VNLSTM-PoseNet: a novel deep ConvNet for real-time 6-DOF camera relocalization in urban streets

Image-based relocalization is a renewed interest in outdoor environments, because it is an important problem with many applications. PoseNet introduces Convolutional Neural Network (CNN) for the first time to realize the real-time camera pose solution based on a single image. In order to solve the problem of precision and robustness of PoseNet and its improved algorithms in complex environment, this paper proposes and implements a new visual relocation method based on deep convolutional neural networks (VNLSTM-PoseNet). Firstly, this method directly resizes the input image without cropping to increase the receptive field of the training image. Then, the image and the corresponding pose labels are put into the improved Long Short-Term Memory based (LSTM-based) PoseNet network for training and the network is optimized by the Nadam optimizer. Finally, the trained network is used for image localization to obtain the camera pose. Experimental results on outdoor public datasets show our VNLSTM-PoseNet can lead to drastic improvements in relocalization performance compared to existing state-of-the-art CNN-based methods.