Beus and Tiu BT87

Corner strength. Similar to FD77, with the following modifications. The arm cutoff parameter $\tau$ is introduced to specify the upper limit for $t_1$ and $t_2$as a fraction of $N$:
$$\begin{align*}t_1 &= \max{\{t:\delta_{i-v,k} \in (-\Delta,\Delta), \forall~1 \le... ...lta,\Delta), \forall~1 \leq v \leq t,~\text{and}~t \leq \tau N \}}, \end{align*}$$
where $\delta_{ik}$ and $\Delta$ are given by (4) and (6), respectively. The corner strength is obtained by averaging (5) between two values $k_1$ and $k_2$:

$$S_i = \frac{1}{k_2-k_1+1} \sum\limits_{k=k_1}^{k_2} S_{ik}$$

Selection procedure. Same as in FD77.
Parameters. The four parameters are the averaging limits $k_1$ and $k_2$, the arm cutoff parameter $\tau$, and the corner strength threshold $S$. The default values are $k_1=4$, $k_2=7$, $\tau = 0.05$, and $S=1500$.