Comments on “A New Operational Method for Estimating Noise in Hyperspectral Images”

In their paper, Gao estimate the additive noise in hyperspectral images by computing the standard deviation of regression residuals. They perform multiple linear regression within spectrally homogeneous regions, which they obtain by means of an “object-seeking” algorithm. This letter shows that the segmentation algorithm is not correct, discusses how this affects the noise estimate, and proposes a correct algorithm that, additionally, decreases the computational load of the method.