![]() ![]() On the basis of structure design of optical system and parameter option of optical components, the visibility of interference fringe with zero background intensity is optimized. interference system itself, the influence of multiple-beam interference is studied and found the error reaches to 8%. Aiming at that ignoring interference signal error by multiple-beam interference in other measuring systems and low visibility of interference fringe due to the problem of. Instrument after being calibrated when manufactured.īased on the basic principle of multiple-beam interference, an intensity distribution formula of the multiple-beam interference is derived for measuring the diameter of single crystal silicon sphere by Fizeau interferometer. The measurement system can be used as a standard measurement Method can measure the profile with a non-uniformity of less than 1%,Īnd laser power within 2% error compared with the calibration power In the measurement field of large laser beams, the Intensity profile as well as the laser power. The method to calibrate the power coefficient is also given.Īfter the laser spot correction, we can obtain the precise laser beam ![]() The methods ofĬorrecting geometric and intensity distortion of the spot are described The layout of the system and the design of aĭiffuse transmission sampling target are emphasized. Measurement method for obtaining a large laser beam intensityĭistribution based on CCD diffuse transmission imaging is proposed. The non-uniformity, centroid, centroid jitter and beam quality. Of its most important characteristics because it yields information on The intensity distribution of a laser beam (laser beam profile) is one This chapter builds on this theoretical knowledge to apply SVMs for classification of multi and hyperspectral remote sensing data. The theoretical background on SVMs has been presented in Chap. Other advantages of SVMs are their ability to adapt their learning characteristic via a kernel function and to adequately classify data on a high-dimensional feature space with a limited number of training data sets thereby overcoming the Hughes Phenomenon. Thus, SVM based classifiers are expected to have more generalization capability than neural networks. While doing so, the upper bound on the generalization error is minimized. Instead, they aim to maximize the margin between two classes of interest by placing a linear separating hyperplane between them. Unlike the popular neural network classifiers, SVMs do not minimize the empirical training error (Byun and Lee 2003). 5, support vector machines (SVMs) have originated from statistical learning theory for classification and regression problems. The method can provide up to 0.1% error in case of using calibration procedures and multiple measurements.Īs discussed in Chap. The choice was based on parameters of commercially available components of the setup. Attainability of <1% error based on choice of parameters of expression was shown. The analytic expressions were obtained analyzing the modelling results for each influencing data. 12-order Super-Lorentz distribution was primary model, because it precisely meets experimental distribution at the output of test beam forming system, although other orders were also used. Errors were modeled for 90% of power beam diameter criteria. Using theoretical evaluations there was found that the key parameters influencing on error are: relative beam size, spatial non-uniformity of the diffuser, lens distortion, physical vignetting, CCD spatial resolution and, effective camera ADC resolution. Super-Lorentz distribution with shape parameter 6-12 was used as a model of the beam. Considering the fact of non-availability of a standard of wide-aperture flat top beam modelling is preferred way to provide basic reference points for development measurement system. However, transmission diffuser method has poor metrological justification required in field of wide aperture beam forming system verification. The method is suitable for continuous and pulsed laser irradiation. ![]() It is impossible to measure such beams with other methods based on slit, pinhole, knife edge or direct CCD camera measurement. ![]() This method is appropriate for precision measurement of large laser beam width from 10 mm up to 1000 mm. Modeled setup is based on CCD camera and transmission diffuser. Instrumental errors of measurement wide-aperture laser beam diameter were modeled to build measurement setup and justify its metrological characteristics. ![]()
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