is proposed and theoretically analyzed. The results show that the first- and second-order Stokes output powers are hardly impacted by the pump power fluctuations due to the clamping mechanism induced by the amplified spontaneous emission near the second-order Stokes shift from the launched pump line. As a result, the low-frequency relative-intensity-noise transfer from the pump power to the laser outputs is greatly suppressed. The results show that the first- and second-order Stokes are both stable. In addition, their powers can be tuned by adjusting one attenuator in the RFL setup. These special behaviors predict that the proposed RFL is highly suitable to be the pump sources in Raman fiber amplifiers.

Taking the group velocity dispersion, Kerr nonlinear effects, gain saturation and gain spectrum of gain medium into account, a equation describing the propagation of optical pulse in the medium is derived. The propagation state of a high power linear chirped pulse in the gain medium is simulated numerically using Split-step Fourier transform method, and the influence of gain dispersion on the profile and power spectrum of optical pulse is discussed emphatically. The results show that when propagating and amplified in the gain medium, the high power super-Gaussian optical pulse′s shape becomes sharp, peak moves to pulse front edge, the spectral peak moves to lower frequency, and the asymmetric oscillation structure is formed in spectral edge. When the gain dispersion of medium increases, the spectrum width of optical pulse becomes narrow, and its peak power decreases. As a result, the gain dispersion will cause loss of the broadband spectrum pulse.

The optical design and properties of fish-eye lens are discussed.A refractive/diffractive IR fisheye lens optical system is presented,whose operating wavelength range is 8 to12 μm,and full field of view is up to 240°. The structure of optical system is reversed telephoto lens, and this type of hyper-wide angle lens can balance the off-axis aberrations against the evenness of marginal image illuminance at its image plane very wel1. The results show that the system has the advantages of simplicity,compactness and long back working distance.Its imaging quality is very well,so that its modulated transferfunction value is higher than 0.5 when cutoff frequency at the 11 lines/mm.

Using the least-squares spline approximation to analyze the photonic band structure, the dispersion parameters of a two-dimensional photonic crystal are quantitatively calculated. Considering the large bandwidth of an ultrashort pulse, average group velocity and average group velocity dispersion are achieved by introducing a weighting factor, which reveals the share of different frequency components. So the pulse evolution can be predicted theoretically. Propagation of ultrashort pulses through the photonic crystals is simulated by using the finite-difference time-domain method. The results of numerical simulations are well consistent with the theoretical predictions. This process for achieving dispersion parameters is valuable for designing photonic-crystal dispersion devices such as dispersion compensator, pulse compressor and pulse stretcher.