40results about How to "Guaranteed invisibility" patented technology

The invention discloses a method for embedding and extracting a strong robustness hologram watermark on the basis of DWT-SVD (Discrete Wavelet Transform-Singular Value Decomposition). The method comprises the following steps: 1) carrying out transform on an original watermark image to generate a Fourier transform encryption hologram digital watermark, and carrying out singular value decomposition to obtain a singular value matrix; 2) carrying out channel separation on an RGB (Red Green Blue) colorful carrier image, carrying out second-level wavelet decomposition on a B component, and carrying out the singular value decomposition on a low-frequency coefficient matrix to obtain the singular value matrix; 3) embedding, multiplying the singular value matrix generated in the step 1) by an embedding coefficient K, embedding the obtained value into the singular value matrix generated in the step 2) through a gray level adding method, carrying out reduction and wavelet inverse transform on the generated singular value matrix, and combining channels to obtain the RGB colorful carrier image which contains the digital watermark; and 4) carrying out extraction, carrying out channel separation on the RGB colorful carrier image which contains the digital watermark, carrying out the second-level wavelet decomposition and the singular value decomposition to obtain the singular value matrix, subtracting the singular value matrix generated in the step 2) from the singular value matrix obtained in the step 4), dividing the obtained value by the embedding coefficient K, and carrying out the inverse transform to obtain original watermark information.

The invention discloses a scattering and wave-transmitting integrated electromagnetic coding metamaterial integrated with multiple phase regulation and control. The scattering and wave-transmitting integrated electromagnetic coding metamaterial is composed of metamaterial basic units of a multi-layer stacked structure. Each basic unit comprises a first metal layer, a first dielectric layer, a honeycomb layer, a second dielectric layer and a second metal layer which are arranged in sequence, wherein the first metal layer comprises a deformed Jerusalem cross, and the second metal layer comprisesa cross groove. Due to the special structural design, the units have anisotropism, and different reflection and transmission characteristics are shown under incidence of x and y polarized waves. According to the invention, the structure is simple, the processing is easy, the RCS reduction can be realized by using a scattering mechanism in a broadband, and a wave-transparent frequency point with high transmissivity exists in an RCS reduction band, so that the working environment of radio equipment is effectively improved.

The invention provides a digital watermarking algorithm for the enhancement of the robustness of a watermarking system, wherein the algorithm comprises the steps of coding specific marking information as a quick response matrix code (QR (Quick Response) code), as a digital watermark, and making use of discrete wavelet transform to embed the QR code into an intermediate frequency coefficient after secondary wavelet decomposition of a carrier image. Therefore, under the premise of assurance of the invisibility of the watermark, the enhancement of the watermark robustness is achieved. The simulation experimental result of a watermark attack indicates that as the digital watermark, the QR code is capable of largely enhancing the robustness of the watermarking system. The digital watermarking algorithm can be widely used in the fields of copyright protection, anti-counterfeiting and the like, and has certain practical value.

The invention belongs to the field of digital watermarking technology and copyright protection, in order to realize self-adaptive simultaneous embedding of a plurality of color watermarks, balance theinvisibility of the embedded watermark image and the robustness of the concealment method to various geometric attacks or image processing attacks. To this end, the technical scheme adopted by the invention is that EVD-HG and DWT-SVD adaptive watermark image processing method, the image to be hidden is firstly scrambled and encrypted by Arnold transform and rotator Gyrator transform; Then, the carrier image is transformed by wavelet transform, the selected frequency part is decomposed by singular value decomposition, and the encrypted color watermarks are embedded into the singular value partof the carrier image. Finally, the singular value part of the secret image is combined with the eigenvector and then the inverse wavelet transform is performed to obtain the carrier image containingthe secret image. The invention is mainly applied to digital watermarking occasions.

Treating original watermark in binary form, the invention constructs pyramidal watermark with descended resolution layer by layer. Meanwhile, using wavelet transform decomposes multimedia data. Then, according to certain rule, some special wavelet coefficients are selected to embed to watermark. Finally, multimedia data with watermark being embedded into can be obtained through wavelet inverse transform. The invention possesses capability of detecting interpolation including interpolation characteristic and region. The invention also discloses rules of classifying interpolation to distinguish occasional interpolation from vicious interpolation. Thus, vulnerable watermark can resist such as JPEG loss compression etc. content lockout operation. The invention insures reliability of multimedia data released or transferred on network so that it is applicable to authentication possibly.

The invention provides a digital watermarking method based on 2DPCA (two-dimensional principal component analysis), belonging to the field of digital watermarking. The method comprises the following steps of: pre-processing an image: performing various non-linear geometrical transform to the primary image to obtain a new image after each transform, extracting an image characteristic vector matrix and an image principal component matrix; watermarking pre-processing; watermarking embedding; recovering the image; and watermarking extracting. As the characteristic vector matrix which is used for extracting the image principal component matrix is unchanged, even though each valve of the image principal component matrix is changed, the fluctuation range of the data in the image principal component matrix is approximately similar; i leading out principal components are selected from the principal component matrix of the primary image; namely, weight values of i different principal components representing image information are accumulated, and the accumulation sum is within the range of 0.4-0.9; and the i leading out principal components are subjected from discrete cosine transform or Fourier transform. The invention, under the precondition of ensuring robustness and invisibility of the digital watermarking, effectively resists attack from the non-linear geometry.

The invention discloses a blind watermark implantation method and device, a blind watermark detection method and device, equipment and a storage medium, and relates to the field of image processing. The blind watermark implantation method comprises the steps of obtaining a target image frame in a to-be-encrypted video; determining the implantation position of a blind watermark in the frequency domain of the target image frame; calculating a blind watermark pixel value through a Sobel operator according to the watermark matrix of the blind watermark and the frequency domain coefficient at the implantation position; filling the frequency domain pixel point of the implantation position with the blind watermark pixel value to obtain an image frame after the blind watermark is implanted; and performing flag bit filling in the spatial domain of the implanted image frame to obtain an encrypted image frame. According to the method, the blind watermark implanted in the image frame can simultaneously achieve high robustness and high resistance to cutting attack.

The invention discloses encrypted kinoform based digital image watermarking embedding and extracting methods and systems. The digital image watermarking embedding method comprises the following steps of: transforming an original watermarking image through non-cascaded phase recovery and random fractional fourier transform (RFrFT) to acquire an encrypted kinoform of the original watermarking image; and adaptively embedding the encrypted kinoform into a carrier image based on a human visual system (MVS) model. In the invention, the safety of the watermarking of the kinoform is enhanced by usinga non-cascaded iterative encryption method; meanwhile, blink watermarking is realized by adopting an adaptive embedding algorithm; and experiments verify that extremely high robustness against various attacks is achieved, and the safety performance is extremely high.

The invention provides a digital watermarking method based on 2DPCA (two-dimensional principal component analysis), belonging to the field of digital watermarking. The method comprises the following steps of: pre-processing an image: performing various non-linear geometrical transform to the primary image to obtain a new image after each transform, extracting an image characteristic vector matrixand an image principal component matrix; watermarking pre-processing; watermarking embedding; recovering the image; and watermarking extracting. As the characteristic vector matrix which is used for extracting the image principal component matrix is unchanged, even though each valve of the image principal component matrix is changed, the fluctuation range of the data in the image principal component matrix is approximately similar; i leading out principal components are selected from the principal component matrix of the primary image; namely, weight values of i different principal componentsrepresenting image information are accumulated, and the accumulation sum is within the range of 0.4-0.9; and the i leading out principal components are subjected from discrete cosine transform or Fourier transform. The invention, under the precondition of ensuring robustness and invisibility of the digital watermarking, effectively resists attack from the non-linear geometry.

The invention relates to a fragile watermark technology based on wavelet transform, which belongs to the field of multimedia signal processing. The invention first processes the original watermark in binary format, constructs a watermark pyramid with decreasing resolution layer by layer, and uses wavelet transform to decompose multimedia data, and then selects some special wavelet coefficients to embed watermark according to certain rules. Finally, the multimedia data embedded with watermark is obtained by inverse wavelet transform. The present invention has multi-resolution tampering detection capability, ensures accurate detection of tampering characteristics and tampering areas, and the present invention also provides a tampering classification rule, so as to distinguish malicious tampering from accidental tampering, so that the fragile watermark can resist such as JPEG Content preservation operations such as lossy compression meet actual needs. The invention can authenticate the authenticity and integrity of the multimedia data or files propagated through the network, so as to ensure the credibility of the multimedia data when it is transmitted and released through the network.

This invention discloses one active digital image content identification method based on wavelet and DCT double areas, which comprises the following steps: send end processes water mark generation, imbedding and image identification and modification initial position, wherein, through above position to generate water mark images to restore property extraction and imbedding water mark and restoring.

The invention provides an error tolerance quantum steganography sub-protocol applicable to collective dephasing noise channels. Logic Bell states are utilized to overcome collective dephasing noise. A quantum covert channel constructed in normal quantum communication and utilized for distributing secret messgaes is established by means of exchange of the two logic Bell states. The Bell state measurement rather than quadri-quantum bit united measurement is utilized for decoding. The error tolerance quantum steganography sub-protocol applicable to the collective dephasing noise channels has the advantages that the channel capacity of the protocol reaches to 4 bits for every turn of covert communication, and invisibility and safety are guaranteed.