Image steganalysis based on deep learning
The present invention provides a method for detecting image steganography based on deep learning, which comprises: filtering images having steganographic class label or true class label in a training set with a high-pass filter to obtain a training set including steganographic class residual images and true class residual images; training a deep network model on said training set to obtain a trained deep model for steganalysis; filtering the image to be detected with said high-pass filter to obtain a residual image to be detected; detecting said residual image to be detected on said deep model so as to determine whether said residual image to be detected is a steganographic image. The method for detecting image steganography in the present invention can create an automatic blind steganalysis model through feature learning and can identify steganographic images accurately.
1. A method for detecting image steganography based on deep learning, characterized by comprising:
filtering images having steganographic class label or true class label in a training set with a high-pass filter to obtain a training set including steganographic class residual images and true class residual images;
training a deep network model on said training set to obtain a trained deep network for steganalysis;
filtering the image to be detected with said high-pass filter to obtain a residual image to be detected;
detecting said residual image to be detected on said trained deep network so as to determine whether said residual image to be detected is a steganographic image.
2. The method for detecting image steganography based on deep learning according to claim 1 , characterized in that said deep network model is a Convolutional Neural Network (CNN).
3. The method for detecting image steganography based on deep learning according to claim 2 , characterized in that said CNN comprises at least two convolutional layers, at least one fully-connected layer and an output layer.
4. The method for detecting image steganography based on deep learning according to claim 3 , characterized in that an activation function for elements in the convolutional layers is a Gauss function.
5. The method for detecting image steganography based on deep learning according to claim 3 , characterized in that an activation function for elements in the fully-connected layer is a ReLU function (6):
f ( x )=max(0, x ) (6).
6. The method for detecting image steganography based on deep learning according to claim 3 , characterized in that an activation function for elements in the output layer is a softmax function (8):
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7. The method for detecting image steganography based on deep learning according to claim 2 , characterized in that said training the deep network model comprises performing an average pooling operation to pooling windows corresponding to the convolutional layer.
8. The method for detecting image steganography based on deep learning according to claim 2 , characterized in that said training a deep network model to obtain the trained deep network for steganalysis comprises:
training the deep convolutional neural network CNN using a back propagation algorithm through minimizing the function shown in formula (9) so as to obtain the trained deep network for steganalysis:
−log z i (9)
wherein i∈{1, 2}.
9. The method for detecting image steganography based on deep learning according to claim 1 , characterized in that said high-pass filter can be either linear or non-linear.
10. The method for detecting image steganography based on deep learning according to claim 1 , characterized in that said image is a gray scale image.