I'm trying to implement color-to-grayscale method from this paper. And they use Verlet's integration as:
$$L^*(t+\Delta t)=\frac{F(t)}{m}\Delta t^2+2L^*(t)-L^*(t-\Delta t),$$
for computing new value of luminance. But they not say how to compute new value of luminance for $t=0$. According to this Wikipedia link I think it could be as:
$$L^*(\Delta t)=\frac{F(0)}{2m}\Delta t^2+L^*(0)$$
Is it correct?