Mesh saliency, the process of detecting visually important regions in 3D meshes, is a significant component in computer graphics, that can be used in various applications such as denoising and simplification. In this paper, we propose a new 3D mesh saliency measure that can identify sharp geometric features in meshes. A local normal-based descriptor is built for each vertex thanks to a spiral path within a 2-hop neighborhood. First, a geometric-based saliency is computed as the mean local alignment between the spiral descriptors within a 1-hop, and weighted by a vertex roughness measure. Second, a spectral-based saliency is computed from the spectral energy of each vertex structure tensor with the gradient defined from the spiral descriptor alignments. The final saliency is then defined as a weighted sum of both. This single-scale saliency can be extended to a multi-scale saliency by decimating the mesh at several scales and averaging back the obtained saliencies after mapping them between decimated meshes. The approach presents competitive results with state-of-the-art.
Images acquired in underwater scenarios may contain severe distortions due to light absorption and scattering, color distortion, poor visibility, and contrast reduction. Because of these degradations, researchers have proposed several algorithms to restore or enhance underwater images. One way to assess these algorithms’ performance is to measure the quality of the restored/enhanced underwater images. Unfortunately, since reference (pristine) images are often not available, designing no-reference (blind) image quality metrics for this type of scenario is still a challenge. In fact, although the area of image quality has evolved a lot in the last decades, estimating the quality of enhanced and restored images is still an open problem. In this work, we present a no-reference image quality evaluation metric for enhanced underwater images (NR-UWIQA) that uses an adapted version of the multi-scale salient local binary pattern operator to extract image features and a machine learning approach to predict quality. The proposed metric was tested on the UID-LEIA database and presented good accuracy performance when compared to other state-of-the-art methods. In summary, the proposed NR-UWQIA method can be used to evaluate the results of restoration techniques quickly and efficiently, opening a new perspective in the area of underwater image restoration and quality assessment.