# Data Hiding Method for Color AMBTC Compressed Images Using Color Difference
## 5 Experimental Results
In Airplane (c), the difference in performance between the CAMABC method and the proposed methods is very large, and both the proposed methods show higher performance than CAMBTC in all ranges. However, PROPOSE#1 is limited embedding ability to 425,000 bits. The Lake (d) also shows a performance graph like that of (c). PROPOSE#1 has a lower EC than that of PROPOSE#2, so after a certain range, its performance degrades sharply. On the other hand, PROPOSE#2 hides 32 bits per block, so initially, the image quality is lower than that of PROPOSE#1, but the moment it exceeds a certain EC, it exceeds the performance limit of PROPOSE#1. Figure 9 evaluates the quality of Lena marked image created the traditional CAMBTC, PROPOSE#1, and PROPOSE#2 by using the human visual system. The marked images of (a), (b), and (c) embed the same 50,000 bits. The CDs obtained from (a), (b), and (c) are 11.58, 10.7388 and 10.8034, respectively, and in the case of (a), the shoulder line and the right edge of the hat are not smooth. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \multirow{2}{*}{**CAMBTC**} & \multirow{2}{*}{\(CD_{t(O-M)}\)} & \multicolumn{2}{c}{**T = 5**} & \multicolumn{2}{c}{**T = 10**} & \multicolumn{2}{c}{**T = 15**} & \multicolumn{2}{c}{**T = 20**} \\ \cline{3-10}  & & **EC** & \(CD_{t(O-S)}\) & **EC** & \(CD_{t(O-S)}\) & **EC** & \(CD_{t(O-S)}\) & **EC** & \(CD_{t(O-S)}\) \\ \hline Lena & 11.5419 & 239,633 & 12.2081 & 438,225 & 14.0086 & 504,081 & 16.0868 & 536,273 & 17.0192 \\ Pepper & 12.4374 & 170,193 & 12.9032 & 384,689 & 15.4278 & 500,129 & 17.6682 & 539,313 & 18.7706 \\ Airplane & 10.3398 & 365,105 & 11.6417 & 460,449 & 12.7021 & 503,825 & 13.5473 & 529,665 & 14.278 \\ Lake & 18.4897 & 180,113 & 18.9001 & 308,353 & 20.3873 & 421,121 & 22.4377 & 475,057 & 23.7682 \\ Baboon & 29.7421 & 129,521 & 29.8709 & 162,593 & 30.194 & 214,673 & 31.1826 & 276,049 & 32.8615 \\ \hline \multirow{2}{*}{**PROPOSED#1**} & \multirow{2}{*}{\(CD_{p(O-M)}\)} & \multicolumn{2}{c}{**T = 5**} & \multicolumn{2}{c}{**T = 10**} & \multicolumn{2}{c}{**T = 15**} & \multicolumn{2}{c}{**T = 20**} \\ \cline{3-10}  & & **EC** & \(CD_{p(O-S)}\) & **EC** & \(CD_{p(O-S)}\) & **EC** & \(CD_{p(O-S)}\) & **EC** & \(CD_{p(O-S)}\) \\ \hline Lena & 10.6977 & 347,489 & 11.3919 & 441,761 & 13.8218 & 472,465 & 15.1749 & 497,649 & 16.8222 \\ Pepper & 12.2976 & 355,665 & 13.679 & 446,321 & 16.3835 & 478,129 & 17.8738 & 500,881 & 19.3211 \\ Airplane & 8.5637 & 406,497 & 9.6877 & 462,929 & 11.2327 & 478,481 & 12.0022 & 493,025 & 13.0615 \\ Lake & 17.0456 & 329,729 & 17.5542 & 389,841 & 19.1579 & 419,105 & 20.4192 & 449,425 & 22.1857 \\ Baboon & 26.1272 & 302,065 & 26.3071 & 331,313 & 27.4723 & 351,073 & 28.6118 & 377,009 & 30.574 \\ \hline \multirow{2}{*}{**PROPOSED#2**} & \multirow{2}{*}{\(CD_{p(O-M)}\)} & \multicolumn{2}{c}{**T = 5**} & \multicolumn{2}{c}{**T = 10**} & \multicolumn{2}{c}{**T = 15**} & \multicolumn{2}{c}{**T = 20**} \\ \cline{3-10}  & & **EC** & \(CD_{p(O-S)}\) & **EC** & \(CD_{p(O-S)}\) & **EC** & \(CD_{p(O-S)}\) & **EC** & \(CD_{p(O-S)}\) \\ \hline Lena & 10.6977 & 399,585 & 12.2793 & 589,025 & 17.0417 & 649,889 & 19.5795 & 698,785 & 22.3666 \\ Pepper & 12.2976 & 416,193 & 14.9094 & 600,257 & 19.9398 & 659,201 & 22.1908 & 704,801 & 24.7835 \\ Airplane & 8.5637 & 517,921 & 10.608 & 631,169 & 13.157 & 661,921 & 14.4979 & 691,585 & 16.2101 \\ Lake & 17.0456 & 365,505 & 18.0093 & 484,577 & 20.953 & 542,145 & 23.1115 & 602,465 & 25.9195 \\ Baboon & 26.1272 & 308,257 & 26.5225 & 365,057 & 28.6964 & 404,353 & 30.6984 & 457,153 & 34.1375 \\ \hline \end{tabular} Notes: PROPOSE#1 (SQ/B: OPAP, M: 16 bits LSB flipping), PROPOSE#2 (SQ: OPAP, M: 32 bits LSB flipping).  
\end{table} 
Table 2: Comparison of CD between the original image and marked image according to the threshold \(T\). Figure 8: CD comparison according to EC.