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I'm following a guide to develop a motion detection security feed and have run into an issue. The author of the tutorial had no issues, but I do.

'''The full code can be found here: https://github.com/ncorbuk/Python-Motion-Detection-system/blob/master/motion_detection.py
'''

I have already tried the option of adding,

" for c in cnt or []: " - This got me further into running the application where I could see the camera screens, however as soon as motion is detected the application crashes and provides the following numpy error:

The truth value of an array with more than one element is ambiguous.
Use a.any() or a.all()

for c in cnt:
 if (cv2.contourArea(c) > 800): 
 (x, y, w, h) = cv2.boundingRect(c)

 cv2.rectangle(frame, (x,y), (x+w, y+h), (0, 255, 0), 2) 

 text = 'Occupied'

 else:
 pass

The expected output, if you have a webcam;
When motion is detected a green rectangle will follow the moving pixels and change the mode from Unoccupied to Occupied, in real time; with no errors.

python opencv typeerror nonetype

share|improve this question

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What version of OpenCV are you using?
  
  – alkasm
  Mar 26 at 0:42
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @AlexanderReynolds I'm using opencv-python==4.0.0.21
  
  – Devshades
  Mar 26 at 0:52
  

  
  
  
  

add a comment | 

0

I'm following a guide to develop a motion detection security feed and have run into an issue. The author of the tutorial had no issues, but I do.

'''The full code can be found here: https://github.com/ncorbuk/Python-Motion-Detection-system/blob/master/motion_detection.py
'''

I have already tried the option of adding,

" for c in cnt or []: " - This got me further into running the application where I could see the camera screens, however as soon as motion is detected the application crashes and provides the following numpy error:

The truth value of an array with more than one element is ambiguous.
Use a.any() or a.all()

for c in cnt:
 if (cv2.contourArea(c) > 800): 
 (x, y, w, h) = cv2.boundingRect(c)

 cv2.rectangle(frame, (x,y), (x+w, y+h), (0, 255, 0), 2) 

 text = 'Occupied'

 else:
 pass

The expected output, if you have a webcam;
When motion is detected a green rectangle will follow the moving pixels and change the mode from Unoccupied to Occupied, in real time; with no errors.

python opencv typeerror nonetype

share|improve this question

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What version of OpenCV are you using?
  
  – alkasm
  Mar 26 at 0:42
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @AlexanderReynolds I'm using opencv-python==4.0.0.21
  
  – Devshades
  Mar 26 at 0:52
  

  
  
  
  

add a comment | 

I'm following a guide to develop a motion detection security feed and have run into an issue. The author of the tutorial had no issues, but I do.

'''The full code can be found here: https://github.com/ncorbuk/Python-Motion-Detection-system/blob/master/motion_detection.py
'''

I have already tried the option of adding,

" for c in cnt or []: " - This got me further into running the application where I could see the camera screens, however as soon as motion is detected the application crashes and provides the following numpy error:

The truth value of an array with more than one element is ambiguous.
Use a.any() or a.all()

for c in cnt:
 if (cv2.contourArea(c) > 800): 
 (x, y, w, h) = cv2.boundingRect(c)

 cv2.rectangle(frame, (x,y), (x+w, y+h), (0, 255, 0), 2) 

 text = 'Occupied'

 else:
 pass

The expected output, if you have a webcam;
When motion is detected a green rectangle will follow the moving pixels and change the mode from Unoccupied to Occupied, in real time; with no errors.

python opencv typeerror nonetype

share|improve this question

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

for c in cnt:
 if (cv2.contourArea(c) > 800): 
 (x, y, w, h) = cv2.boundingRect(c)

 cv2.rectangle(frame, (x,y), (x+w, y+h), (0, 255, 0), 2) 

 text = 'Occupied'

 else:
 pass

share|improve this question

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

share|improve this question

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

edited Mar 26 at 0:05

Alex W

28.6k77 gold badges6868 silver badges8585 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

asked Mar 25 at 23:59

DevshadesDevshades

322 bronze badges

1 Answer
1

active

oldest

votes

1

In Opencv4.0, findContour() returns only 2 values, contours and hierachy. So in the line 57 in motion_detection.py you have to change

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[1]

to

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[0].

share|improve this answer

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thank you so much @Ha Bom, your answer has solved my problem!
  
  – Devshades
  Mar 26 at 1:10
  

  
  
  
  

add a comment | 

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1

In Opencv4.0, findContour() returns only 2 values, contours and hierachy. So in the line 57 in motion_detection.py you have to change

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[1]

to

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[0].

share|improve this answer

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thank you so much @Ha Bom, your answer has solved my problem!
  
  – Devshades
  Mar 26 at 1:10
  

  
  
  
  

add a comment | 

1

In Opencv4.0, findContour() returns only 2 values, contours and hierachy. So in the line 57 in motion_detection.py you have to change

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[1]

to

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[0].

share|improve this answer

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thank you so much @Ha Bom, your answer has solved my problem!
  
  – Devshades
  Mar 26 at 1:10
  

  
  
  
  

add a comment | 

In Opencv4.0, findContour() returns only 2 values, contours and hierachy. So in the line 57 in motion_detection.py you have to change

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[1]

to

cnt = cv2.findContours(dilate_image.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[0].

share|improve this answer

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges

share|improve this answer

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges

answered Mar 26 at 1:06

Ha BomHa Bom

1,71522 gold badges66 silver badges2020 bronze badges