1. A method for tracking objects in an environment, comprising: acquiring a first sequence of images of the environment with a camera having a first frame rate, wherein the camera is a visible light camera; acquiring a second sequence of images of the environment with a sensor having a second frame rate, wherein the sensor is a thermal infrared (IR) sensor, and wherein the second frame rate is substantially lower than the first frame rate; tracking objects in the first sequence of images to obtain tracks; detecting warm regions in the second sequence of images to obtain detections; aligning spatially and temporally the tracks and the detections; and verifying whether the tracks and detections coincide after the aligning.