(19)
(11)EP 2 202 644 A3

(12)EUROPEAN PATENT APPLICATION

(88)Date of publication A3:
12.07.2017 Bulletin 2017/28

(43)Date of publication A2:
30.06.2010 Bulletin 2010/26

(21)Application number: 09180473.2

(22)Date of filing:  22.12.2009
(51)Int. Cl.: 
G06F 17/14  (2006.01)
(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

(30)Priority: 25.12.2008 JP 2008331190

(71)Applicant: CANON KABUSHIKI KAISHA
Ohta-ku Tokyo 146-8501 (JP)

(72)Inventor:
  • Nakayama, Tadayoshi
    Ohta-ku Tokyo (JP)

(74)Representative: Garner, Jonathan Charles Stapleton 
Canon Europe Ltd European Patent Department 3 The Square
Stockley Park Uxbridge, Middlesex UB11 1ET
Stockley Park Uxbridge, Middlesex UB11 1ET (GB)

  


(54)Data transforming apparatus and control method thereof


(57) This invention implements a fast lossless transform almost free from a delay with a small calculation amount. The lossless transform can be used to perform lossless coding and lossy coding quickly. A first calculation means (111) multiplies data D0, D1, D2, and D3 input to the input terminals (101-104) by respective weighting coefficients {a0, al, a2, a3} of {1/2, -1/2, -1/2, -1/2}, and summates the products. A rounding means (113) in the first calculation means (111) rounds the sum into an integer and outputs the integer value E. A second calculation means (112) multiplies the value E by weighting coefficients {b0, b1, b2, b3} of {-1, 1, 1, 1} set for the respective input data, and adds the products to the respective input data. This invention sets, for the relationship between the first and second weighting coefficients, a condition that a0*b0 + a1*b1 + a2*b2 + a3*b3 = -2 or 0.