EP0366435A2
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EP
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Orthogonal and inverse orthogonal transform apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1989-10-25
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Granted: —
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Expires: 2009-10-25
Abstract
Abstract An orthogonal transform apparatus wherein in N-th order DCT or DST, the multiplier used for weighting N orthogonal coefficients Yi (i=0, ..., N-1) is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N) to thereby considerably reduce the number of multiplications in both orthogonal and inverse orthogonal transform as compared with the conventional. Since the number of multiplications required for calculating one orthogonal coefficient can be reduced, it is possible to reduce operation errors to be caused by multiplications. Further, it is possible to improve the operation precision of an orthogonal coefficient for lower frequency components which have an important role from the standpoint of visual sense. Finally, by applying the orthogonal transform apparatus to two dimensional orthogonal transform and two dimensionally weighting after obtaining two dimensional orthogonal coefficients, it becomes possible to reduce the number of multiplications while performing a desired two dimensional weighting.
Inventors
- 👤 Tatsuro Juri
- 👤 Shinya Kadano
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 23:04
CPC Classifications
G; G06; G06F; G06F17/00; G06F17/10; G06F17/14; G06F17/147; H; H04; H04N; H04N19/00; H04N19/10; H04N19/102; H04N19/124; H04N19/126; H04N19/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
70 words
An orthogonal transform apparatus wherein in N-th order DCT (Discrete Cosine Transform) or DST (Discrete Sine Transform), the multiplier (coefficient) used for weighting N orthogonal coefficients Yi (where 0 ≦ i < N) in N-th order orthogonal transform is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N)
Claim 2
Dependent Claim
70 words
An orthogonal transform apparatus wherein in N-th order DCT (Discrete Cosine Transform) or DST (Discrete Sine Transform), the multiplier (coefficient) used for weighting N orthogonal coefficients Yi (where 0 ≦ i < N) in N-th order orthogonal transform is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N)
Claim 3
Dependent Claim
74 words
An inverse orthogonal transform apparatus wherein in N-th order IDCT (Inverse Discrete Cosine Transform) or IDST (Inverse Discrete Sine Transform), the multiplier (coefficient) used for weighting N orthogonal coefficients Yi (where 0 ≦ i < N) in N-th order inverse orthogonal transform is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N)
Claim 4
Dependent Claim
74 words
An inverse orthogonal transform apparatus wherein in N-th order IDCT (Inverse Discrete Cosine Transform) or IDST (Inverse Discrete Sine Transform), the multiplier (coefficient) used for weighting N orthogonal coefficients Yi (where 0 ≦ i < N) in N-th order inverse orthogonal transform is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N)
Claim 5
Dependent Claim
41 words
An orthogonal transform apparatus wherein there are carried out N/2 sets of butterfly operations in log₂(N) stages, and addition, subtraction or multiplication operation with respect to each butterfly operation in N-th order DCT (Discrete Cosine Transform) or DST (Discrete Sine Transform).
Claim 6
Dependent Claim
41 words
An orthogonal transform apparatus wherein there are carried out N/2 sets of butterfly operations in log₂(N) stages, and addition, subtraction or multiplication operation with respect to each butterfly operation in N-th order DCT (Discrete Cosine Transform) or DST (Discrete Sine Transform).
Claim 7
Dependent Claim
38 words
An inverse orthogonal transform apparatus wherein there are carried out N/2 sets of butterfly operation sin log₂(N) stages, and addition, subtraction or multiplication operation, in N-th order IDCT (Indirect Discrete Cosine Transform) or IDST (Indirect Discrete Sine Transform).
Claim 8
Dependent Claim
38 words
An inverse orthogonal transform apparatus wherein there are carried out N/2 sets of butterfly operation sin log₂(N) stages, and addition, subtraction or multiplication operation, in N-th order IDCT (Indirect Discrete Cosine Transform) or IDST (Indirect Discrete Sine Transform).
Claim 9
Dependent Claim
221 words
An orthogonal transform apparatus comprising eight inputs (X0, X1, X2, X3, X4, X5, X6, X7) supplied to the apparatus; first butterfly operation means for obtaining (A0, A1, A2, A3, A4, A5, A6, A7) given by: A0 = X0 + X7 A1 = X1 + X6 A2 = X2 + X5 A3 = X3 + X4 A4 = X0 - X7 A5 = X1 - X6 A6 = X2 - X5 A7 = X3 - X4 second butterfly operation means for obtaining (B0, B1, B2, B3, B4, B5, B6, B7) given by: B0 = A0 + A3 B1 = A1 + A2 B2 = A0 - A3 B3 = A1 - A2 B4 = A4 + C4 (A5 + A6) B5 = A5 + C4 (A4 + A7) B6 = A4 - C4 (A5 + A6) B7 = A5 - C4 (A4 + A7) and third butterfly operation means for obtaining DCT-ed orthogonal coefficients (Z0, Z1, Z2, Z3, Z4, Z5, Z6, Z7) given by: Z0 = B0 + B1 Z4 = B0 - B1 Z2 = B2 + C4 (B2 + B3) Z6 = B2 - C4 (B2 + B3) Z1 = B4 + 2C4C6 (B4 + B5) Z7 = B4 - 2C4C6 (B4 + B5) Z3 = B6 + 2C2C4 (B6 + B7) Z5 = B6 - 2C2C4 (B6 + B7)
Claim 10
Dependent Claim
221 words
An orthogonal transform apparatus comprising eight inputs (X0, X1, X2, X3, X4, X5, X6, X7) supplied to the apparatus; first butterfly operation means for obtaining (A0, A1, A2, A3, A4, A5, A6, A7) given by: A0 = X0 + X7 A1 = X1 + X6 A2 = X2 + X5 A3 = X3 + X4 A4 = X0 - X7 A5 = X1 - X6 A6 = X2 - X5 A7 = X3 - X4 second butterfly operation means for obtaining (B0, B1, B2, B3, B4, B5, B6, B7) given by: B0 = A0 + A3 B1 = A1 + A2 B2 = A0 - A3 B3 = A1 - A2 B4 = A4 + C4 (A5 + A6) B5 = A5 + C4 (A4 + A7) B6 = A4 - C4 (A5 + A6) B7 = A5 - C4 (A4 + A7) and third butterfly operation means for obtaining DCT-ed orthogonal coefficients (Z0, Z1, Z2, Z3, Z4, Z5, Z6, Z7) given by: Z0 = B0 + B1 Z4 = B0 - B1 Z2 = B2 + C4 (B2 + B3) Z6 = B2 - C4 (B2 + B3) Z1 = B4 + 2C4C6 (B4 + B5) Z7 = B4 - 2C4C6 (B4 + B5) Z3 = B6 + 2C2C4 (B6 + B7) Z5 = B6 - 2C2C4 (B6 + B7)
Claim 11
Dependent Claim
26 words
An orthogonal transform apparatus according to Claim 1, wherein weighting in orthogonal transform is greater for an orthogonal coefficient for low frequency than for high frequency.
Claim 12
Dependent Claim
80 words
An orthogonal transform apparatus wherein two-dimensional DCT or DST, the multiplier (coefficient) used for weighting N orthogonal coefficients Yi (where 0 ≦ i < N) in N-th order orthogonal or inverse orthogonal transform is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N) and wherein each orthogonal coefficient after the two-dimensional orthogonal transform is subjected to two-dimensional weighting.
Claim 13
Dependent Claim
80 words
An orthogonal transform apparatus wherein two-dimensional DCT or DST, the multiplier (coefficient) used for weighting N orthogonal coefficients Yi (where 0 ≦ i < N) in N-th order orthogonal or inverse orthogonal transform is one of, a combination of two or more of, or a multiple of one of, the following four sets: · COS (i/2N) · SIN (i/2N) · 1/COS (i/2N) · 1/SIN (i/2N) and wherein each orthogonal coefficient after the two-dimensional orthogonal transform is subjected to two-dimensional weighting.
References Cited (Backward Citations)
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