a hypothesis independent method named HMSD is presented in this paper which is based on the matched subspace detector,and where the noise power is estimated using different methods. As the number of target pixel in the HSI is much limited,it is convenient to use the target-free data to calculate the noise variance under the null hypothesis.The noise under
the alternative hypothesisis unknown and can be estimated using the MLE method.The detailed information
about the method is discussed in the following.