基于離散余弦變換彩色圖像的數字水印研究

閭楓

摘要： 為了在彩色圖像中嵌入彩色數字水印，同時保持原始彩色圖像的完整性及健壯性，提出基于空間域和頻率域間轉換，配合RGB色彩系統，利用離散余弦變換將圖像的空間域表示轉換為頻率域，將彩色數字水印頻域系數經適當處理后嵌入圖像的低頻部分，使嵌入的彩色數字水印能抵抗各種圖像處理時的破壞。實驗結果表明：應用該方法嵌入彩色數字水印，不僅不破壞原始彩色圖像品質，而且能抵抗外界的破壞，成功取回所嵌信息。

關鍵詞： 彩色圖像； 彩色數字水印； 頻率域； 離散余弦變換

中圖分類號：TP391文獻標志碼：A 文章編號：1006-8228（2012）09-33-04

Study on color image digital watermarking based on discrete cosine transform

Lv Feng

（Changzhou College of Information Technology, Changzhou, jiangsu 213164, China）

Abstract: Color digital watermark embedded in color images has becoming a hot topic in current study on how to maintain the integrity and robustness of the original color image. Based on transitions between the spatial and frequency domain, combined with RGB color system, a method is proposed so that it transforms the spatial domain into frequency domain by discrete cosine transform method, and embeds the frequency domain coefficients of color digital watermark into lower frequency part of images after proper processing. In this way, the embedded color watermark can resist any kinds of image destructions. The experimental results show that applying the proposed method to embed color digital watermark is not only harmless to the quality of the original color image, but also resistant to outer destructions, in which way the embedded information can be successfully retrieved.

Key words: color images； color digital watermark； frequency domain； discrete cosine transform