Numeración aleatoria y espaciado de subfiguras en salida pdf

Question

La numeración de las subfiguras en mi salida en pdf es algo aleatoria, pero en el editor la numeración es como debería ser.

Donde las subfiguras están numeradas correctamente de (a) a (d), pero cuando se exportan a pdf, esto es lo que obtengo:

También me gustaría preguntar ¿por qué el espaciado horizontal en la primera fila de figuras es diferente? La configuración para cada línea es la misma pero la primera fila no sigue.

No sé cómo solucionar esto. Aquí hay un LaTeXcódigo de la figura:

%% LyX 2.3.2-2 created this file.  For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[english]{IEEEtran}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\usepackage{graphicx}

\makeatletter
\@ifundefined{showcaptionsetup}{}{%
 \PassOptionsToPackage{caption=false}{subfig}}
\usepackage{subfig}
\makeatother

\usepackage{babel}
\begin{document}
\begin{figure*}
\subfloat[]{\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_0_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_1_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_2_ground_truth}}}

\subfloat[]{\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_0_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_1_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_2_ground_truth}}}

\subfloat[]{\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_0_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_1_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_2_ground_truth}}}

\subfloat[]{\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_0_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_1_ground_truth}}\enskip{}\subfloat{\includegraphics[width=0.28\paperwidth]{volume_4_2_ground_truth}}}

\caption{Comparison}
\end{figure*}

\end{document}

Answer 1

Si entendí correctamente que solo necesita cuatro títulos (de (a) a (d), uno por fila), simplemente puede eliminar el anidado \subfloat:

\documentclass[english]{IEEEtran}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\usepackage{graphicx}

\makeatletter
\@ifundefined{showcaptionsetup}{}{%
 \PassOptionsToPackage{caption=false}{subfig}}
\usepackage{subfig}
\makeatother

\usepackage{babel}
\begin{document}
\begin{figure*}
\centering
\subfloat[]{%
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}%
}

\subfloat[]{%
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}%
}

\subfloat[]{%
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}%
}

\subfloat[]{%
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}\enskip
    \includegraphics[width=0.25\paperwidth]{example-image}%
}

\caption{Comparison}
\end{figure*}

\end{document}

Answer 2

Utilice \includegraphicsel comando dentro de minipáginas del ancho deseado.

\documentclass[english]{article}
\usepackage[T1]{fontenc}
\usepackage{graphicx}
\usepackage{subcaption}
\begin{document}

\begin{figure*}
\begin{minipage}{0.3\textwidth}
\includegraphics[width=\linewidth]{volume_4_0_ground_truth}
\end{minipage}\hspace*{\fill}
\begin{minipage}{0.3\textwidth}
\includegraphics[width=\linewidth]{volume_4_1_ground_truth}
\end{minipage}\hspace*{\fill}
\begin{minipage}{0.3\textwidth}
\includegraphics[width=\linewidth]{volume_4_2_ground_truth}
\end{minipage}\vspace{15pt}

\begin{minipage}{0.3\textwidth}
\includegraphics[width=\linewidth]{volume_4_0_ground_truth}
\end{minipage}\hspace*{\fill}
\begin{minipage}{0.3\textwidth}
\includegraphics[width=\linewidth]{volume_4_1_ground_truth}
\end{minipage}\hspace*{\fill}
\begin{minipage}{0.3\textwidth}
\includegraphics[width=\linewidth]{volume_4_2_ground_truth}
\end{minipage}
\caption{Comparison}
\end{figure*}

\end{document}

Se puede incluir un título si lo desea usando el comando:\captionof{subfigure}{Caption (a)}