US 2008/0175429 A1 · METHOD AND APPARATUS FOR STEGANALYSIS FOR TEXTURE IMAGES

Abstract

Embodiments of the invention are directed toward methods for steganalysis that improve the detection of steganography in texture images. The methods combine features extracted from the image spatial representation and from a block discrete cosine transform (BDCT) representation with multiple different block sizes (i.e., N×N) to improve detection of data hidden in texture images. Image data that is to undergo steganalysis can be provided to embodiments of the invention in at least one of spatial (pixel) and JPEG format. When JPEG format is provided, the image is first decompressed to spatial representation, from which the features are extracted when the block size is at least one 2×2, 4×4, and 16×16. When the block size is 8×8, the JPEG coefficients (JPEG quantized 8×8 BDCT coefficients) derived directly from the JPEG image are used to extract features. In addition, the method is also effective as a universal steganalyzer for both texture and smooth/non-texture images. Embodiments of the invention also (1) utilize moments of 1-D and 2-D characteristic functions; (2) Prediction-error; and (3) all wavelet subbands including the low-low subbands.

Claims31

Dependent claims

A method for steganalysis of an image comprising:

inputting a two-dimensional (2-D) spatial representation of the image;
generating non-overlapping, N×N block decompositions of the spatial representation of the image;
applying N×N block discrete cosine transforms (BDCT) to each of the non-overlapping, N×N block decompositions;
determining BDCT coefficient 2-D arrays of for each N×N block;
extracting moments of a characteristic function from the spatial representation of the image and each of the BDCT coefficient 2-D arrays;
generating features based at least on the extracted moments of the characteristic function;
and
classifying the image based at least on the generated features.

5 more elements

A processor-readable medium containing software code that, when executed by a processor, causes the processor to implement a method for steganalysis of an image comprising:

inputting a two-dimensional (2-D) spatial representation of the image;
generating non-overlapping, N×N block decompositions of the spatial representation of the image;
applying block discrete cosine transform (BDCT) to each of the non-overlapping, N×N block decompositions;
determining BDCT coefficient 2-D arrays;
extracting moments of a characteristic function from the spatial representation of the image and each of the BDCT coefficient 2-D arrays;
generating features based at least on the extracted moments of the characteristic function;
and
classifying the image based at least on the generated features,
wherein the block size N is at least one of 2, 4, 8 and 16.

6 more elements

A processor-readable medium containing software code that, when executed by a processor, causes the processor to implement a method for steganalysis of an image comprising:

inputting a JPEG representation of the image;
performing a JPEG decompression of the JPEG representation;
reconstructing a spatial representation of the image from the JPEG decompression
performing entropy decoding of the JPEG representation;
re-ordering the entropy decoded JPEG representation;
generating non-overlapping, N×N block decompositions of the spatial representation of the image;
applying block discrete cosine transform (BDCT) to each of the non-overlapping, N×N block decompositions;
determining BDCT coefficient 2-D arrays;
forming 8×8 JPEG coefficient from the re-ordering of the entropy decoding of the JPEG representation;
extracting moments of a characteristic function from the spatial representation of the image, BDCT coefficient 2-D arrays and 8×8 JPEG coefficients 2-D arrays;
generating features based at least on the extracted moments of the characteristic function;
and
classifying the image based at least on the generated features.

10 more elements

Dependencies are inferred from the claim text.

Method and apparatus for steganalysis for texture images

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Method and apparatus for steganalysis for texture images

Life of this patent

Abstract

Claims31