Algorithm 2 Implementation using High-Pass Filtering

Require: Gaussian filter $G_{\sigma }$     procedure TranslateIntensity(${\mathbf{y}}_{t-1}^I,{\tilde{\mathbf{x}}}_{t-1}^I$)         ${\tilde{\mathbf{x}}}_{t-1}^{I_L}={\tilde{\mathbf{x}}}_{t-1}^I\ast G_{\sigma }$         ${\tilde{\mathbf{x}}}_{t-1}^{I_H}={\tilde{\mathbf{x}}}_{t-1}^I-{\tilde{\mathbf{x}}}_{t-1}^{I_L}$         ${\mathbf{y}}_{t-1}^{I_L}={\mathbf{y}}_{t-1}^I\ast G_{\sigma }$         ${\mathbf{y}}_{t-1}^{I_H}={\mathbf{y}}_{t-1}^I-{\mathbf{y}}_{t-1}^{I_L}$         ${\mathbf{x}}_{t-1}^I={\tilde{\mathbf{x}}}_{t-1}^{I_L}+{\mathbf{y}}_{t-1}^{I_H}$         return ${\mathbf{x}}_{t-1}^I$