Chuanshuoge: opencv 17 canny edge detection

Thursday, 18 March 2021

gray scale

canny edge detection

#main.py

import numpy as np

import cv2

cap = cv2.VideoCapture("assets/Santa Barbara.mp4")

high = 200

low = 100

trackbars_img = np.uint8(np.full((50, 500, 3), 255))

cv2.imshow('trackbars', trackbars_img)

def high_change(x):

global high

high = x

def low_change(x):

global low

low = x

cv2.createTrackbar('low', 'trackbars', 100, 150, low_change)

cv2.createTrackbar('high', 'trackbars', 200, 255, high_change)

while True:

ret, frame = cap.read()

width = int(cap.get(3))

height = int(cap.get(4))

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

canny = cv2.Canny(gray, low, high)

cv2.imshow('frame', frame)

cv2.imshow('gray', gray)

cv2.imshow('canny', canny)

if cv2.waitKey(1) == ord('q'):

break

if cv2.waitKey(1) == ord('p'):

# wait until any key is pressed

cv2.waitKey(-1)

cap.release()

cv2.destroyAllWindows()

reference:

Chuanshuoge