An Enhancement Framework Based on Gradient Domain Tone Mapping and Fuzzy Logical for X-ray Image of Complex Workpiece

Abstract X-ray images of complex workpiece often suffer low brightness and contrast in industrial defect inspection. In this paper, we propose an enhancement framework to improve the visual quality. In detail, a logarithm transformation is first to increase global brightness, and then, to increase local contrast, we propose a novel gradient domain tone mapping operator, in which we design a new gradient attenuation function based on fuzzy entropy and construct a new cost function constrained by a hybrid regularization. Finally a fuzzy enhancement operator is performed on the result obtained by minimizing the new cost function, to further increase contrast and prevent halo artifacts created by manipulating the gradient domain. Experiments show that the proposed method produces good visual effect for defect inspection for X-ray image of complex workpiece.