Abstract. Deblurring is a vital image pre-processing procedure to improve the quality of images. It is a classical ill-posed problem. A new blind deblurring method based on image sparsity prior is proposed here. The proposed image sparsity prior combines patch-wise minimal and maximal pixels of latent image, and improves gradually the image sparsity during deblurring. An algorithm that is different with half quadratics splitting algorithm is applied under the maximum a posterior (MAP) framework. Experiment results demonstrate that the proposed method can keep more subtle texture and sharpened edges, reduce the artefacts in visual, and the corresponding evaluated indexes perform favourably against it of the state-of-the-art methods on synthesized, natural and remote sensing images (RSI) quantitatively.

Bond strength of glass fibre-reinforced polymer (GFRP) bars with helically wound ribs was experimentally investigated in this study and compared to that of smooth glass fibre-reinforced polymer bars and steel bars. A total of 63 pullout specimens are tested. Variables of the tests involved four types of bars, namely, glass fibre-reinforced polymer bar with helically wound ribs, smooth glass fibre-reinforced polymer bar, ribbed steel bar and smooth steel bar, as well as different bonding agents, including normal concrete, high-performance concrete, grout and epoxy resin. Test results showed that bond failure of glass fibre-reinforced polymer bars with helically wound ribs is because of the shearing off of the ribs with small slips, and the ribs helically wound can improve the bond strength of glass fibre-reinforced polymer bars by 3∼14 times, which is around 13, 9·31 and 15·7 MPa in concrete, grout and epoxy resin, respectively. In addition, polypropylene fibres in high-performance concrete can improve the bond behaviour of anchors.