DSHPoolF: deep supervised hashing based on selective pool feature map for image retrieval

Abstract

Deep supervised hashing has turned up to unravel many large-scale image retrieval challenges. Although deep supervised hashing accomplishes good results for image retrieval process, requisite for further improving the retrieval accuracy always remains the primal focus of interest. In Deep hashing methods, feature representation happens at the outset of the fully connected (FC) layers, causing shortage of spatial information owing to its global nature, whereas deeper pooling layers preserve semantically similar information by retaining the images spatial information, which can result in uplifting the retrieval performance. Hereby, for enhancing the image retrieval accuracy through exploring spatial information, a novel way of deep supervised hashing based on Pooled Feature map (DSHPoolF) is proposed to generate compact hash codes that explore the spatial information by weighing the informative Feature maps from the last pooling layer. This is achieved, firstly, by weighing the last pooling layers Feature map in two ways, namely average–max-based pooling and probability-based pooling strategies. Secondly, informative Feature maps are selected with the help of the weights. In addition to this, the informative Feature maps play a key role in optimizing quantization error together with the loss function and classification errors in a single-step, point-wise ranking manner. This proposed DSHPoolF method is assessed using three datasets (CIFAR-10, MNIST and ImageNet) that unveils primitive outcome in comparison with other existing prominent hash-based methods.