Copyright protection for elemental image array by hypercomplex Fourier transform and an adaptive texturized holographic algorithm

Digital media zero watermark copyright protection algorithm based on embedded intelligent edge computing detection

With the rapid development of computer technology and network communication technology, copyright protection caused by widely spread digital media has become the focus of attention in various fields. For digital media watermarking technology research emerge in endlessly, but the results are not ideal. In order to better realize the copyright identification and protection, based on the embedded intelligent edge computing detection technology, this paper studies the zero watermark copyright protection algorithm of digital media. Firstly, this paper designs an embedded intelligent edge detection module based on Sobel operator, including image line buffer module, convolution calculation module and threshold processing module. Then, based on the embedded intelligent edge detection module, the Arnold transform of image scrambling technology is used to preprocess the watermark, and finally a zero watermark copyright protection algorithm is constructed. At the same time, the robustness of the proposed algorithm is tested. The image is subjected to different proportion of clipping and scaling attacks, different types of noise, sharpening and blur attacks, and the detection rate and signal-to-noise ratio of each algorithm are calculated respectively. The performance of the watermark image processed by this algorithm is evaluated subjectively and objectively. Experimental data show that the detection rate of our algorithm is the highest, which is 0.89. In scaling attack, the performance of our algorithm is slightly lower than that of Fourier transform domain algorithm, but it is better than the other two algorithms. The Signal to Noise Ratio of the algorithm is 36.854% in P6 multiplicative noise attack, 39.638% in P8 sharpening edge attack and 41.285% in fuzzy attack. This shows that the algorithm is robust to conventional attacks. The subjective evaluation of 33% and 39% of the images is 5 and 4. The mean values of signal to noise ratio, peak signal to noise ratio, mean square error and mean absolute difference are 20.56, 25.13, 37.03 and 27.64, respectively. This shows that the watermark image processed by this algorithm has high quality. Therefore, the digital media zero watermark copyright protection algorithm based on embedded intelligent edge computing detection is more robust, and its watermark invisibility is also very superior, which is worth promoting.

Real-time and ultrahigh accuracy image synthesis algorithm for full field of view imaging system

In this paper, we propose a real time, ultrahigh accuracy and full-field-of-view (RUF) algorithm for full field of view (FOV) imaging system. The proposed algorithm combines rough matching and precise matching method to stitch multiple images with the whole FOV in short time and high imaging quality. In order to verify real-time imaging effect of RUF algorithm, we also fabricate a multi-camera imaging system which includes 19 independent cameras. And the experiment result practically illustrates that full-FOV system can achieve good performances under a near-limiting FOV of 360° × 240° with low distortion, meanwhile, optical resolution reaches up to 95 megapixels. 100% registration-accuracy RUF algorithm for imaging in one second can be widely applied to any optical imaging engineering field with large FOV, such as remote sensing imaging, microscopy imaging, monitoring system engineering fields and so on.

An Adaptive and Secure Holographic Image Watermarking Scheme

A novel adaptive secure holographic image watermarking method in the sharp frequency localized contourlet transform (SFLCT) domain is presented. Based upon the sine logistic modulation map and the logistic map, we develop an encrypted binary computer-generated hologram technique to fabricate a hologram of a watermark first. Owing to the enormous key space of the encrypted hologram, the security of the image watermarking system is increased. Then the hologram watermark is embedded into the SFLCT coefficients with Schur decomposition. To obtain better imperceptibility and robustness, the entropy and the edge entropy are utilized to select the suitable watermark embedding positions adaptively. Compared with other watermarking schemes, the suggested method provides a better performance with respect to both imperceptibility and robustness. Experiments show that our watermarking scheme for images is not only is secure and invisible, but also has a stronger robustness against different kinds of attack.

Ownership protection of holograms using quick-response encoded plenoptic watermark

In actual applications of three-dimensional (3D) holographic display, the holograms need to be effectively stored and transmitted through the network. Thereby, there is an urgent demand for protecting the ownership of holograms against piracy and malicious manipulation. This paper realizes an ownership protection for holograms by embedding the watermark into the optimized cellular automata (OCA) domains. This work has the advantages of simultaneously improving the imperceptibility by selecting the "best" rule and OCA domains for watermark embedding and increasing robustness via the property of the multiple memory of the plenoptic image. We present experimental results of the visual quality of watermarked holograms and the robustness of 3D watermark to verify the performance of the proposed watermarking method. Experimental results confirm the imperceptibility and robustness of the proposed method.

Imperceptible reversible watermarking of radiographic images based on quantum noise masking

BACKGROUND AND OBJECTIVE

Advances in information and communication technologies boost the sharing and remote access to medical images. Along with this evolution, needs in terms of data security are also increased. Watermarking can contribute to better protect images by dissimulating into their pixels some security attributes (e.g., digital signature, user identifier). But, to take full advantage of this technology in healthcare, one key problem to address is to ensure that the image distortion induced by the watermarking process does not endanger the image diagnosis value. To overcome this issue, reversible watermarking is one solution. It allows watermark removal with the exact recovery of the image. Unfortunately, reversibility does not mean that imperceptibility constraints are relaxed. Indeed, once the watermark removed, the image is unprotected. It is thus important to ensure the invisibility of reversible watermark in order to ensure a permanent image protection.

METHODS

We propose a new fragile reversible watermarking scheme for digital radiographic images, the main originality of which stands in masking a reversible watermark into the image quantum noise (the dominant noise in radiographic images). More clearly, in order to ensure the watermark imperceptibility, our scheme differentiates the image black background, where message embedding is conducted into pixel gray values with the well-known histogram shifting (HS) modulation, from the anatomical object, where HS is applied to wavelet detail coefficients, masking the watermark with the image quantum noise. In order to maintain the watermark embedder and reader synchronized in terms of image partitioning and insertion domain, our scheme makes use of different classification processes that are invariant to message embedding.

RESULTS

We provide the theoretical performance limits of our scheme into the image quantum noise in terms of image distortion and message size (i.e. capacity). Experiments conducted on more than 800 12 bits radiographic images of different anatomical structures show that our scheme induces a very low image distortion (PSNR∼ 76.5 dB) for a relatively important capacity (capacity∼ 0.02 bits of message per pixel).

CONCLUSIONS

The proposed watermarking scheme, while being reversible, preserves the diagnosis value of radiographic images by masking the watermark into the quantum noise. As theoretically and experimentally established our scheme offers a good capacity/image quality compromise that can support different watermarking based security services such as integrity and authenticity control. The watermark can be kept into the image during the interpretation of the image, offering thus a continuous protection. Such a masking strategy can be seen as the first psychovisual model for radiographic images. The reversibility allows the watermark update when necessary.

Designing optical 3D images encryption and reconstruction using monospectral synthetic aperture integral imaging

This paper realizes an optical 3D images encryption and reconstruction by employing the geometric calibration algorithm to the monospectral synthetic aperture integral imaging system. This method has the simultaneous advantages of improving the quality of 3D images by eliminating the crosstalk from the unaligned cameras and increasing security of the multispectral 3D images encryption by importing the random generated maximum-length cellular automata into the Fresnel transform encoding algorithm. Furthermore, compared with the previous 3D images encryption methods of encrypting 3D multispectral information, the proposed method only encrypts monospectral data, which will greatly minimize the complexity. We present experimental results of 3D image encryption and volume pixel computational reconstruction to test and verify the performance of the proposed method. Experimental results validate the feasibility and robustness of our proposed approach, even under severe degradation.

Optical encryption via monospectral integral imaging

Optical integral imaging (II) uses a lenslet array and CCD sensor as the 3D acquisition device, in which the multispectral information is acquired by a color filter array (CFA). However, color crosstalk exists in CFA that diminishes color gamut, resulting in the reduced resolution. In this paper, we present a monospectral II encryption approach with a monospectral camera array (MCA). The monospectral II system captures images with the MCA that can eliminate color crosstalk among the adjacent spectral channels. It is noteworthy that the captured elemental images (EIs) from the colored scene belong to grayscale; the colored image encryption is converted to grayscale encryption. Consequently, this study will significantly save the calculation load in image encoding and decoding (nearly reduced 2/3) compared with the similar works. Afterwards, an optimized super-resolution reconstruction algorithm is introduced to improve the viewing resolution.