<FONT face=Verdana>Traditional image enhancement algorithms are sensitive to the noise and can easily fall into a sub or over enhancement for medical images. In this paper

two different mathematics expressions of pixel quantum bit are given first according to the basic principle of quantum signal processing. Then

aiming at the characteristics of medical images and combining with gray correlative characteristics of pixels in 3×3 neighborhoods

a medical image enhancement operator is proposed based on quantum probability statistics. In order to optimize the effect of image enhancement

the gray threshold parameter of the operator is adaptively chosen based on the sub-sampling image entropy. Using subjective and objective evaluation

experimental results demonstrated that our method considered both global and local image information and can improve medical images quality effectively.