Hough line detection first converts the image to an edge map (Sobel/Canny), then for each edge pixel iterates θ∈[0,π) computing ρ=x·cosθ+y·sinθ to vote in parameter space, extracts peaks and inverse-transforms to recover line segments overlaid on the original image.

1. edge_map = Sobel/Canny(I)
2. ∀ edge pixel (x,y): ∀θ∈[0,π): ρ = x·cosθ + y·sinθ → accumulator(ρ,θ)++
3. peak extraction → line segments