Automatic and robust method for relative radiometric calibration

摘要

The process of relative radiometric calibration (RRC) is an important step for detecting change and monitoring environment through analyzing multi-temporal satellite images. Two key issues that focus on the RRC are how to extract invariant targets that have little or no variation in their reflectance between two images and how to acquire a linear function that expresses the relationship between the digital counts (DNs) of the two images. In this paper, an automatic method for selecting invariant targets which cover the range of bright, midrange, and dark data values is developed, and a robust estimator, which can be effective in tolerating with up to 50 percent outlier contamination, for calculating the gain and the offset of the linear function is described. The proposed methods are automatic and robust. We have applied the proposed method experimentally to synthesized images and real SPOT images, and experiment results have shown the feasibility of our algorithms.