The structure of the magnetic mirror array device is designed. The modulation transfer function (MTF) of this device is calculated as well as that of magnetic mirror array image intensifier. The limiting resolutions of 117 lp/mm and 121 lp/mm of the magnetic mirror array device, by means of the analysis of MTF curves with the actual parameters, are obtained at X and Y directions in which the Nyquist frequencys are 0.55 and 0.59 respectively; while the limiting resolutions of magnetic mirror array image intensifier based on this device are 87 lp/mm and 89 lp/mm, and the corresponding Nyquist frequencys are 0.49 and 0.52 respectively. The results show that the difference between two curves at X and Y directions can be reduced to ensure better image quality. The calculation of this research provides an important theoretical basis for further research on the magnetic mirror array image intensifier.

A ［2-methyl-6-［2-(2, 3, 6, 7-tetrahydro-1H, 5H-benzo［ij］ quinolizin-9-yl) ethenyl］-4H-pyran-4-ylidene］ propane-dinitrile (DCM2) sub-monolayer was inserted in the electron transporting layer of organic light emitting devices (OLEDs). Based on the different position of deposited DCM2 sub-monolayer, the electroluminescence (EL) spectra，brightness intensity and current efficiency of these four devices show that DCM2 sub-monolayer located at the N,N′-bis-(1-naphthyl)-N, N′-diphenyl-1, 1′-biph-enyl-4, 4′-diamine(NPB)/(8-hydroxyquinoline) aluminium(Alq) hetero-junction interface obtained most excitons. The obtained results will be helpful for the optimal design and operation of OLEDs.

To study the dynamic process excited by femtsecond laser,a carrier model with three energy level and trap is constructed,with which the electron rate equation is obtained.The numerical simulation is used to calculate the electron number change of each energy level and the differentiated absorbtion rate as the time goes by.With the change of the electron’s absorption cross-section,differentiated absorbtion rate will have a ultrafast change process.Compared with the experimental result of Fanxin Wu,the differentiated absorbtion rate curves are basically the same,which shows the model have some rationality.

The relationship between the birefringence of Fe3O4 magnetic fluids and the ambient temperature (in the range of 20~80 ℃) at several different magnetic field strengths (lies in 0~200 mT) are investigated. The results show that similar dependence of birefringence on magnetic field strength and temperature happens for magnetic fluids with different concentrations. Moreover, the birefringence of the magnetic fluid is inversely proportional to the ambient temperature at fixed magnetic strength and proportional to the magnetic field strength at fixed ambient temperature. In a given temperature and magnetic field strength, the birefringence of the magnetic fluid with high concentration is larger than that with low concentration. The phenomena and results are analyzed carefully and the physical mechanism is clarified in detail.

In order to study the output characteristic of Nd∶GdVO4 influenced by 808 nm and 879 nm, coupled by comparison of the CW output laser efficency pumped by the two different wavelengths, the structure of the energy levels of the Nd∶GdVO4 crystal is investigated, and it is found that another absorption wavelength of 879nm is realatively strong. The output characteristics under 808 nm LD pumping and under 879 nm LD pumped are analyzed by experiments. The processes of pumping Nd∶GdVO4 crystal by laser beams of 808 nm and 879 nm wavelength are different. The pumping by 808 nm LD is a process of transfering energy by an indirect way. During the process,the obvious hot load will occur. But pumping by 879 nm LD will drive Nd3+ ions into the laser emitting level, to avoid useless heat generation during no-radiation transition and reduce the thermal effects efficiently.Theoretically, the quantum efficiency of 879 nm is greater than that of 808 nm,so the heat produced from the crystal with pumping should be small. The way of pumping Nd∶GdVO4 crystal is used by laser diode from straight line cavity experimental program, and the process of producing 1 063 nm CW by pumping Nd∶GdVO4 crystal is studied using two different pumping wavelengthes. Lasers under these two different pumping wavelengths are obtained. With the same experimental conditions, the output slope efficiency of pumping crystal by 879 nm LD is a bit higher than by 808 nm in low power. But the output slope efficiency of 879nm is greater than that of 808 nm in high power, and the maximum reaches 38%. Meanwhile, a laser of 1 341 nm is achieved when the pumping at 808 nm, which could be a kind of light source for optical communication.

The interactions between a chirped ultra-short pulse and two-level medium on near-resonant were investigated. According to the semi-classical theory of light-matter interaction, the modified Bloch equations with chirped terms were established, and an accurate and efficient fourth-order Runge-Kutta method were applied for solving the equations. After numerical simulation, the relationships between the sign (and value) of chirp and Bloch vectors were obtained, and the influences of signs of detuning and chirp on Bloch vectors were also gained. The numerical results show that, the sign and value of chirp have obvious modulation effects on the transient coherence and steady-state of Bloch vectors, which provides us to control the two-level system by adjusting the pulse chirp.

A laser-diode array side-pumped Nd∶YAP intra-cavity frequency-tripled 447 nm pulse blue laser was reported. After high peak power of polarized 1 341.4 nm fundamental laser was generated by using high frequency laser-diode array side-pump Nd∶YAP crystal, V-type resonator and LN crystal for Q-switched, 670.7 nm red laser second harmonic generation(SHG) was obtained with Ⅱcritical phase matching(CPM) KTP ctystal, and 447.1 nm blue laser by sum frequency mixing(SFM) of the 1 341.4 nm and 670.7 nm radiation was obtained withⅠCMP LBO ctystal. The experimental results show that a optimited V-type resonator can increase the efficiency of nonlinear conversion. At the incident pumping power of 92.4 W, the output power of polarized blue laser is 887 mW, the peak power of blue laser is 17.7 kW, and the pulse width is 50 ns, corresponding to an optical-to-optical conversion efficiency of 0.96%.

Using dispersing prism and KTP crystal typeⅡphase matching for intracavity frequency-doubling, the Nd∶YAG ceramic laser at the wavelength of 660 nm is studied. Suitable film parameters of resonant cavity reflectors are designed according to 1 319 nm line of Nd∶YAG ceramic, side-pumped Nd∶YAG ceramic crystal with 1.1at% Nd doping and dimensions of Φ3×50 mm. Cavity parameters are designed based on the ceramic thermal focal length. Under repetition rate of 1 000 Hz and single pulse pumped energy of 144 mJ, the output energy of 3.9 mJ at 660 nm is obtained. The optic-optic efficiency is 2.71%. The results form the basis for the further development of the high power high efficiency ceramic red laser.

In order to extend visualized detection to near ultraviolet and near infrared waveband for industrial testing, under the requirement of achromatic and passive thermal design, broad-waveband optical system working in 300～1 100 nm range is designed, and prototype for industrial testing is developed. Inverted telephoto construction is adopted to achieve an enough back focal length, and splitting the optical beams into three is achieved by insetting a coating prisms within the back focal length, near ultraviolet, visual and near infrared are imaged in three beams respectly. Reasonably lens material is chose to realize achromatic design. The system is passive thermal by moving a lens. The designed system has a field-of-view of ±3.5°, the effective focal length, F/# , back focal length and total length is 66.5 mm, 3.3 nm, 63 mm and 132 mm respectively. The results indicate that all MTF is more than 0.3 at 50 lp/mm, and a good performances is achieved over a temperature range (－10～+50)℃, the image requirement is met. Prototype exhibit excellent resulting during experiment. The system gathers as much information as possible about the detected objects by extending waveband, and a good advantage is exhibited in industrial and agricultural testing.

In order to achieve the wide angle,large relative aperture and uniform illumination of corona detectors,a novel catadioptric omnidirectional optical system applied in the corona detector is presented which operates in the region of Solar Blind UV/visible.Operating principle of the dual spectral panoramic corona detector is introduced.And,the structure of the dual spectral panoramic imaging system is determined by assigning optical parameters of the primary (panoramic shell) and secondary (relay optics) groups.After investigating the origin and characters of the aberrations in the panoramic imaging system,methods for balancing aberration between the two groups and improving illumination uniformity are proposed.Finally,dual spectral panoramic imaging systems satisfying specifications are obtained.The field of view of the system achieves 360°× (45°~90°) and relative aperture extends to 1:2,the diameter of 80% encicled energy of SBUV panoramic imaging system is 20μm,smaller than the pixel size of ICCD,the MTF value of visible panoramic imaging system is higher than 0.5@83lp/mm over all fields,and the illumination uniformity on the images of SBUV /visible detectors is superior to 99.8%.The present results show that application of panoramic annular lens to the corona detector can satisfy the design requirements.

Based on diffraction theory, effect of sub-aperture on point spread function of stitching system is analyzed, and after Fourier transformation of point spread function, effect on the Modulus of the OTF is acquired. The sub-aperture distribution is added to the real designed optical system through embedded program, and effect of sub-aperture distribution on image quality of stitching system is simulated. Through contrast of calculation result from diffraction theory and simulated result by design software embedded program, the simulated result is verified. Effects of sub-aperture distribution on optical systems with the same relative aperture are simulated. For reflective systems which have the same relative aperture and central-obscuration, effect of sub-aperture distribution on optical stitching system is tested. After comparision of simulated result and tested result, it is shown that, effect of sub-aperture distribution on optical stitching systems with the same relative aperture is uniform. It provides theoritical proof for practability of study on optical stitching prototype.

According to the test requirements of the inner wall of a pipeline, an optical system of pipeline endoscope is designed, which is based on particular optical feature of gradient index lens and microscope. The system has the advantage of large depth of field. In the condition of required magnification, the depth of field of the system is increased by 200 than the initial system, which is achieved by the radial gradient in the reflective index of gradient index lens. The system is more suitable for pipeline internal surface inspection based on the feature of the nearly spherical surface of image plane. Combined with CCD, the digitalization test of pipeline endoscope is realized. Clear image of the defects in the inner wall of a pipeline, such as the crack and abrasions, can be checked conveniently by monitor in a larger extant of depth of field.

A two-dimensional triangular lattice photonic crystal heterostructure is designed for solar reflector.The reflectivity of the incident electromagnetic wave in the visible to near infrared wavelength range is simulated by the transfer matrix method and the variation of reflectivity with different incident angle is studied.The results shows that the structure displays perfect reflection for the near-infrared incident light at normal incidence.As the deflection angle increases,it shows high reflectance in visible-near infrared wavelength range.The structure should enable new application for omnidirectional total reflector for the visible to near infrared light.

A new method of producing blue light based on the interaction of shockwave and photonic crystal was studied. The change of refractive index of compressed photonic crystals was simulated. At wavelength of 470 nm, parameter of photonic crystals was selected coherently, the variation of band gap was studied, and velocity of shock wave was calculated. The influence factors of linewidth and central wavelength of blue light was analyzed. The results show that the distance between shock wave front and reflecting surface is the dominating factor of blue light′s line width. The linewidth of output light varies with the distance between the shock wave and the reflective plane, when the distance is large, the linewidth is small, when the distance is smaller, the linewidth is great. The linewidth of output light can be controlled by the filter of photonic crystal, in order to access stability or change bandwidth of the output light. The change of environmental temperature and absorption characteristics of photonic crystal materials will influence the band gap distribution of photonic crystal, which will further influence the central wavelength of blue light. These results are useful to research and develop new source of blue light, and also provide a new technique to produce other coherent light sources.

To overcome disadvantages of low transmission efficiency and high dependence on the incident angle for the transmitting type polarization beam splitter (PBS), a highly efficient PBS based on a two-dimensional photonic crystal slab is proposed, which consists of a honeycomb lattice of GaAs cylinders in air. The PBS has a normal refraction for TE polarization and a negative refraction for the other polarization (TM polarization) so that it can separate these two polarization beams totally in space. Anti-reflection layers (ARLs) at the surfaces of the photonic crystal slab are introduced and relevant parameters are optimized to improve the transmission efficiency. Two-dimensional finite difference time domain (FDTD) simulation results show that, in a wide angle range (about 20°), in a normalized circular frequency range of ω=0.20~0.23×2πc/a, the transmission intensity can reach over 98% for both TE and TM polarization.

A scheme for teleportation of an arbitrary two-qubit state using a four-qubit linear cluster-class state is proposed. Quantum teleportation can be successfully realized with a certain probability if the receiver can adopt an appropriate collective unitary transformation after receiving the sender′s Bell-state measurement information. The scheme is more practical than previous ones using maximally entangled states as the quantum channel. In addition, an important conclusion is obtained from the above scheme that a maximally four-qubit entangled state (cluster state) is extracted from a single copy of the cluster-class state with the same probability as the teleportation.

Based on physical model of two-qubit quantum computer, two kinds of rules were proposed by solving single-body and two-body the time-dependent Schrdinger equation for designing nuclear magnetic resonance pulse sequence parameter of Grover quantum algorithm. Specified parameters were given through two kinds of designing rules and numerical simulations were carried out as specifying parameters. Results from the simulations show that target state is a pure basis state after running specified parameters by solving two-body the time-dependent Schrdinger equation and the expectation value of z-component of target state agrees with the theoretical values with a precision about 10－3. It is confirmed that rules of designing parameter is correct.

Based on the principle of quantum coherence and quantum spatial positioning, the experimental scheme of the quantum spatial positioning is designed. The spectrum characteristics of the entanglement photons with spontaneous type-II parametric down-conversion pumped by a broadband frequency pulse laser are discussed. The characteristics of the second-order coherent function and the impact of the phase matching conditions on the quantum spatial positioning are analyzed. It is shown that awith the increase of the pump band-width, the coherence of entangled biphoton is diminished, and the measuring accuracy of the quantum spatial positioning is also reduced.

Rewritable collinear holographic image storage was realized in a genetically mutated bacteriorhodopsin BR-D96N film by using its photochromic property. For a BR-D96N film with 3.0 optical density, under 632.8 nm, 700 mW/cm2 recording light (optical reference ratio is about 1∶1.2), the optimum recording time is about 3 s, the optimum reconstruction light intensity is about 50 mW/cm2, and the safetime of the hologram is about 10 min. The experiment shows that, in collinear holographic storage system, simple optical setup, small volume, low environmental effect and the high density storage can be realized; and it is proved that the BR-D96N film has advantages like short storage time, high light sensitivity, high reversibility, long-term stability and easy used, which can be used as a higher sensitive rewritable collinear holographic storage media.

In order to achieve a real-time and visual observation of multi-plane images, a method using light-emitting materials is proposed. A 3D object can be divided into a series of 2D slices along the optical axis. With an efficient and fast 3D Gerchberg-Saxton algorithm, a computer-generated phase hologram is obtained and a numerical reconstruction is carried out on the computer. The process of 3D Gerchberg-Saxton algorithm is expounded, and the experiment for reconstruction and visualization of multi-plane images based on LC-SLM is conducted. With the grey level-phase curve of the LC-SLM, the computer-generated phase hologram is converted to gray-scale hologram, which is loaded to the LC-SLM to reconstruct the 3D light fields. The fluorescence characteristic of quantum dot materials is used to achieve the visualization of the light fields. Experimental results show that the optical reconstruction is in good agreement with numerical simulation. This technique is applicable in medicine, military, 3D display, micromachining and micro-technology.

For optimizing design of the High Dynamic Range Imaging system and evaluating its performance perfectly, the information theory is applied to the High Dynamic Range Imaging system, the High Dynamic Range Imaging system is considered as a communication system, and the image quality of High Dynamic Range Imaging system is evaluated according to the end-to-end mutual information. Introducing the influence of LCoS as a spatial light modulator to CMOS sampling imaging model, mathematical model of the High Dynamic Range Imaging system based on mutual information is established. According to the model, the factors, such as the ratio of LCoS pixel number to CMOS pixel number, aperture ratio of LCoS and CMOS pixel, relative displacement and relative rotation angle, which affect the mutual information, and the reasons why the system image quality decline are analyzed. According to computer simulation, the relationships between the ratio of LCoS pixel number to CMOS pixel number and the mutual information, aperture ratio of LCoS and CMOS pixel and the mutual information, relative displacement and the mutual information, relative rotation angle and the mutual information are demonstrated, and the influence of these factors on the mutual information is analyzed. The simulation results show that the best matching condition between LCoS array and CMOS array is that one LCoS pixel corresponds to one CMOS pixel with smaller CMOS pixel, higher aperture of LCoS and CMOS pixel, no relative displacement and no relative rotation.

Reckoning on the strong interfere of background information to anomaly detection for hyperspectral image,a kind of anomaly detection algorithm based on background error cumulation is proposed.First,it constructs the background subspace.Then it projects every pixel into this subspace to obtain background error data for later anomaly detection,which suppresses background and makes target stand out.Experiments on real hyperspectral image show that the proposed algorithm outperforms other algorithms,and obtains better detection results.

A kind of liquid-based and electrically-controlled optical imaging apparatus is provided, which is a cylindrical chamber holding three liquid layers. A kind of insulating liquid is sandwiched between two layers of conducting liquids. A layer of transparent electrode and a layer of insulating layer are coated inside the chamber in turn. Two different external voltages can be applied between the electrode and two layers of conducting liquids, which respectively control two liquid interfaces in the chamber. These two voltages can be matched appropriately to change the focal length and keep the image plane of the apparatus stable simultaneously. Taking the infinite object as an example and based on the Gauss Optics Theory, detailed calculations concerning the relationship between the voltages and the focal length of the apparatus are given. The relevant simulation result that the zoom ratio of the apparatus can be 1∶1.5 shows that such an apparatus is a viable variable focal length optical imaging system.

Based on the accurate definition of light intensity of nonparaxial scalar beams at the transverse plane, a comparative study of the beam widths, far-field divergence angles and M2 factors defined by the power in the bucket and second-order moment is made. Taking the nonparaxial diffraction of a small circular aperture as an example, the detailed numerical calculation is performed. The results show that the beam width, far-field divergence angle and M2 factor defined by the power in the bucket are less than that defined by the second-order moment. Both M2 factors tend to zero as beam waist vanishes, the propagation of beam width defined by the power in the bucket is different from the hyperbolic law.

To analyze the influence of misaligned parameters of circular aperture and optical component on propagation properties of flattened Gaussian beam when flattened Gaussian beams passing through an optical system, an approximate analytical expression of the output field distribution for flattened Gaussian beam passing through an misaligned optical system with misaligned circular aperture is derived using approximate expanded formula of misaligned circular aperture function and generalized diffraction formula appropriate for misaligned optical system. The relations of output field distribution to the parameters of flattened Gaussian beam, the aperture size and various misaligned parameters of aperture and optical element, etc. are given. Some influences of various misaligned parameters on output field distribution are analyzed quantificationally for given optical system. Result shows that various misaligned components effect on the intensity distribution of output beam. But the influence of misaligned lens is more obvious than that of misaligned aperture when misaligned parameters value is small.

The non-line of sight single scattering channel model and its solution in ellipsoidal coordinates are introduced.According to vertical transmitter-receiver model, the influence of atmospheric channel on ultraviolet communication system is analyzed. Under different weather conditions and different communication distances, the transmission loss, time-delay and pulse broaden etc. caused by atmospheric channel are quantificationally analyzed and simulated. The simulation results show that: the curve of energy attenuation with visibility dependence has inflection point that the better weather and the higher visibility do not result in greater system receiving energy; when the visibility equals to 18 km, the minimum of energy attenuation occurs; energy attenuation nonlinearly increases with the increase of communication distance, and the energy attenuation is almost 100 dB when the communication distance equals to 1 km; with the increase of the communication distance, both time delay and pulse broaden approximately linearly increase; the time delay is close to 5 μs and pulse broaden is greater than 10 μs when the communication distance equals to 1 km.

For better understanding the light propagation in a double clad fiber (DCF), the perfect circular double clad fiber is numerically investigated by using the coupled mode method with translating the DCF into a single mode fiber (SMF) and an annular core fiber (ACF).The coupling coefficients between the LP01 mode of the SMF and the guided modes of the ACF are calculated. The results show that the LP0n modes of the ACF have greater coupling coefficients than the other guided modes, and for the LP0n modes the coupling coefficient of the high-order mode is larger than that of the low-order mode. The field distribution in the DCF core calculated by the coupled mode equations shows a quasi-periodic distribution along the DCF. The average period of the field distribution increases with the increasing of wavelength for different DCF parameters and the average normalized power of the field distribution is closely related to the chosen parameters of the DCF.

According to the perturbation theory for magneto-optic (MO) effects and nonlinear effects, the nonlinear coupled-mode equations are derived for optical pulses propagating in magneto-optic nonlinear fibers. The time and frequency domain schemes of magneto-optic effects in the modified split-step Fourier method are brought into comparison, and it is found that both of them are the same, when the step-length is short enough. According to the coupling of magneto-optic effects, nonlinear effects and dispersion, the propagation characteristics of optical pulses in the MO fibers are analyzed in detail. By approporiately adjusting the MO coupling coefficient, the pulse shape can be flexiblely controlled, and the frequency chirp related to the nonlinear effects is also be changed, which is useful for the dynamic reshaping function based on pulse widening. The theoretical analysis results presented in the article may help to develop novel magneto-optic information processing devices with applications to the fields of fiber optic communications and fiber optical sensors etc.

According to the model of multi-photon nonlinear Compton scattering,the influence of the multi-photon nonlinear Compton scattering on the strong Langmuir turbulence spectra in the laser-plasma is studied. A new mechanism of the strong Langmuir turbulence formed by the incident light and scattered optical is given.The revised equation met by the mutual action on the transverse plasma wave,the strong Langmuir turbulence wave and ion acoustic wave and its results of the numerical number modulation are also given. The results show that because the collision frequency between the transverse plasma wave and strong Langmuir turbulence wave is greatly increased by Compton scattering, along the time evolution,the transformation of the energy from the small-k region to the large-k region between the transverse plasma wave and Langmuir wave is faster than that before Compton scattering,and the strenuous collapsing is taken place at the same time. During the anaphase of collapse,the nonlinear effect of the laser-plasma excites out the high degree resonance waves. The energy is diverted from one of the resonance wave to another,and the infinite high degrees resonance wave is formed. The phenomenon on breakage of the wave,the strong Langmuir turbulence controlled by the modulation instability,the stronger laser filamentation and energy egalitarian are taken place. The research results will provide a theoretic support for the further study on the increasing speed mechanism of the strong Langmuir turbulence,abnormal collision and laser heating experimentation and fast igniting experimentation.

Symmetrical slit-step Fourier numerical method is used to simulate the soliton transmission properties in the fibers presenting birefringence. The inferences of the group velocity mismatch (GVM), which denotes the magnitude of the birefringence, on the soliton transmission are analyzed. It is shown that the intensity of the two polarization component of the soliton are hardly varying when the GVM is small, and the soliton is undeformed on the whole in the transmission process. When the GVM is greater, the wider the width and the weaker the intensity of the soliton pulse become rapidly, and the soliton can not undeform transmission. If the birefringence of the fiber is randomly varying, the intensity of the two polarization component of the soliton is changed irregularly with the transmission distance, and the composite intensity of the soliton pulse is hardly varied as the two polarization component compensates each other. The interaction of solitons is influenced by the magnitude of the birefringence; the greater the GVM is, the shorter distance of the soliton with no-interaction. If amplitude rate is chosen appropriately, using the traditional unequal amplitude imputing method, it can still restrain the interaction of the solitons effectively.

To solve multi-camera pose estimation problem with the coexistence of point and line segment under the industry visual scene, a new pose estimation algorithm for multi-camera from point and line correspondences is proposed. The method uses geometric restriction between multiple calibrated cameras, and globally processes point and line segment feature from overlapping and non-overlapping views of multi-camera rig, finally obtains more robust and accurate pose estimation. In the proposed method, the formulation of datum of multiple cameras is unfined, and the sum of object-space collinearity error of point and coplanarity error of line segment all cameras are used as error function. Finally, an iterative algorithm is developed to minimize the error function. The experimental results prove the effectiveness and superiority of the algorithm for pose estimation.

When measuring glyoxal directly in the atmosphere by Long Path Differential Optical Absorption Spectroscopy (LP-DOAS), the analysis of glyoxal strongly suffers from the cross interference of other absorbers or structure (Xe lamp-structure, H2O, O4 and NO2 absorption). The retrieval method of glyoxal-the elimination of interfering absorption or structure was studied. The Xe lamp-structure will change nonlinearly resulted from the change of pressure broadening and Doppler Broadening with the change of of Xe lamp pressure or temperature. The different lamp reference spectra detected at different time were interpolated to eliminate lamp structure and the resulting residual structures caused by an incorrect elimination were a factor of three below the detection limit of glyoxal; high amount of H2O in the atmosphere cause the nonlinear absorption of H2O and the observed band shape to vary with the column density of H2O. Two H2O absorption spectra with higher and lower column density were interpolated to eliminate nonlinear H2O absorption and the resulting residual structures caused by an incorrect elimination were ten times below the detection limit of glyoxal. In addition, the strong absorption of interfering species NO2 and O4 were also accurately removed. Low detection limit (0.15 ppbv) and low systematic errors (~10 %) were achieved by the accurate elimination of interfering structures. In the end, glyoxal was routinely detected during the daytime on the outskirts of Guangzhou, where mixing ratios ranged from less than detection limit (0.15 ppbv) to 1.66 ppbv. The variation and range of glyoxal concentration detected agreed well with the results reported.

The focal length of measured lens can be figured out accurately according to its relation to the slope coefficient of Moiré fringes.An approach is presented to determine the location of grating centre at the level of pixel by Canny operator and detection based on mathematical morphology.The sub pixel localization is presented based on Gauss curve fitting.The localization accuracy is proved less than 0.1 pixel by calibrating the standard fringes.Then the grating is set as the reference to calibrate the equivalent length of CCD pixel to ensure the slope and width measuring of fringes accurate.The error of focal length is 0.10%.

An automatic camera focusing scheme used in video conference is presented.The proposed scheme consists of two phases: focus adjusting and focus monitoring.In the focus adjusting phase,mountain climbing algorithm is used to search the peak point of the focusing criteria function.The focus searching range is reduced by the concept of hyperfocal distance,and the searching step size is adapted dynamically.Therefore,the searching process is speeded up,and good subjective quality of pictures is guaranteed.Moreover,to eliminate the influence of scene changes during the searching process,a return-examination method is used.In the focus monitoring phase,focus adjusting is conditionally triggered based on the results of shot change detection,which helps to guarantee focus quality and avoid frequently refocusing.Experimental results validate the performance and robustness of the proposed scheme.It has been integrated in the products of video conference terminal.

Aiming at the problem that one-dimensional generalized fuzzy entropy thresholding failed to segment the noised image, a two-dimensional membership function on the two-dimensional histogram is defined and a two-dimensional generalized fuzzy entropy thresholding method is presented. The proposed method segments an image with the pixel intensity and with the pixel′s local average gray value, which considered more image information. In order to improve the speed and select suitable parameter, a nesting optimal searching process is designed with particle swarm optimization for two-dimensional generalized fuzzy entropy thresholding algorithm. Experiment results show that two-dimensional generalized fuzzy entropy thresholding method has good adaptability with noised images.

To solve the error propagation of whole frame loss in video transmission,a whole frame error concealment algorithm based on multiple-frame extrapolation is presented.Bidirection motion vector extrapolation method from available neighboring frames is used to get the motion vection candidate sets of the lost frame.A weighted multi-frame boundary matching errors criterion is presented to estimate the distortion of both the lost frame and its succeeding frame,and the optimal motion vection is determined from the motion vection candidate sets.Finally,adaptive overlapped blockmotion compensation is used to reconstruct the lost frame.Simulation results show that the presented algorithm can recover the lost frame and effectively suppress error propagetion.Compared with other conventional methods,the proposed algorithm achieves 0.5~1 dB gain in terms of average PSNR and provides much better error concealment results.