Multi-image iterative parallel phase retrieval methods are widely used in measurement and imaging, due to their simplicity and effectiveness. However, the retrieved image will have foggy diffuse noise, since some unknown cross-talk factors exist in iterative calculation. In this paper, a new updated method is embedded into the calculation process of phase retrieval. The iterative strategy of phase retrieval is updated to enhance robustness for noisy images. Experimental and simulated results have demonstrated that the improved algorithm has faster convergence speed and higher anti-noise performance.

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Oxygen detection techniques are essential for marine environment and ecology researches. In this paper, the development of luminescence intensity-based sensor system for dissolved oxygen (DO) measurement is presented. The sensor film consists of tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy) 3 Cl 2 ) as photosensitive indicator which is immobilized within the mixture of tetraethoxylsiane (TEOS) and methyl triethoxysilane (MTEOS) membrane. The laboratory experimental results show that the ratio of the fluorescence intensity of the sensor correlates well with DO concentration from 0 to 32.96 mg/l. Depending on the charge-coupled device (CCD) camera used, the proposed system can monitor the 0.9×0.9 cm areas with 9×9 µm resolutions and it can be used for oxygen distribution measurement in spatial and temporal scale for undersea monitoring applications.