1. A method for enhancing an ultrasound image for use in an ultrasound imaging system, comprising: using the processor to perform the steps of: reading the ultrasound image; segmenting the ultrasound image into a feature region and a non-feature region based on gradient information and gray-scale information in the image, and then performing different data processing on the image classified as the feature region and the non-feature region respectively; merging the processed feature region and non-feature region to produce an enhanced Image; wherein the step of segmenting the image comprises a step of extracting distinct boundaries in the ultrasound image by means of the gradient information and a step of extracting brighter regions in the ultrasound image by means of the gray-scale information to generate a gray image template; shrinking the read ultrasound image, wherein the step of extracting the distinct boundaries comprises sub-steps of: setting a gradient threshold such that the number of pixels in the shrunk image each having a gradient value greater than the gradient threshold accounts for a predetermined percentage of total pixels; and generating a gradient image template so that the gradient image template includes the pixels each having a gradient value greater than the gradient threshold; and wherein the step of extracting the brighter regions comprises sub-steps of: setting a gray threshold; and generating an initial gray image template so that the initial gray image template includes the pixels in the gradient image template and pixels in the shrunk image each having a gray scale intensity greater than the gray threshold.