Image restoration is a critical procedure for underwater images, which suffer from serious color deviation and edge blurring. Restoration can be divided into two stages: de-scattering and edge enhancement. First, we i...Image restoration is a critical procedure for underwater images, which suffer from serious color deviation and edge blurring. Restoration can be divided into two stages: de-scattering and edge enhancement. First, we introduce a multi-scale iterative framework for underwater image de-scattering, where a convolutional neural network is used to estimate the transmission map and is followed by an adaptive bilateral filter to refine the estimated results. Since there is no available dataset to train the network, a dataset which includes 2000 underwater images is collected to obtain the synthetic data. Second, a strategy based on white balance is proposed to remove color casts of underwater images. Finally, images are converted to a special transform domain for denoising and enhancing the edge using the non-subsampled contourlet transform. Experimental results show that the proposed method significantly outperforms state-of-the-art methods both qualitatively and quantitatively.展开更多
The misalignment of optical vortex(OV) beams, including transversal displacement and tilt, occurs in many situations, including on reflection or refraction at an interface between two different media and in propagatio...The misalignment of optical vortex(OV) beams, including transversal displacement and tilt, occurs in many situations, including on reflection or refraction at an interface between two different media and in propagation and tracking systems for optical communications. We propose a reliable method to determine and subsequently eliminate tilt and transversal displacement in an OV beam. An experimental setup was established to verify the proposed method, and the experimental results showed good agreement with those of the numerical simulations.Using the measured misalignments, the initial orbital angular momentum spectrum can be recovered in free space.展开更多
Underwater hostile channel conditions challenge video transmission designs. The current designs often treat video coding and transmission schemes as individual modules. In this study, we develop an adaptive transceive...Underwater hostile channel conditions challenge video transmission designs. The current designs often treat video coding and transmission schemes as individual modules. In this study, we develop an adaptive transceiver with channel state information(CSI) by taking into account the importance of video components and channel conditions. The design is more effective than the traditional ones. However, in practical systems, perfect CSI may not be available. Therefore, we compare the imperfect CSI case with existing schemes, and validate the effectiveness of our design through simulations and measured channels in terms of a better peak signal-to-noise ratio and a higher video structural similarity index.展开更多
Strawberries are a kind of nutritious fruit but they are easily spoilt by mold.Therefore,it is significant to prolong the shelf life of strawberries for the avoidance of their numerous wastes.To achieve the aforementi...Strawberries are a kind of nutritious fruit but they are easily spoilt by mold.Therefore,it is significant to prolong the shelf life of strawberries for the avoidance of their numerous wastes.To achieve the aforementioned objective,in this paper,the edible and biodegradable natural polymers of gelatin/zein were used to prepare the antibacterial fiber films loaded with cinnamaldehyde by electrospinning method.The fibers prepared in this study were smooth and bead-free,with the average diameters ranging from 1.46 to 2.02μm.The successful encapsulation of cinnamaldehyde in obtained fiber films was confirmed by Fourier transform infrared spectra.The prepared fiber films decomposing at about 230℃ were shown by thermogravimetric analysis curves,indicating their high thermal stability.The amorphous structure of the polymers in the produced fiber films was displayed by X-ray diffraction curves.Compared with the untreated strawberries,strawberries treated with fiber films encapsulated with 15 wt%and 20 wt%cinnamaldehyde showed the smallest changes in appearance,weight loss rate,hardness,pH,and total soluble solids at 6 d.The shelf life of strawberries was increased to 6 days by the fiber films containing 15 wt%and 20 wt%cinnamaldehyde.The fiber films prepared in this study were potentially expected to be used as edible antibacterial packaging films,nutrient and drug carriers.展开更多
基金the National Natural Science Foundation of China (Nos. 61571377, 61471308, and 61771412)the Fundamental Research Funds for the Central Universities, China (No. 20720180068).
文摘Image restoration is a critical procedure for underwater images, which suffer from serious color deviation and edge blurring. Restoration can be divided into two stages: de-scattering and edge enhancement. First, we introduce a multi-scale iterative framework for underwater image de-scattering, where a convolutional neural network is used to estimate the transmission map and is followed by an adaptive bilateral filter to refine the estimated results. Since there is no available dataset to train the network, a dataset which includes 2000 underwater images is collected to obtain the synthetic data. Second, a strategy based on white balance is proposed to remove color casts of underwater images. Finally, images are converted to a special transform domain for denoising and enhancing the edge using the non-subsampled contourlet transform. Experimental results show that the proposed method significantly outperforms state-of-the-art methods both qualitatively and quantitatively.
基金supported by the National Natural Science Foundation of China (Nos. 61571377, 61771412, and 61871336)the Fundamental Research Funds for the Central Universities (No. 20720180068)
文摘The misalignment of optical vortex(OV) beams, including transversal displacement and tilt, occurs in many situations, including on reflection or refraction at an interface between two different media and in propagation and tracking systems for optical communications. We propose a reliable method to determine and subsequently eliminate tilt and transversal displacement in an OV beam. An experimental setup was established to verify the proposed method, and the experimental results showed good agreement with those of the numerical simulations.Using the measured misalignments, the initial orbital angular momentum spectrum can be recovered in free space.
基金Project supported by the National Natural Science Foundation of China(Nos.61571377,61471308,and 61771412)the Fundamental Research Funds for the Central Universities,China(No.20720180068)the Research Fund for the Visiting Scholar Program by the Scholarship Council of China(Nos.201506310080 and 201506315026)
文摘Underwater hostile channel conditions challenge video transmission designs. The current designs often treat video coding and transmission schemes as individual modules. In this study, we develop an adaptive transceiver with channel state information(CSI) by taking into account the importance of video components and channel conditions. The design is more effective than the traditional ones. However, in practical systems, perfect CSI may not be available. Therefore, we compare the imperfect CSI case with existing schemes, and validate the effectiveness of our design through simulations and measured channels in terms of a better peak signal-to-noise ratio and a higher video structural similarity index.
文摘Strawberries are a kind of nutritious fruit but they are easily spoilt by mold.Therefore,it is significant to prolong the shelf life of strawberries for the avoidance of their numerous wastes.To achieve the aforementioned objective,in this paper,the edible and biodegradable natural polymers of gelatin/zein were used to prepare the antibacterial fiber films loaded with cinnamaldehyde by electrospinning method.The fibers prepared in this study were smooth and bead-free,with the average diameters ranging from 1.46 to 2.02μm.The successful encapsulation of cinnamaldehyde in obtained fiber films was confirmed by Fourier transform infrared spectra.The prepared fiber films decomposing at about 230℃ were shown by thermogravimetric analysis curves,indicating their high thermal stability.The amorphous structure of the polymers in the produced fiber films was displayed by X-ray diffraction curves.Compared with the untreated strawberries,strawberries treated with fiber films encapsulated with 15 wt%and 20 wt%cinnamaldehyde showed the smallest changes in appearance,weight loss rate,hardness,pH,and total soluble solids at 6 d.The shelf life of strawberries was increased to 6 days by the fiber films containing 15 wt%and 20 wt%cinnamaldehyde.The fiber films prepared in this study were potentially expected to be used as edible antibacterial packaging films,nutrient and drug carriers.
