Parameters Of CCD Camera Research Articles

Phase error evaluation technique based on Fourier transform for refractive index detection limit of microfluidic differential refractometer

A novel phase error evaluation technique based on Fourier Transform Method is presented to estimate the phase error resolution from the spatial interference pattern. The highest phase error resolution is 3.4 × 10−8 × 2 π rad in simulation. The simulation has shown the validity of the proposed technique compared to the result in real experiment. The influence of bit depth, size of the pixel and the spatial period of the interference fringe on the phase error resolution is also discussed in detail. The results are helpful for choosing the suitable parameters of CCD camera and controlling the whole size of the integrated microfluidic differential refractometer.

Parameters Choice of Active Infrared Night Vision System to Vehicles

Infrared Night vision system is significant for night driving, developed greatly on vehicles and becoming a trend. Study on overall design and parameters choice of active infrared night vision system has been carried out, analyzed and calculated vital parameters of CCD camera and infrared light source. Bring out technical methods and design way to provide references for related researchers.

Smear correction of frame transfer CCD camera based on the integrating sphere

We put forward a method to measure the frame transfer time of CCD camera based on the integrating sphere, and to solve the smear problem of frame transfer CCD camera by using the measured frame transfer time. The experiments of measuring and correcting frame transfer parameters of CCD camera by imaging the integrating sphere without and with a sticky stripe were carried out, and calibrated results are discussed and compared with uncalibrated results. This method can provide a practical approach to verify the design of the timing sequence for frame transfer CCD camera.

A Camera Calibration Method Based on Free Points

A new accurate calibrating technique for intrinsic parameters and extrinsic parameters of CCD camera is described. The camera model is derived by the pinhole projection theory. Then other parameters of the model are resolved under the radial alignment constraints and orthogonal constraints. In order to get a fine initial guess for the nonlinear searching solution, the least square method is introduced, and finally uses radial alignment constraint method to get the results. The experimental results show that the mean absolute differences in x direction and y direction are 0.0070 and 0.1430 separately while the standard deviation are 0.5006 and 1.2046 separately.

Noise in off-axis type holograms including reconstruction- and CCD camera parameters

Noise in off-axis type holograms including reconstruction- and CCD camera parameters

Noise in off-axis type holograms including reconstruction and CCD camera parameters

Phase and amplitude images as contained in digital holograms are commonly extracted via a process called “reconstruction”. Expressions for the expected noise in these images have been given in the past by several authors; however, the effect of the actual reconstruction process has not been fully appreciated. By starting with the Quantum Mechanical intensity distribution of the off-axis type interference pattern, then building the digital hologram on an electron-by-electron base while simultaneously reconstructing the phase/amplitude images and evaluating their noise levels, an expression is derived that consistently describes the noise in simulated and experimental phase/amplitude images and contains the reconstruction parameters. Because of the necessity to discretize the intensity distribution function, the digitization effects of an ideal CCD camera had to be included. Subsequently, this allowed a comparison between real and simulated holograms which then led to a comparison between the performance of an “ideal” CCD camera versus a real device. It was concluded that significant improvement of the phase and amplitude noise may be obtained if CCD cameras were optimized for digitizing intensity distributions at low sampling rates.

Traceable measurements for beam propagation ratio M2

This paper reports an investigation into measurement techniques and infrastructure suitable for underpinning traceable calibration of devices for beam propagation parameter measurement. The accurate knowledge of the M2 parameter is required for a diverse range of applications including semiconductor manufacture, process control, laser machining, thin-film transistors (TFT), fundamental research into frequency doubling, and the production and characterisation of optical components. Characterisation of the size and position of the beam waist is essential for the correct hazard classification of extended source laser systems using the IEC 60825 series of standards. A system for measuring beam propagation factor measurement has been developed at NPL based on the methodology outlined in the ISO 11146 series of standards. This methodology uses spatial intensity profile measurements of the beam at defined points along the direction of propagation of the beam through a beam waist produced by a convex lens. The beam widths obtained using a CCD and a converging second moment method, are fitted to a hyperbolic propagation envelope and the beam propagation coefficients are obtained from this shape. The traceability of this method has been provided by using graticules calibrated against length standards and carefully measured CCD camera parameters.

A Rapid Calibration Method for the Laser Scanning 3D Measurement System

A rapid calibration method for the parameters of a laser light plane scanning 3D measurement system is proposed. The mathematic model and the calibrated parameters of the measurement system are presented. A novel orthogonal calibration jig composed of two orthogonal planes is designed. The CCD camera parameters and the light plane parameters of the measurement system can be rapidly calibrated with the orthogonal calibration jig. The laser scanning 3D measurement system is calibrated with the calibration jig. A standard plane is measured at different positions. The accuracy is better than 0.1mm.

Machine Vision and Data Reconstruction for Measuring Free Form Surface

Reverse engineering of free-form surfaces is one of the most challenging technologies in advanced manufacturing. With the development of industry more and more sculptured surfaces, such as molds and turbine blades, are required to measure quickly and accurately. Optical non-contact probes possess many advantages, such as high speed, no measuring force, in comparison with contact ones. The ability of stereovision probe with CCD cameras in gathering a large amount of information simultaneously makes it the most popularly used one in sculptured surface measurements. So based on the laser triangular principle, a measuring and testing device with two CCD cameras was designed, and its accuracy was analyzed. With a virtual 3D target in form of a grid plate, all the intrinsic and extrinsic parameters of CCD camera including the uncertainty of image scale factor and optical center of camera can be readily calibrated. In order to obtain all the required data with high accuracy in a short time, the curvature-based adaptive sampling strategy is presented. Due to huge amount of arbitrary scattered points, the Delaunay triangular division and Bezier interpolation and NURBS interpolation are applied to get a continuous surface.