Title:
【発明の名称】周波数から時間領域への変換方法及び装置
Document Type and Number:
Japanese Patent JP2962970
Kind Code:
B2
Abstract:
An IDCT method decimates a 2-D IDCT into two 1-D IDCT operations and then operates separately on the even and odd pixel input words. In a common processing step, selected input values are passed directly to output adders and subtractors, while others are multiplied by constant, scaled cosine values. In a pre-common processing step, the lowest-order odd input word is pre-multiplied by 2ROOT 2, and the odd input words are summed pairwise before processing in a common processing step. In a post-common processing step, intermediate values corresponding to the processed odd input words are multiplied by predetermined coefficients to form odd resultant values. After calculation of the even and odd resultant values, the high-order and low-order outputs are formed by simple subtraction/addition, respectively, of the odd resultant values from/with the even resultant values. The input values are preferably scaled upward by a factor of 2ROOT 2. Selected bits of some intermediate resulting data words are optionally adjusted by forcing these bits to either "1" or "0". The IDCT system includes a pre-common processing circuit (PREC), a common processing circuit (CBLK), and a post-common processing circuit (POSTC), which perform the necessary operations in the respective steps. The system also includes a controller (CNTL) to generate signals to control the loading of system latches and, preferably, to time-multiplex the application of the even and odd input words to latches in the pre-common circuit.
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Inventors:
Mark Anthony Jones
Kevin Douglas Dewar
Martin William Sazulan
Kevin Douglas Dewar
Martin William Sazulan
Application Number:
JP15700393A
Publication Date:
October 12, 1999
Filing Date:
June 28, 1993
Export Citation:
Assignee:
Disco Vision Associates
International Classes:
H04N1/41; G06F17/14; G06T1/20; H04N7/30; (IPC1-7): G06F17/14; G06T1/00; H04N1/41; H04N7/30
Other References:
ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ ＯＮ ＡＣＯＵＳＴＩＣＳ，ＳＰＥＥＣＨ，ＡＮＤ ＳＩＧＮＡＬ ＰＲＯＣＥＳＳＩＮＧ，ＶＯＬ．３８，ＮＯ．３（１９９０−３）ｐｐ．５５３−５５７
ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ ＯＮ ＡＣＯＵＳＴＩＣＳ，ＳＰＥＥＣＨ，ＡＮＤ ＳＩＧＮＡＬ ＰＲＯＣＥＳＳＩＮＧ，ＶＯＬ．ＡＳＳＰ−３５，ＮＯ．１０（１９８７−１０）ｐｐ．１４５５−１４６１
ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ ＯＮ ＳＩＧＮＡＬ ＰＲＯＣＥＳＳＩＮＧ，ＶＯＬ．３９，ＮＯ．２（１９９１−２）ｐｐ．５４４−５４６
Ｐｒｏｃｅｅｄｉｎｇｓ ｏｆ ＩＳＣＡＳ ８５ ｖｏｌ．２（１９８５）ＩＥＥＥ ＰＲＥＳＳ，Ｎｅｗ Ｙｏｒｋ ＵＳＡ，ｐｐ．９４１−９４４
ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ ＯＮ ＡＣＯＵＳＴＩＣＳ，ＳＰＥＥＣＨ，ＡＮＤ ＳＩＧＮＡＬ ＰＲＯＣＥＳＳＩＮＧ，ＶＯＬ．ＡＳＳＰ−３５，ＮＯ．１０（１９８７−１０）ｐｐ．１４５５−１４６１
ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ ＯＮ ＳＩＧＮＡＬ ＰＲＯＣＥＳＳＩＮＧ，ＶＯＬ．３９，ＮＯ．２（１９９１−２）ｐｐ．５４４−５４６
Ｐｒｏｃｅｅｄｉｎｇｓ ｏｆ ＩＳＣＡＳ ８５ ｖｏｌ．２（１９８５）ＩＥＥＥ ＰＲＥＳＳ，Ｎｅｗ Ｙｏｒｋ ＵＳＡ，ｐｐ．９４１−９４４
Attorney, Agent or Firm:
Fujihiko Motohiko