Direction Estimation of Aerial Image Object Based on Neural Network

Abstract

Due to the inherent periodicity of the angle, the direction of the object detected by the current rotating object detection algorithm is fuzzy. In order to solve this problem, this paper proposes a rotating object direction estimation method based on a neural network, which determines the unique direction of the object by predicting the direction vector of the object. Firstly, we use the two components (sin θ, cos θ) of the direction vector and the length and width parameters of the object to express the object model. Secondly, we construct a neural network model to predict the parameters used to express the object model. However, there is a constraint that the sum of the squares of the two components of the direction vector of the object is equal to 1. Because each output element of the neural network is independent, it is difficult to learn the constrained data between such neurons. Therefore, the function transformation model is designed, and the network transformation layer is added. Finally, affine transformation is used to transform the object parameters and carry out regression calculation, so as to detect the object and determine the direction of the object at the same time. This paper uses three sets of data to carry out the experiment, which are DOTA 1.5, HRSC, and UCAS-AOD data sets. It can be seen from the experimental results that for the object with correct ground truth, the proposed method can not only locate the object but also estimate the direction of the object accurately.

Keywords

• object detection
• direction estimation
• direction vector
• neural network