[SOLVED] CS4243 Tutorial 3

Q1: Consider the plot of a straight line in (a). Give the equation of the line in slope-intercept, double-intercept and normal form.

Q2: Consider the two points 𝑝1 = (2,1) and 𝑝2 = (−1,3) shown in (b). Using the slope-intercept form of a line (𝑦 = 𝑚𝑥 + 𝑏), estimate the Hough accumulator values for detecting a straight line. For the accumulator 𝐴(𝑚, 𝑏), use a range of (−1 ≤ 𝑚 < 5, −1 ≤ 𝑏 < 5), where 𝑚 and 𝑏 increment by values of 1. What is the detected line based on the maximum found in the accumulator and how does this compare to the true line?

(a) (b)
Coding:

• Apply cv2.HoughLines to Line.jpg, using 80 and 50 as thresholds and compare the results

• Apply cv2.HoughCircles to Circle.jpg, and investigate the influence of param1 and param2 o Blur the image with Median filter with size=5
o Set circle radius with minRadius=50, maxRadius=65 and minDist=40 o Try to set param1 and param2 as {80, 20}, {80, 10} and {50, 20}, and see the difference on outputs
o Apply circle detection on the unblurred image using the best parameters found above and check for differences in the output

Past Quiz Questions: • AY2122_Quiz1: Q6