Robust Hashing Based on Quaternion Gyrator Transform for Image Authentication

Image hashing is one of the most effective methods in many image processing applications including image recognition or authentication, tampering detection, image retrieval, etc. In this paper, we propose a novel image hash method based on quaternion gyrator transform, which is more secure and compact in addition to its robustness and discriminative properties. In this proposed method, the quaternion gyrator transform (QGT), like the traditional quaternion Fourier transform which is a linear regular integral ratio transform is applied to effectively extract image features. Firstly, our hash function needs to scale all pictures to a fixed size. And the quaternion gyrator transform is used to transform each non-overlapping block in the original image for extracting the feature map of the source image. For each block, the inner product of the feature and a random weight is used to be one bit of the final image hash. Experiments with different image databases are conducted to test and verify the efficiency of our method. The result has proved that our method of constructing hash is robust to most of the content-preserving operations with a good distinction. Compared with some state-of-the-art hash algorithms, our algorithm is more excellent and has better performance in robustness and distinguishability.