You can merge small, adjacent fixations in Data Viewer to clean up noisy data. There are two main methods: a simple, general-purpose tool and an advanced procedure designed specifically for reading research. To automatically merge fixations that are close to each other based on simple distance and duration criteria.
How to enable it:
Alternative: The 4-Stage Fixation Cleaning Tool
Data Viewer's 4-Stage Fixation Cleaning tool can be used to apply a multi-stage approach to clean up / merge fixations based on multiple criteria. This option is intended for use only by reading researchers who want to follow a cleaning procedure that is established in their field. To perform this action, right click in the top panel of the Data tab in the Inspector window and select "Perform 4-stage Fixation Cleaning".
A prompt with options to perform the four stages will appear and the stages can be applied individually or in sequence:
How to enable it:
- In the Inspector window, go to the Preferences tab.
- Select Data Filters.
- Check the box for Merge Nearby Fixations and set your desired amplitude and duration thresholds.
Alternative: The 4-Stage Fixation Cleaning Tool
Data Viewer's 4-Stage Fixation Cleaning tool can be used to apply a multi-stage approach to clean up / merge fixations based on multiple criteria. This option is intended for use only by reading researchers who want to follow a cleaning procedure that is established in their field. To perform this action, right click in the top panel of the Data tab in the Inspector window and select "Perform 4-stage Fixation Cleaning".
A prompt with options to perform the four stages will appear and the stages can be applied individually or in sequence:
- STAGE 1 - For each Interest Area, Data Viewer checks for each fixation whether it’s time duration is shorter or equal to the STAGE 1 duration threshold. If not, the current fixation will not be cleaned; if it is, Data Viewer checks the duration and distance of the fixation immediately before and after the current fixation. The fixation will be merged to the neighboring fixation if its duration is longer than the threshold value and its distance along the X axis (in degrees) from the current fixation is shorter or equal to the STAGE 1 distance threshold. If both the previous and next fixations meet the above criterion, the current fixation will be merged to the longer one of the two.
- STAGE 2 - This stage is similar to STAGE 1 except you should set shorter fixation duration and a longer distance value relative to STAGE 1 so that additional fixation merging can occur.
- STAGE 3 - Data Viewer rechecks all of the data to find Interest Areas that include at least three fixations smaller than the STAGE 3 threshold duration and no fixations larger than the threshold duration. It then merges the shorter fixations into the larger ones.
- STAGE 4 - Data Viewer rechecks all fixations and deletes every fixation that is shorter than minimum duration or larger than the maximum duration threshold.