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The exponential growth of data raises an unprecedented challenge in data analysis: how to retrieve interesting information from such large-scale data. Hash learning is a promising solution to address this challenge, because it may bring many potential advantages, such as extremely high efficiency and low storage cost, after projecting high-dimensional data to compact binary codes. However, traditional hash learning algorithms often suffer from the problem of semantic inconsistency, where images with similar semantic features may have different binary codes. In this paper, we propose a novel end-to-end deep hashing method based on the similarities of binary codes, dubbed CSDH (Code Similarity-based Deep Hashing), for image retrieval. Specifically, it extracts deep features from images to capture semantic information using a pre-trained deep convolutional neural network. Additionally, a hidden and fully connected layer is attached at the end of the deep network to derive hash bits by virtue of an activation function. To preserve the semantic consistency of images, a loss function has been introduced. It takes the label similarities, as well as the Hamming embedding distances, into consideration. By doing so, CSDH can learn more compact and powerful hash codes, which not only can preserve semantic similarity but also have small Hamming distances between similar images. To verify the effectiveness of CSDH, we evaluate CSDH on two public benchmark image collections, i.e., CIFAR-10 and NUS-WIDE, with five classic shallow hashing models and six popular deep hashing ones. The experimental results show that CSDH can achieve competitive performance to the popular deep hashing algorithms. [ABSTRACT FROM AUTHOR]

In order to improve the limitations of manual features and poor feature semantics in the feature extraction process of existing content-based encrypted speech retrieval methods, and as well as improve retrieval accuracy and retrieval efficiency, a content-based encrypted speech retrieval scheme with deep hashing was proposed. Firstly, the original speech file is encrypted by using Henon mapping chaotic encryption to construct encrypted speech library. Secondly, adopting secondary feature extraction method to extract the spectrogram feature, and using the spectrogram as the input of the designed convolutional neural network (CNN) for model training and deep hashing feature learning, to obtain the deep hash binary code of original speech, and upload it to the deep hash index table in the cloud. In addition, the batch normalization (BN) method is introduced to improve robustness and generalization ability of the model. Finally, establish a one-to-one mapping relationship between the encrypt speech in the encrypted speech library and the hash sequence in the deep hash index table. When retrieving for speech users, the normalized Hamming distance algorithm is used for retrieve matching. The experimental results show that the deep hash binary code constructed by the proposed method has strong discriminability and robustness, and it still has high recall rate, precision rate and retrieval efficiency under various general content preserving operations. [ABSTRACT FROM AUTHOR]

Content-based histopathology image retrieval can be a useful technique for help in diagnosing various diseases. The process of retrieving images is often time-consuming and challenging due to the need for high-dimensional features when trying to model complex content. Hashing methods can therefore be employed to resolve the challenge by producing binary codes of different lengths. Deep hashing methods are frequently superior to traditional machine learning approaches but are affected by the size of training sets. In addition, back-propagation learning can further complicate the generation of binary values. Hence, this paper proposes a novel Siamese deep hashing model, named histopathology Siamese deep hashing (HSDH), for histopathology image retrieval. Two designed deep hashing models with shared weights and structures are used to generate hash codes. A Hamming distance layer is then applied to evaluate the similarity of the generated values. A highly effective loss function is also introduced that incorporates a modified version of the standard contrastive loss function with an error estimation term to improve both the training and retrieval phases. In the retrieval phase, the trained model compares a query image with all the training images and ranks the most similar images. According to the experimental results on two publicly available databases, BreakHis and Kather, the HSDH model outperforms other state-of-the-art hashing-based methods in histopathology image retrieval. [ABSTRACT FROM AUTHOR]