Robust and Imperceptible Watermarking on Medical Images using Coefficient Pair Modification
Authors: Novamizanti Ledya , Suksmono Andriyan Bayu , Danudirdjo Donny , Budiman Gelar 
Published: January 2023

Sensitive data including medical images and electronic patient records (EPR) have potential value in the era of big data and telemedicine applications. Distribution of medical images and EPR over public networks requires a high level of privacy and security. Robust and imperceptible watermarking techniques are needed to provide copyright preservation for medical images and protect patient information security. This paper improves the technique of Coltuc et al. by modifying the discrete cosine transform (DCT) coefficient pairs in the watermark embedding formula. Our proposed formula ensures that the difference between the two coefficients is at least ????. If the difference between the two coefficients is less than ????, then the new pixels are modified so that the difference is equal to ????. The proposed method was evaluated on a variety of medical images, including X-ray, CT, US, MRI, and Colonoscopy, and compared to numerous robust watermarking techniques of the recent time. The experimental results demonstrate that the suggested method outperforms contemporary robust watermarking techniques in terms of imperceptibility, robustness, and security. The peak signal noise ratio (PSNR) for all modalities of watermarked medical images exceeds 54 dB, and the average PSNR is approximately 56 dB. The proposed method is outstanding compared to Coltuc's method due to a 93% and 14% increase in bit error rate (BER) and normalized correlation (NC), respectively. Our work is superior to various state-of-the-art robust watermarking techniques, allowing it to be employed effectively in medical applications.
ABSTRAK: Data sensitif termasuk imej perubatan dan rekod pesakit elektronik (EPR) mempunyai potensi nilai dalam era aplikasi data besar dan teleperubatan. Pengedaran imej perubatan dan EPR melalui rangkaian awam memerlukan tahap privasi dan keselamatan yang tinggi. Teknik penanda air yang mantap dan tidak dapat dilihat diperlukan untuk menyediakan pemeliharaan hak cipta untuk imej perubatan dan melindungi keselamatan maklumat pesakit. Kertas kerja ini menambah baik teknik Coltuc et al. dengan mengubah suai pasangan pekali transformasi kosinus diskret (DCT) dalam formula pembenaman tera air. Formula yang dicadangkan kami memastikan bahawa perbezaan antara dua pekali adalah sekurang-kurangnya ????. Jika perbezaan antara dua pekali kurang daripada ????, maka piksel baharu diubah suai supaya perbezaannya sama dengan ????. Kaedah yang dicadangkan telah dinilai pada pelbagai imej perubatan, termasuk X-ray, CT, US, MRI, dan Kolonoskopi, dan dibandingkan dengan banyak teknik penanda air yang mantap pada masa terkini. Keputusan eksperimen menunjukkan bahawa kaedah yang dicadangkan mengatasi teknik penanda air teguh kontemporari dari segi ketidakjelasan, keteguhan dan keselamatan. Nilai PSNR untuk semua modalitas imej perubatan bertanda air melebihi 54 dB, dan nilai purata PSNR adalah lebih kurang 56 dB. Kaedah yang dicadangkan adalah cemerlang daripada kaedah Coltuc kerana masing-masing peningkatan 93% dan 14% dalam BER dan NC. Kerja kami lebih unggul daripada pelbagai teknik penanda air teguh terkini, membolehkan ia digunakan dengan berkesan dalam aplikasi perubatan.