Example
"""
CannyTrackbar function allows for a better understanding of
the mechanisms behind Canny Edge detection algorithm and rapid
prototyping. The example includes basic use case.
2 of the trackbars allow for tuning of the Canny function and
the other 2 help with understanding how basic filtering affects it.
"""
import cv2
def empty_function(*args):
pass
def CannyTrackbar(img):
win_name = "CannyTrackbars"
cv2.namedWindow(win_name)
cv2.resizeWindow(win_name, 500,100)
cv2.createTrackbar("canny_th1", win_name, 0, 255, empty_function)
cv2.createTrackbar("canny_th2", win_name, 0, 255, empty_function)
cv2.createTrackbar("blur_size", win_name, 0, 255, empty_function)
cv2.createTrackbar("blur_amp", win_name, 0, 255, empty_function)
while True:
cth1_pos = cv2.getTrackbarPos("canny_th1", win_name)
cth2_pos = cv2.getTrackbarPos("canny_th2", win_name)
bsize_pos = cv2.getTrackbarPos("blur_size", win_name)
bamp_pos = cv2.getTrackbarPos("blur_amp", win_name)
img_blurred = cv2.GaussianBlur(img.copy(), (trackbar_pos3 * 2 + 1, trackbar_pos3 * 2 + 1), bamp_pos)
canny = cv2.Canny(img_blurred, cth1_pos, cth2_pos)
cv2.imshow(win_name, canny)
key = cv2.waitKey(1) & 0xFF
if key == ord("c"):
break
cv2.destroyAllWindows()
return canny
img = cv2.imread("image.jpg")
canny = CannyTrackbar(img)
cv2.imwrite("result.jpg", canny)
