Conditional Expressions for Blind Deconvolution: Multi-point form
  We present conditional expression (CE) for finding blurs convolved in given images. The CE is given in terms of the zero-values of the blurs evaluated at multi-point. The CE can detect multiple blur all at once. We illustrate the multiple blur-detection by using a test image. 
S. Aogaki, I. Moritani, T. Sugai, F. Takeutchi, and F.M. Toyama