Ultrasound image coding based on subband decomposition and speckle synthesis
We present a study of ultrasound image compression based on subband decomposition and speckle synthesis. It is well-known that one signature characteristic of ultrasound images is the presence of speckle noise. The high frequency nature of speckle noise poses great challenges to standard coding techniques. In this study, ultrasound images are first decomposed into subbands with good spatial-frequency separation. To better separate the noise spectrum from high frequency signal content, selected high frequency subbands are further decomposed. The separation results in a structure image and a speckle image. Ultrasound images are coded such that the structure image is coded using a wavelet-based method and the speckle noise is reproduced using synthesized high frequency subbands at the decoder end. While the impact on diagnostics is yet to be investigated, this coding scheme enables efficient compression while maintaining the signature appearance of ultrasound images.