Hough transform python numpy

1. What is the purpose of Hough transform?
2. Where can I find Hough transform?
3. Which preprocessing is required before Hough line?

What is the purpose of Hough transform?

The Hough transform (HT) [Hough62] is a technique that locates shapes in images. In particular, it has been used to extract lines, circles and ellipses (or conic sections). In the case of lines, its mathematical definition is equivalent to the Radon transform [Deans81].

Where can I find Hough transform?

If two edge points lay on the same line, their corresponding cosine curves will intersect each other on a specific (ρ, θ) pair. Thus, the Hough Transform algorithm detects lines by finding the (ρ, θ) pairs that have a number of intersections larger than a certain threshold.

Which preprocessing is required before Hough line?

Edge detection is often used as preprocessing to Hough preprocessing to Hough transform.