V. Senthooran, L. Ranathunga, KokSheik Wong
Abstract: Imperceptibility and the embedding capacity are the two most important characteristics to be considered in the image based steganographic research studies. In the frequency domain, however, the secret message is first transformed into frequency domain and then the secret messages are embedded in the DCT transformed quantized coefficients. Many researchers have shown that the optimized modified quantization tables in the embedding process in DCT domain significantly reduce the distortion in the quality of stego-images and increase the embedding capacity of stego-image. This paper intends to review and analysis of the performance and efficiency of using optimized quantization tables instead of default JPEG tables within JPEG based image steganography and suggest optimized modified table for data embedding with comparison of previous methods. Data embedding capacity, Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR) have been analyzed by modifying quantization tables entry for standard test images and they show the significance performance based on the quantization table modification. In addition to that, we suggest novel technique for data embedding based on quantization table modification.
Keywords: quantization tables, steganography, JPEG, DCT, stego-image, MSE, PSNR