关键词: 图像哈希, 混合特征, 颜色矢量角度, 二次图像, 显著性边缘像素点, Logistic映射, 加密机制

Abstract: In order to solve the problem as low robustness and tamper detection ability induced by ignoring the color feature and angle feature of the image in current image Hashing technology, which mainly uses the image gray information to generate the Hash sequence, the robust color image Hashing algorithm based on mixed features and color vector angles is designed by extracting the color information and angle features of color images. Firstly, the linear interpolation and Gauss low-pass filter are introduced to preprocess the initial image for enhancing the robustness of content preserving operations such as scaling and noise. Then, the filtered image is divided into a series of non overlapping sub-blocks, and the secondary image is obtained by using the singular value decomposition method to process each sub-block. By designing the robust feature extraction method, the color vector angle of two images is calculated to obtain the perceptual features of the image for determining the salient feature points. A mixed feature is formed by combining the extracted two features, and a new feature sequence is outputted based on quantization method. The encryption mechanism is designed based on the Logistic map to confuse the feature sequence, and it can obtain the robust Hash sequence. Finally, the Hamming distance is used to detect the authenticity of image content. The experimental results show that the proposed algorithm has higher robustness and tamper detection accuracy compared with the current Hash technique.

Key words: image Hash, mixed feature, angle of color vector, secondary image, salient edge points, Logistic mapping, encryption mechanism