Image anomaly detection method based on variational auto-encoder

A self-encoder and anomaly detection technology, applied in the field of deep learning, can solve the problems of high memory complexity, dependence, and limited application, and achieve the effect of low memory complexity, low memory complexity, and strong anomaly detection ability

Active Publication Date: 2020-08-28
XIDIAN UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

proposed a support vector machine method (OC-SVM) in the paper "Estimating the Support of a High Dimensional Distribution", which can construct a hyperplane model of positive data and divide the data on the other side of the hyperplane into Anomaly classes are used to obtain ideal anomaly detection results. The disadvantage of this method is that the result depends largely on the selection of regularization parameters and kernel functions. When the amount of data is huge, the memory complexity is very high, which limits this method. Applications in Large-Scale Image Anomaly Detection Tasks
The disadvantage of this type of method is that because the general loss function is used to replace the customized anomaly detection target, the target of anomaly detection cannot affect the hidden layer features extracted by the network at all, making this method often suboptimal
[0005] In summary, the traditional anomaly detection method applied in the image field will not have a good anomaly detection effect due to the large amount of data in the image dataset. The deep anomaly detection method represented by the encoder and the variational autoencoder is used in the anomaly detection task. When , due to the lack of customized anomaly detection targets or the lack of tolerance for the diversity of normal samples, the performance of the deep model is often not fully utilized

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Embodiment 1

[0027] Anomaly detection is widely used in many fields. Among the anomaly detection technologies that have been researched and developed, they involve detection scenarios such as credit card fraud detection, network intrusion detection, medical diagnosis, and image denoising. Considering that images play an important role in the transmission of information in today's information age, it is of great significance to detect anomalies in images and then analyze or delete the detected anomalies. The present invention addresses the problem of anomaly detection on images.

[0028]The exploding number of images puts new requirements on anomaly detection, which makes it difficult for traditional anomaly detection methods to deal with it, and deep anomaly detection methods occupy the mainstream position. The anomaly detection methods represented by autoencoders and variational autoencoders have certain deficiencies, which limit their ability to achieve better detection results in anomal...

Embodiment 2

[0043] The image anomaly detection method based on the variational self-encoder is the same as embodiment 1, the feature corresponding to each normal image sample in the calculation training set in step (3a) needs to calculate the mean and standard deviation of the feature corresponding to each normal image sample, Finally, samples are taken from the standard normal distribution, and the features are calculated. Specific steps are as follows:

[0044] 3a1) Calculate the mean value of the features corresponding to each normal image sample in the training set

[0045] According to the following formula, calculate each normal image sample x in the training set i The mean μ of the corresponding feature i :

[0046] mu i =Relu(y i,K )W 1,K+1 +b 1,K+1

[0047]

[0048] Among them, μ i Represents the mean value of the feature corresponding to the i-th normal image sample in the training set, Relu represents the linear rectification function Rectified Linear Unit, which is...

Embodiment 3

[0060] The image anomaly detection method based on the variational self-encoder is the same as embodiment 1-2, and the specific formula of the reconstructed sample corresponding to each normal image sample in the calculation training set in step (3b) is as follows:

[0061]

[0062]

[0063] in, Represents the reconstructed sample corresponding to the ith normal image sample in the training set, Sigmoid represents the activation function, y i,M Represents the output of the activation function of the i-th normal image sample in the Mth hidden layer of the decoder part of the variational autoencoder, M represents the number of hidden layers after the feature layer and before the output layer, W 2,M+1 Represents the weight coefficient matrix that maps the Mth hidden layer of the decoder part of the variational autoencoder to the output layer, b 2,M+1 Indicates the bias vector that maps the Mth hidden layer of the decoder part of the variational autoencoder to the output l...

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Abstract

The invention discloses an image anomaly detection method based on a variational auto-encoder, in particular to an anomaly detection method integrating a variational auto-encoder and support vector data description, solving the problems of separation of two stages of anomaly detection and feature extraction, limitation of anomaly detection performance and incapability of coping with high-dimensional and large-scale anomaly detection tasks in traditional anomaly detection in the prior art. The image anomaly detection method comprises the steps of collecting image data; performing data set division and data preprocessing; constructing an anomaly detection model based on the variational auto-encoder; training an anomaly detection model; calculating a threshold value for distinguishing normaland abnormal image data according to the trained model; and judging whether the to-be-detected image is an abnormal image or not by using the trained model. According to the image anomaly detection method, support vector data description is adopted to perform distance constraint on the features extracted by the variational auto-encoder, and the extracted features are more suitable for anomaly detection, and the memory complexity is low, and the image anomaly detection method can be applied to high-dimensional and large-scale anomaly detection tasks.

Description

technical field [0001] The invention belongs to the technical field of deep learning, and mainly relates to image anomaly detection, in particular to an image anomaly detection method based on a variational autoencoder, which is used for image anomaly detection in combination with support data vector description. Background technique [0002] The task of anomaly detection is to identify data that is inconsistent with expectations, and such inconsistent data is usually defined as an anomaly. Anomaly detection has important responsibilities in many domains. Among the anomaly detection technologies that have been researched and developed, they involve applications such as credit card fraud detection, network intrusion detection, and medical diagnosis. The present invention addresses the problem of anomaly detection on images. [0003] The methods applied to image anomaly detection are divided into traditional anomaly detection technology and deep anomaly detection technology....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/00G06K9/62
CPCG06T7/0002G06T2207/10028G06T2207/20081G06F18/2411G06F18/214Y02T10/40
Inventor 周宇梁晓敏张维
Owner XIDIAN UNIV
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