Optical reconstruction of three-dimensional object from digital holograms using phase information calculated by continuous wavelet transform

Saraç Z. | Tayyar D.Ö. | Ecevit F.N.

Article | 2011 | Proceedings of SPIE - The International Society for Optical Engineering8074

We propose to record digital Fourier hologram of a 3D diffused object and to reconstruct numerically and optically by using phase-only information. This phase-only information is obtained by using 1D-Continuous Wavelet Transform (1DCWT) from the intensity of digital Fourier Hologram. 3D object image is obtained by numerical reconstruction on computer and optical reconstruction by using a phase-modulated liquid crystal spatial light modulator (SLM). Numerical and experimental results are presented. © 2011 SPIE.

Monitoring of mining induced land subsidence by PALSAR and TerraSAR-X

Deguchi T. | Kutoglu H.

Conference Object | 2012 | Proceedings of SPIE - The International Society for Optical Engineering8536

In this study, we applied InSAR time series analysis using PALSAR and TerraSAR-X data to Zonguldak Hardcoal Basin in Republic of Turkey in order to monitor mining induced surface displacement. Zonguldak coal area is located along the Black Sea 240 km eastward from Istanbul. Recently, ground deformation caused by underground exploration has come to the surface, and it has been destroying roads and buildings. We utilized PALSAR and TerraSAR-X data for the detail analysis on the recent land subsidence induced by mining activities. PALSAR data in the fine beam mode were obtained from an ascending orbit, TerraSAR-X data in the StripMap m . . .ode were from a descending orbit. The vertical and the east-west displacement were calculated by the composition of the deformation vectors of PALSAR and TerraSAR-X. Additionally, the source depth of the main anomaly detected near the campus of Zonguldak Karaelmas University (ZKU) was estimated by vector analysis using the vertical and east-west displacement. As a result, it was approximately 80 to 100 meters under the sea level. On the other hand, the depth of coal production zones is recorded 300 to 560 meters under the sea level. Thus, it was supposed that the anomaly near the university had been caused by not only mining activities but also the other factor in the shallower geological formation. Because some historical documents said that some caves existed in the limestone formation bedded over coal formations and domestic wastewater is injected into these caves, perhaps the cause of land subsidence is considered the expansion of caves' space resulted from the solution of limestone rocks by the wastewater injection. © 2012 SPIE Daha fazlası Daha az

Phase recovery from interference fringes by Hilbert transform

Saraç Z. | Birkök H.G. | Emir A. | Dursun A.

Conference Object | 2009 | Proceedings of SPIE - The International Society for Optical Engineering7443

This paper proposes the use of the Hilbert transform for analysis of fringe patterns, which are obtained in Michelson Interferometer. The fringe patterns are evaluated by Continuous wavelet transform and Hilbert transform algorithms to obtain phase map and refractive index. Continuous wavelet transform algorithm shows a better filtering effect. However Hilbert transform algorithm gives a noisy result, since its frequency spectrum has harmonic noise. Results show that the phase map is affected by Hilbert Filter. © 2009 SPIE.

Optical signal processing of interference fringes by Hartley transform method

Kaya, Hakan | Saraç, Zehra | Özer, Mahmut | Taşkın, Halit

Proceedings | 2010 | Proceedings of SPIE - The International Society for Optical Engineering7746

In this paper, the processing of interference fringes is achieved by Hartley transform method. The experimental and simulated interference fringe patterns are used for the signal analysis. Phase results are presented. These are compared with phase obtained by Fourier transform method. Disadvantages and advantages of Hartley transform method used for the evaluation of interference fringe patterns are given. © 2010 SPIE.

Automatic Processing of Interferometric SAR and accuracy of surface deformation measurement

Deguchi T. | Kato M. | Akcin H. | Kutoglu H.S.

Conference Object | 2006 | Proceedings of SPIE - The International Society for Optical Engineering6363

Interferometric Synthetic Aperture Radar (InSAR), one of typical application techniques of SAR data, is used to generate Digital Elevation Model (DEM) while it is also used to measure spatial surface deformation. The former and the later techniques are usually differentiated as InSAR and Differential InSAR respectively. In this paper, we focus the later technique as InSAR. We measured ground deformation using automatic InSAR processing and verified accuracy of obtained results. The study area is Zonguldak coalfield, located along the Black Sea coast approximately 240 kilometer away from Istanbul to the east, Republic of Turkey. In t . . .his region, underground coal mining has been undergoing since 1848 and 3 million ton per year of hard coal has been produced. Recently, this coal mining is found to be causing subsidence around this area. Since the whole damage has not been grasped, we tried to measure the amount of surface deformation using InSAR. As a result, some phase anomalies were detected just above mining drifts, and the largest deformation amounts among those was 204 millimeter per 4.5 months in slant range direction. In addition, InSAR results are corresponded with GPS measurement results within 9 millimeter variations Daha fazlası Daha az

Determination of Thermal Lens effect by white light interferometry

Tayyara D.O. | Emir A. | Saraç Z.

Conference Object | 2009 | Proceedings of SPIE - The International Society for Optical Engineering7389

This paper proposes the characterization of thermal lens by white light interferometry on the Methylene -blue/water solution. Thermal lens effect is determined by local phase, which is obtained by analyzing the thermal lens fringes with single sideband modulation method. © 2009 SPIE.

A reconfigurable microwave photonic filter based on four wave mixing in a silicon nanophotonic waveguide

Li J. | Adams R. | Sarac Z. | Berardo D. | Chen L.R.

Conference Object | 2013 | Proceedings of SPIE - The International Society for Optical Engineering8915

We describe the design and characterization of a silicon nanophotonic waveguide (SNW) and its use in a reconfigurable microwave photonic filter (MPF). The SNW is dispersion tailored for efficient on-chip four-wave-mixing. We use the onchip four-wave-mixing to increase the number of taps in our multiple tap delay line MPF. The tap levels are controlled by a programmable filter. Using a 12 mm long SNW reduces the footprint by five orders of magnitude compared to silica highly nonlinear fiber while only requiring approximately two times more input power. © 2013 SPIE.

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