mulSpectrums

Core and matricesfunctionOpenCV 5.0.0

import { mulSpectrums } from '@banou/opencv-wasm'

Use after await initOpenCV(). See the initialization and named imports guide.

Explore visually: Discrete Fourier transform →

Represent a signal as a combination of spatial frequencies.

VISUAL WALKTHROUGHSignal

REFERENCE INPUTMixed spatial frequencies

A slow oscillation and a faster ripple are added in the input signal.

→

RESULTReconstruct after removing the ripple

Removing the bin-12 component and its conjugate leaves the slow component. Grey retains the input for comparison.

Computed 64-sample Fourier example. The result demonstrates an optional frequency filter, not a change performed automatically by dft.

Performs the per-element multiplication of two Fourier spectrums.

The function cv::mulSpectrums performs the per-element multiplication of the two CCS-packed or complex matrices that are results of a real or complex Fourier transform.

The function, together with dft and idft, may be used to calculate convolution (pass conjB=false ) or correlation (pass conjB=true ) of two arrays rapidly. When the arrays are complex, they are simply multiplied (per element) with an optional conjugation of the second-array elements. When the arrays are real, they are assumed to be CCS-packed (see dft for details).

mulSpectrums(a: Mat, b: Mat, c: Mat, flags: number, conjB: boolean): void;

2 available overloads

mulSpectrums(a: Mat, b: Mat, c: Mat, flags: number): void;

mulSpectrums(a: Mat, b: Mat, c: Mat, flags: number, conjB: boolean): void;

a

first input array.

b

second input array of the same size and type as src1 .

c

Output destination, filled by the native operation. output array of the same size and type as src1 .

flags

operation flags; currently, the only supported flag is cv::DFT_ROWS, which indicates that each row of src1 and src2 is an independent 1D Fourier spectrum. If you do not want to use this flag, then simply add a 0 as value.

conjB

optional flag that conjugates the second input array before the multiplication (true) or not (false).

Upstream declaration ↗

These signatures describe this package. Upstream documentation can mention optional backends that are absent from this build. Check runtime compatibility before choosing a backend or file format.