Patent ID: 11922964
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 5:
6. The PSD optimization device according to claim 5,
wherein linear constraints regarding the variables u and v are

Au=v,Bu=c,u≥0

where A=[Λ 0 0], B=[I, I, I], c is the PSD estimation value of enhanced signals of the sound source at the target sound direction-of-arrival θS, Λ(∈RΩ×Ω) is a predetermined sparse matrix, I(∈RΩ×Ω) is an identity matrix, and Ω is the number of frequency bands,
F1(u) and F2(v) are each, F
       1
      
      (
      u
      )
     
     =
     
      
       1
       2
      
      ⁢
      
       
        
        
         
          W
          
           1
           /
           2
          
         
         (
         
          u
          -
          
           φ
           ^
          
         
         )
        
        
       
       2
       2
      
     
    
   
  
  
   
    
     
      
       F
       2
      
      (
      v
      )
     
     =
     
      
       μ
       ⁢
       
        
         
         v
         
        
        1
       
      
      +
      
       
        ρ
        2
       
       ⁢
       
        
         
         
          v
          -
          
           
            v
            ^
           
           
            
             φ
             ^
            
            S
           
          
         
         
        
        2
        2
       
      
     
    
   
  
 

where, W
      
       1
       /
       2
      
     
     =
     
      
       [
       
        
         
          
           
            
             w
             S
            
            ⁢
            I
           
          
         
         
          0
         
         
          0
         
        
        
         
          0
         
         
          
           
            
             w
             IN
            
            ⁢
            I
           
          
         
         
          0
         
        
        
         
          0
         
         
          0
         
         
          
           
            
             w
             BN
            
            ⁢
            I
           
          
         
        
       
       ]
      
      ⁢
      
       (
       
        
         w
         S
        
        ,
        
         w
         IN
        
        ,
        
         
          w
          BN
         
         ∈
         
          R
          +
         
        
       
       )
      
     
    
   
  
  
   
    
     
      φ
      ^
     
     =
     
      
       [
       
        
         
          φ
          ^
         
         S
         T
        
        ,
        
         
          φ
          ^
         
         IN
         T
        
        ,
        
         
          φ
          ^
         
         BN
         T
        
       
       ]
      
      T
     
    
   
  
  
   
    
     
      
       v
       ^
      
      
       
        φ
        ^
       
       S
      
     
     =
     
      A
      ⁢
      
       φ
       ^
      
     
    
   
  
 

and μ, ρ(∈R+) are weighting coefficients,
wherein functions Dp⋅, Dq⋅, and Dr⋅, and dual variables ˜p, ˜q, and ˜r, regarding dual variables p, q, and r, are each defined in the following Expressions,

Dp⋅=Dp−1,Dq⋅=Dq−1,Dr⋅=Dr−1 

{tilde over (p)}=∇Dp(p),{tilde over (q)}=∇Dq(q),{tilde over (r)}=∇Dr(r)

wherein the PSD updating unit includes
a first variable calculator that calculates ut+1, which is a result of updating the variable u for a t+1′th time, by the following Expression,, u
   
    t
    +
    1
   
  
  =
  
   arg
   ⁢
      
   
    
     min
     u
    
    (
    
     
      
       F
       1
      
      (
      u
      )
     
     +
     
      
       J
       
        D
        p
        
       
      
      (
      
       Au
       ⁢
       
        
        
         
          p
          ~
         
         t
        
       
      
      )
     
     +
     
      
       J
       
        D
        q
        
       
      
      (
      
       Bu
       ⁢
       
        
        
         
          
           q
           ~
          
          t
         
         -
         c
        
       
      
      )
     
     +
     
      
       J
       
        D
        r
        
       
      
      (
      
       u
       ⁢
       
        
        
         -
         
          
           r
           ~
          
          t
         
        
       
      
      )
     
    
    )
   
  
 

a first dual variable calculator that calculates ˜pt+1/2, which is an intermediate updating result of the dual variable ˜p for the t+1′th time, by the following Expression,

{tilde over (p)}t+1/2={tilde over (p)}t−2Aut+1 

a second dual variable calculator that calculates ˜qt+1, which is a result of updating the dual variable ˜q for the t+1′th time, by the following Expression,

{tilde over (q)}t+1={tilde over (q)}t−2(But+1−c)

a third dual variable calculator that calculates ˜rt+1/2, which is an intermediate updating result of the dual variable ˜r for the t+1′th time, by the following Expression,

{tilde over (r)}t+1/2={tilde over (r)}t−2ut+1 

a second variable calculator that calculates vt+1, which is a result of updating the auxiliary variable v for the t+1′th time, by the following Expression,, v
   
    t
    +
    1
   
  
  =
  
   arg
   ⁢
      
   
    
     min
     v
    
    (
    
     
      
       F
       2
      
      (
      v
      )
     
     +
     
      
       J
       
        D
        p
        
       
      
      (
      
       v
       ⁢
       
        
        
         -
         
          
           p
           ~
          
          
           t
           +
           
            1
            /
            2
           
          
         
        
       
      
      )
     
    
    )
   
  
 

a fourth dual variable calculator that calculates ˜pt+1, which is a result of updating the dual variable ˜p for the t+1′th time, by the following Expression, and

{tilde over (p)}t+1={tilde over (p)}t+1/2+2vt+1 

a fifth dual variable calculator that sets ˜r=[˜r1T, ˜r2T, ˜r3T]T, and calculates ˜rt+1, which is a result of updating the dual variable ˜r for the t+1′th time, by the following Expression, r
    ~
   
   i
   
    t
    +
    1
   
  
  =
  
   {
   
    
     
      
       
        
         
          r
          ~
         
         i
         
          t
          +
          
           1
           /
           2
          
         
        
        (
        
         
          if
          ⁢
             
          
           
            r
            ~
           
           i
           
            t
            +
            
             1
             /
             2
            
           
          
         
         ≥
         0
        
        )
       
      
     
     
      
       
        -
        
         
          
           r
           ~
          
          i
          
           t
           +
           
            1
            /
            2
           
          
         
         (
         otherwise
         )
        
       
      
     
    
    ⁢
    
     
      (
      
       
        i
        =
        1
       
       ,
       2
       ,
       3
      
      )
     
     .