# [PERSON]'s Entropy Based Multilevel Thresholding Using a Novel Meta-Heuristics Algorithm
## 4 Simulation Results and Discussion
### Visual Evaluation of the Segmented Image  
The following Figures 6 and 7 are the segmented images with threshold-level k = 8, through observation, we could obtain that our proposed method can effectively segment images. Hydration products could be separated in the microscopic image of cement. In Figure 6, when the threshold level is 8, in the test image \"Baboon\", the image segmented by ALO-Renyi, DE-Renyi, SSA-Renyi, PSO-Renyi is darker overall, the color and contrast difference between the baboon's nose and the surrounding area is not very obvious. At the same time, the images segmented by WOA-Renyi and GA-Renyi are brighter overall. The areas of the baboon face are not distinguished clearly, but the overall image of the \"Baboon\" segmented by HRO-Renyi is moderate in brightness. The area of the image has obvious contrast; in the test image \"cameraman\", the boundary between the person and the background in the segmented image by HRO-Renyi is clearer, and the color contrast between the regions is obvious; in the test images \"house\" and \"pepper\", compared with other methods, the segmented images by HRO-Renyi has better visual effects and stronger layering. Therefore, HRO-Renyi has better perceptual quality and more obvious contrast on standard image datasets than other algorithms as a whole. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Test Image**} & \multirow{2}{*}{**k**} & \multicolumn{2}{c}{**PNSR**} & \multicolumn{2}{c}{**SSIM**} \\ \cline{3-6}  & & **HRO-OTSU** & **HRO-Renyi** & **HRO-OTSU** & **HRO-Renyi** \\ \hline \multirow{4}{*}{baboon} & 2 & **6.7981** & 6.7363 & **0.3064** & 0.3046 \\  & 4 & 8.7101 & **9.8992** & 0.4904 & **0.551** \\  & 6 & **13.9917** & 12.1854 & **0.6913** & 0.659 \\  & 8 & **15.084** & 14.953 & 0.7477 & **0.7657** \\  & 2 & 6.6695 & **8.5097** & **0.4680** & 0.4088 \\ \multirow{4}{*}{cameraman} & 4 & 11.9553 & **15.895** & 0.5338 & **0.5502** \\  & 6 & 12.0709 & **13.9544** & 0.5876 & **0.6126** \\  & 8 & 14.2463 & **19.6721** & 0.6179 & **0.6813** \\  & 2 & 6.6118 & **7.0059** & **0.4383** & 0.4045 \\ \multirow{2}{*}{house} & 4 & **12.2213** & 12.3194 & 0.6033 & **0.7013** \\  & 6 & 10.8699 & **12.7908** & 0.6534 & **0.6687** \\  & 8 & 15.1439 & **16.2506** & 0.7387 & **0.7747** \\  & 2 & 6.9852 & **7.3017** & **0.4342** & 0.4176 \\ \multirow{2}{*}{pepper} & 4 & **14.3867** & 11.797 & **0.5631** & 0.5484 \\  & 6 & **15.7046** & 14.2376 & 0.6296 & **0.6346** \\  & 8 & **20.5632** & 15.8249 & 0.6924 & **0.6949** \\  & 2 & 6.4293 & **11.6851** & **0.1016** & 0.0731 \\ \multirow{2}{*}{image1} & 4 & 9.427 & **14.2248** & **0.2454** & 0.2398 \\  & 6 & 11.5935 & **17.4116** & 0.3735 & **0.3996** \\  & 8 & 13.2339 & **17.299** & 0.4871 & **0.5351** \\  & 2 & 5.9105 & **10.412** & **0.1759** & 0.0712 \\ \multirow{2}{*}{image2} & 4 & 9.0231 & **11.7494** & **0.2733** & 0.2611 \\  & 6 & 9.8523 & **14.0487** & 0.3483 & **0.4269** \\  & 8 & 11.1423 & **14.2233** & 0.4068 & **0.5407** \\  & 2 & 5.6788 & **10.0547** & **0.124** & 0.0804 \\ \multirow{2}{*}{image3} & 4 & 8.6725 & **11.3931** & **0.2026** & 0.1928 \\  & 6 & 9.4832 & **13.0616** & 0.2672 & **0.31** \\  & 8 & 10.0703 & **16.5418** & 0.3247 & **0.419** \\ \multirow{2}{*}{image4} & 2 & 6.1726 & **8.7871** & **0.1582** & 0.1142 \\  & 4 & 9.073 & **11.7971** & **0.2418** & 0.2189 \\ \multirow{2}{*}{image3} & 6 & 11.1861 & **13.5219** & 0.3362 & **0.3522** \\  & 8 & 12.082 & **16.2838** & 0.4051 & **0.4489** \\ \hline \hline \end{tabular}
\end{table} 
Table 4: PNSR, SSIM, regional consistency, and regional contrast. In the SEM image of cement \"image1\", the microscopic cement material in the image divided by WOA-Renyi shows a large-area adhesion phenomenon, which makes it difficult to distinguish the components of each material. Images segmented by ALO-Renyi, DE-Renyi, SSA-Renyi, PSO-Renyi, and GA-Renyi contain relatively little cement micro-materials, while the images segmented by HRO-Renyi, not only are the cement microscopic substances easy to identify, but they are rich in variety and quantity.