Digital multitoning is an advanced form of halftoning-based printing technique which renders multiple tones at each pixel of an image. This superior scheme delivers an improved print quality in terms of smooth texture, homogeneity and the suppression of artefacts. This Letter examines the potential scope of multitoning as an effective strategy to embed a binary watermark within a multitoned image. The proposed method uses the significant difference among the highpass wavelet coefficients achieved by discrete wavelet transform for watermark embedding. Furthermore, an improvised ordered dithering technique using adaptive threshold quantisation is also incorporated, which not only makes the proposed method time-efficient but also offers uniformity to the final image. The proposed watermarking technique is imperceptible and yields watermarked images with high peak signal-to-noise ratio value. Experimental simulations demonstrate that the proposed watermarking method is superior to the state-of-the-art methods in the context of both objective and subjective assessments.

中文翻译：

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多色调图像中基于显着差异的水印

数字多色调是一种高级形式的基于半色调的印刷技术，它在图像的每个像素上呈现多种色调。这种卓越的方案在平滑纹理、均匀性和伪影抑制方面提供了改进的打印质量。这封信研究了多色调作为在多色调图像中嵌入二进制水印的有效策略的潜在范围。该方法利用离散小波变换实现的高通小波系数之间的显着差异进行水印嵌入。此外，还结合了使用自适应阈值量化的临时有序抖动技术，这不仅使所提出的方法具有时间效率，而且还为最终图像提供了均匀性。所提出的水印技术是不可察觉的并且产生具有高峰值信噪比值的水印图像。实验模拟表明，所提出的水印方法在客观和主观评估的背景下都优于最先进的方法。