estimateTranslation2D

geometryfunctionOpenCV 5.0.0

import { estimateTranslation2D } from '@banou/opencv-wasm'

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

ARGUMENTSfrom_, to, inliers, method

→

FUNCTIONestimateTranslation2D

→

RETURN TYPEVec2d

Call structure. A void return can still write to destination arguments. The parameter descriptions define inputs, outputs and ownership.

Computes a pure 2D translation between two 2D point sets.

It computes

\begin{bmatrix}
x\\
y
\end{bmatrix}
=
\begin{bmatrix}
1 & 0\\
0 & 1
\end{bmatrix}
\begin{bmatrix}
X\\
Y
\end{bmatrix}
+
\begin{bmatrix}
t_x\\
t_y
\end{bmatrix}.

cv::Vec2d t = cv::estimateTranslation2D(from, to, inliers);
cv::Mat T = (cv::Mat_<double>(2,3) << 1,0,t[0], 0,1,t[1]);

The function estimates a pure 2D translation between two 2D point sets using the selected robust algorithm. Inliers are determined by the reprojection error threshold.

Note: The RANSAC method can handle practically any ratio of outliers but needs a threshold to distinguish inliers from outliers. The method LMeDS does not need any threshold but works correctly only when there are more than 50% inliers.

See: estimateAffine2D, estimateAffinePartial2D, getAffineTransform

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat, method: number, ransacReprojThreshold: number, maxIters: number, confidence: number, refineIters: number): Vec2d;

7 available overloads

estimateTranslation2D(from_: Mat, to: Mat): Vec2d;

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat): Vec2d;

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat, method: number): Vec2d;

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat, method: number, ransacReprojThreshold: number): Vec2d;

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat, method: number, ransacReprojThreshold: number, maxIters: number): Vec2d;

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat, method: number, ransacReprojThreshold: number, maxIters: number, confidence: number): Vec2d;

estimateTranslation2D(from_: Mat, to: Mat, inliers: Mat, method: number, ransacReprojThreshold: number, maxIters: number, confidence: number, refineIters: number): Vec2d;

from_

First input 2D point set containing (X,Y).

to

Second input 2D point set containing (x,y).

inliers

Output destination, filled by the native operation. Output vector indicating which points are inliers (1-inlier, 0-outlier).

method

Robust method used to compute the transformation. The following methods are possible:

• RANSAC - RANSAC-based robust method
• LMEDS - Least-Median robust method RANSAC is the default method.

ransacReprojThreshold

Maximum reprojection error in the RANSAC algorithm to consider a point as an inlier. Applies only to RANSAC.

maxIters

The maximum number of robust method iterations.

confidence

Confidence level, between 0 and 1, for the estimated transformation. Anything between 0.95 and 0.99 is usually good enough. Values too close to 1 can slow down the estimation significantly. Values lower than 0.8-0.9 can result in an incorrectly estimated transformation.

refineIters

Maximum number of iterations of the refining algorithm. For pure translation the least-squares solution on inliers is closed-form, so passing 0 is recommended (no additional refine).

Returns

A 2D translation vector [t_x, t_y]^T as cv::Vec2d. If the translation could not be estimated, both components are set to NaN and, if inliers is provided, the mask is filled with zeros.

\par Converting to a 2x3 transformation matrix:

\begin{bmatrix}
1 & 0 & t_x\\
0 & 1 & t_y
\end{bmatrix}

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.