{'fraction_non_alphanumeric': 0.021739130434782608, 'fraction_numerical': 0.003105590062111801, 'mean_word_length': 4.525714285714286, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Colour image-hiding scheme using human visual system

Abstract This paper proposes a spatial-domain image-hiding scheme for colour images. The objective is to conceal as much information of the secret image in the cover image as possible, while retaining the quality of the stego-image. This is achieved by manipulating colour images in the YUV colour space. The main idea is to embed the most significant bits of the Y and the quantized U and V components of the secret image in the Y components of the cover image pixels. To enhance the image quality, a threshold mechanism is adopted which takes the human visual effect into consideration. The experimental results demonstrate high peak signal-to-noise ratio, and show that the difference between the stego-image and the cover image is almost imperceptible. In the proposed scheme, the cover image can embed a secret image as large as two-thirds of the cover image size if the secret image is in the 4:2:0 format.