# How to remove undesired lines in table

I want to remove the red marked line in the below picture, does anyone know how to do it?

The Latex script I use is:

\begin{tabular}{|c|c||c|c|c|}\hline
\multicolumn{2}{|c||}{\backslashbox{Challenges~}{Input~~}}
& 2D & 3D & 2.5D \\\hline \hline
\multirow{4}{*}{Changes}
&viewpoint & 1 & 2 & 3\\\hline
&illumination & 1 & 2 & 3\\\hline
&scale & 1 & 2 & 3\\\hline
&deformation & 1 & 2 & 3\\\hline

\multirow{2}{*}{\specialcell{Content \\ Changes}}
&occlusion & 1 & 2 & 3\\\hline
&\specialcell{background \\ cluster} & 1 & 2 & 3\\\hline
\end{tabular}

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How are the macros \specialcell and \backslashbox defined. Please consider augmenting your code snippet to form an MWE (minimum working example, i.e., a LaTeX file that starts with \documentclass and ends with \end{document}) that's compilable and produces the output shown in the screenshot. –  Mico Aug 4 '14 at 8:42

Tha table could be improved using hhline: it helps double lines intersect nicely with other (single or double) lines. I also used the makecell package that is designed to allow linebreaks inside tabular cells (and also common formatting of cells contents):

\documentclass{scrartcl}
\usepackage[utf8]{inputenc}
\usepackage{multirow}
\usepackage{hhline}
\usepackage{colortbl}
\usepackage{diagbox}
\usepackage{makecell}
\setlength\doublerulesep{3pt}

\begin{document}

\begin{tabular}{|c|c||c|c|c|}
\hhline{--||---}
\multicolumn{2}{|c||}{\backslashbox{Challenges~}{Input~~}}
& 2D & 3D & 2.5D \\
\hhline{==::===}
\multirow{4}{*}{Changes}
&viewpoint & 1 & 2 & 3\\
\hhline{~-||---}
&illumination & 1 & 2 & 3\\
\hhline{~-||---}
&scale & 1 & 2 & 3\\
\hhline{~-||---}
&deformation & 1 & 2 & 3\\
\hhline{--||---}
\multirowcell{3}{Content \\ Changes}
&occlusion & 1 & 2 & 3\\
\hhline{~-||---}
&\makecell{background \\ cluster} & 1 & 2 & 3\\
\hhline{--||---}
\end{tabular}

\end{document}

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