2.2.4. Feature Extraction

In the *i*-th matching interval [*Ri*, *Ri*+1], the interval velocity ratio (*IVR*) of corresponding points is calculated as follows:

$$\begin{cases} v\_j = \sqrt{(\mathbf{x}\_j - \mathbf{x}\_{j-1})^2 + (y\_j - y\_{j-1})^2} \\ v\_j' = \sqrt{(\mathbf{x'}\_j - \mathbf{x'}\_{j-1})^2 + (y'\_j - y'\_{j-1})^2} \\ IVR\_i = \frac{100}{R\_i' - R\_i + 1} \sum\_{j=R\_i+1}^{R\_i'} \min(\frac{v\_j + 1}{v\_{j-1}' + 1}, \frac{v\_j' + 1}{v\_{j+1}'}) \end{cases} \tag{13}$$
