1. Unsupervised Phonocardiogram Analysis With Distribution Density Based Variational Auto-Encoders
- Author
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Shengchen Li and Ke Tian
- Subjects
Medicine (General) ,Computer science ,0206 medical engineering ,abnormality detection ,02 engineering and technology ,phonocardiogram analysis ,unsupervised learning ,03 medical and health sciences ,symbols.namesake ,0302 clinical medicine ,R5-920 ,Representation (mathematics) ,Phonocardiogram ,business.industry ,auto-encoder ,Pattern recognition ,General Medicine ,Density estimation ,Brief Research Report ,020601 biomedical engineering ,Autoencoder ,Skewness ,030221 ophthalmology & optometry ,symbols ,Kurtosis ,Medicine ,Unsupervised learning ,Artificial intelligence ,business ,Gaussian network model ,data density - Abstract
This paper proposes an unsupervised way for Phonocardiogram (PCG) analysis, which uses a revised auto encoder based on distribution density estimation in the latent space. Auto encoders especially Variational Auto-Encoders (VAEs) and its variant β−VAE are considered as one of the state-of-the-art methodologies for PCG analysis. VAE based models for PCG analysis assume that normal PCG signals can be represented by latent vectors that obey a normal Gaussian Model, which may not be necessary true in PCG analysis. This paper proposes two methods DBVAE and DBAE that are based on estimating the density of latent vectors in latent space to improve the performance of VAE based PCG analysis systems. Examining the system performance with PCG data from the a single domain and multiple domains, the proposed systems outperform the VAE based methods. The representation of normal PCG signals in the latent space is also investigated by calculating the kurtosis and skewness where DBAE introduces normal PCG representation following Gaussian-like models but DBVAE does not introduce normal PCG representation following Gaussian-like models.
- Published
- 2021
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