Fig. 7.

Error of regression weights on real MRI images. Weights are estimated within each pair of regions at multi-contrast images. The vertical axis represents the percentage that estimation values lies in the range of the horizontal axis. a-c list the frequency that ${‖{\tilde{\mathbf{X}}}^{+}\left(\mathbf{y}-\mathbf{X}\mathbf{b}\right)‖}_2$, ${‖{\tilde{\mathbf{X}}}^{+}\left(\mathbf{d}-\mathbf{C}\mathbf{b}\right)‖}_2$ and ${‖\tilde{\mathbf{b}}-\mathbf{b}‖}_2$ occurs in the range of the horizontal axis in (a-c), respectively