I have created a table in LaTeX. But text from two different rows is being overlapped. I tried with manipulating row height, but problem persists. Kindly help. 
Code is pasted here.
\begin{table}[]
\centering
\caption{My caption}
\label{my-label}
%\renewcommand{\arraystretch}{1.8}
%\setlength{\extrarowheight}{10pt}
\begin{tabular}{|l|l|c|l|l|l|l|}
\hline
\multicolumn{1}{|c|}{\begin{tabular}[c]{@{}c@{}}Sl.\\ No.\end{tabular}} & \begin{tabular}[c]{@{}l@{}}Filter \&\\ Parameters\end{tabular} & \begin{tabular}[c]{@{}c@{}}Window\\ Size\end{tabular} & SSI & ENL & SMPI & SSIM \\ \hline
\multicolumn{1}{|c|}{1} & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Lee \\ (Noise\\ Variance=0.25)\end{tabular}} & $3\times3$ & 0.711 & 13.402 & 46.151 & 1.00 \\ \cline{1-1} \cline{3-7}
\multicolumn{1}{|c|}{2} & & $5\times5$ & 0.650 & 16.031 & 42.696 & 1.00 \\ \cline{1-1} \cline{3-7}
\multicolumn{1}{|c|}{3} & & $7\times7$ & 0.624 & 17.364 & 41.050 & 1.00 \\ \hline
\multicolumn{1}{|c|}{4} & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Frost\\ ($k=1$)\end{tabular}} & $3\times 3$ & \multicolumn{1}{c|}{0.616} & \multicolumn{1}{c|}{17.814} & \multicolumn{1}{c|}{38.340} & \multicolumn{1}{c|}{1.00} \\ \cline{1-1} \cline{3-7}
\multicolumn{1}{|c|}{5} & & $5\times 5$ & \multicolumn{1}{c|}{0.540} & \multicolumn{1}{c|}{23.240} & \multicolumn{1}{c|}{31.953} & \multicolumn{1}{c|}{1.00} \\ \cline{1-1} \cline{3-7}
\multicolumn{1}{|c|}{6} & & $7\times 7$ & \multicolumn{1}{c|}{0.506} & \multicolumn{1}{c|}{26.493} & \multicolumn{1}{c|}{28.350} & \multicolumn{1}{c|}{1.00} \\ \hline
\multicolumn{1}{|c|}{7} & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Frost\\ ($k=2$)\end{tabular}} & $3\times 3$ & \multicolumn{1}{c|}{0.618} & \multicolumn{1}{c|}{17.703} & \multicolumn{1}{c|}{38.203} & \multicolumn{1}{c|}{1.00} \\ \cline{1-1} \cline{3-7}
\multicolumn{1}{|c|}{8} & & $5\times 5$ & \multicolumn{1}{c|}{0.543} & \multicolumn{1}{c|}{22.935} & \multicolumn{1}{c|}{31.993} & \multicolumn{1}{c|}{1.00} \\ \cline{1-1} \cline{3-7}
\multicolumn{1}{|c|}{9} & & $7\times 7$ & \multicolumn{1}{c|}{0.511} & \multicolumn{1}{c|}{25.911} & \multicolumn{1}{c|}{28.468} & \multicolumn{1}{c|}{1.00} \\ \hline
10 & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Frost\\ ($k=0.5$)\end{tabular}} & $3\times 3$ & 0.616 & 17.863 & 38.403 & 1.00 \\ \cline{1-1} \cline{3-7}
11 & & $5\times 5$ & 0.538 & 23.370 & 31.944 & 1.00 \\ \cline{1-1} \cline{3-7}
12 & & $7\times 7$ & 0.503 & 26.758 & 28.305 & 1.00 \\ \hline
13 & \multirow{3}{*}{\begin{tabular}[t]{@{}l@{}}Enhanced Lee\\ ($k=1$, \\ $C_v=0.2615$,\\ $C_max=1.2247$)\end{tabular}} & $3\times 3$ & 0.613 & 18.004 & 39.158 & 1.00 \\ \cline{1-1} \cline{3-7}
14 & & $5\times5$ & 0.528 & 24.301 & 34.316 & 1.00 \\ \cline{1-1} \cline{3-7}
15 & & $7\times 7$ & 0.484 & 28.959 & 31.464 & 1.00 \\ \hline
16 & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Enhanced Lee\\ ($k=2$, \\ $C_v=0.2615$, \\ $C_max=1.2247$)\end{tabular}} & $3\times 3$ & 0.621 & 17.584 & 38.570 & 1.00 \\ \cline{1-1} \cline{3-7}
17 & & $5\times 5$ & 0.538 & 23.350 & 34.651 & 1.00 \\ \cline{1-1} \cline{3-7}
18 & & $7\times 7$ & 0.497 & 27.395 & 32.071 & 1.00 \\ \hline
19 & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Enhanced Lee\\ ($k=0.5$, \\ $C_v$=0.2615, \\ $C_max$=1.2247)\end{tabular}} & $3\times 3$ & 0.610 & 18.202 & 39.583 & 1.00 \\ \cline{1-1} \cline{3-7}
20 & & $5\times 5$ & 0.523 & 24.731 & 34.269 & 1.00 \\ \cline{1-1} \cline{3-7}
21 & & $7\times7$ & 0.478 & 29.689 & 31.286 & 1.00 \\ \hline
22 & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Enhanced Frost\\ ($k=1$, \\ $C_v=0.2615,$\\ $C_max=1.2247$)\end{tabular}} & $3\times 3$ & 0.616 & 17.846 & 38.206 & 1.00 \\ \cline{1-1} \cline{3-7}
23 & & $5\times 5$ & 0.540 & 23.239 & 31.829 & 1.00 \\ \cline{1-1} \cline{3-7}
24 & & $7\times 7$ & 0.506 & 26.471 & 28.198 & 1.00 \\ \hline
25 & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Enhanced Frost\\ ($k=2$, \\ $C_v=0.2615$, \\ $C_max=1.2247$)\end{tabular}} & $3\times 3$ & 0.617 & 17.762 & 37.913 & 1.00 \\ \cline{1-1} \cline{3-7}
26 & & $5\times 5$ & 0.543 & 22.972 & 31.721 & 1.00 \\ \cline{1-1} \cline{3-7}
27 & & $7\times 7$ & 0.511 & 25.909 & 28.184 & 1.00 \\ \hline
28 & \multirow{3}{*}{\begin{tabular}[c]{@{}l@{}}Enhanced Frost\\ ($k=0.5$, \\ $C_v=0.2615$, \\ $C_max=1.2247$)\end{tabular}} & $3\times 3$ & 0.615 & 17.880 & 38.345 & 1.00 \\ \cline{1-1} \cline{3-7}
29 & & $5\times 5$ & 0.538 & 23.352 & 31.897 & 1.00 \\ \cline{1-1} \cline{3-7}
30 & & $7\times 7$ & 0.503 & 26.717 & 28.244 & 1.00 \\ \hline
31 & \multirow{3}{*}{GammaMap} & $3\times 3$ & 0.608 & 18.319 & 40.178 & 1.00 \\ \cline{1-1} \cline{3-7}
32 & & $5\times 5$ & 0.521 & 24.903 & 34.421 & 1.00 \\ \cline{1-1} \cline{3-7}
33 & & $7\times 7$ & 0.475 & 29.945 & 31.384 & 1.00 \\ \hline
\end{tabular}
\end{table}
Best Answer
Assuming you can't widen the text-width (so you can avoid the 4-line subtables that are causing the problem), you can increase the vertical spacing after each line by adding some extra space to each row. Just append
[..]to each\\at the end of the table rows, where..is any length (e.g.,1ex). In the code below I defined\extraas a\newlengthto make it easy to adjust. Too small and the rows still overlap. Too big and you run out of room on the page. The image uses\extraequal to.8ex.I would strongly consider breaking the table into two tables and increase the spacing a bit; it still looks cramped to me.
Here is the code with [\extra] appended to each row.