# Reversible Image Processing for Color Images with Flexible Control
## 4 Experimental Results
### Visual and Quantitative Evaluation
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Brightness**} & \multicolumn{4}{c}{**Saturation**} & \multicolumn{2}{c}{**Hue**} \\ \cline{2-11}  & & \multicolumn{2}{c}{**Difference in**} & & & & & & & & & \\ \multicolumn{11}{c}{**Standard**} & \multicolumn{2}{c}{**Difference**} & \multicolumn{2}{c}{**RCE**} & \multicolumn{2}{c}{**Difference**} & \multicolumn{2}{c}{**Absolute**} \\  & & \multicolumn{2}{c}{**Deviations**} & & & & & & & & & \\ \cline{2-11}  & & \multicolumn{2}{c}{**Saturation Improvement**} & & & & & & & & & \\ \multicolumn{11}{c}{**S**} = 0 & \multicolumn{2}{c}{**\(I_{S}\) = 20**} & \multicolumn{2}{c}{\(I_{S}\) = 20**} & \multicolumn{2}{c}{\(I_{S}\) = 20} & \multicolumn{2}{c}{\(I_{S}\) = 0} & \multicolumn{2}{c}{\(I_{S}\) = 20} & \multicolumn{2}{c}{\(I_{S}\) = 0} & \multicolumn{2}{c}{\(I_{S}\) = 0} \\ \hline \multirow{2}{*}{Sharpening} & \(I_{VSH}=1\) & \(1.94\) & \(1.69\) & \(2.08\) & \(3.21\) & \(0.5076\) & \(0.5066\) & \(1.43\) & \(16.08\) & \(2.71\) & \(2.12\) \\  & \(I_{VSH}=2\) & \(3.52\) & \(3.12\) & \(4.44\) & \(6.07\) & \(0.5138\) & \(0.5123\) & \(0.53\) & \(14.86\) & \(4.28\) & \(3.87\) \\ \hline \multirow{2}{*}{Smoothing} & \(I_{VSM}=1\) & \(-1.55\) & \(-1.96\) & \(3.06\) & \(5.57\) & \(0.4939\) & \(0.4923\) & \(1.68\) & \(16.87\) & \(3.66\) & \(2.80\) \\  & \(I_{VSM}=2\) & \(-4.04\) & \(-4.71\) & \(6.83\) & \(12.50\) & \(0.4842\) & \(0.4815\) & \(1.42\) & \(16.99\) & \(6.19\) & \(5.34\) \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Brightness \\ increase \\ \end{tabular} } & \(I_{VI}=15\) & \(-1.05\) & \(-1.22\) & \(15.44\) & \(15.71\) & \(0.4959\) & \(0.4952\) & \(1.51\) & \(20.75\) & \(2.38\) & \(1.12\) \\  & \(I_{VI}=30\) & \(-2.61\) & \(-2.59\) & \(29.04\) & \(29.20\) & \(0.4898\) & \(0.4898\) & \(0.78\) & \(20.79\) & \(2.64\) & \(1.14\) \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Brightness \\ decrease \\ \end{tabular} } & \(I_{VD}=15\) & \(-0.80\) & \(-0.84\) & \(-12.29\) & \(-11.91\) & \(0.4968\) & \(0.4967\) & \(0.06\) & \(12.02\) & \(2.86\) & \(2.28\) \\  & \(I_{VD}=30\) & \(-2.57\) & \(-2.57\) & \(-24.44\) & \(-23.82\) & \(0.4899\) & \(0.4899\) & \(-3.18\) & \(6.64\) & \(3.61\) & \(3.16\) \\ \hline \multirow{2}{*}{CE} & \(I_{VC}=15\) & \(4.56\) & \(4.21\) & \(1.63\) & \(2.12\) & \(0.5179\) & \(0.5165\) & \(-1.26\) & \(14.32\) & \(2.43\) & \(1.39\) \\  & \(I_{VC}=30\) & \(8.39\) & \(7.99\) & \(3.27\) & \(3.56\) & \(0.5329\) & \(0.5313\) & \(-6.47\) & \(10.46\) & \(3.10\) & \(1.47\) \\ \hline \multirow{2}{*}{CE by prev. [12]} & \(I_{VC}=15\) & \(5.64\) & - & \(-1.10\) & - & \(0.5221\) & - & \(-0.46\) & - & \(0.76\) & - \\  & \(I_{VC}=30\) & \(10.14\) & - & \(-0.55\) & - & \(0.5397\) & - & \(-0.24\) & - & \(0.87\) & - \\ \hline \multirow{2}{*}{CE by prev. [1]} & \(I_{VC}=15\) & \(4.88\) & - & \(3.23\) & - & \(0.5191\) & - & \(0.59\) & - & \(16.72\) & - \\  & \(I_{VC}=30\) & \(7.27\) & - & \(9.40\) & - & \(0.5285\) & - & \(3.76\) & - & \(30.56\) & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Evaluations of brightness control, saturation improvement, and hue preservation. Figure 6: Raw image and output images through proposed and previous methods [1; 12] (Ship). (**a**) Raw image. (**b**) Sharpening (\(I_{VSH}=2\)). (**c**) Smoothing (\(I_{VSM}=2\)). (**d**) Brightness increase (\(I_{VI}=30\)). (**e**) Brightness decrease (\(I_{VD}=30\)). (**f**) CE (\(I_{VC}=30\)). (**g**) Saturation improvement (\(I_{S}=20\)). (**h**) CE under previous method [12] (\(I_{VC}=30\)). (**i**) CE under previous method [1] (\(I_{VC}=30\)). mation to be embedded as described in Section 3.1.3. This embedding process causes slight perceptual distortion and deteriorates the performance of each function.