Deep Learned Cumulative Attribute Regression

Learning regression-based machine learning models for computer vision problems is a challenging task due to noisy features, variation in pose and illumination, occlusion, etc. Typically the problem is compounded by the non-uniform distribution of labels in the training data, resulting in parts of the label space that suffer from data sparsity and a problem of label imbalance in general. Deep Convolutional Neural Networks (CNN) have shown remarkable success on a number of computer vision tasks such as object classification and face recognition. However, they too suffer from sparse and imbalanced training datasets for regression problems, even when those datasets are very large. Cumulative Attributes have previously been proposed to address the issue of label imbalance, but to date this concept has not been integrated with Deep Learning. In this work, we propose a CNN-based framework for learning regression models by using Cumulative Attributes as intermediate features. We evaluate our method on a number of tasks which includes pain intensity estimation, Facial Action Unit intensity estimation and age estimation. Our results show that the proposed method is robust to imbalance and sparsity present in the training datasets, and performs significantly better than the current methods where CNNs are learnt directly for regression.