The traditional image Compressive Sensing (CS) conducts block-wise sampling with the same sampling rate. However, some blocking artifacts often occur due to the varying block sparsity, leading to a low rate-distortion performance. To suppress these blocking artifacts, we propose to adaptively sample each block according to texture features in this paper. With the maximum gradient in 8-connected region of each pixel, we measure the texture variation of each pixel and then compute the texture contrast of each block. According to the distribution of texture contrast, we adaptively set the sampling rate of each block and finally build an image reconstruction model using these block texture contrasts. Experimental results show that our adaptive sampling scheme improves the rate-distortion performance of image CS compared with the existing adaptive schemes and the reconstructed images by our method achieve better visual quality.

Aiming at the problem that the filtering effect of inductor capacitance inductor (LCL) filter becomes worse when the Photovoltaic (PV) system works at low power, this paper presents a control strategy to change the switching frequency according to the instantaneous output power of the inverter. By analyzing the design method of each parameter of LCL filter, a single-stage PV grid-connected inverter structure is used to establish the frequency loop based on grid voltage-oriented vector control to determine the optimal switching frequency under the current power state. The design methods of power detector, frequency calculation and frequency hysteresis comparator are analyzed in detail. Finally, the waveforms of grid-connected current before and after frequency conversion are contrasted by MATLAB simulation to verify the feasibility and effectiveness of the inverter control strategy.

Photovoltaic (PV) modules convert solar energy into electricity; however, in actual applications, the conversion efficiency of PV modules is low. This is because the temperature of PV modules increases, most of the incoming solar radiation absorbed is discarded to the PV modules as wasted heat; this wasted heat generated can be utilized and transferred to a heat exchanger in contact to the rear PV modules. A proposed model is considered with a variation of solar cell temperature due to solar radiation and its effects on output power are modeled and evaluated, seeing PV modules as a thermal absorber, a part of the heat dissipated in the PV modules can be recovered by means of a heat transfer fluid running behind the PV modules, this method improves the PV efficiency, as well as produces thermal and electrical energy simultaneously, thus, the PV modules provide a multifunctional performance cited above, this plays the role of a hybrid solar collector system. The aim of this study is to improve the efficiency of the PV module, through the analysis of a detailed Photovoltaic-Thermal (PVT) collector model performance. The study also estimates the electrical power and thermal energy produced; using MATLAB as an application-oriented design method, the method proposed in this paper can better improve the efficiency of PV power generation and has a wide range of application prospects.

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