This paper gives on equation 22 an estimator for the mean reversion level of the variance process under the real world measure. The context is the Heston model, where the variance is stochastic and the paper is trying to give a proxy for the determination of the Heston model parameters under the real word measure.
My question is: I perfectly understand equation 22, but it is not really clear to me if I should use the historical log-returns to do the computation. Could you please confirm that all I need to compute the estimator in equation 22 are the historical log-returns?
The equation 22, wich I refer to, is the following: $$\hat{\bar{\nu}}^{*} := \frac{1}{T}\sum_{k=1}^{K}\left[\ln\left( \frac{S(t_k)}{S(t_{k-1})}\right)\right]^2$$
Thank you