Table 1 Features considered by the covariance descriptor depending on the application

$\begin{array}{l}\left[\begin{array}{llllll}x& y& \left|I_x\right|& \left|I_y\right|& \left|I_{\mathit{\text{xx}}}\right|& \left|I_{\mathit{\text{yy}}}\right|\end{array}\right]\\ \left[\begin{array}{llllllll}x& y& I& \left|I_x\right|& \left|I_y\right|& \left|I_{\mathit{\text{xx}}}\right|& \left|I_{\mathit{\text{yy}}}\right|& \theta (x,y)\end{array}\right]\\ \left[\begin{array}{lllllll}x& y& I& g_{00}(x,y)& g_{01}(x,y)& \cdots & g_{74}(x,y)\end{array}\right]\end{array}$

$\begin{array}{l}\left[\begin{array}{llllllll}x& y& \left|I_x\right|& \left|I_y\right|& \sqrt{I_x^2+I_y^2}& \left|I_{\mathit{\text{xx}}}\right|& \left|I_{\mathit{\text{yy}}}\right|& \mathit{\text{arctan}}\frac{\left|I_x\right|}{\left|I_y\right|}\end{array}\right]\\ \left[\begin{array}{llllllll}x& y& \left|I_x\right|& \left|I_y\right|& \sqrt{I_x^2+I_y^2}& \mathit{\text{arctan}}\frac{\left|I_x\right|}{\left|I_y\right|}& \mathbf{\text{G}}& \sqrt{{\mathbf{\text{G}}}_x^2+{\mathbf{\text{G}}}_y^2}\end{array}\right]\end{array}$

$\begin{array}{l}\left[\begin{array}{lllllll}x& y& R& G& B& \left|I_x\right|& \left|I_y\right|\end{array}\right]\\ \left[\begin{array}{lllllllll}x& y& R& G& B& \left|I_x\right|& \left|I_y\right|& \left|I_{\mathit{\text{xx}}}\right|& \left|I_{\mathit{\text{yy}}}\right|\end{array}\right]\\ \left[\begin{array}{lllllll}x& y& H& S& V& \left|I_x\right|& \left|I_y\right|\end{array}\right]\\ \left[\begin{array}{llllll}x& y& R& G& B& {\text{Var}}_{\text{LBP}}\end{array}\right]\\ \left[\begin{array}{lllllll}x& y& I& \text{sin}\left({\text{LBP}}_{{\theta }_0}\right)& \text{cos}\left({\text{LBP}}_{{\theta }_0}\right)& \text{sin}\left({\text{LBP}}_{{\theta }_1}\right)& \text{cos}\left({\text{LBP}}_{{\theta }_1}\right)\end{array}\right]\\ \left[\begin{array}{lllllllll}x& y& R& G& B& \text{sin}\left({\text{LBP}}_{{\theta }_0}\right)& \text{cos}\left({\text{LBP}}_{{\theta }_0}\right)& \text{sin}\left({\text{LBP}}_{{\theta }_1}\right)& \text{cos}\left({\text{LBP}}_{{\theta }_1}\right)\end{array}\right]\end{array}$