Color-secure digital image compression

The wide spread acquisition and use of ultra-high resolution color images obtained from high-resolution imaging sensors introduces open problems of optimal storage and transmission while securing important color information as well as preserving fine details in these high quality images. This paper describes a steganography-based paradigm for high-quality compression of fine-detailed color megapixel images highly applicable to forensic imaging applications. Our scheme combines space-domain and frequency-domain image processing operations where in the space domain, color-brightness separation is exploited, and in the frequency domain, discrete cosine transform energy compaction properties of the transformed luminance image is exploited. Experimental results as well as empirical observations show that our technique is very competitive with the highest quality JPEG image compression standard in the overall fidelity of the decompressed image while achieving high compression ratios. However, the main purpose of this new compression scheme is not to compete with the JPEG standard in terms of visual quality measures, but to provide a means for securing vital color information in the original image from potential tampering while allowing high compression ratios without loss of important fine details.