KR20030017251A - Reduction of transposition process from the two dimensional inverse discrete cosine transform(2-D IDCT) based on the row-column decomposition - Google Patents

Abstract

PURPOSE: A two-dimensional inverse discrete cosine transform structure based on row-column decomposition is provided to remove a pre-process in the IDTC structure and decrease initial delay time in data processing. CONSTITUTION: A two-dimensional inverse discrete cosine transform structure based on row-column decomposition includes a front-end one-dimensional IDCT(1), a back-end one-dimensional IDCT(2) and an intermediate shifter(3). The front-end one-dimensional IDCT receives compressed video data and processes the first one-dimensional IDCT. The back-end one-dimensional IDCT processes the second one-dimensional IDCT with respect to the result of the front-end one-dimensional IDCT. The intermediate shifter temporarily stores the result from the front-end one-dimensional IDCT and provides inputs in unit of bits to the back-end one-dimensional IDCT.

Description

Reduction of transposition process from the two dimensional inverse discrete cosine transform (2-D IDCT) based on the row-column decomposition}

The present invention relates to a two-dimensional IDCT structure for reconstructing an image compressed by DCT in DCT / IDCT based image signal processing among digital image signal processing methods.

Recently, with the development of digital technology and digital mobile communication technology, interest in multimedia is increasing rapidly. In particular, as the need for high-speed transmission of digital image data has emerged, technical research on high-speed compression and reconstruction of digital image signals has been actively conducted, and as a result, a technical consultation body called MPEG has been formed, which is based on DCT / IDCT. The video compression method is adopted.

The conventional matrix decomposition type two-dimensional IDCT structure has a form consisting of one one-dimensional IDCT and one transpose memory (FIG. 2) and a form consisting of two one-dimensional IDCTs and one transposing memory (FIG. 3). Since the structures of these shapes require transposition after 1-dimensional IDCT processing, data processing bottlenecks occur and the initial delay time increases. In addition, there is a disadvantage that the area is increased due to the presence of the pre-memory memory.

The present invention aims to reduce the area of the entire circuit and reduce the initial delay for data processing by eliminating the transposition process from the matrix decomposition type two-dimensional IDCT.

1 is a two-dimensional IDCT structure diagram according to the present invention

* Explanation of symbols for the main parts of the drawings

1: front one-dimensional IDCT 2: rear one-dimensional IDCT

3: middle shifter 4: ROM LUT

2 is a 2D IDCT structure based on a matrix decomposition method according to the related art.

3 is a 2D IDCT structure 2 based on a conventional matrix decomposition type.

In order to achieve the above object, the 2D IDCT according to the present invention receives the compressed image data and processes the first 1D IDCT and processes the first 1D IDCT (1) and the second results from the front end 1D IDCT. It consists of an intermediate shifter 3 which temporarily stores the results from the preceding one-dimensional IDCT 2 and the preceding one-dimensional IDCT that processes the one-dimensional IDCT and inputs the bit-wise input to the subsequent one-dimensional IDCT.

Both one-dimensional IDCTs use a partitioning algorithm. Therefore, we replace the product of the input and the coefficient with a ROM that stores a subtotal and an accumulator that accumulates it.

The front-end one-dimensional IDCT performs a matrix-vector product of an 8X8 input data matrix and one selected vector of eight 8X1 IDCT coefficients, and outputs a one-dimensional IDCT result vector of 8X1 as a result. The intermediate shifter stores the result vector of this one-dimensional IDCT and immediately inputs this value into the input terminal of the rear two-dimensional IDCT bit by bit. Finally, the trailing one-dimensional IDCT calculates the final two-dimensional IDCT by performing the product of the 8X8 IDCT coefficient matrix and the 8X1 vector which is the result of the preceding one-dimensional IDCT of the IDCT.

As shown in FIG. 1, since there is no transposition between the front one-dimensional IDCT and the rear one-dimensional IDCT, the result of the front one-dimensional IDCT can be directly input and used as the rear one-dimensional IDCT.

As described above, the present invention is a structure that eliminates the transposition process in the matrix decomposition type two-dimensional IDCT, has a small area and a small initial delay time.

Claims (1)

Structure with no transposition in 2D IDCT of matrix decomposition using segmentation algorithm