Split beamer and alignment

Question

I'm using this beamer theme and I want to change the title page in something like this where both text and image are vertically and horizontally centered in their minipage:

I tried the following code but far away from the result:

\setbeamertemplate{title page}
{
    \begin{minipage}[t][0.7\textheight][t]{\textwidth}
        \topskip0pt
        \vspace*{\fill}
            \centering
            \huge TITLE
        \vspace*{\fill}
    \end{minipage}

    \nointerlineskip
    \colorbox{green}{\begin{minipage}[b][0.3\textheight][t]{\textwidth}
        \begin{minipage}[t]{0.48\linewidth}
            \vspace*{\fill}
                \small Author: \\
                \large Scot Shaw \\
                \small Advisor: \\
                \large Eric Heller 
            \vspace*{\fill}
        \end{minipage}
        \begin{minipage}[t]{0.48\linewidth}
            \includegraphics[scale = 0.3]{example-image}
        \end{minipage}
    \end{minipage}
    }
}

Any ideas on how I can do that?