An image sample upsampling method based on convolutional self-coding

A technology of convolutional self-encoding and image samples, which is applied in the field of image sample upsampling based on convolutional self-encoding, can solve problems such as large noise, imbalance, and lack of physical meaning in imagery, and achieve simple network scale and training process Simple, visibility-enhancing effects

Active Publication Date: 2019-04-02
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Downsampling refers to undersampling the majority class before classification, which can solve the imbalance of classification, but it will cause a waste of samples and affect the overall accuracy of classification; upsampling refers to oversampling the minority class through methods such as difference, generally However, for image data, upsampling samples directly from the image level will cause two problems:
[0004] First, the new images created may not necessarily conform to the visual senses of the human eye, for example: Synthetic minority over-sampling technique (Smote algorithm) [2] ;
[0005] Second, the new image created is easy to introduce a lot of noise, such as the upsampling algorithm based on the generated confrontation network
[0006] In response to the above problems, some methods perform upsampling from the feature level, but upsampling only by features does not have the physical meaning of iconography, and for learning algorithms such as deep learning, the relevant parameters of the feature extraction module can only be obtained through upsampling. previous samples for learning

Method used

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  • An image sample upsampling method based on convolutional self-coding
  • An image sample upsampling method based on convolutional self-coding
  • An image sample upsampling method based on convolutional self-coding

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Embodiment 1

[0038] The embodiment of the present invention proposes an image upsampling method based on convolutional self-encoding, see figure 1 , figure 2 , the method includes the following steps:

[0039] 101: Cut out each 3D MRI sample, cut out the 2D image of the tumor area, and normalize the scale of all 2D images; build a network structure in the form of a cascaded encoder and decoder, and as a model;

[0040] 102: Train the model by setting the learning rate and loss function; use the adaptive moment estimation optimizer to optimize the trained model;

[0041] 103: Input any random positive samples into the trained network, obtain the low-dimensional features extracted by the encoder, calculate the Euclidean distance center point of 8 groups of features, and randomly select 1 group of features among the 8 groups of features to obtain new features;

[0042] 104: Input the new feature into the decoder for image reconstruction, and output the positive sample image.

[0043] Whe...

Embodiment 2

[0052] The following combined with specific examples, image 3 The scheme in Example 1 is further introduced, see the following description for details:

[0053] (1) Minority class sample division, the method is as follows:

[0054] Step 1: Divide the minority class samples into different sets by class.

[0055] Step 2: Randomly select several cases in the positive samples, and randomly select several cases in the negative samples as the verification set; the rest of the data is used as the training set.

[0056] Step 3: Cut out each 3D MRI (magnetic resonance imaging) sample, cut out a 2D image of the area where the tumor is located, and normalize all the 2D images to 224×224.

[0057](2) Network structure construction, the method is as follows:

[0058] Step 1: Input 224×224 minority class samples (i.e., positive samples) into the convolutional encoder, which consists of multiple cascaded feature extraction modules and pooling layers. The feature extraction module consis...

Embodiment 3

[0075] The scheme in embodiment 1 and 2 is further introduced below in conjunction with specific example, see the following description for details:

[0076] (1) Data preparation:

[0077] (a) Divide the dataset

[0078] The samples were divided into different sets according to the class, and the data sources were 96 cases of undisclosed breast tumor MRI, including: 27 cases of malignant tumor samples and 69 cases of benign tumor samples.

[0079] Randomly select 5 cases in the malignant tumor samples (positive samples), and randomly select 10 cases in the benign tumor samples (negative samples) as the verification set; the rest of the data are used as the training set.

[0080] (b) Data preprocessing

[0081] Each 3D MRI sample was cropped to get a 2D image of the tumor area, and all 2D images were normalized to a uniform size of 224×224.

[0082] Finally, 1847 training set data (including 387 positive samples and 1460 negative samples) and 365 verification set data (inclu...

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Abstract

The invention discloses an image sample upsampling method based on convolution self-coding, and the method comprises the steps of carrying out the cutting of each three-dimensional magnetic resonanceimaging sample, obtaining two-dimensional images of a region where a tumor is located through cutting, and carrying out the scale normalization of all the two-dimensional images; building a network structure in a form of cascade connection of an encoder and a decoder, and serving as a model; training the model by setting a learning rate and a loss function; carrying out optimization processing onthe trained model by adopting an adaptive moment estimation optimizer; inputting any random positive sample into the trained network to obtain low-dimensional features extracted by the encoder, calculating Euclidean distance center points of eight groups of features, and randomly selecting one group of features from the eight groups of features to obtain new features; and inputting the new features into a decoder for image reconstruction, and outputting a positive sample image. According to the method, the feature extraction is carried out through the encoder, sample enhancement is carried outon samples at the feature level, image reconstruction is carried out through the decoder, upsampling of a few types of samples is obtained, and the method can be used for balance preprocessing of classification problems.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to an image sample upsampling method based on convolutional self-encoding. Background technique [0002] Imbalanced data classification refers to the classification in which the number of samples of a certain class in the data set is much smaller than the number of other classes. The class with a large number of samples is called the majority class, and the class with a small number of samples is called the minority class [1] , in general, the classification accuracy of the majority class is much higher than that of the minority class. But in real life, minority classes often require higher accuracy, such as: disease samples in medical images, illegal intrusion samples in the Internet, and illegal cheating samples in online games. The data balance processing technology refers to normalizing the amount of different types of data to the same scale through preprocessing meth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T9/00
CPCG06T9/002Y02T10/40
Inventor 褚晶辉李晓川吕卫
Owner TIANJIN UNIV
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