Normalize gaze coordinates to screen-relative units

Transforms raw gaze coordinates (in pixels) to normalized coordinates where:

• (0,0) represents the center of the screen

• Coordinates are scaled to [-1,1] range

• Also calculates the normalized distance from screen center

Usage

normalize_gaze_coords(pupil_df, screen_width, screen_height)

Arguments

pupil_df

A data frame containing raw gaze coordinates (eye_x, eye_y)

screen_width

The screen width in pixels

screen_height

The screen height in pixels

Value

A data frame with added columns:

• eye_x_norm: Normalized x coordinate [-1,1]

• eye_y_norm: Normalized y coordinate [-1,1]

• gaze_dist_from_center: Normalized distance from screen center