Building Corner Detection in Aerial Images with Fully Convolutional Networks
School of Computer Science and Technology, Soochow University, Suzhou 215006, China
Provincial Key Laboratory for Computer Information Processing Technology, Soochow University, Suzhou 215006, China
Author to whom correspondence should be addressed.
Sensors 2019, 19(8), 1915; https://doi.org/10.3390/s19081915
Received: 30 January 2019 / Revised: 13 April 2019 / Accepted: 20 April 2019 / Published: 23 April 2019
(This article belongs to the Special Issue Deep Learning Remote Sensing Data)
In aerial images, corner points can be detected to describe the structural information of buildings for city modeling, geo-localization, and so on. For this specific vision task, the existing generic corner detectors perform poorly, as they are incapable of distinguishing corner points on buildings from those on other objects such as trees and shadows. Recently, fully convolutional networks (FCNs) have been developed for semantic image segmentation that are able to recognize a designated kind of object through a training process with a manually labeled dataset. Motivated by this achievement, an FCN-based approach is proposed in the present work to detect building corners in aerial images. First, a DeepLab model comprised of improved FCNs and fully-connected conditional random fields (CRFs) is trained end-to-end for building region segmentation. The segmentation is then further improved by using a morphological opening operation to increase its accuracy. Corner points are finally detected on the contour curves of building regions by using a scale-space detector. Experimental results show that the proposed building corner detection approach achieves an F-measure of 0.83 in the test image set and outperforms a number of state-of-the-art corner detectors by a large margin.