A Comprehensive Synthetic Underwater Image Dataset

The dataset contains 100 photographic images that are treated as ground-truth images. On each ground truth image, the effects of underwater environment are applied and 150 synthetic underwater images are generated. Hence, the data set contains 100 ground-truth photographic images and 100*150=15000 synthetic underwater images. Four effects of the underwater environment, i.e., color cast, blurring, contrast reduction, and low light, are considered. These effects are applied individually and in combinations. Four effects result in a total of 15 combinations, and the effect of each combination is varied by considering 10 levels. This results in a total of 150 images for a single ground-truth image. In addition to this, 21 focus metrics are evaluated on all these 1,50,100 images. The metrics calculated are Absolute central moment (ACMO), Brenner's focus measure (BREN), Image curvature (CURV), Gray-level variance (GLVA), Gray-level local variance (GLLV), Gray-level variance normalized (GLVN), Squared gradient (GRAS), Helmli's measure (HELM), Histogram entropy (HISE), Histogram range (HISR), Energy of Laplacian (LAPE), Diagonal Laplacian (LAPD), Modified Laplacian (LAPM), Variance of Laplacian (LAPV), Tenengrad variance (TENV), Vollat's correlation (VOLA), Wavelet ratio (WAVR), Wavelet sum (WAVS), and Wavelet variance (WAVV). The literature categorizes these metrics as gradient-based and non-gradient-based.