Fig. 9.

To compare the intrinsic information content of ultrasound images, the embedding should be held constant. (top left) A DAS image ϕ_DAS is displayed using a log-scale DAS embedding ${\rho }_{\text{log}}^{\text{DAS}}$. (top middle) An SLSC image ${\varphi }_{\text{lin}}^{\text{SLSC}}$ is displayed using a linear-scale SLSC embedding ${\rho }_{\text{lin}}^{\text{SLSC}}$ and has a sharply different appearance. (top right) The SLSC image is placed on the same embedding as the log-scale DAS image via histogram matching, resulting in a fairer visual comparison of the underlying information content. (bottom left) The gCNR, CR, CNR, and SNR are computed on ϕ_DAS using a linear scale DAS embedding ${\rho }_{\text{lin }}^{\text{DAS}}$. (bottom middle) The same are computed for ϕ_SLSC using the SLSC embedding, yielding very different CR and SNR values. (bottom right) The same values are computed for ϕ_SLSC using ${\rho }_{\text{lin }}^{\text{DAS}}$, allowing quantitative analysis of the underlying image that is not confounded by ${\rho }_{\text{lin}}^{\text{SLSC}}$. Note that gCNR (i.e. d_TV) does not depend on the embedding and is thus invariant under histogram matching.