# US 5,706,220 A · System and method for implementing the fast wavelet transform

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- Number: US 5,706,220 A
- Document ID: US5706220A
- Status: Granted
- Kind: A
- Application number: 08/645,575
- Filed: 1996-05-14
- Granted: 1998-01-06
- Earliest claimed: 1996-05-14
- Assignees: LSI Logic Corporation
- Inventors: Manoucher Vafai; Loganath Ramachandran; Mody Lempel
- Web page: https://patentgrep.com/patent/US5706220A

## CPC

- H04N 19/63: using sub-band based transform, e.g. wavelets
- G06F 17/148: {Wavelet transforms}
- H04N 19/42: characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation (H04N19/635 takes precedence)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A system and method implementing a fast wavelet transform by shifting a pair of pixels into a single shift register and using a multimode quadrature mirror filter to eliminate the need of downsampling the filtered signals and to decrease the area required to implement the device on a semiconductor chip.

## Claims

### Claim 1

In an integrated circuit device for wavelet transformation, including a shift register and a multimode filter, in a wavelet compression system for multimedia computing; a method for transforming a signal of pixels comprising:
shifting a pair of pixels into a first pair of cells of the shift register and shifting another pair of pixels out of a last pair of cells of the shift register;
switching the multimode filter to a high-pass mode;
passing all pixels currently contained in the shift register .through the multimode filter to form a high-pass output;
switching the multimode filter to a low-pass mode; and
passing all pixels currently contained in the shift register through the multimode filter to form a low-pass output.

### Claim 2 (depends on 1)

The method of claim 1, wherein the signal of pixels represents a two-dimensional image.

### Claim 3 (depends on 1)

The method of claim 1, wherein switching the multimode filter comprises reversing the order of the filter coefficients and multiplying every other filter coefficient by a value of negative one.

### Claim 4 (depends on 2)

The method of claim 2, wherein the signal of pixels is ordered along either a horizontal direction or a vertical direction of the two-dimensional image.

### Claim 5 (depends on 3)

The method of claim 3, wherein the multimode quadrature mirror filter has a filter tap which is even in number.

### Claim 6

A wavelet-based compression system for multimedia computing, the system comprising:
digitized pixels of a two-dimensional image;
a clock transmitting clock cycles;
a shift register into which two of the digitized pixels are shifted per two clock cycles;
a multimode filter, with a high-pass mode and a low-pass mode, into which the digitized pixels contained in the shift register are transferred each clock cycle; and
a mode input which toggles a multimode filter between the high-pass mode and the low-pass mode once per clock cycle.

### Claim 7 (depends on 6)

The system of claim 6, wherein the multimode filter has a filter tap which is even in number.

### Claim 8 (depends on 7)

The system of claim 7, wherein the multimode filter comprises a multimode quadrature mirror filter and switching the multimode quadrature mirror filter comprises reversing the order of the filter coefficients and multiplying every other filter coefficient by a value of negative one.