  As prior knowledge of objects or object features helps us make relations for
similar objects on attentional tasks, pre-trained deep convolutional neural
networks (CNNs) can be used to detect salient objects on images regardless of
the object class is in the network knowledge or not. In this paper, we propose
a top-down saliency model using CNN, a weakly supervised CNN model trained for
1000 object labelling task from RGB images. The model detects attentive regions
based on their objectness scores predicted by selected features from CNNs. To
estimate the salient objects effectively, we combine both forward and backward
features, while demonstrating that partially-guided backpropagation will
provide sufficient information for selecting the features from forward run of
CNN model. Finally, these top-down cues are enhanced with a state-of-the-art
bottom-up model as complementing the overall saliency. As the proposed model is
an effective integration of forward and backward cues through objectness
without any supervision or regression to ground truth data, it gives promising
results compared to state-of-the-art models in two different datasets.
