Digital voice evidence collection and tamper recovery method based on DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform)

A technology of digital voice and recovery method, which is applied in the direction of voice analysis, transmission system, electrical components, etc., can solve the problems of lack of high-frequency parts and multiple noises in reconstructed signals, and achieve the benefits of popularization and application and improve credibility Effect

Inactive Publication Date: 2016-08-24
XINYANG NORMAL UNIVERSITY
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with the original signal, the reconstructed signal lacks high-frequency parts and introduces more noise

Method used

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  • Digital voice evidence collection and tamper recovery method based on DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform)
  • Digital voice evidence collection and tamper recovery method based on DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform)
  • Digital voice evidence collection and tamper recovery method based on DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform)

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Embodiment Construction

[0035] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

[0036] 1. Signal compression:

[0037] (1) the original speech signal A={a l ,1≤l≤L} is divided into I frames, and the i-th frame is denoted as A i .

[0038] (2) Perform a downsampling operation on A, and the downsampling sampling frequency f' is smaller than the sampling frequency f of the original signal. The down-sampled signal is denoted as A', the length is L', and L'=L·f' / f. And A' is divided into I frames, and the i-th frame is recorded as A' i .

[0039] (3) to A' i Carry out D-order DWT, the approximate component is denoted as C1 i , C1 i That is, the first part of the compressed signal with a length of M.

[0040] (4) Set the detail component obtained after DWT in step (3) to zero, and then perform D-order inverse DWT, and the obtained signal is denoted as IA′ i . Denote the residual signal as E i ,E i = A' i -IA' i ....

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Abstract

The invention discloses a digital voice evidence collection and tamper recovery method based on DWT (Discrete Wavelet Transform) and DCT (Discrete Cosine Transform). The method comprises the steps of dividing voice signals A into I frames, wherein each frame has three fragments; compressing the voice signals by adopting a method based on DWT and DCT to obtain signals for tamper recovery, and performing scrambling operation on each frame of compressed signals; and then, mapping frame numbers to an integer sequence, embedding the integer sequence into the front two fragments of signals respectively, and embedding the scrambled signals into the third fragment. The method can realize tamper recovery on the reconstructed attacked contents during evidence collection on the authenticity of the digital voice contents.

Description

technical field [0001] The invention belongs to speech signal processing, in particular to a compression method for recovering tampered digital speech signals. Generates signal for recovery; embeds frame number and compressed signal at the same time. The frame number is used as the identification of each frame for tampering and positioning, and the compressed signal is used to reconstruct the attacked content. Based on this, digital voice forensics and tampering recovery methods are proposed to improve the credibility and public acceptance of digital voice. Background technique [0002] Voice signal, as one of the earliest digitized signals, is widely used in telephone communication, broadcasting, etc., and has become the main carrier of information transmission and communication. Speech signals often represent important content or instructions, which will arouse the attacker's interest and be attacked. The content expressed by the post-attack signal will be quite differe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L19/018G10L19/16H04L29/06
CPCG10L19/018G10L19/16H04L63/123H04L63/126
Inventor 刘正辉李然祁传达刘宏兵
Owner XINYANG NORMAL UNIVERSITY
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