Patent ID: 11871211
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 5:
6. The recording medium according to claim 5, wherein converting the calculated spherical harmonics expansion coefficient comprises converting the spherical harmonics expansion coefficient into the weight factor for the superposition of the multipole sources, in accordance with Expression (3):, [
      
       Math
       .
          
       3
      
      ]
     
    
   
   
    
   
  
  
   
    
     
      D
      μ
      v
     
     =
     
      
       -
       
        
         4
         ⁢
         π
        
        jk
       
      
      ⁢
      
       {
       
        
         
          
           
            ∑
            
             n
             =
             0
            
            ∞
           
           
            
             j
             n
            
            ⁢
            
             A
             n
             0
            
            ⁢
            
             
              F
              n
              0
             
             (
             
              π
              2
             
             )
            
           
          
         
         
          
           (
           
            
             μ
             +
             v
            
            =
            0
           
           )
          
         
        
        
         
          
           
            1
            
             
              (
              
               -
               jdk
              
              )
             
             μ
            
           
           ⁢
           
            
             ∑
             
              n
              =
              
               μ
               +
               v
              
             
             ∞
            
            
             
              j
              
               n
               +
               v
              
             
             ⁢
             
              
               F
               n
               
                 
                
                 μ
                 +
                 v
                
               
              
              (
              
               π
               2
              
              )
             
             ⁢
             
              (
              
               
                
                 
                  μ
                  +
                  v
                 
                
               
               
                
                 v
                
               
              
              )
             
             ⁢
             
              {
              
               
                A
                n
                
                 μ
                 +
                 v
                
               
               +
               
                
                 
                  (
                  
                   -
                   1
                  
                  )
                 
                 
                  μ
                  +
                  
                   2
                   ⁢
                   v
                  
                 
                
                ⁢
                
                 A
                 n
                 
                  
                   -
                   μ
                  
                  -
                  v
                 
                
               
              
              }
             
            
           
          
         
         
          
           (
           
            
             μ
             +
             v
            
            >
            0
           
           )
          
         
        
       
      
     
    
   
   
    
     Expression
     ⁢
        
     
      (
      3
      )
     
    
   
  
 

Dμν: the weight factor for the superposition of the multipole sources
A: the spherical harmonics expansion coefficient
m,n: an order and a degree of a multipole in each of an x-axis direction and a y-axis direction where −n≤m≤n, n≥0, m=μ+ν
j: an imaginary unit
d: an interval between neighboring speakers
k: a wave number (k=2πf/c)
f and c denote frequency and sound speed of a sound signal to be controlled, respectively.