A Deep Learning Application for Detecting Facade Tile Degradation

Abstract

Facade tiles of buildings are likely to weaken, crack, or fall off due to aging or out of natural causes such as temperature variations during daytime and nighttime and earthquakes. Tile spalling of tall buildings often leads to accidents or even severe casualties. In view that a routine thorough inspection is costly, this study aims to develop a cost-effective means to detect facade tile degradation of tall buildings through machine learning. We leverage a drone to film outer walls of high-rise buildings at several dozens of sites, from which training data are produced for learning and validation. We resort to a convolutional neural network with deep learning capabilities that is trained with sufficient knowledge to identify hazardous conditions of cracked tiles in two or three levels. Core to our implementation is Jetson TX2—an embedded system—which is programmed in light of AlexNet over Keras and TensorFlow, open-source libraries for deep neural network programming. To heighten learning quality subject to limited amount of training data, image preprocessing involving gray-level transformation, thresholding, and morphological operations is introduced. Experimental results corroborate that our scheme achieves a correct classification rate of over 86%. Our development serves a moderate approach to deep learning in daily contexts, a practical scenario over which to inspire other applications.