Adaptive control and signal enhancement of an ultrasound display

This invention relates to a procedure for improving displayed ultrasound images and corresponding audio output and, more particularly, to a method and apparatus for adaptively deciding whether image information is noise or signals containing information and for selectively enhancing the information signals in relation to the noise. The invention implements a method for adaptively using raw image data (before compression) to produce pixel display values in an ultrasound system in accord with variations in signal-to-noise ratio. Initially, for each subject pixel of an image, a first regional value is derived by taking into account values of a neighborhood of pixels that includes the subject pixel. The first regional value is then compared to a threshold value related to noise and each subject pixel is assigned a classification as a tentative signal pixel if the regional value equals or exceeds the threshold value. Any pixel value not so classified is considered a tentative noise pixel. A second regional value is then derived for each subject pixel by taking into account first regional classifications of a second neighborhood of pixels that includes the subject pixel. If the number of signals classified as signal in the second neighborhood is less than a second threshold, the subject pixel is classified as noise. Otherwise the subject pixel is classified as a signal pixel. The actual values of the subject pixels are then adjusted to improve a display of the ultrasound image and the corresponding audio presentation (for Doppler). The method also alters the threshold noise value in accordance with second regional pixel values classified as noise pixels.