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35 results about "Joint likelihood" patented technology

A likelihood is a probability of the joint occurence of all the given data for a specified value of the parameter of the underlying probability model. A joint distribution is a probability model for the joint occurence of values from two possibly correlated random variables.

Hyperspectral image super-resolution processing method based on a convolutional network

The invention discloses a hyperspectral image super-resolution processing method based on a convolutional network, mainly solves the problem that a hyperspectral image generated in the prior art is low in resolution, and adopts the implementation scheme that firstly, a training sample and a test sample are formed by an acquired low-resolution hyperspectral image and a high-resolution multispectralimage; then constructing a convolutional network composed of an inference sub-network and a generation sub-network; training the convolutional network by using the training sample, and obtaining theconvolutional network with the highest similarity between the approximate distribution and the real distribution by maximizing a joint likelihood function of the low-resolution hyperspectral image andthe high-resolution multispectral image; and finally, inputting the test sample into the trained convolutional network, and carrying out optimization processing on the generated high-resolution hyperspectral image to obtain a final high-resolution hyperspectral image. According to the method, the resolution of generating the high-resolution hyperspectral image is improved by utilizing the deep convolutional neural network, and the method can be used for medical diagnosis, remote sensing, computer vision and monitoring.
Owner:XIDIAN UNIV

Positron emission cerenkov-gamma bi-radiation imaging method and device

The invention provides a positron emission cerenkov-gamma bi-radiation imaging method. The positron emission cerenkov-gamma bi-radiation imaging method comprises the following steps: placing a visible light photon detector and a gamma photon detector, and acquiring a pulse data set; calculating a joint likelihood probability function of a multi-dimensional data sample during each time period; judging that whether the currently received data slot comes from a positron emission event or not; accumulating all the positron emission events; establishing a transfer function of the system for each voxel; and inverting the input of the transfer function. The invention further provides a positron emission cerenkov-gamma bi-radiation imaging device. The positron emission cerenkov-gamma bi-radiation imaging device comprises a proton-rich isotope injection module, a multi-radiation detector module, a multi-case time coincidence module, a system transfer function acquiring module and a nuclide distribution image reconstruction module. With the adoption of the method and the device provided by the invention, the spatial resolution, device sensitivity and imaging signal-to-noise ratio of the positron imaging device can be effectively improved, and the positron emission cerenkov-gamma bi-radiation imaging method is particularly suitable for the application of the positrons in nondestructive testing and biomedical imaging.
Owner:NANJING RAYCAN INFORMATION TECH

Graph learning model based on reconstructed graph

ActiveCN110097112AOvercoming the co-occurrence imbalanceOvercoming the failure to consider the interlinkages between imagesCharacter and pattern recognitionNaive bayes nearest neighborCo-occurrence
The invention discloses a graph learning model based on a reconstructed graph, and belongs to the field of image annotation, and the method comprises the following steps: searching a semantic nearestneighbor of a test image through an improved nearest neighbor algorithm, constructing a similar matrix, carrying out the clustering of the image through a random dot product graph, mining the internalconnection of the image, obtaining a weighted similar matrix, and obtaining a preliminary image annotation result through a graph learning algorithm. The relation between the labels is used for labeling, the co-occurrence imbalance between the labels is considered in the process, a nearest graph theory model is introduced, and the problem of label imbalance is effectively solved. The random dot product image is used for reconstructing a transfer matrix of labels, and the problem of image label coexistence asymmetry is solved. Further, a Naive Bayes nearest neighbor classifier is used to establish a joint likelihood function between the image and the tag. The image labeling model based on the reconstructed image model is provided according to the characteristic of unbalanced classificationof the image labels, and the recall rate of the labels can be effectively increased.
Owner:DALIAN UNIV OF TECH

Downlink time frequency synchronization method jointly using synchronization sequence and OFDM cyclic prefixes

ActiveCN109639616ASolve the problem of difficult time-frequency synchronizationImprove synchronicityMulti-frequency code systemsSignal-to-noise ratio (imaging)Communications system
The invention discloses a downlink time frequency synchronization method jointly using a synchronization sequence and OFDM cyclic prefixes. The method achieves downlink time frequency synchronizationof a communication system by jointly using the synchronization sequence and multiple OFDM cyclic prefixes and can solve the problem that in a communication scene, due to factors such as large frequency offset and low signal to noise ratio, time frequency synchronization of an OFDM system is difficult. According to the method, one-dimensional time offset searching is conducted according to a time offset likelihood function, and after a time offset estimation value is obtained, a frequency offset estimation value is obtained by conducting one-dimensional frequency offset searching on a frequencyoffset likelihood function or directly using a low-complexity frequency offset estimation method. In the method, in a timing synchronization stage, time offset likelihood function values of multiplesynchronization cycles can be selected to be subjected to incoherent combination to improve the estimation accuracy degree. Compared with a synchronization method that two-dimensional time offset searching is directly conducted according to the time frequency joint likelihood function to obtain time offset and frequency offset, the method has the advantage that the searching complexity is greatlyreduced. The method is not only suitable for an initial synchronization stage of a communication system, but also suitable for a tracking synchronization stage of the communication system.
Owner:SOUTHEAST UNIV

Multi-sensor joint detection method based on decision-making level and signal level data fusion

The invention discloses a multi-sensor joint detection method based on decision-level and signal-level data fusion. The multi-sensor joint detection method comprises the following steps: S1, obtaining observation values of target signals acquired by node sensors; S2, transmitting observation values acquired by the node sensors under different transmission conditions to a fusion center in different data transmission forms; S3, establishing a joint likelihood function according to the prior information; S4, performing maximum likelihood estimation on unknown parameters; S5, calculating a detection statistic based on a generalized likelihood ratio criterion; S6, setting a detection threshold by deducing approximate distribution of detection statistics; S7, comparing the detection statistic with the detection threshold, and outputting a detection result. According to the method, through combined utilization of multi-source and multi-level data, target information in the data can be reserved as much as possible, the problem that the information utilization rate is insufficient due to the fact that different levels of data are difficult to fuse is effectively solved, and meanwhile the detection performance of a multi-sensor system can be further improved by setting the optimal local judgment threshold value.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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