Using Accelerometer Data to Estimate Surface Incline and Its Walking App Potential

Walking is a fundamental human activity and its diminution a potential morbidity factor. Recent developments in mobile computing have enabled ubiquitous monitoring of walking activity via the smartphone accelerometers. Typically, walking apps map accelerometer values to caloric values through a calibration algorithm. However, these calibration algorithms assume a flat surface, which is not always true and can introduce significant errors. In this paper, we outline a novel calibration method that estimates surface inclination for uphill walking, thus, improving the caloric estimation in mobile walking apps.