Compressing JPEG compressed image using reversible data hiding technique

Abstract

1 Abstract-Since the concept of reversible data hiding technique was introduced, many researchers have applied it for authentication of uncompressed images. In this paper, an algorithm is introduced to compress JPEG files again without any loss in image quality. The proposed method can modify an entire segment of VLC codeword sequence to embed a bit of data. The modified codewords may destroy the correlation, or the smoothness, between neighboring pixels of the recovered image. The data extractor utilizes the smoothness change to know the hidden data. For this, a novel smoothness measurement function which uses both inter-and intra-MAD values is proposed. When the smoothness change is small, two consecutive segments are concatenated to extract correct data with higher smoothness sensitivity. As a result, compression ratio or embedding capacity is increased in most natural images.

Lossless Quality Steganographic Color Image Compression

“…50% compression rate), while Kang et. al in [18] were able to improve the JPEG compression rate by adding an extra 0.36% to a current rate.…”

“…[1], the dual domain watermarking for authentication and compression method presented in [40], the DCT-based data-hiding method to embed color information in JPEG grey level images published in [10], the Semantic compression method for greyscale image compression proposed by Zhang & Zhang [39], and the Reversible Data Hiding-based compression Technique proposed by Kang et. al [18].…”

“…In [18] the authors implement a lossless compression technique for further compressing JPEG compressed images by hiding some of the image data inside the entropy coded portion of the JPEG quantized DCT coefficients. The maximum compression rates they have been able to achieve for grey-scale images was 0.36% above the already compressed JPEG image.…”