Multi-DisNet: Machine Learning-Based Object Distance Estimation from Multiple Cameras

In this paper, a novel method for distance estimation from multiple cameras to the object viewed with these cameras is presented. The core element of the method is multilayer neural network named Multi-DisNet, which is used to learn the relationship between the sizes of the object bounding boxes in the cameras images and the distance between the object and the cameras. The Multi-DisNet was trained using a supervised learning technique where the input features were manually calculated parameters of the objects bounding boxes in the cameras images and outputs were ground-truth distances between the objects and the cameras. The presented distance estimation system can be of benefit for all applications where object (obstacle) distance estimation is essential for the safety such as autonomous driving applications in automotive or railway. The presented object distance estimation system was evaluated on the images of real-world railway scenes. As a proof-of-concept, the results on the fusion of two sensors, an RGB and thermal camera mounted on a moving train, in the Multi-DisNet distance estimation system are shown. Shown results demonstrate both the good performance of Multi-DisNet system to estimate the mid (up to 200 m) and long-range (up to 1000 m) object distance and benefit of sensor fusion to overcome the problem of not reliable object detection.