## 3 Materials and Methods: Eye-Tracking Experiment
### Data Analysis and Result
#### 3.5.1 Analysis of the Sight-Focused Area  
The collected sight-focused areas are analyzed using a heat map, and the key focus area and design elements of the coating design of the machine tools are summarized. Some of the heat map results obtained by the experiment are shown in Figure 4. The level of focus is achieved by distinguishing between different colors in the pictures.  
The color of the focus area in Figure 4, moving from green to red, represents a gradual increase in the user's visual attention to the elements of the area. The visual heat maps of the subjects in the three experiments are analyzed separately. In Experiment 1 (scale of logo  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Eye-Tracking Metric** & **Implication** \\ \hline \multirow{2}{*}{Residence time} & The total amount of time spent focusing on a certain area of interest, including all the fixation points and eye movements in the area of interest, as well as the time of the return visit. \\ \hline \multirow{2}{*}{Number of fixation points} & The total number of fixation points in the area of interest, which is closely related to the residence time. \\ \hline \multirow{2}{*}{Fixation duration} & The average duration of time spent on all the fixation points, which is usually in the range of 150 ms\(\sim\)300 ms. \\ \hline \hline \end{tabular}
\end{table}
Table 1: Eye-tracking indicators in the eye-tracking experiment.  
Figure 4: Illustration of the user-focused area.  
and machine tool model), 76% of the subjects preferred a logo and machine model height to machine tool height ratio of 0.125 to 0.15, which demonstrates that the size range allows the user to quickly identify the logo and machine tool model.  
In Experiment 2 (typographic position of the logo and machine type), 63% of the subjects preferred a layout with the logo and machine tool model on the top left and right of the machine tool. The layout is convenient for the human eye in distinguishing the information conveyed by the logo and the machine tool model and is consistent with the goal that the information is not easily obscured, which is an important reference for the optimization of the following coating design scheme.  
In Experiment 3 (color coating scheme of machine tools), 53.4% of the subjects provided the strongest feedback when observing the heat map formed in Experiment C-1, followed by Experiment C-4. This indicates that the subjects preferred the form of color coating scheme in which the observation window is coated with dark grey, the machine tool bed is coated with a relatively light grey, the machine tool base is coated with the darkest grey and enhanced by the color of the logo, and the observation window area with the deeper coating extension is the key area of the machine tool, whose color scheme can quickly attract the user's attention. Meanwhile, the darkest-coated base enhances the visual feeling of the lighter top and heavier bottom, increasing the stability of the machine. The lightest-coated machine bed is embellished with a red logo and the machine tool model number, conveying the message of the machine and increasing its aesthetics while transmitting the machine tool information.  
In Experiment 4 (color matching scheme of the machine tools), the subjects' feedback on the different shades of the color matching schemes was collected and analyzed. This area of the heat map shows that the subjects provided stronger feedback on the color matching scheme of the observation window with a higher color concentration. This indicates that in the process of selecting the color scheme, it is important to try to provide the observation window and the machine tool bed form with a more obvious color contrast, enabling the viewer to more clearly distinguish between the primary and secondary areas. The body should be coated mainly in grey so as to avoid visual fatigue caused by large areas of bright colors.