## 3 Materials and Methods
### Eye-Tracking-Guided Acquisition of Product Styling Samples
#### 3.3.2 Operational Procedure of the Eye-Tracking Experiment  
The experimental participants recruited for this study were consistent with those in the prior extension evaluation phase, aged 25-45 years, representing the primary user demographic for industrial robots. Participants comprised industry professionals including industrial designers, robotics engineers, manufacturing procurement specialists, and general users. Thirty participants (mean age = 33.23 years, SD = 5.69, 50% female) completed the experiment. All exhibited normal physiological function with corrected-to-normal visual acuity and absence of color vision deficiencies. Participants provided written informed consent, with anonymized data storage ensuring dissociation of eye-tracking records from personal identifiers (coded P01-P30). Experimental equipment consisted of a Tobii EyeTracker 5 (Tobii AB, Danderyd, Sweden) mounted below a 19-inch monitor at 60 cm viewing distance, operating at 133 Hz sampling rate with 0.5\({}^{\circ}\) spatial accuracy. Testing occurred in a quiet environment with ambient illumination. Twenty grayscale-converted robot images (Sample NO.01-NO.20), standardized for size and background, served as stimuli. Images were presented in five sequential blocks of four samples each. Each block allowed 20 s of free viewing, during which participants were instructed to comprehensively observe all image regions. Following each block, a content-verification question ensured observational engagement. All thirty participants completed the eye-tracking measurements following this protocol. The experimental procedure is illustrated in Figure 5, with specific workflow details as follows:  
Figure 4: Sample design of industrial cleaning robots. Figure 3: The crawling results of sample images of industrial cleaning robots. Experimental preparation  
Prior to experimentation, device calibration was performed. The viewing distance between participants and the screen was standardized at approximately 90 cm to ensure precision in eye-tracking data acquisition. A 9-point calibration procedure was conducted using the eye-tracker to guarantee accurate capture of ocular movements and eye-movement metrics. Testing occurred in a controlled environment with uniform lighting and minimal auditory disturbances, minimizing interference from ambient light and noise to enable participant concentration on experimental tasks according to standard protocols. Experiment implementation  
Data collection  
During experimentation, the following eye-tracking metrics were recorded:  
First fixation duration--indicating the response time to initial visual engagement with a region, reflecting attentional capture speed;  
Total fixation duration--representing cumulative dwell time within areas of interest (AOIs), indicating cognitive processing depth;  
Regression count--quantifying repeated fixations on specific regions, reflecting engagement intensity;  
Scampath--mapping the spatiotemporal trajectory of visual transitions across the sample, revealing scanning priorities and sequential patterns. Following the experiment, data underwent verification and archiving procedures. Completeness checks ensured sample-wise eye-tracking data integrity, confirming absence of loss or artifacts. Secured backups were created for subsequent analysis. Finally, a closing statement was displayed to participants acknowledging their contribution and outlining subsequent data handling procedures. Extraction of Stylistic Design Elements for Industrial Cleaning Robots Based on Eye-Tracking  
Heatmaps from all 30 participants were superimposed, exemplified by Sample 9 (Figure 6). Analysis revealed that participant fixations predominantly clustered on four robotic regions during observation: top (denoted X), front fascia (Y), side profile (Z), and base (K). Subsequent examination of the remaining 29 samples demonstrated consistent spatial attention patterns.