ULTRASONIC IMAGE STORAGE DEVICE AND METHOD

IMPROVED ULTRASONIC IMAGE STORAGE DEVICE AND METHOD An improved ultrasonic imaging system and method are provided for medical diagnostic purposes. In order to store additional digital ultrasonic imaging information in a limited memory, a first digital signal representative of a video input signal is provided. The first digital signal comprises a series of digital amplitude samples of the transverse component of the input signal. A second series of samples is provided from the first series. Each element of the second series is the arithmetic average of a group of elements of the first series. Since the number of elements of the second series is less than the number of elements of the first series, memory density of the transverse component of the input signal is decreased. The second digital signal series is companded to form a third digital signal series, the third digital signal series being stored. The companding provides a third digital signal which is a non-linear function of the second digital signal such that the granularity of the stored signal is increased in regions of high diagnostic interest at the expense of decreased resolution in areas of low diagnostic interest. When it is desired to display the stored digital image, the third digital signal is retrieved from the storage means and decompanded to provide the reconstituted second digital signal which is thereafter directed to a video display.