Space Field Information Hiding Technique Base On Human Visual Sensitivity Characteristics

Currently, carriers used for information hiding are text, image, voice, and video,yet methods adopted are essentially the same. With large redundancy in space, imagesare the mostly used information hiding carrier. Two kinds of techniques forinformation hiding with images as carriers are available, one is transform domainbased, the other spatial domain based. The first technique is robust yet computationalheavy, and hard to implement information hiding and batch processing in WEBapplications. To achieve information hiding with high capacity and fast operation, thespace-based technique is desirable. Traditional space-based algorithm uses regionswith high gray scales only, leaving regions with high gray scales useless, not alongthe utilization of human visual sensitivity characteristic, although it is helpful forhigh capacity in information hiding.To take account of human visual sensitivity characteristic, as well as informationhiding rate, capacity, and visual effect, an algorithm based on normalized curve ofhuman visual sensitivity is proposed. Based on normalized curve of human visualsensitivity, the algorithm uniformly distributes bits within the carrier in regions wherehuman visual sensitivity is low, so that the bits’ distribution is centrosymmetric withrespect to normalized curve of human visual sensitivity, with more bits in regionswith high or low gray scales, and fewer bits in regions with moderate gray scales. Thealgorithm is more reasonable than traditional ones with progress both in visual effectand hiding bits’ distribution by transforming bits in regions with high gray scales nearmoderate ones to regions with low gray scales. Experiments manifest using thealgorithm proposed, that the information hiding rate can reach up to50%with highercapacity, sounder bit distribution, and lower distortion rate in the same capacity.An encryption policy adapted to the algorithm proposed is conceived in thisarticle, including scrambling encryption for carriers and chaotic encryption forinformation to be hidden. Experiments suggest that the combined encryption policy ismore preferable and safer than just embedding the information sequentially into acarrier.