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42results about How to "Retain relevance" patented technology

Airplane three-dimensional attitude computation method

The invention provides an airplane three-dimensional attitude computation method. Firstly, preprocessing is carried out on an image to be processed by the adoption of Gaussian smooth filtering to eliminate influences of noise on follow-up algorithms; secondly, the smoothened image is segmented by the adoption of a fuzzy C-means clustering algorithm (FCM) to obtain a binary image, then Hough conversion is carried out on the binary image obtained through segmentation, a part, with obvious linear features, on a target is detected, feature points of the part, with non-obvious linear features, on the target are extracted by the adoption of a framework, and then linear fitting is carried out on the feature points on the framework to obtain a target axis; finally, the obtained axis, the actual size of the target, camera parameters and other information are combined, and a three-dimensional attitude parameter of the target under a camera coordinate system is calculated by means of projective geometry knowledge. On the basis of geometrical features capable of reflecting the structure of an object and by means of Hough conversion and framework extraction of the whole target image, the obtained axis is more accurate, and the obtained three-dimensional attitude parameter is more precise.
Owner:INST OF OPTICS & ELECTRONICS - CHINESE ACAD OF SCI

Extended target tracking method based on combination of skeleton characteristic points and distribution field descriptors

The invention provides an extended target tracking method based on combination of skeleton characteristic points and distribution field descriptors. The extended target tracking method comprises the following steps: firstly, preprocessing images to be processed by using Gaussian smooth filtering to remove influence of noise on a subsequent algorithm; and subsequently, cutting the smoothed images by using a fuzzy C-means clustering algorithm FCM to obtain binary images, carrying out Hough transform on the cut and obtained binary images to detect a part with an obvious linear characteristic on the target, extracting characteristic points from a part without obvious linear characteristic on the target by using a skeleton, then carrying out linear fitting on the characteristic points on the skeleton to obtain a target axis, taking a intersection point of the straight lines of the obtained axis as an initial track point, then calculating a distribution field in a certain neighborhood field of the point and searching a best position in the neighborhood field when a next frame comes, so as to obtain the current best track point. Through the extended target tracking method, the fuzziness problem is solved; and the extended target tracking method is capable of stably tracking the extended target under a condition with a great posture change.
Owner:INST OF OPTICS & ELECTRONICS - CHINESE ACAD OF SCI

JPEG image bit stream encryption method based on alternating current statistical characteristic change

The invention discloses a JPEG image bit stream encryption method based on alternating current statistical characteristic change. The method comprises: in a JPEG bit stream, a user selects the last non-zero communication coefficient entropy code in a part of image blocks by using a user key to encrypt; hiding the secret information into a part of image block entropy codes through a histogram translation method; statistical characteristics are obtained through a user secret key and an alternating current coefficient, a direct current coefficient encryption secret key and an alternating currentcoefficient encryption secret key are generated in a self-adaptive mode, inter-group scrambling and differential coding iteration scrambling are carried out on the direct current coefficient, and intra-block scrambling and inter-block scrambling are carried out on the alternating current coefficient; and the receiver extracts secret information from the encrypted bit stream and decrypts the secretinformation, recovers the direct current coefficient and the alternating current coefficient encryption key according to the user key and the alternating current coefficient statistical characteristics in the encrypted bit stream, decrypts the alternating current coefficient and the direct current coefficient, recovers the alternating current coefficient entropy code in each image block entropy code, and obtains the original bit stream. The method is high in security and small in encrypted file expansion.
Owner:SOUTHWEST JIAOTONG UNIV

Approximation method of label set probability density function

InactiveCN106202001ASimplified Ensemble Probability Density Function RepresentationRetain relevanceComplex mathematical operationsCorrelation coefficientNormal density
The invention discloses an approximation method of a label set probability density function. An existing set probability density function approximation method does not consider the real correlation between targets, and is unsuitable for a generalized multi-target system. Therefore, the invention provides a set probability density function approximation method based on correlation between the targets. The method comprises the following steps of: firstly computing a correlation coefficient between the Bernoulli sets corresponding to the targets; and then grouping the Bernoulli sets according to the obtained correlation coefficient; secondly providing the probability density function of each group of subsets based on the computing criterion of the set marginal probability density function; and finally utilizing a mutual independent relation between the subsets to jointly represent the multi-target posterior probability approximation by the probability density function of each group of subsets. Through the adoption of the method disclosed by the invention, not only the real correlation between the targets is retained, but also the dimensionality reduction of the high-dimensional and complex set multi-target probability density is performed; the representation of the set probability density function is greatly simplified, the approximation error is small, and the method has good engineering application prospects.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Stereoscopic video robust watermarking method based on tensor decomposition

The invention discloses a stereoscopic video robust watermarking method based on tensor decomposition. A watermark is embedded into the watermark embedding end, the brightness components of the left viewpoint color video and the right viewpoint color video are converted into third-order tensors; tensor decomposition is carried out on the third-order tensor; the two-dimensional matrix representations of the two feature maps containing the main energy are synthesized into a three-dimensional matrix in sequence; the three-dimensional matrix is converted into a three-order tensor; tensor decomposition is carried out on the third-order tensor; non-overlapping sub-image block processing is carried out on the obtained feature map containing the main energy, to-be-embedded blocks are determined,a coefficient in a left singular matrix of each to-be-embedded block is modified according to each bit in an original binary watermark sequence to obtain a corresponding watermark-containing block, and inverse operation is carried out on the watermark-containing block to finally obtain a watermark-containing three-dimensional video; at a watermark extraction end, image block processing is performed in the same way, to-be-extracted blocks are determined according to the to-be-embedded blocks, and watermark information are extracted from each to-be-extracted block. The method has the advantages of being good in robustness and imperceptibility.
Owner:COLLEGE OF SCI & TECH NINGBO UNIV

A 3D Attitude Calculation Method for Aircraft

The invention provides an airplane three-dimensional attitude computation method. Firstly, preprocessing is carried out on an image to be processed by the adoption of Gaussian smooth filtering to eliminate influences of noise on follow-up algorithms; secondly, the smoothened image is segmented by the adoption of a fuzzy C-means clustering algorithm (FCM) to obtain a binary image, then Hough conversion is carried out on the binary image obtained through segmentation, a part, with obvious linear features, on a target is detected, feature points of the part, with non-obvious linear features, on the target are extracted by the adoption of a framework, and then linear fitting is carried out on the feature points on the framework to obtain a target axis; finally, the obtained axis, the actual size of the target, camera parameters and other information are combined, and a three-dimensional attitude parameter of the target under a camera coordinate system is calculated by means of projective geometry knowledge. On the basis of geometrical features capable of reflecting the structure of an object and by means of Hough conversion and framework extraction of the whole target image, the obtained axis is more accurate, and the obtained three-dimensional attitude parameter is more precise.
Owner:INST OF OPTICS & ELECTRONICS - CHINESE ACAD OF SCI

Encryption method of jpeg image bit stream based on the change of AC statistical characteristics

A JPEG image bitstream encryption method based on the change of AC statistical characteristics, the user selects the last non-zero AC coefficient entropy encoding in the part of the image block in the JPEG bitstream by the user key, and uses it as secret information through the histogram translation method It is hidden in the entropy coding of some image blocks, the statistical characteristics are obtained from the user key and the AC coefficient, the encryption key of the DC coefficient and the encryption key of the AC coefficient are adaptively generated, and the inter-group scrambling and differential coding iterative setting are performed on the DC coefficient respectively. Intra-block and inter-block scrambling of the AC coefficients; the receiver extracts the secret information from the encrypted bit stream and decrypts it, and recovers the DC coefficient and AC coefficient encryption keys from the user key and the statistical characteristics of the AC coefficients in the encrypted bit stream , and decrypt the AC coefficients and DC coefficients, restore the AC coefficient entropy coding in each image block entropy coding, and obtain the original bit stream. The method has high security and the encrypted file has a small extension.
Owner:SOUTHWEST JIAOTONG UNIV
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