*4.2. Net Comparison*

To compare the performance of different networks, given the characteristics of the input sample data, the networks of different layers were established, trained, and used in bottom tracking experiments. The results are shown in Table 4.


**Table 4.** Comparison of Results Obtained by Using the Networks of Different Layers.

As seen from Table 4, with a sufficient number of samples, the deeper networks demonstrated better learning rates and higher training, validation, and bottom tracking accuracies, but required a longer calculation time. Meanwhile, each convolution operation would further reduce the data size. Therefore, the maximum number of network convolution layers was limited due to the limitations in the input data size. In this paper, a network of 10 layers was adopted (Figure 4).
