The key issue to restore the defocus blurred image is how to choose a degradation model of blurred image. Based on the fractional Fourier transform (FrFT) combining with the clarity-evaluation-function, we present an approach for the restoration of defocus blurred image. This method constructs a defocused imaging model based on FrFT and estimates the lost phase signals from the intensity signals by an iterative phase retrieval approach, in which the sharp restored image can be acquired by implementing inverse FrFT on complex image signal made from the estimated phase signals and intensity signals. Using this model combing with the clarity-evaluation-function, the FrFT order can be changed adaptively. Consequently, the sharper image can be obtained in the end. Experimental results show the effectiveness, the robustness, and the low complexity of this approach, which make it more suitable for real-time environment.
Integrating vertical-axis runners into ball valves for energy harvesting from pressurized pipes in water supply systems has become a promising scheme of self-supplying power (referred to as the “GreenValve” scheme). In addition to energy harvesting, the GreenValve configuration also has the function of fluid regulating, which makes a qualitative breakthrough in both structure and function. However, the runner specially used to match the ball valve has not been fully studied and designed. Hence, based on the traditional Savonius rotor, a modified semi-elliptical runner is proposed in this study. To better match the ball valve structurally, the roundness of the runner at blade tip position is improved and, thus, the initial runner configuration is obtained. Moreover, research on blade profile flatness and runner aspect ratio is conducted in FLUENT software to be more functionally compatible with the ball valve. Numerical results indicate that the GreenValve always performs best in terms of shaft power at 25% opening regardless of the aspect ratio and the flatness. When the flatness value is equal to 0.7, the GreenValve presents the maximum shaft power and the second highest flow coefficient which is only 1.9% lower than the maximum value. Comparison results of three models with different aspect ratios reveal that the model with the smallest aspect ratio has a slight reduction in flow capacity while a significant improvement in shaft power, reaching a maximum shaft power of 78.6W.
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