Fitting a line to a set of points

In some applications, it could be important to not only detect lines in an image, but also to obtain an accurate estimate of the line's position and orientation. This recipe will show you how to estimate the exact line that best fits a given set of points.

How to do it...

The first thing to do is to identify points in an image that seem to be aligned along a straight line. Let's use one of the lines we detected in the preceding recipe. The lines detected using cv::HoughLinesP are contained in std::vector<cv::Vec4i> called lines. To extract the set of points that seem to belong to, let's say, the first of these lines, we can proceed as follows. We draw a white line on a black image and intersect it with the Canny ...

Get OpenCV 3 Computer Vision Application Programming Cookbook - Third Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.