AbdulWahab Kabani and Mahmoud R. El-Sakka, "Object Detection and Localization using Deep Convolutional Networks with Softmax Activation and Multi-class Log Loss", International Conference on Image Analysis and Recognition, ICIAR'2016, LNCS 9730, pp. 358-366, Springer-Verlag Berlin Heidelberg, July 2016, Povoa de Varzim, Portugal.
We introduce a deep neural network that can be used to localize and detect a region of interest (ROI) in an image. We show how this network helped us extract ROIs when working on two separate problems: a whale recognition problem and a heart volume estimation problem. In the former problem, we used this network to localize the head of the whale while in the later we used it to localize the heart left ventricle from MRI images. Most localization networks regress a bounding box around the region of interest. Unlike these architecture, we treat the problem as a classification problem where each pixel in the image is a separate class. The network is trained on images along with masks which indicate where the object is in the image. We treat the problem as a multi-class classification. Therefore, the last layer layer has a softmax activation. Furthermore, during training, the mutli-class log loss is minimized just like any classification task.