The generation and control mechanisms of a broadband supercontinuum (SC) in photonic crystal fibers (PCF) with twozero dispersion wavelengths are demonstrated by simulating the evolution process of a femtosecond pulse numerically. The results reveal that the intrinsic higherorder dispersions and nonlinear effects of PCFs cause the pump pulse, whose center wavelength locates between the anomalous dispersion region, decay into fundamental solitons and two dispersive waves simultaneously. In virtue to the enhancement of the two dispersive waves by their phasematched solitons, SC will be formed by the two dispersive waves, on which oscillations happen for the interference. Then, the limited effect on the SC applied by the two dispersive waves is analyzed quantitatively by comparing the SCs in three PCFs with different geometrical parameters. Meanwhile, the effects of the geometrical parameters are demonstrated. Based on the above conclusions, considering the analysis on the relationships between the center wavelengths of the dispersive waves and the dispersion curves of PCFs as well as their geometrical parameters, a method to control the range of SC is promoted based on the design of the geometrical parameters. As an example, a flat SC extending to the visible region is achieved by optimizing the geometrical parameter in theory.

The nonlinear optical properties of two kinds of metallophthalocyanines with different central ions, 2,9,16,23tetra(pcarboxyphenyloxy) phthalocyanine cobalt (pHPcCo) and 2,9,16,23tetra(pcarboxyphenyloxy) phthalocyanine zinc (pHPcZn), are investigated mainly by UVVISNIR spectroscopy and picosecond Zscan technique with 532 nm and 1 064 nm excitation. The optical properties of these two compounds are discussed using the theories of лelectron conjugated structures and resonant/nonresonant enhancement, respectively. The obtained results demonstrate that the stronger ability of the central ion to attract electron, the larger absorption band shifts towards long wavelength. Both the two metallophthalocyanines have positive thirdorder nonlinear susceptibilities. Under the excitation of wavelength of 532 nm close to the resonance field, the thirdorder nonlinear susceptibility χ(3) of pHPcZn and pHpcCo is almost twoorder of magnitude larger than at 1 064 nm.With the stronger ability of the central ion to attract electron，the thirdorder nonlinear susceptibility χ(3) of pHPcZn is larger than pHpcCo, and shows a maximum value, 1.76×10－10 esu, under the excitation of wavelength of 532 nm.

A folded MachZehnder interferometer in a holetype silicon photonic crystal is proposed, which consists of one splitter and several mirrors. Light propagates between them employing selfcollimation effect. Its performance is investigated based on finitedifference timedomain simulation technique. The two complementary transmission spectra at two output ports are both in the shape of sinusoidal curves in the frequency range from 0.255c/a to 0.270c/a. The peak spacing becomes smaller when the length difference between the two interfering branches is increased. This folded MachZehnder interferometer with compact structure is much smaller than nonfolded interferencetype filters in photonic crystals. It may work as a wavelength division demultiplexer in highdensity photonic integrated circuits.

Blueshifted spectra of supercontinuum generation in photonic crystal fibers are studied theoretically and experimentally. The influences of input power on supercontinuum spectra generation are analyzed. The research results show that when the power of the laser is low, the theoretical results obtained by the nonlinear Schrodinger equation including selfphase modulation,selfsteeping and intrapulse Raman scattering agree with the experimental results. However, when the power of the laser is high, the theoretical and experimental blueshifted spectra are different. Therefore, the influences of the cross phase modulation and fourwave mixing effects on the supercontinuum generation are discussed, which provide the mechanism for the buleshifted spectra of supercontinuum generation.

The physical model of twodimensional suerconducting photonic crystal is established. Taking atomic nonharmonic oscillation into account with the help of twofluid model, the equation of photonic band structure is obtained using the method of plane wave expansion. Taking a superconducting photonic crystal YBaCuO as example, the influences of temperature on the photonic band structure are analyzed. The calculations show that the twodimensional photonic crystals have the wider band gaps at the lower temperature, which narrows with the increases of temperature.

A new theory of narrow bandwidth photonic crystal optical filter, which consists of GaAs/AlxGa1－xAs multiple quantum wells, is proposed. The anomalous dispersion behavior caused by excitons absorption in GaAs/AlxGa1－xAs MQW under an external electric field is investigated. The results show that there is a strong dispersion and small absorption region in the near resonant frequency of the anomalous dispersion material. Thus, a narrow transmission band will appear in the photonic band gap due to the dispersion in that region, of which corresponding maximum transmission value is about 0.73 and the bandwidth of the all solidstate filter is about 4.9 nm. This filter can be tuned by an external electric field. It provides guidance for the design of the new solidstate filter.

A novel miniaturized camera module with 1.3 megapixels for electronic endoscope is developed and presented. This module realizes longdistance and highfidelity transmission of image data adopting LowVoltage Differential Signaling technology. It includes a 1/5.5 inch CMOS image sensor with a resolution of 1 280×1 024 pixel2, a small integrated lens with field of view of 140° and two electric circuit boards. The lens fixed with inner screw thread is cemented directly onto the nonoptical part of the image sensor′s surface. Two printed circuit boards are assembled vertically, which reduces the size of the module down to 5.5 mm in width, 5.2 mm in height and 15.0 mm in length. The 10bit parallel digital signals are encoded into lowvoltage differential signals before they are output through a twisted pair. A demonstration system is developed to evaluate the performance of the camera module. Experimental results show that the module′s resolution reaches to 136 lp·mm－1, and the image transmission length is over 2 meters. The compact size, high resolution image, wide field of view and longdistance transmission enable the camera module to be used in video endoscopy, especially for HDTV gastroscopes and colonoscopes.

The impact of the refractive index and thickness of substrate on the light extraction efficiency of flipchip LED is analyzed through simulation analysis. And a new diamondshaped structure is proposed. The results show that the light extraction efficiency is improved to a good purpose in the diamondshaped LED, resulting in an increase in the light extraction efficiency by 1.51,2.03 or 3.65 times when the substrate is Si, Sapphire or SiC espectively.

In order to develop low loss,highperformance 157 nm fluoride coatings, 157 nm fluoride optical thin film performance is studied. On the base of fluorede single layer study, 157 nm HR and AR coatings are designed and deposited with different fluoride high and low refractive index materials. Their reflectivity,transmittance,optical loss and other properties are discussed and compared.In the analysis of several fluoride films and their combined properties, the fluoride combinations of 157 nm HR and AR coatings are optimized selected. To get a highperformance 157 nm HR coating, the NdF3/AlF3 HR mirror is designed and made,and its reflectance is nearly up to 93%. Under the present experimental conditions, the LaF3/AlF3 157 nm AR coanting is designed and deposited, and its residual reflectance is less than 0.17%.

The analytical expressions for the phase shift on reflection of Distributed Bragg Reflectors (DBRs) with odd and even numbers were derived based on the transfermatrix method.The expression for the penetration depth of DBR as a function of phase shift was given according to the relationship between the phase shift and the reflection delay.The DBR with the structure of［HL］2H was fabricated by electron beam evaporation and the transmittance spectrum,and phase shift and penetration depth were measured or simulated.The microcavity organic light emitting diode (MOLED) was fabricated using the designed DBR.The measured effective cavity length of the MOLED fit well with the calculated one.

Based on the multibeam interference principle, a transmitting intensity expression of a Gaussian beam incidenting obliquely on an angletuned narrowband filter is derived. According to the result, the influence of the incidence angle on the transmission of a Gaussion beam is investigated theoretically. The calculation and experiment results show that the size of the transmitting beam spot is brodened obviously in oblique incidence. When the incident angle of the thinfilm filter is relatively small, the position of the peak of the transmitting beam is shifted and the beam is not in Gaussian distribution. When the incident angle of the filter is relatively large, the transmitting beam consists of a series of spaceseparated beams.

In order to provide the basis for differentiating PAHs and test PAHs in environment, snchronous fluorescence spectra of ten kinds of standards PAHs(naphthalene, fluorine, anthracene, phenanthrene, pyrene, acenaphthene, chrysene, 1,2benzo［A］ anthracene, benzo［k］ fluoranthene, benzophenanthrene) and their mixed solutions(anthracene/ naphthalene/ fluorine, acenaphthene/ fluoranthene/phenanthrene and pyrene /1,2benzo［A］ anthracene/benzo［k］ fluoranthene/benzophenanthrene)are measured. The differences of the excitation and emission wavelength Δλ are obtained when the characteristic peaks are the most evident. Based on above results, the composites of the three kinds mixed solutions are identified by synchronous fluorescence spectra. The results show that it is easy to distinguish anthracene, naphthalene and fluorine when Δλ equals 3 nm.For acenaphthene, pyrene and phenanthrene, Δλ equals 3 nm or 10 nm,the three composites can be differentiated. It is relative simple when Δλ equals 10nm. For the mixed solution of chrysene, 1,2benzo［A］ anthracene, benzo［k］ fluoranthene and benzophenanthrene, it is the best when Δλ equals 5 nm, but only chrysene, 1,2benzo［A］ anthracene and benzo［k］ fluoranthene could be identified, benzophenanthrene is indefinite.

In order to predict the spectral reflectance of rectoverso halftone images, the scattering of light within paper and the ink penetration in the substrate are considered and the color spectral reflectance precise prediction model for rectoverso halftone images is proposed. Based on the assumption that ink is a nonscattering medium, paper is a strong scattering substrate,both of which have the same refractive index, the WilliamsClapper model is proposed.The inkspreading model includes nominaltoeffective dot area coverage functions for each of the different ink overprint conditions by the least square curve fitting method and the network structure of multiple reflection. It turned out that the modeled and the measured colors agree very well, confirming the validity of the used model. The new model provides a theoretical foundation for color prediction analysis of rectoverso halftone images and the development of prints quality detection system.

The distributed optical fiber sensing technology based on coherent optical timedomain reflectometer (COTDR) is researched. The measurement mechanism of distributed temperature sensing techniques based on COTDR is analyzed. Simulation model is established and sensing system performance is analyzed in simulation according to the composition and principles of sensing system. Finally, a temperature resolution of 0.01 ℃ and a spatial resolution of 1 m are achieved by the MATLAB simulation.

A joy stick transducer based on fiber Bragg grating (FBG) is presented. The sensitivity is analyzed theoretically via discussing the mechanical properties of the elastic element and the strain sensing characteristics of the FBG. By detecting the changing of central wavelength of FBG at different load forces, the response characteristics of the aircraft Joy stick transducer based on fiber Bragg grating are investigated. The experimental results demonstrate that there exists a linear relationship between the central wavelength of FBG and load force, which is consistent with the theoretical analysis. The sensitivities of horizontal and vertical are 2.07 pm·N－1 and 1.80 pm·N－1, respectively, which are consistent with the simulation.

Based on the coupledwave theory of single volume grating and matrix theory, the coupledwave equation of stratified volume grating illuminated by femtosecond pulse is acquired. Solutions for the diffraction intensity spectrum and instantaneous diffraction intensity are obtained. The research results show that the diffraction characteristics depend on the parameters of the stratified gratings, such as the thickness of the buffer layers and grating layers, grating periods and the refractive index modulations of the grating. Through modulating these parameters, diffraction pulses with different shapes and bandwidths can be obtained. The results will be utilized to design devices employed in optical communication and pulse shaping.

A novel lowreflectivity Fiber Bragg Grating sensor system with a combination of time division multiplexing mode, a narrow wavelength swept laser is proposed and demonstrated for achieving multiple sensing points, longdistance, quasidistributed measurement. Time division multiplexing mode and the low reflectivity Fiber Bragg Gratings which have the close center wavelength are used to monitor multiple points simultaneously. And, Erdoped fiber and Raman amplification method is proposed to extend the sensing distance. The middle of the system involves a Raman pump for amplifying FBG reflected signal,and the Erbiumdoped fiber uses the remaining Raman pump power to generate amplification of spontaneous emission and amplify sensing signal. Experimental results show that an excellent optical SNR of 15 dB has been achieved for 200 km transmission distance. In the static strain and temperature experiments at the distance of 200 km, the linearities achieve more than 0.999.

In order to develop the laser interferometer velocimetry in the experimental research of shock wave physics and explosion physics, an allfiber velocity interferometer is presented. The singlemode fiber is adopted as optical transmission and delay components for this interferometer, which detects Doppler beat signals caused by velocity change to two moments of t and t－τ. Because of little velocity change of objects to be tested corresponding to twobeam optical signals of two moments, which almost have equivalent frequency shift, and the beat frequency is also significantly lowered. Meanwhile, the fringe constant (value τ) can be flexibly adjusted in accordance with velocity change rate of objects to be tested, thereby making the beat signal frequency caused by velocity change less than the system bandwidth within the time scale of τ, so as to solve the problem of recording system corresponding to bandwidth limitation and extend upper limit of velocity measurement. As result of the adoption of singlemode fiber, only one space pattern in the fiber participates in interference, even the light returned from diffusereflection surface can preferably participate in interference after the mode selection of singlemode fiber, thereby realizing the measurement to diffusereflection target. Two fringe constants of 1.5 m·s－1 and 150 m·s－1 are adopted to conduct the Hopkinson bar experiment at lowvelocity process and laserdriven experiment at highvelocity process. The experimental result proves the feasibility of this interference technique.

A waveguidebased twodimensional meniscus thin lens is proposed for mmwave quasioptical power combining in a closed structure. The proposed waveguide lens is operated in TE10 mode, and the effects of the dispersion are discussed. A matching layer is included to improve the combining efficiency. A tenway power combiner using Rexolite material is given as a designed example at 30 GHz. Simulations show that the designed meniscus lens can achieve a combining efficiency of 92.6% at the design frequency of 30 GHz, and cover the entire Kaband with more than 80% efficiency.

In order to solve the problem in deflection control of deflection algorithm,a deflection routing algorithm based on priority and burst loss threshold in OBS networks is proposed.It drops some high priority deflected bursts to provide QoS for low priority nondeflected bursts.When competition occurs,in order to protect high priority burst,low priority bursts are segmented and deflected.Then,the node uses threshold check function to decide whether to drop or to preempt the resource of low priority nondeflected bursts on deflected route.Simulation results show that although the proposed algorithm increase a little delay,it can efficiently prevent deflected burst from contending with nondeflected burst on deflected route,and reduce packet loss probability of entire networks and protect the integrity of some high priority bursts.As a result,the scheme can efficiently improve the performance of OBS networks.

Finite element model of ultraprecision glass molding press for micro aspherical glass lenses is built by the nonlinear finite element software MSC.Marc. Numerical simulation analysis is carried out. Compared to residual stress of formed lens and mould distribution under the different processing parameters, the optimal molding velocity and the range of molding temperature of ultraprecision glass molding press are obtained. The research results are helpful for the mass production of micro aspherical glass lenses.

In order to gain the phase retardation and birefringence of mica wave plate according to the increase of the wavelength, the phase retardation of the mica wave plate is measured continuously in the spectral region of 400~770 nm using a spectroscopic ellipsometer. After the calibration of the mica plate, the experimental data are collected by the detector and sent to the computer. From the outputted data, the retardation can be obtained according to the increase of the wavelength. With the measured phase retardation, the birefringence of the mica wave plate can be calculated. The birefringence dispersion curve and dispersion formula are also gained. The proposed method can measure a mica wave plate with arbitrary phase retardation and has the merits of convenient, quick and high accuracy.

Based on the study of basic principle of interferometry using 2D FFT arithmetic,a method to measure the length is proposed.The gauge block,as a measured sample,is placed into the light path in a TwymanGreen interferometer,and the interference fringes are generated between the reference beam and the reflected beam of the tested block upper surface and the assistant plane respectively.The interferogram is collected by a image acquisition system.The algorithm processing software is used to achieve block edge identification,region extension,filtering,phase unwrapping etc.The length distribution with block information can be obtained in the whole field and the length of the gauge block can be obtained automatically.The results indicate that the proposed method has advantages of high precision,whole field and noncontact in the measuring.

Aiming at the thermal mismatch caused by different Coefficients of Thermal Expansion (CTE) of each material in Chip on Board(COB), Digital Image Correlation (DIC) is used to measure the thermomechanical coupling effect in COB packaging structures, and effects of different type substrate are compared. The experiment results are compared with both the results of FEM simulations and the theoretical model. Experimental results reveal that DIC can successfully be applied to the analysis of the thermomechanical coupling effect and provide an availability consult to the design of MEMS apparatus.

A measuring method of transverse mode in a laser beam is presented, which is based on the spatial distribution of single pulse energy in a pulsed laser. An algorithm for this method is designed and proved to be reliable in theory and experiments. The spatial distribution curve of single pulse energy is derived by numerical simulation for Qswitched diode pumped solid state laser. The transverse mode proportion calculated by this method is exactly equal to those calculated directly by numerical simulation. An experiment is also conducted to measure transverse mode proportion by using this new measuring method. Spatial distribution of single pulse energy is obtained by testing single pulse energy at different positions in different planes. The transverse mode proportion in Qswitched diode pumped solid state laser is calculated by forming a system of equations with those testing data which is consonant with the spatial distribution curves of single pulse energy fitted by the calculated proportion and transverse mode distribution in those different planes.

In order to obtain accurate measurement of 3D shape, a shape measurement method using phaseshifting electronic speckle pattern interferometry(ESPI) is proposed. A carrier pattern on the object surface is produced by electronic speckle pattern interferometry. The carrier pattern is curved because of the modulation of the altitude of the object surface, which causes the changes of the phase of the carrier pattern. Then the phase changes of the object surface can be extracted by phaseshifting algorithms. Finally the shape of the object surface can be derived by the relationship between the phase changes and the altitude of the surface. The principle of the proposed method is introduced. Surface of a small ball is tested using the method. The experimental results prove that the phaseshifting electronic speckle pattern interferometry is useful for the measurement of an object surface,and indicate that the method has the virtue of high sensitivity because the carrier pattern is produced by electronic speckle pattern interferometry.

A temporal and spatial filter algorithm is presented to detect Infrared(IR) weak point targets moving slowly in the scenarios with cloud clutter and noise. Firstly, IR image sequence is processed by the normalization preprocess. Secondly, a filter is used to process the image sequence in the temporal domain, and then a target enhancement algorithm is constructed to suppress the residual dots which are attributed to the cloud clutter and noise. Finally, the computer simulations are made to verify the performance of the presented algorithm, and the results confirmed its effectiveness.

In order to predict the spectral reflectance of rectoverso halftone images, the scattering of light within paper and the ink penetration in the substrate is considered and the color spectral reflectance precise prediction model for rectoverso halftone images is proposed. Based on the assumption that the colorant is nonscattering, the paper is strong scattering substrate and both the colorant and ink have the same reflective index, the light along oblique path from the WilliamsClapper model is introduced for taking into account ink spreading. By the multiple internal reflections between the paper substrate and the printair interface of light, a phenomenon occurs when printing an ink halftone in superposition with one or several solid inks. The inkspreading model includes nominaltoeffective dot area coverage functions for each of the different ink overprint conditions by the least square curve fitting method and the network structure of multiple reflections. The modeled and the measured colors agree very well, which confirms the validity of the used model, and provides a theoretical foundation for color prediction analysis of rectoverso halftone images and the development of prints quality detection system.

In order to switch the dual Field of View Infrared optical system quickly,and satisfy the requirements of the portability and installation,a lightweight hybrid refractivediffractive dual FOV IR optical system is designed.The system adopts reimaging and hybrid refractivediffractive system,is optimized by optical design software,and the image quality is also evaluated.The temperature compensation is also analyzed,and the temperature compensation curves are also shown.The system can be switched from 120 mm/60 mm and the work wavelength is between 3.7～4.8 μm.The results indicate that the efficiency of the cold shield is 100%; at the Nyquist frequency 33 lp/mm of the detector,the MTF of the offaxial field is higher than 0.3,and the system’s optical length is 200 mm.The whole system consists of 7 pieces of lenses,and the dual FOV can be switched by shifting only one piece of them,which makes the system simple,lightweight with high quality imaging.

Temperature filed distributing of a high resolution space telescope is analyzed by thermaloptical method based on optical frontwaveerror theory, and thermal contral target is ascertained. The thermal tests in the vacuum are carried out to validate the analysis. Tests results indicate that the ideal focal plane position vs temperature level are linearity, and changes scope approximately 0.08～0.1 mm·℃－1. As the macrocosmic temperature changing within (20±1)℃, system MTF change about 0.02. When the temperature grads are more than 2 ℃ in axis direction and diameter direction, the ideal focal plane position departure happenes and the MTF decline obviously if unfocus.

A new application of the fivequbit cluster state is investigated for economic and simple controlled teleportation of an arbitrary twoqubit state. In this scheme, a fivequbit cluster state is shared by a sender (Alice), a controller (Charlie) and a receiver (Bob), and the sender only needs to perform Bellstate measurements and the controller performs a singlequbit projective measurement. The receiver can reconstruct the arbitrary twoqubit state by performing some appropriate unitary transformations on his qubits after he knows the measured results of both the sender and the controller. This controlled teleportation scheme is deterministic, and the probability of successful controlled teleportation is 100%. In comparison with the controlled teleportation scheme using the same quantum channel, the proposed scheme do not need to make multiparticle joint measurement that makes this scheme simpler.

A new scheme for controlled teleportation of an arbitrary twoparticle state is proposed in detail, using a fourparticle cluster state as quantum channel and EPR state to achieve control. First of all, the sender applies to the controller, and then the controller performs the Bellbased measurement on the two particles of his own. And the controller notifies the sender to achieve entanglement swapping. Then, the sender makes the appropriate unitary transformation and performs a Newman measurements on the four particles of his own. And the results inform the receiver. According to the sender′s measurement results, the receiver can reconstruct the arbitrary twoparticle state after he makes the appropriate unitary transformation on his own particles. The success probability of the program is 100%.

In order to construct quantum secret sharing protocols among many parts,a Nparticle entangled state that has a large persistency of entanglement is introduced,and a quantum secret sharing protocol between one party and （N－1） parties is presented using the proposed entangled state.During constructing secret sharing,Alice chooses randomly unitary operation I or σx for the sent particles,and chooses a part of the particles to check the safeness of channel; then Alice chooses another part of the particles to check the honesty of partners and the safeness of channel by the operations of (N－1) parties.The protocol carries on examination to the eavesdropper for many times,so that it can insure the safeness of channel and the usability of the secret strings.Finally,there are n［1－(N－1)/2 N－1］/6 sharing secret bits among Alice and （N－1）parties.

Considering three twolevel atoms initially in the GHZ state, two atoms of the three atoms are put into initially empty cavity and made resonant interaction. The twoatom entanglement properties inside cavities are investigated by means of the quantum theory and numerical calculations. Through comparing the results if a rotation operation and direct selective measurement is performed or not, the influences of a rotation operation and stateselective measurement of the atom outside the cavity on the twoatom entanglement evolution inside cavities are discussed. The results obtained using the numerical method show that the twoatom entanglement properties inside cavities is controlled by manipulating the atom outside the cavity, and it can be strengthened by seleting suitable rotation angle.

The fidelity of threephoton W state teleportation token bus network is calculated. The calculation indicates that, for a given analysis angle θ, the fidelity are related only with the coefficient |a|2s during the processes of quantum network communication. With the increase of analysis angles, the maximum fidelity of the corresponding coefficient |a|2s correspondingly reduced. When θ=π/4, π/2, 3π/4, the fidelity are up to the maximum 1, and the corresponding |a|2s are 0.724, 0.5, and 0.276, respectively. For a given coefficient |a|, the fidelity are related only with the analysis angles θ. If |a|=0, the fidelity is always 0 regardless of the value of θ. When |a|=|b|=0.7071 and θ=π/2, 3π/2, the fidelity are up to the maximum 1.

A quantitative model of width measurement for irregular crack is established. A novel method on distinction between true and pseudo cracks is presented, which uses the theory of edge detection and morphological dilation operation. By selecting two approximate equivalent sets of target pixels and background pixels at the marginal areas of cracks′ both sides, the best threshold is calculated adaptively. Then the edge′s pixels and the movement of crack through the binarization image are extracted. Using the quantitative model, the width of crack can be measured. The experimental results show that the proposed method can effectively overcome the image noise, manipulate any irregular crack, and also remove the pseudo crack. The repeatability precision of the method is superior to 0.1 mm.

Utilizing the contourlet′s advantages of multiscale, localization, directionality and anisotropy, a multifocus image fusion algorithm based on directional windows statistics in contourlet domain is developed. Source images are firstly decomposed to the domain of the contourlet transform, then the image fusion is implemented in subbands with different scale and direction combining with region statistics. Regional variance and local energy are adopted as fusion rules in lowpass and highpass subbands, respectively. And the fused image is obtained through inverse transform. Compared to traditional gradient pyramid algorithm and wavelet based algorithm, experimental results show that the directional windows method can detect image features more effectively and the fused image has better subjective visual effect.

Abstract:By analyzing of the causes and features of impulse noises in radiography, a joint denoising method based on impulse noise segmentation and data repair is presented. The radiograph is reconstructed from its grayreduced image by geodesic dilation method, and impulse noises are segmented from the differential image between the reconstructed image and the radiograph by the global thresholding technique. The impulse noises in the radiograph are removed by an improved NLmeans filter method. To avoid an intrinsic problem that fixes noise by noise in the classical NLmeans method, the improved NLmeans method limits the searching area of the similar pixels. An equation is used to describe the improved NLmeans filter. The experimental results show that impulse noises in different radiographs can be removed effectively by the joint method, and the trivial information of the radiographs remains with high fidelity.