Harmonic imaging: a model for ultrasonic speckle reduction

We present a speckle reduction method called Harmonic Imaging (HI). It is derived from a multi component scattering model for biological tissues. The backscattered ultrasound quadrature signal is modeled as the sum of three components after demodulation. The first component represents nonresolvable diffuse scatterers, the second subresolvable quasiperiodic scatterers, and the third resolvable quasiperiodic scatterers and mirroring surfaces. The HI images produced using radio frequency data from a phantom and from tissues in vivo are more blurred than ordinary envelope images, but the signal to noise ratio and tissue contrast were higher for the HI images