Image adaptive sampling using reinforcement learning

Adaptive sampling and mesh representation of images play an important role in image compression and vectorization. In this paper, a multi-points stochastic gradient multi-armed bandits algorithm, a generalization of the gradient bandit algorithm, is presented to adaptively sample points in images. By modeling the adaptive image sampling as a multi-arm selection decision-making problem, we first propose an efficient action selection strategy based on a parameterized probability distribution, and then define an adaptive reward function according to the restored image of Delaunay triangulation and a feature map function, and the reward function can overcome the sparse reward issue effectively. As a result, the proposed multi-points stochastic gradient multi-armed bandits algorithm is used to evaluate the reward of each action. At last, a prescribed number of sampling points are selected using a simple and effective strategy according to the average reward of each pixel. The quality of reconstructed images based on sampled points is estimated, and experimental results demonstrate the proposed algorithm achieves a better reconstruction accuracy than that of existing methods.