# Underwater Degraded Image Restoration by Joint Evaluation and Polarization Partition Fusion
## 3 Experimental Results and Discussion  
This paper uses three evaluation indicators for objective evaluation. According to the experimental results, the range of Entropy values is within 10, the range of EME values is within 20, and the range of Contrast values is within 50. The three differences are large, and in order to facilitate lateral comparison, so that the results of the experiments are more intuitive, the values of the same evaluation indicator for each group of experiments were normalized by percentage occupancy (values ranging from 0 to 1). Where EME is shown in Equation (33), the better the quality of image restoration, the larger the EME value obtained. Image information Entropy is also a common index for image quality evaluation, which reflects the degree of image information richness from the perspective of information theory. The larger the Entropy, the clearer the image. For Contrast, a larger value means that the image outline is clear, and the details of the information are richer [21]. In Experiment 1, objectively, the EME value of [PERSON]'s method is quite high, but the Entropy and Contrast values are the lowest. The Entropy and Contrast values of our method are enhanced significantly, and EME is improved by 2.1 times more than the original image, so we are able to recover the image information effectively. Moreover, subjectively, the method in this paper has the best recovery results, resulting in good recovery of both low and high polarization regions. In Experiment 2, [PERSON]'s method has the highest EME value and our method has the second highest, but both [PERSON]'s Entropy and Contrast values are lower than those in our method; subjectively, the rest of the methods fail to recover the image effectively in the low polarization region, and our method is subjectively better. In Experiment 3, the EME values of both [PERSON]'s method and our method are significantly enhanced, with EME increasing by 1.06 and 1.004 times, respectively. Our method has the highest Entropy value, which is better than that of [PERSON]'s method, and in contrast, both our method and [PERSON]'s method improve significantly and similarly to each other's. In Experiment 4, [PERSON]'s method has the highest EME value and [PERSON]'s method [22] has the second highest, but subjectively, our method is better, and the EME value of our method is also improved by 1.05 times compared to the original image, which is better than [PERSON]'s method. The Entropy and Contrast values of our method are also much higher than those of the other methods, as shown in Table 2 and Figure 8.  
In reality, target composition is complex, as it does not have only one kind of polarization characteristic, and when using the traditional method to recover images, some of the low polarized regions are poorly recovered. The method in this paper has significant advantages over other methods when a target has complex polarization information. The method in this paper can optimize the recovery of high and low polarization regions separately; for a low polarization region, because its polarization is similar to the polarization of the backscattered light, recovery using the traditional method cannot distinguish between the target and the background, which often results in the recovered image becoming darker, or even the same as the background. The method in this paper uses the polarization difference method to recover the low polarization region, uses the multiple optimization indexes to recover the high polarization region, and finally, fuses the low polarization region and the high polarization region. In this paper, several groups of experiments are conducted. Figure 9 is a three-dimensional, disaggregated bar chart showing the results of four group experiments. Subjectively, the experimental results as a whole have been fully restored, and the information has been retained completely. Our method can fully recover the low polarization region, effectively remove the scattering effect, and enhance