利用感知對比能量將診斷資訊隱藏於醫學影像之研究

Patient Information Concealed in a Medical Image by Perceptual Contrast Energy

翟皓緯(Hao-Wei Jhai) ； 陳文儉(Wen-Jan Chen)

《科學與工程技術期刊》 4卷2期 (2008/06) Pp. 1-9

https://doi.org/10.7117/JSET.200806.0001

摘要

近年來，隨著醫療影像的數位化，醫療影像的保護及認證在醫療機構的資訊傳遞中已愈顯重要。爲了避免病人資訊或編號遭到惡意的篡改，在這篇論文中，我們提出了利用基於人類感知技術的數位浮水印方法將病人診療資訊嵌入醫療影像當中，首先利用Perceptual Quality Measure(PQM)並控制臨界值大小將醫療影像分爲明顯與不明顯區域，將病人資訊嵌入不明顯區域中以減少醫師的誤判可能。然後使用在離散餘弦轉換(discrete cosine transform, DCT)域下的浮水印方法，來維持加入浮水印後影像的視覺品質及強韌度。實驗顯示出在加入浮水印後影像遭惡意僞造或是一般影像處理，譬如提高對比亮度、清晰化及JPEG壓縮後，在不需要原圖的情況下仍可萃取出病人診療資訊，以達到認證的效果。

關鍵字

醫療影像 ； perceptual quality measure PQM ； 數位浮水印 ； 離散餘弦轉換

並列摘要

Recent developments in computer science have enabled the digitalization of medical images; moreover, the copyright and authentication protection of these images is becoming increasingly important in the transmission of data between hospitals. In this research, a perceptual model-based digital watermarking technique for embedding patient information in a medical image is proposed. First, the Perceptual Quality Measure (PQM) method is used to classify a medical image into significant and insignificant regions by controlling the threshold, and embedding patient information in the insignificant regions to increase the peak signal-to-noise ratio (PSNR). Then, a blind-image watermarking method in the discrete cosine transform (DCT) domain is used to achieve high quality and robustness in the concealed images. The experimental results indicate that the watermark can be clearly extracted by illegal forgery and image-processing techniques such as brightness/contrast enhancement, filter-sharpening, adding noise and JPEG lossy compression.

並列關鍵字

medical image ； perceptual quality measure PQM ； digital watermarking ； discrete cosine transform DCT ； blind image watermarking