Examining the gaze behaviors of harvester operators: an eye-tracking study

Abstract

In forest harvesting, operators must visually monitor the terrain, machinery, the stand and the trees they are cutting in order to plan, evaluate and adjust their tasks. To exploit increasing opportunities to automate these tasks and create decision support systems it is essential to understand not only what forestry workers do, but also what they look at and why they focus on specific aspects during specific tasks. This knowledge may also aid operator training and knowledge transfer between age and experience groups. Eye-tracking (ET) is therefore a potentially valuable technique that may facilitate both extraction of implicit knowledge and elucidation of operators' information acquisition strategies. However, real world ET-recordings are sensitive to environmental variations and analyzing them is time consuming. Thus, the aims of this study were to examine the utility of a head-mounted eye-tracking system in forest harvesting machines in a natural setting and obtain information on operators' visual behavior (gaze patterns) during harvesting. The output from the eye-tracker was affected by large head movements, changes in illumination and (possibly) vibrations. The gaze pattern analysis revealed that the operators looked at the harvester head or forest most of the time, but their gaze behaviors varied during different harvesting operations. They looked at the monitor, canopy and falling trees less frequently during first thinning than during second thinning and final felling. The results suggest that some harvesting information is gathered in advance to get an overview and plan the work, but most eye movements closely follow actions.

Analyzing Online Videos: A Complement to Field Studies in Remote Locations

“…Although the number of relevant videos was less than what we expected, the collected videos show more operators and have a much longer duration than Häggström et al [12] (see Table 1). Although the duration of videos of Nurminen et al [23] was much longer, with 12 hours and 30 minutes, it is quite understandable why they needed much longer duration, considering the objective of their study.…”

“…Nurminen et al [23] were able to estimate the time consumption of operators of both forest harvesters and forwarders in performing their tasks, while Spinelli and Visser [30] were able to calculate delays in harvester operations. Both Häggström et al [12] and Wallmyr [33] were able to determine where operators were looking at when performing their tasks.…”

“…Although we cannot have detailed analysis on areas of attention when operating forest harvesters like what Häggström et al [12] and Wallmyr [33] have done using eyetracking glasses (see Fig. 2), we are still able to determine where the operators were looking at when performing their tasks.…”

“…Looking at some prior field studies that investigated forest harvesters-related issues, we found that most field studies were able to observe a limited number of operators and forest harvesters. Sirén [28], Häggström et al [12], and Nurminen et al [23] respectively observed four, six, and eight operators in their studies. Wallmyr [33] observed operators of several types of industrial vehicles, including one forest harvester.…”

1st workshop on user interfaces for heavy vehicles

“…Interaction in heavy vehicles is significantly different to automobiles. In heavy vehicles, the focus is on performing a task rather than on driving per se [5,7]. The operator is often a professional, sometimes trained to operate the vehicle.…”