MULTIDIRECTIONAL MOTION DETECTION ADN DISPLAY IN REAL-TIME ULTRASONICSCANNERS

A new method for multidirectional motion detection and display in a re al-time ultrasonic scanner is presented. The image is generated by a s uperposition of a grey scale image representing static structures and a colour-coded pattern representing the displacement amplitude of the moving interfaces. This is a truly duplex system where the image is ev aluated for both interface motion and static structures. The displacem ent detection, based on image subtraction. features high accuracy and high signal to noise ratio, since the technique displays in colour onl y the regions where the changes occur, and all other echoes representi ng static structures are cancelled. The technique is able to detect an y slow interface motion within the image area with a resolution of 0.0 1 mm. The flexibility of the design allows the module to be used as a stand alone unit or to be incorporated in existing ultrasonic equipmen t.