I was trying to use a tracebar to change the value of shresholds for Canny. Here is my code:When I run, I got this error:
Code:
#HoughLinesP import cv2import numpy as npfilename = input("Enter name of file to process: ")original = cv2.imread(filename)height, width = original.shape[:2]Max=1000Min=1000def blank(x): # null function for trackbar pass;MaxVal = (f'MaxVal 0: {Max-1}')MinVal = (f'MinVall 0: {Min-1}')cv2.namedWindow('window', cv2.WINDOW_NORMAL)cv2.resizeWindow('window', width, height)cv2.createTrackbar(MaxVal, 'window', 0, Max-1, blank)cv2.createTrackbar(MinVal, 'window', 0, Min-1, blank)while True:maxv = cv2.getTrackbarPos(MaxVal, 'window')minv = cv2.getTrackbarPos(MinVal, 'window')edge=cv2.Canny(original,minv,maxv)lines=cv2.HoughLinesP(edge, 1, np.pi/180, threshold =100, # lines minLineLength=20, maxLineGap =10) for i in range(len(lines)):for x1, y1, x2, y2 in lines[i]:cv2.line(original, (x1, y1), (x2, y2), (0, 255, 0), 2)cv2.imshow("houghline",original)# cv2.waitKey()# cv2.destroyAllWindows()if cv2.waitKey(1) == 32: # stop when space bar hitcv2.destroyAllWindows()Please helpEnter name of file to process: sidewalk.jpg
QSocketNotifier: Can only be used with threads started with QThread
QStandardPaths: wrong permissions on runtime directory /run/user/1000, 0770 instead of 0700
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
Traceback (most recent call last):
File "/home/ricky/Desktop/moduleç»ä¹ /module5.py", line 227, in <module>
for i in range(len(lines)):
^^^^^^^^^^
TypeError: object of type 'NoneType' has no len()
Statistics: Posted by ricky2777 — Sat Feb 08, 2025 3:55 am