Patent ID: 11871036
Assignee: KOREA UNIVERSITY RESEARCH AND BUSINESS FOUNDATION
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 2:
3. The apparatus for compressing JPEG images according to claim 1, wherein the decoding unit further comprises an inverse quantization unit to generate an 8×8 block of decoded pixel values (P) using the following Equation 2 including a first pixel block partially decoded using a DC matrix and a second pixel block partially decoded using an AC matrix:, p
     =
     
      
       
        [
        
         
          idct
          ⁡
          (
          
           QF
           ∘
           
            DC
            
             8
             ×
             8
            
           
          
          )
         
         +
         
          idct
          ⁡
          (
          
           QF
           ∘
           
            AC
            
             8
             ×
             8
            
           
          
          )
         
        
        ]
       
       +
       
        128
        
         8
         ×
         8
        
       
      
      =
      
       
        [
        
         
          p
          DC
         
         +
         
          p
          AC
         
        
        ]
       
       +
       
        128
        
         8
         ×
         8
        
       
      
     
    
   
   
    
     [
     
      Equation
      ⁢
         
      2
     
     ]
    
   
  
 

where pDC=idct(QF◯DC8×8) is a pixel partially decoded using the DC matrix, DC8×8 is an 8×8 block of DC components in the quantized DCT coefficients (D), QFx,y is a quantization table of 8×8 block at location (x, y), pAC=idct(QF◯AC8×8) is a pixel block partially decoded using the AC matrix, and AC8×8 is an 8×8 block of AC components in the quantized DCT coefficients (D).