35 results about "Quantization index modulation" patented technology

The invention discloses a video watermarking method based on a visual attention mechanism. Binary-system watermark information is embedded into a DCT domain in a visual non-saliency area of an MPEG-2 video key frame is selected to achieve the purpose of video copyright protection. The video watermarking method comprises the following steps of decoding a carrier video and obtaining the video key frame I; adopting a Koch and Itti visual remarkable model to analyze visual saliency of the video key frame and dividing a visual saliency area; selecting the visual non-saliency area human eyes are not too sensitive to, performing fixed-step-length odd-even quantization index modulation on a DCT direct current coefficient of luminance component and embedding watermark information; analyzing the visual saliency of the video key frame with embedded watermarks, judging a watermark embedding area and extracting the watermark information according to watermark embedding rules. The visual attention feature of the human eyes is effectively utilized in the video watermarking method, the invisibility of the video watermarks is improved, the video watermarking method has good robustness on common video attacks, and contradiction between the watermark invisibility and the robustness is effectively relieved.

A hybrid watermark insertion method includes the steps of dividing the digital image into a low frequency region and a high frequency region using an edge map of the digital image; inserting a watermark into the low frequency region of the image by employing a watermarking method using a human visual system (HVS); and inserting the watermark into the high frequency region of the image by employing a quantization index modulation (QIM) method. A hybrid watermark extraction method includes the steps of estimating a reference value used when inserting a watermark, and searching a maximum value of correlation coefficients in an image of the watermark image while changing the estimated reference value within a designated range, to thereby find out the watermark insertion method. Accordingly, the watermark insertion method can be easily identified, thereby enabling the watermark extraction in a more readily manner.

It is an adaptive expanding transform jitter modulation watermarking method. The expanding transform jitter modulation watermarking has the advantages both quantitative index modulation watermarking and spread spectrum communication system, and it has a good performance against attack. However, the original STDM method uses the fixed quantization step, which takes no account of human perceptual model, so its performance is greatly limited. The invention introduces a human perception model/signal quality evaluation method to the original STDM, used to measure the distortion introduced by watermarking and compute a weighted sequence, and the use of weighted plastic watermarking idea changes host signals, to make the local variable capacity of the host signal apply for the human perception system; re-designing the quantization step to meet the distortion conditions determined by un-perceptibility. Using the method described in the invention, the embedded watermark can fully use the local characteristics of carrier signal, adaptive design the quantization step, greatly enhance the watermark robustness, and at the same time achieve a good watermark un-perceptibility.

The invention discloses a color image watermark embedding and detecting method based on quaternion Legendre moment correction. First, the Legendre invariant theory for traditional gray images is extended to a quaternion level, and a quaternion Legendre moment invariant suitable for describing color image content is constructed; and then, a digital watermark is embedded into a low-frequency region of a discrete quaternion cosine transform domain by a quantization index modulation (QIM) method. During watermark detection, part of low-order quaternion Legendre moment invariants are selected as feature vectors to obtain a least squares support vector machine (LS-SVM) training model so as to improve the performance of a color image classifier. Simulation experiments show that the method has good imperceptibility, and has good robustness to conventional signal processing (especially for the color attack mode) and de-synchronization attack.

The invention discloses a digital image watermarking method based on the local index torque characteristic. Characteristic points of an original image are extracted and screened through brightness probability density gradient Harris-Laplace operators, and a screened characteristic point image is obtained; in the obtained characteristic point image, round areas with the characteristic points as circle centers are extended into square areas, and local characteristic areas are constructed and screened; the index toque of the obtained local characteristic area image is obtained through calculation, needed stable index toque is selected, the amplitude values of the index torque are modified with a quantization index modulation method, and watermarking information is embedded; the selected index torque is respectively reconstructed before or after the watermarking information is embedded, two reconstructed images are obtained and subjected to difference value calculation, the obtained difference values are overlaid into the local characteristic areas corresponding to the original image, and small images with watermarks are obtained; watermarking information is embedded into all the local characteristic areas.

The invention discloses a blind audio watermark implementing method based on logarithmic quantization index modulation, and belongs to the technical field of audio watermarks. The blind audio watermark implementing method is characterized by including sufficiently utilizing robustness of vector norms and imperceptibility of the logarithmic quantization index modulation based on mu-law companding; improving safety and robustness of a watermark by the aid of a chaos sequence encryption watermark image; converting the sectioned vector norms of wavelet approximate components into a transform domain via the mu-law companding; then embedding an encryption binary watermark image; and extracting the binary watermark image after the watermark is attacked. The audio watermark algorithm has the advantages of high volume, fine tone, imperceptibility and robustness and low complexity, the watermark still can be correctly extracted by the aid of the method under various watermark attack conditions, and accordingly amplitude attack can be effectively resisted by the method.

The invention relates to a system for embedding auxiliary information in a media signal such as an audio visual signal. An apparatus comprises a quantization index modulator (103) which generates a modified signal by quantization index modulation of the media signal. The modified signal has distortions relative to the media signal which are dependent on the auxiliary information. The apparatus further comprises a perception processor (107) which generates a perceptual characteristic indicative of a perceptual sensitivity of the media signal to the distortions. The quantization index modulator (103) and perception processor (107) are coupled to a compensation processor (105) which generates an output signal by modifying a strength of the distortions of the modified signal in response to the perceptual characteristic. The invention combines quantization index modulation watermarking with perceptual models to provide an improved trade off between watermark imperceptibility and detection reliability.

The invention provides an anti-fake method for digital print. The method includes the steps of: a) at a built-in end, processing carrier images, fixing special corners and coordinates thereof, then generating a binary form of digital watermark information, and using quantization index modulation for watermark embedding; b) at a detecting end, transforming images such as registration and interpolation, then detecting to acquire information, and processing the information for statistical decision. The anti-fake method for digital print is capable of resisting noise and geometric transformations of print, and being widely used in the printing field.

The invention provides a method for embedding a watermark in a video. The method comprises the following steps of extracting more than one video frame from the video, and performing the following treatment on each extracted video frame X, wherein the treatment comprises the steps of performing singular value decomposition X=UsigmaVT to obtain a singular value matrix sigma=diag(sigma 1, sigma 2,ellipsis sigma n), wherein U and V are two unitary matrixes; grouping the singular values sigma 1, sigma 2, ellipsis sigma n in the singular value matrix; performing quantitative index modulation on the grouped singular values to obtain a singular value matrix sigma` embedded with the watermark; performing singular value decomposition inverse process X`=Usigma`VT on the singular value matrix sigma` embedded with the water mark to obtain a video frame X` embedded with the water mark; processing the more than one video frame to obtain more than one video frame X` and combining into the video embedded with the water mark. The method for embedding the watermark enables the video embedded with the watermark to achieve better video quality.

The invention discloses an angle quantification index modulation image watermarking method based on a compressed sensing technology. A chaotic sequence is adopted to construct a sparse random measurement matrix as an observation matrix, and a compressed sensing technology and an angle quantification index modulation algorithm are utilized to safely and snugly embed watermark information into a compressed sensing domain of a carrier image. The invention also provides an angle quantification index modulation image watermarking system based on a compressed sensing technology. The system includesan observation matrix constructing module, a watermark embedding module, an information transmission module and a watermark extracting module. According to the angle quantification index modulation image watermarking method and system based on a compressed sensing technology, the watermark information is embedded into the compressed sensing domain of the carrier image through the angle quantification index modulation algorithm at a sending end, related information of the observation matrix and the embedding position of the watermark serve as a key to be sent to a receiving end, watermark extraction is realized, the advantages of good concealing property, high security and the like are achieved, and very high robustness is shown when conventional watermark attacks such as noise, filtering,image compression, amplitude scaling and the like are resisted.

The invention discloses a vector geospatial data digital watermark method based on DFT coefficient combination. The method comprises steps that the watermark information is generated; a map is taken as an object, and a watermark carrier model is established based on the DFT coefficient combination polynomial; the map object is taken as a unit, the watermark information is modulated into each map object based on the established watermark carrier model; the watermark information is extracted for verification. The method is advantaged in that based on the DFT coefficient combination polynomial ofa geometric object feature point set, the classical quantization index modulation method is utilized to modulate the watermark information into each DFT coefficient of the polynomial, so watermark intensity is distributed to multiple coefficients, without reducing robustness of the algorithm, watermark invisibility is effectively improved, and the high fidelity of the data is achieved.

The invention provides a tactile digital watermark embedding and detecting method based on electrostatic force, and belongs to the field of information security. The method includes: carrying out Edgedetection and texture extraction on an original picture and a user-defined vector diagram respectively; obtaining an original picture edge texture tactile feature and a user-defined vector diagram texture tactile feature through texture extraction, carrying out DES encryption fusion on the two features to obtain a tactile digital watermark, and embedding the tactile digital watermark into the original picture by using a quantitative index modulation algorithm; The method comprises the following steps: at a detection end, extracting a watermark, performing DES decryption separation on the watermark to obtain an original picture edge texture tactile feature and a user-defined vector diagram texture tactile feature, performing tactile modeling and rendering on the two parts respectively, re-superposing the two parts together, and inputting the two parts into an electrostatic force tactile terminal to realize tactile reproduction. According to the method, the digital watermark is embeddedand detected by additionally providing a tactile dimension, so that the anti-counterfeiting performance of the digital watermark is greatly improved, and the applicability and the safety of the watermark are enhanced.