resize

Image processingfunctionOpenCV 5.0.0

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

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

Explore visually: Image resizing →

Sample the source on a new pixel grid at a different resolution.

VISUAL WALKTHROUGHGeometry

REFERENCE INPUTFour neighbouring source samples

A magnified patch makes the interpolation arithmetic visible.

→

RESULTInterpolate one destination value

Repeat the mapping and interpolation for every destination pixel. Other interpolation flags use different sampling rules.

Illustrative example. The stages explain the method; they are not a live OpenCV execution.

imgproc_filter

Resizes an image.

The function resize resizes the image src down to or up to the specified size. Note that the initial dst type or size are not taken into account. Instead, the size and type are derived from the src,dsize,fx, and fy. If you want to resize src so that it fits the pre-created dst, you may call the function as follows:

    // explicitly specify dsize=dst.size(); fx and fy will be computed from that.
    resize(src, dst, dst.size(), 0, 0, interpolation);

If you want to decimate the image by factor of 2 in each direction, you can call the function this way:

    // specify fx and fy and let the function compute the destination image size.
    resize(src, dst, Size(), 0.5, 0.5, interpolation);

To shrink an image, it will generally look best with #INTER_AREA interpolation, whereas to enlarge an image, it will generally look best with #INTER_CUBIC (slow) or #INTER_LINEAR (faster but still looks OK).

See: warpAffine, warpPerspective, remap

resize(src: Mat, dst: Mat, dsize: Size, fx: number, fy: number, interpolation: number): void;

4 available overloads

resize(src: Mat, dst: Mat, dsize: Size): void;

resize(src: Mat, dst: Mat, dsize: Size, fx: number): void;

resize(src: Mat, dst: Mat, dsize: Size, fx: number, fy: number): void;

resize(src: Mat, dst: Mat, dsize: Size, fx: number, fy: number, interpolation: number): void;

src

input image.

dst

Output destination, filled by the native operation. output image; it has the size dsize (when it is non-zero) or the size computed from src.size(), fx, and fy; the type of dst is the same as of src.

dsize

output image size; if it equals zero (None in Python), it is computed as:

\texttt{dsize = Size(round(fx*src.cols), round(fy*src.rows))}

Either dsize or both fx and fy must be non-zero.

fx

scale factor along the horizontal axis; when it equals 0, it is computed as

\texttt{(double)dsize.width/src.cols}

fy

scale factor along the vertical axis; when it equals 0, it is computed as

\texttt{(double)dsize.height/src.rows}

interpolation

interpolation method, see #InterpolationFlags

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.