Deep end-to-end learning based stereo matching methods have achieved great success as witnessed by the leaderboards across different benchmarking datasets. Depth information in stereo vision systems are obtained by a dense and accurate disparity map, which is computed by a robust stereo matching algorithm. However, previous works adopt network layer with the same size to train the feature parameters and get an unsatisfactory efficiency, which cannot be satisfied for the real scenarios by existing methods. In this paper, we present an end-to-end stereo matching algorithm based on "downsize" convolutional neural network (CNN) for autonomous driving scenarios. Firstly, the road images are feed into the designed CNN to get the depth information. And then the "downsize" full-connection layer combined with subsequent network optimization is employed to improve the accuracy of the algorithm. Finally, the improved loss function is utilized to approximate the similarity of positive and negative samples in a more relaxed constraint to improve the matching effect of the output. The loss function error of the proposed method for KITTI 2012 and KITTI 2015 datasets are reduced to 2.62 and 3.26% respectively, which also reduces the runtime of the proposed algorithm. Experimental results illustrate that the proposed end-to-end algorithm can obtain a dense disparity map and the corresponding depth information can be used for the binocular vision system in autonomous driving scenarios. In addition， our method also achieves better performance when the size of the network is compressed compared with previous methods.
Keywords: binocular vision; convolutional neural network; image sensor; stereo matching.