2D impulse response

Figure compares the impulse response of the 19-point filter with that of the improved 5-point filter. The medium of the impulse response is a homogeneous medium, in which the velocity is 2000 m/s, the anisotropy parameters $\varepsilon=0.4$ and $\delta=0.2$, and the tilting angle $\varphi=\frac{\pi}{6}$. The travel time for the three impulse are 0.4 s, 0.6 s and 0.8 s, respectively. From Figure , we can see that the impulse response of the improved 5-point filter is very similar to that of the 19-point filter at low-angle energy but is different from the 19-point filter at high-angle energy. The improved 5-point filter is accurate for the energy up to $50^{\circ}$ in the impulse response, compared to the 19-point filter.