How the Saturated Pixels violate the assumption that the image formation process in linear?
Blind deconvolution assumes that the blurred image is the result of distorting the original image by convolution. Convolution is a linear process, i.e. the image is just a sum of shifted and scaled versions of the original image. Pixel saturation, on the other hand, is a non-linear process, which cannot be modeled by convolution. Consequently, it cannot be handled by conventional blind deconvolution techniques. Also note that saturation is irreversible, i.e. once a quantity is saturated its original value cannot be recovered.