The present invention discloses an
edge detection-based
grayscale image steganography method. The objective of the invention is to carry out concealed communication in a
public transport channel and prevent the theft and disclosure of confidential information. According to the method, a
grayscale image is divided into two parts according to an
edge detection method, namely a contour pixel sequence and a non-contour pixel sequence; based on different characteristics of the pixel sequence obtained through the
image edge detection and other pixels, steganographic data are embedded into a contour part and a non-contour part according to different embedding rates; and therefore, high efficiency, reliability and concealment of an steganographic image can be improved in aspects such as
image sensing and security. The method is divided into two stages, namely, the embedding stage and extraction stage of confidential information; in an
embedding process, in order to ensure the integrity of the confidential information, contour extraction is performed by using the high bits of the pixel value of an image, and the embedding of the confidential information is performed by using the low bits of the pixel value of the image; in the embedding stage, the
encryption of the confidential information and the conversion of a binary sequence are ensured, and then the binary sequence is embedded into the pixel value of the image; and in the extraction stage, it can be ensured that the binary sequence can be extracted from the steganographic image, and therefore, the confidential information can be obtained through decoding conversion and restoration.