In order to measure the mean height of long distance burst, a double line scanning CCD measurement system is established and its theoretical model is built.First, telescopic optical system is used to image the burst, and the image is transformed by a cylindrical lens.Then, Zemax software is used to simulate the optical system, whose spot diagram show that the system can effectively measure the mean height of burst within 5 meters at a long distance of 20m.Finally, the spot center is acquired by means of the curve fitting and linear calibration is carried out for uncertain parameters of the system.Experimental results indicate that the maximal height is 3 m approximately at a long distance of 20 m.The mean error is 1.95%.The presented system can reach the acquirement of long distance and wide range.Furthermore, the uncertainty of distance can be eliminated naturally by using the double line scanning CCD system.

To clearly measure the surface topography of specimen and the relationship among specimens, a multi-scale measurement method based on Digital Micromirror Device (DMD) was proposed, and then a control method and measurement strategy of DMD were researched.Without any changes of measurement device, the parameters of structured light based on DMD could be controlled by software programming.Theoretically, different scale measurement for surface topography, from 0.1 μm level to 1 mm level, could be achieved.A multi-scale measurement device based on DMD has been set up, and the experiment results indicate that, the axial accuracy and transverse resolution of the device could achieve at 1μm level, and the microstructure could be scanned quickly.This multi-scale measurement method could be widely applied in surface topography measurement to solve some multi-scale problems.

If Zhang’s camera calibration results are optimized with SBA directly, different sets of camera parameters (internal parameters and distortion parameters) will be obtained.Based on the mathematical model of SBA and the equality constraints of camera parameters, a Constrained Sparse Bundle Adjustment (CSBA) algorithm is proposed with a new block matrix partition strategy to improve the efficiency of solving sparse linear equations.Simulation experiments are implemented to verify that unified camera parameters can be obtained even if the pixel coordinates don’t have zero-mean Gaussian error.Finally, the CSBA algorithm is applied to a binocular stereo vision system.The experimental results demonstrate that the CSBA algorithm can optimize the camera parameters and position parameters simultaneously, and improve the accuracy of 3D reconstruction.

The workspace Measuring and Positioning System (wMPS) is an indoor large-scale positioning system based on the intersection of laser planes.Station network layout is a system of structural factors that directly affects the system measuring accuracy.To get a better layout, we analyzed the measuring equation of the system and pointed out that the condition number of measurement matrix can be a quantitative indicator to planes intersection and gave the mathematical model.The optimum network layout was achieved with the Genetic algorithm which was designed based on the quantitative indicator.The experimental results show that this method can effectively improve the measurement precision.

To overcome problems in current six Degree-of-freedom (DOF) measurement, such as poor portability, low precision and speed, the paper demonstrates a laser target measurement setup based on embedded system.Cooperating with a total station, laser target can achieve six-DOF measurement.A spot center positioning algorithm is proposed which suits for embedded system, and an attitude resolving algorithm based on non-modeled camera calibration.Tested by experimental results, the laser target angel measurement precision of pitch and roll is 0.005 degree, and azimuth angle measurement precision is 0.006 2 degree with a position measurement precision equaling to total station.The present system is able to be applied to wide measuring situations.

In the structured light depth acquisition system, a system calibration method is proposed to reduce the measurement error when the heights of the projector system and camera system’s pupil centers are unequal.N frames orthogonal gratings and a cubic object are used to complete the calibration.Under the orthogonal light illumination, the shadow position of the cube and the grating line direction on the cube are served as references to complete the system coarse calibration.The phase modulated by the height of the cube in the horizontal direction is calculated to guide the system delicate calibration.This method can provide theoretical foundation for the system calibration and technical assistance for the researchers without experience in depth acquisition process.Experiment results demonstrate the effectiveness of the proposed method.

Aerospace products have high-precision measurement requirements for attitude parameters, and cubic mirror-theodolite alignment measurement method is widely used.Based on the principle of theodolite auto collimation research, product attitude adjustment measurement proposed by real-time measurement, principle of the method, the scope and application experience have been introduced.This method can achieve real-time measurement of the product, adjustment of the operation is accuracy and immediate intervention, reduce the number of instrument station calibration and product attitude measurement frequency, improve measurement efficiency, and reduce operating strength.

Thermal stress due to the mismatch between the coating and substrate is an important factor to ensure the reliability of the coating for its various structural and function applications at high temperature.In the present work, the thermal stress distributions through the thickness of TiO2 coating-substrate systems, as well as the effect of the mismatch between the coating and substrate, and the intermediate composite layer (which is a graded composite made of the SiO2 and TiO2 materials) on the thermal stress are evaluated by Finite Element Method (FEM).The results show that TiO2 coating on Si substrate exhibits high thermal stress at high temperature compared to the sapphire//TiO2 system and TiO2-SiO2 material as the intermediate composite layer is effective for decreasing and controlling the stress distribution.

In the distributed temperature sensing system of Brillouin optical time domain reflectometer based on the electro-optical modulation, the power of reference light exported from the electro-optic modulator will fluctuate while using microwave sweeper.According to the principle of correlation detection, the fluctuations of reference light power will affect the power of Brillouin scattering light, and it will cause large error in temperature measurement.Therefore, a method that can adjust the microwave power based on the output light power feedback of electro-optic modulator has been proposed to keep the power of reference light of Brillouin optical time domain reflectometer stable.The experimental results show that the method can suppress the fluctuation of the first-order edge wave band peak power exported from the electro-optic modulator effectively, and the temperature measuring accuracy has been increased from 6 ℃ to 2 ℃.

The theoretical model of the eccentric core fiber is established according to the traditional optical transmission theory.Moreover, the expression of evanescent wave of eccentric core is deduced according to Fresnel equation so that the depth of penetration is solved.Through the structure modeling of eccentric core optical fiber completed by BeamPROP module, the variation trend of modal field distribution, evanescent wave, as well as fundamental mode effective index with the eccentric distance is obtained.The simulation result shows that the evanescent wave declines with the increase of δ.The fundamental mode effective index increases as δ dose, and it will be stabilized when δ equals 8 μm.

In order to solve the sensitivity problem of the temperature in the solution refractive index measurement, a new scheme for refractive index sensing with cascaded Long-period Grating(LPG) and Fiber Bragg Grating(FBG) was presented by using insensitive to refractive index of fiber Bragg grating.The results show that the two resonance wavelength of cascaded fiber grating possesses linearity with the change of temperature, however, only one resonance wavelength shift with the change of the solution refractive index.Thus by using the cascaded fiber grating, we can simultaneously measure the refractive index and temperature, to compensate measuring error by temperature variations.

In monitoring intrusion incidents based on phase-sensitive Optical Time Domain Reflectrometer(φ-OTDR), the method compositing the past records of a single point and the data of neighboring points distinguishes intrusion from noise by the data change in a period and in neighboring area, and the system can locate the intrusion point where the optical intensity will change for the reason of interference.Based on this method, this paper is about a research on three parts, they are the threshold processing based on self-adaption mean value, analysis and simulation on frequency responses, and classifying the frequency information consists in the intrusion incidents.A group of experiments in 25 different frequencies confirm that the threshold has a good adaptability, the frequency responses agree with analysis and simulation, and the algorithm can classify the frequency information accurately.Therefore, this research will contribute to applying φ-OTDR to security system.

For the key problem of droplet analyzer optical fiber and capacitance sensor poor measurement repeatability which impact droplet analysis measurement accuracy, the sensor structure was redesigned by increasing shielding structure in the external of capacitance sensor annular plate.Digital capacitance signal measurement method was used instead of excitation type analog measurement method.The minimum and maximum standard deviations measured by capacitance sensor are 0.001 7 pF and 0.002 4 pF.The optical fiber signal measurement circuit was improved, and infinite gain low-pass filter was used which avoided self-excited oscillation caused by high magnification.The peak standard deviation measured by optical fiber sensor is 0.019 9 V, and the droplet analyzer accuracy is improved.

Due to some limitations for the applicability and location area of trilateral localization algorithm, a four-LED weighted positioning algorithm is proposed.By utilizing the characteristics of indoor visible light transmission such as the short distance and high positioning accuracy, in the mean time, considering the actual situation of deployment of LED indoor lighting, the transmission distance information as a weighted factor is introduced in the positioning algorithm to improve the positioning accuracy and expands the location area.Simulation results show that the proposed location algorithm is guaranteed to achieve average positioning error below 18 cm in 5 m×5 m×3 m space area, and effectively improve the indoor positioning precision and universality of application and system robustness.

The surface-profile precision of lens is a main factor which influences the performance of the optical system.There are three main reasons which influence the lens surface-profile most, and they are the supporting structure, gravity and thermal load.In order to achieve the goal of getting high surface-profile precision of the lens (Φ>200 mm), a new multi-points flexible supporting structure is designed.Then, the influence of gravity and thermal load with the designed structure is analyzed.The results are as follows: for the deformation caused by gravity, the surface root-mean-square (RMS) value is 6.78 nm and 3.46 nm for the upper and lower surface respectively; for the deformation caused by thermal load, the surface (RMS) value is 8.30 nm and 5.57 nm for the upper and lower surface respectively.The designed structure with multi-point flexible support can effectively reduce the influence of precision loss which is caused by gravity and thermal load, and meet the requirements of high surface-profile precision of large-aperture lens for transmission-type optical system(RMS<λ/50, λ=632.8 nm).