\begin{figure}[t]
\centering
% \includegraphics[trim={10cm 4.2cm 0 0},clip,width=0.3\linewidth]{imgs/reg_results_wf.pdf}
% \includegraphics[trim={10cm 0 0 4.2cm},clip,width=0.6\linewidth]{imgs/reg_results_wf.pdf}
% \includegraphics[trim={0 0 0 0.5cm},clip,width=1\linewidth]
\includegraphics[width=1\linewidth]
{imgs/reg_results_hard2.pdf}
\caption{\textbf{Left}, Greedy and ANTs both fail on this randomly selected hard case, even with CR=30$^\circ$. Interestingly, they even \textit{reverse} the CR initialization as the optimization is dominated by FOV shape. In contrast, LOTUS leverages the initial CR to achieve good registration results. All panels show a center axial slice. \textbf{Right}, RE as a function of  CR on hard cases. LOTUS significantly improves registration compared to the baselines.
} 
\label{reg_results_hard}
% \vspace{-4mm}
\end{figure}