Proceedings of Topical Meeting on Optoinformatics (pdf-format, 1.21 ...

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22 OPTOINFORMATICS’05 A number <strong>of</strong> implemented image processing algorithms for system calibration and data analysis are discussed and several experimental results are given for automotive glass surfaces with different shapes and defects. A measurement <strong>of</strong> a spherical mirror with known radius has been used for calibration purposes and also has been included to show the precision <strong>of</strong> the developed technique. A video projector was used in the system with a resolution 1024x768 pixels. A progressive scan camera was applied for image recording. The digitisation resolution is 768x576 pixels. Figure 2 shows some key stages during the process <strong>of</strong> specular surface measurement. A piece <strong>of</strong> automotive glass (800 x 500mm) has been measured. A number <strong>of</strong> fringe patterns are grabbed shifted in both directions, see figure 2 (a) and (b) and the wrapped phase is calculated for the x and y directions, as shown in figures 2 (c) and (d). A masking algorithm separates the background area from the measurement object. The unwrapped phase is obtained by applying the unwrapping algorithm to the wrapped phase distribution. Calculated surface height map distribution and its scaled pr<strong>of</strong>ile view are shown in figure 2 (e) and (f) respectively. (a) (b) (c) (d) (e) (f) Figure 2. Measurement <strong>of</strong> the automotive side glass Finally, aspects <strong>of</strong> implementing the reflective fringe technique are discussed in terms <strong>of</strong> further development and configuration <strong>of</strong> the measurement system for the needs <strong>of</strong> the glass industry. This technique showed the ability to provide accurate non-destructive 3-D shape and defect inspection <strong>of</strong> the reflective measurement surface <strong>of</strong> curved or flat glass and can be used as a key element for glass quality control system on-line or in a laboratory environment.
SAINT-PETERSBURG, October 17 – 20, 2005 23 THE APPLICATION OF DIRECT INTEGRAL-GEOMETRIC METHODS FOR THE ANALYSIS OF SOME EXPERIMENTAL INTERFEROMETRIC IMAGES A.A. Aliverdiev Institute <strong>of</strong> Physics, Daghestan Scientific Center <strong>of</strong> Russian Academy <strong>of</strong> the Science 367003, Russia, Daghestan, Makhachkala, 94 Yaragskogo Street E-mail: aliverdi@frascati.enea.it, URL: http://aliverdi.rusf.net Here we present our approach to apply the direct integral-geometric methods in analysis <strong>of</strong> interferometric images. These approaches give the possibility to increase the precision <strong>of</strong> further physical analysis, and the automation <strong>of</strong> some steps <strong>of</strong> analysis. In our resent works we have considered the use <strong>of</strong> the back [1-4] and direct [4-10] Radon transform for the different physical applications. Here we report some new data about the application <strong>of</strong> the direct Radon transform for the interferometric image analysis, which we already tested for the experimental data diagnostic <strong>of</strong> laser plasma and for the ESPI measurements. We already reported [11] some results <strong>of</strong> an experimental investigation <strong>of</strong> the temporal evolution <strong>of</strong> plasmas produced by laser irradiation. The experimental set up includes a Nd:glass high power laser system with typical intensity <strong>of</strong> 10 14 W/cm 3 and duration 600 ps, a probe beam (Nd:YAG converted to 2ω) coupled to an interferometer and to a streak-camera with ps/µm resolution. The density <strong>of</strong> free electrons in that conditions could be considered proportional to the phase shift in the interferometric a streak-camera image. So, the precision <strong>of</strong> the determination <strong>of</strong> phase shift is the crucial point <strong>of</strong> the analysis. But unfortunately the quality <strong>of</strong> real experimental interferograms is not good. The separate time-dependence <strong>of</strong> the streak-camera image intensity for the certain x 0 doesn't contain the full information about the real phase shift cause <strong>of</strong> presence <strong>of</strong> a strong noise, which can be resulted and in the neglecting or shift <strong>of</strong> a real extremes, both in the appearance <strong>of</strong> a false extremes. But from other hand, the averaging by axis x doesn't give the good results, because <strong>of</strong> it smoothes the picture. To overcome this problem we <strong>of</strong>fer the averaging with time shifts, with a characteristic velocity more or less correspondent to real velocity. The peculiarities <strong>of</strong> this method are discussed in the present report for the first time. We also present the method <strong>of</strong> image analysis for the automatic set up <strong>of</strong> an Electronic Speckle Pattern Interferometry (ESPI). The idea <strong>of</strong> our method is to make a direct Radon-like transformation for each pixel (x 0 , y 0 ) a 2D field <strong>of</strong> an image brightness s0 B(x,y): g( x y s = ∫ B x + s ⋅ − p ⋅ y + s ⋅ + p ⋅ dp 0, 0 )( , φ ) ( 0 cos( φ) sin( φ), 0 sin( φ) cos( φ)) , where −s0 ( s , φ) are the normal co-ordinates <strong>of</strong> the Radon-like transformation, p is the variable <strong>of</strong> integration, and then we calculate the rms spatial deviation by s 2 2 σ s ( φ) = ( g( s, φ) − g( s, φ) ) , the maximum <strong>of</strong> which determines two value: (i) s s immediate max φ ( σ s ), and (ii) the corresponded angle φ (( σ s ) max ) . Similar transformation we already used in some other applications. So, from 2D function B(x,y) we have two
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