Currently, our most significant risk is head pose estimation – head pose is not being successfully classified for distracted driving. Finding a relation between a driver’s distance from the camera and the angles of the head that will constitute as looking away from the road is very difficult. To solve this, we are looking into ways to better calibrate the head pose estimation. One idea for calibration is to have the driver look up, down, left and right, measuring the angles and determining the threshold angles of looking away from the road. We will test this calibration step with a variety of chair heights and distances from the steering wheel.
Another risk is that since the accelerometer does not directly measure velocity, our calculated mph values increasingly drift from the actual velocity value over time. This affects our ability to control issuing of feedback based on the velocity of the car. This issue occurs because we are calculating velocity by integrating samples of the acceleration (by adding (accel_curr – accel_prev) * 0.5 * (curr_time – prev_time) to prev calculated velocity). We also tried subtracting the initial measured y acceleration from each later measured y acceleration, but the calculated y acceleration still becomes very inaccurate over time. When updating our velocity calculation every 0.5s and keeping the accelerometer stationary, the calculated y acceleration becomes -2 m/s (~1mph in reverse) after only a minute. Possible mitigation strategies include subtracting the average y acceleration value that (over 10 or so samples) as a calibration step. Another option would be to purchase a different sensor that measures velocity directly.
No changes have been made to the existing design of the system since last week.
We updated our Gantt chart to reflect what we have completed and reprioritize the tasks that we have left. This coming week we finish integration and get started with testing the entire system in a car (stationary initially). In the current schedule, Yasser has 2 weeks of slack and Sirisha and Elinora have 1 week of slack.
Images of head pose working (when angle and distance from camera are kept constant):
