3/22/2023 0 Comments Big aperture camera mqThe 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. While we can get the maximum or minimum depth of field by working at each end of the aperture range, sometimes we want a more intermediate level of depth of field, limiting focus to a specific range of distances within the overall photograph. One way to do this is to choose a mid-range f/stop, like f/5.6, and shoot a test frame. In image playback, use the magnifying function of the LCD to zoom in and check the depth of field make adjustments if necessary and reshoot.Instrumental errors of measurement wide-aperture laser beam diameter were modeled to build measurement setup and justify its metrological characteristics. When choosing lenses for landscape photography, we usually want to see as much detail as possible from foreground to background we want to achieve the maximum depth of field by choosing a small aperture (higher f/stop, like f/8 or f/11). This helps direct the viewer's attention to the subject. Aperture for Portraitsįor classic portraiture we separate our subject from the surroundings by using "selective focus." Choosing a large aperture (lower f/stop, like f2.8) creates very shallow depth of field with only the subject, or just a portion of the subject, in focus. Now that we know how to control depth of field, what determines the choices we make in selecting the aperture? We use focus and depth of field to direct attention to what is important in the photograph, and we use lack of focus to minimize distractions that cannot be eliminated from the composition. While there are no rules, there are some guidelines for selecting Aperture priority.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |