Compression detection, Image quality, JPEG
نویسنده
چکیده
The paper presents two methods of prior JPEG-compression detection. In the first method the histogram of chrominance is analysed. In JPEGcompressed images the histogram contains significantly more local maxima than in uncompressed files. The second method is based on neighbouring pixel Ø value difference. In JPEG-compressed image the distribution of these values is different than the distribution counted on the edges of compression 8x8 blocks. These differences are summed up to create a classifier that allows to assess if the image was compressed.
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