Digital watermarking : applicability for developing trust in medical imaging workflows state of the art review

Medical images can be intentionally or unintentionally manipulated both within the secure medical system environment and outside, as images are viewed, extracted and transmitted. Many organisations have invested heavily in Picture Archiving and Communication Systems (PACS), which are intended to facilitate data security. However, it is common for images, and records, to be extracted from these for a wide range of accepted practices, such as external second opinion, transmission to another care provider, patient data request, etc. Therefore, confirming trust within medical imaging workflows has become essential. Digital watermarking has been recognised as a promising approach for ensuring the authenticity and integrity of medical images. Authenticity refers to the ability to identify the information origin and prove that the data relates to the right patient. Integrity means the capacity to ensure that the information has not been altered without authorisation. This paper presents a survey of medical images watermarking and offers an evident scene for concerned researchers by analysing the robustness and limitations of various existing approaches. This includes studying the security levels of medical images within PACS system, clarifying the requirements of medical images watermarking and defining the purposes of watermarking approaches when applied to medical images

Analisis Watermarking Citra Digital Dengan Menggunakan Reversible by Difference Expansion Dengan Domain Spatial Quads

ABSTRAKSI: Teknologi informasi berkembang dengan sangat pesat seiring dengan semakin meningkatnya kebutuhan akan kecepatan pertukaran data. Namun perkembangan teknologi informasi ini juga memicu permasalahan baru yaitu tentang kepemilikan dan hak cipta dari suatu data, pemalsuan data, pengubahan data secara illegal, dan lain sebagainya. Salah satu solusi dari permasalahan tersebut adalah watermarking. Banyak metode watermarking yang sudah dikembangkan untuk berbagai tujuan. Salah satu contohnya yaitu reversible watermarking by difference expansion with spatial quads domain. Metode ini memanfaatkan difference antar pixel – pixel yang bertetanggaan dalam sebuah quad vector untuk menyisipkan bit – bit label watermark. Kelebihan dari metode ini adalah kemampuannya untuk mengembalikan image host persis sama seperti sebelum dilakukan penyisipan. Dengan kelebihan ini, sebuah image dapat diwatermark berkali –kali dan tetap dapat dikembalikan persis seperti semula. Karakteristik lain dari metode ini adalah tingkat robustness label watermark yang disisipkan sangatlah rendah. Sedikit saja perubahan dilakukan pada image yang sudah terwatermark akan menyebabkan label watermark tidak akan bisa dikenali pada saat ekstraksi. Untuk proses ekstraksi, metode ini membutuhkan sebuah location map dan key. Ukuran location map sangat besar sehingga keberadaannya cukup mengurangi tingkat invisibility image terwatermark. Peniadaan location map akan menyebabkan jumlah bit yang harus disisipkan menjadi berkurang sehingga invisibility menjadi bertambah. Dengan ciri – ciri tersebut maka metode ini sangat cocok diterapkan untuk content authentification.Kata Kunci : reversible difference expansion, reversible watermarking, bitmap, least significant bits (LSB), domain spatial.ABSTRACT: Information technology developing rapidly as the need of fast data exchange increase. But since every people can copy, edit or even admit data of other person as his, there rise new issue about the belonging and copyright of data, counterfeit data, and illegal editting. One of many technicque that can be used to solve these issue is watermarking.Many watermarking method that had been developed for many purpose. Reversible watermarking by difference expansion with spatial quads domain is an example. This method using difference between adjacent pixels in quad vector to embed bits of watermark label. The advantage of this method is it’s ability to restore the host image after extraction exactly the same as the host image before embedding process. With this advantage, an image can be watermarked many times and still can be restored perfectly. The other characteristic of this method is robustness of the watermark label is very low. Slight distortion in watermarked image can make the watermark label can not be identified anymore. For Extraction process, this method needs location map and key. The size of location map is very large that can make the watermarked image quality lower. If the location map is disabled then the amount of bits that will be embedded decrease so the invisibility of the watermarked image will increase. This method is suitable to be applied for content authentification since this method has these characteristic.Keyword: reversible difference expansion, reversible watermarking, bitmap, least significant bits (LSB), domain spatial

Reversible Data Hiding Using Hybrid Method of Difference Expansion on Medical Image

Data hiding in the image can cause permanent distortion (irreversible), in other applications such as medical images, distortion can cause misdiagnosis. To overcome these problems, a special scheme is required for the embedding data on medical image. Reversible data hiding is a scheme that can restore the image to original image without distortion after the embedded information is extracted. Difference Expansion (DE) is one of the schemes in reversible data hiding that is simple and easy to implement. In this paper, we propose two schemes based a hybrid combination of DE to increase on capacity and visual quality. Medical image has characteristics is the large of smooth block areas, in which DE method is applied to the non-smooth areas image. We used four different medical images to evaluate the proposed scheme. The results showed that the proposed scheme has a high capacity and better visual quality than the original scheme and similar schemes have been proposed previously. Embedding capacity of the proposed scheme is up to 0.66 bpp with visual quality of PSNR value is up to 48 dB

ROI-based reversible watermarking scheme for ensuring the integrity and authenticity of DICOM MR images

Reversible and imperceptible watermarking is recognized as a robust approach to confirm the integrity and authenticity of medical images and to verify that alterations can be detected and tracked back. In this paper, a novel blind reversible watermarking approach is presented to detect intentional and unintentional changes within brain Magnetic Resonance (MR) images. The scheme segments images into two parts; the Region of Interest (ROI) and the Region of Non Interest (RONI). Watermark data is encoded into the ROI using reversible watermarking based on the Difference Expansion (DE) technique. Experimental results show that the proposed method, whilst fully reversible, can also realize a watermarked image with low degradation for reasonable and controllable embedding capacity. This is fulfilled by concealing the data into ‘smooth’ regions inside the ROI and through the elimination of the large location map required for extracting the watermark and retrieving the original image. Our scheme delivers highly imperceptible watermarked images, at 92.18-99.94dB Peak Signal to Noise Ratio (PSNR) evaluated through implementing a clinical trial based on relative Visual Grading Analysis (relative VGA). This trial defines the level of modification that can be applied to medical images without perceptual distortion. This compares favorably to outcomes reported under current state-of-art techniques. Integrity and authenticity of medical images are also ensured through detecting subsequent changes enacted on the watermarked images. This enhanced security measure, therefore, enables the detection of image manipulations, by an imperceptible approach, that may establish increased trust in the digital medical workflow

Protection of medical images and patient related information in healthcare: Using an intelligent and reversible watermarking technique

This work presents an intelligent technique based on reversible watermarking for protecting patient and medical related information. In the proposed technique ‘IRW-Med’, the concept of companding function is exploited for reducing embedding distortion, while Integer Wavelet Transform (IWT) is used as an embedding domain for achieving reversibility. Histogram processing is employed to avoid underflow/overflow. In addition, the learning capabilities of Genetic Programming (GP) are exploited for intelligent wavelet coefficient selection. In this context, GP is used to evolve models that not only make an optimal tradeoff between imperceptibility and capacity of the watermark, but also exploit the wavelet coefficient hidden dependencies and information related to the type of sub band. The novelty of the proposed IRW-Med technique lies in its ability to generate a model that can find optimal wavelet coefficients for embedding, and also acts as a companding factor for watermark embedding. The proposed IRW-Med is thus able to embed watermark with low distortion, take out the hidden information, and also recovers the original image. The proposed IRW-Med technique is effective with respect to capacity and imperceptibility and effectiveness is demonstrated through experimental comparisons with existing techniques using standard images as well as a publically available medical image dataset

Peningkatan Performa Metode Steganografi Berbasis Difference Expansion Menggunakan Reduksi Selisih

Pertukaran data medis dilakukan untuk mempermudah profesional kesehatan untuk merawat pasien. Untuk hal itu, otentikasi menjadi perhatian utama untuk menjamin data medis yang bersangkutan adalah milik pasien yang benar dan juga berasal dari sumber yang benar. Salah satu metode yang dapat digunakan untuk keperluan tersebut adalah data hiding. Namun, metode yang digunakan tidak boleh menyebabkan distorsi yang permanen terhadap media yang digunakan karena dapat menyebabkan kesalahan diagnosa. Difference Expansion adalah satu metode yang mampu memenuhi persyaratan tersebut. Metode ini masih bisa menjadi topik yang menarik untuk diteliti. Khususnya pada kapasitas penyisipan data dan similarity antara cover image dengan stego image. Metode yang baik adalah metode yang mampu menyediakan kapasitas dan similarity citra yang tinggi. Pada penelitian ini, kami mengusulkan metode berbasis DE dengan berfokus pada dua masalah tersebut. Secara lebih terperinci, kami melakukan reduksi terhadap nilai selisih piksel agar menghasilkan tingkat similarity yang lebih baik dan mampu menyediakan kapasitas pesan yang lebih besar. Selain itu, kami menggunakan piksel median sebagai base point untuk menghitung selisih menggantikan piksel pertama pada masingmasing blok. Hasil percobaan yang dilakukan pada 5 citra medis menunjukkan bahwa metode yang diusulkan berhasil meningkatkan PSNR serta kapasitas penyisipan

Data Security using Reversible Data Hiding with Optimal Value Transfer

In this paper a novel reversible data hiding algorithm is used which can recover image without any distortion. This algorithm uses zero or minimum points of an image and modifies the pixel. It is proved experimentally that the peak signal to noise ratio of the marked image generated by this method and the original image is guaranteed to be above 48 dB this lower bound of peak signal to noise ratio is much higher than all reversible data hiding technique present in the literature. Execution time of proposed system is short. The algorithm has been successfully applied to all types of images