lineToBorderPoints

Intersection points of lines in image and image border

Syntax

points = lineToBorderPoints(lines,imageSize)

Description

points = lineToBorderPoints(lines,imageSize) computes the intersection points between one or more lines in an image with the image border.

Examples

Find Intersection Points Between a Line and Image Border

Load and display an image.

I = imread('rice.png');
figure; 
imshow(I); 
hold on;

Define a line with the equation, 2 * x + y - 300 = 0.

aLine = [2,1,-300];

Compute the intersection points of the line and the image border.

points = lineToBorderPoints(aLine,size(I))

points = 1×4

  149.7500    0.5000   21.7500  256.5000

line(points([1,3]),points([2,4]));

Input Arguments

lines — Line matrix

M-by-3 matrix (default)

Line matrix, specified as an M-by-3 matrix, where each row must be in the format, [A,B,C]. This matrix corresponds to the definition of the line:

A * x + B * y + C = 0.

M represents the number of lines.

lines must be double or single.

imageSize — Image size

integer (default) | row vector

Image size, specified as a row vector in the format returned by the size function.

Output Arguments

points — Intersection points

M-by-4 matrix

Intersection points, returned as an M-by-4 matrix. The function returns the matrix in the format of [x₁, y₁, x₂, y₂]. In this matrix, [x₁ y₁] and [x₂ y₂] are the two intersection points. When a line in the image and the image border do not intersect, the function returns [-1,-1,-1,-1].

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2011a