Two-Class Weather Classification.

Given a single outdoor image, we propose a collaborative learning approach using novel weather features to label the image as either sunny or cloudy. Though limited, this two-class classification problem is by no means trivial given the great variety of outdoor images captured by different cameras where the images may have been edited after capture. Our overall weather feature combines the data-driven convolutional neural network (CNN) feature and well-chosen weather-specific features. They work collaboratively within a unified optimization framework that is aware of the presence (or absence) of a given weather cue during learning and classification. In this paper we propose a new data augmentation scheme to substantially enrich the training data, which is used to train a latent SVM framework to make our solution insensitive to global intensity transfer. Extensive experiments are performed to verify our method. Compared with our previous work and the sole use of a CNN classifier, this paper improves the accuracy up to 7-8 percent. Our weather image dataset is available together with the executable of our classifier.