Patent ID: 11902430
Assignee: SHANGHAI MARITIME UNIVERSITY
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 4:
5. The quantum color image encrypting method based on modification direction according to claim 2, wherein:
the computing the second extract function for the modified pixel group comprises:
assuming that the pixel group of carrier image embedded with the secret data based on modification direction changes from [gYX1,gYX2] to [eYX1,eYX2], directly computing the value of the second extract function of the modified pixel group [eYX1, eYX2] so as to extract the secret data, then:, E
    YX
  
  =
  
    
      
        w
        yx
        1
      
      ⁢
      
        w
        yx
        2
      
    
    =
    
      
        E
        ⁡
        
          (
          
            
              e
              YX
              1
            
            ,
            
              e
              YX
              2
            
          
          )
        
      
      =
      
        
          
            (
            
              
                e
                YX
                1
              
              +
              
                
                  e
                  YX
                  2
                
                ×
                2
              
            
            )
          
          ⁢
          
            
          
          ⁢
          mod
          ⁢
          
            
          
          ⁢
          4
        
        =
        
          
            
              (
              
                
                  E
                  
                    Y
                    ⁢
                    X
                  
                  0
                
                ⁢
                
                  E
                  
                    Y
                    ⁢
                    X
                  
                  1
                
                ⁢
                …
                ⁢
                
                  
                
                ⁢
                
                  E
                  
                    Y
                    ⁢
                    X
                  
                  
                    q
                    -
                    1
                  
                
                ⁢
                
                  E
                  
                    Y
                    ⁢
                    X
                  
                  q
                
                ⁢
                
                  E
                  
                    Y
                    ⁢
                    X
                  
                  
                    q
                    +
                    1
                  
                
              
              )
            
            ⁢
            
              
            
            ⁢
            mod
            ⁢
            
              
            
            ⁢
            4
          
          =
          
            
              E
              
                Y
                ⁢
                X
              
              q
            
            ⁢
            
              
                E
                YX
                
                  q
                  +
                  1
                
              
              .