Objective to investigate whether laser speckle imaging technique can be used to monitor the changes of spinal cord hemodynamics.

Laser speckle imaging technology provides a new measure for studying CBF monitoring under the effect of the ultraprofound hypothermia.

So far people have put forward some basic methods for evaluate the MTF values of the lens, such as knife-edge method, laser speckle method and extended frequency aperture (EFA) method.