DLT.js

This is a package that compute DLT (Direct Linear Transformation) matrix, which can be used to transform points from one coordinate to another.

For details about DLT, please see https://www.cs.ubc.ca/grads/resources/thesis/May09/Dubrofsky_Elan.pdf.

Install

npm install dltjs

Usage

import dlt from 'dltjs';
 
 
let p0 = [[0, 0], [0, 1], [1, 0], [1, 1]];
let p1 = [[1, 1], [1, 2], [0, 1], [2, 2]];
let M = dlt.dlt2d(p0, p1);
 
let p = [3, 3];
console.log(dlt.transform2d(M, p));

Reference

• dlt.dlt2d(p0, p1) Given two sets of points p0, p1, solve the transform matrix which can transform points in p0 to points in p1. Both p0, p1 must contain at least 4 points (only the first 4 points will be used). Each point should be a tuple in format of [x, y]. This function will return a 3x3 matrix which contains the transforms required. The last element (M[2][2]) is guaranteed to be 1.

• dlt.transform2d(M, p) Transform point p with matrix M. Point p should be in format of [x, y]. The input M is the return value from dlt.dlt2d() and M[2][2] should be 1. The return value is the transformed point in format of [x, y].