Development of a camera-based perspective transform method for quantifying passenger-vehicle driver direct visibility

The Insurance Institute for Highway Safety developed a camera-based perspective transformation method for measuring driver direct visibility. This data collection method captures the driver’s full vertical and 360 lateral field of view (FOV) including pillars, side mirrors, hood and door beltlines. All-around maps of the visible ground points are generated without the need for a physical grid or external curtain setup, which is ideal for field data collection. A rig with standardized eye heights is installed in the driver’s seat to take photos every 15° laterally, with a 130° vertical FOV. The driver’s eye point is measured relative to the vehicle left front corner at ground level then camera lens characteristics are used to complete a perspective transformation, allowing annotated points on the images to be projected onto a virtual ground. This method was compared to a traditional grid method to confirm accuracy, with all forward and side points varying less than 0.6 m distance. Points directly behind the driver, which are farther in the distance and highly sensitive to chosen pixel varied up to 2.3 m. Repeatability and reproducibility assessments showed good agreement, with all variations in distance less than 1 m. Data from these visibility maps will quantify the range of blind zones in vehicles and provide guidance to improve driver visibility.