This application is directed to augmenting training images used for generating a model for monitoring vehicle drivers. A computer system obtains a first image of a first driver in an interior of a first vehicle and separates, from the first image, a first driver image from a first background image of the interior of the first vehicle. The computer system obtains a second background image and generates a second image by overlaying the first driver image on the second background image. The second image is added to a corpus of training images to be used by a machine learning system to generate a model for monitoring vehicle drivers. In some embodiments, at least one of the first driver image and the second background image is adjusted to match lighting conditions, average intensities, and sizes of the first driver image and the second background image.