idft

Core and matricesfunctionOpenCV 5.0.0

import { idft } 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.

Calculates the inverse Discrete Fourier Transform of a 1D or 2D array.

idft(src, dst, flags) is equivalent to dft(src, dst, flags | #DFT_INVERSE) .

Note: None of dft and idft scales the result by default. So, you should pass #DFT_SCALE to one of dft or idft explicitly to make these transforms mutually inverse. See: dft, dct, idct, mulSpectrums, getOptimalDFTSize

idft(src: Mat, dst: Mat, flags: number, nonzeroRows: number): void;

3 available overloads

idft(src: Mat, dst: Mat): void;

idft(src: Mat, dst: Mat, flags: number): void;

idft(src: Mat, dst: Mat, flags: number, nonzeroRows: number): void;

src

input floating-point real or complex array.

dst

Output destination, filled by the native operation. output array whose size and type depend on the flags.

flags

operation flags (see dft and #DftFlags).

nonzeroRows

number of dst rows to process; the rest of the rows have undefined content (see the convolution sample in dft description.

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.