perspectiveTransform

Core and matricesfunctionOpenCV 5.0.0

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

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

Explore visually: Homography and RANSAC →

Estimate a projective mapping between two views of a plane, rejecting inconsistent point matches.

VISUAL WALKTHROUGHGeometry

REFERENCE INPUTTentative correspondences

Eight tentative matches include two inconsistent pairs, shown in orange.

→

RESULTRecover the projective plane

The accepted mapping bends a rectangular grid into perspective. Every grid intersection uses the same projective transform as the inlier points.

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

Performs the perspective matrix transformation of vectors.

The function cv::perspectiveTransform transforms every element of src by treating it as a 2D or 3D vector, in the following way:

(x, y, z)  \rightarrow (x'/w, y'/w, z'/w)

where

(x', y', z', w') =  \texttt{mat} \cdot \begin{bmatrix} x & y & z & 1  \end{bmatrix}

and

w =  \fork{w'}{if \(w' \ne 0\)}{\infty}{otherwise}

Here a 3D vector transformation is shown. In case of a 2D vector transformation, the z component is omitted.

Note: The function transforms a sparse set of 2D or 3D vectors. If you want to transform an image using perspective transformation, use warpPerspective . If you have an inverse problem, that is, you want to compute the most probable perspective transformation out of several pairs of corresponding points, you can use getPerspectiveTransform or findHomography .

See: transform, warpPerspective, getPerspectiveTransform, findHomography

perspectiveTransform(src: Mat, dst: Mat, m: Mat): void;

src

input two-channel or three-channel floating-point array; each element is a 2D/3D vector to be transformed.

dst

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

m

3x3 or 4x4 floating-point transformation matrix.

Upstream declaration ↗

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