please help find the error in python opencv

Question

I made a hand recognition project that tells which hand is that left or right.

but i got an error in color describing cvt

i used mediapipe and opencv.

this is the full code of my project:

# Importing Libraries
import cv2
import mediapipe as mp

# Used to convert protobuf message to a dictionary.
from google.protobuf.json_format import MessageToDict

# Initializing the Model
mpHands = mp.solutions.hands
hands = mpHands.Hands(
    static_image_mode=False,
    model_complexity=1,
    min_detection_confidence=0.75,
    min_tracking_confidence=0.75,
    max_num_hands=2)

# Start capturing video from webcam
cap = cv2.VideoCapture(0)

while True:
    # Read video frame by frame
    success, img = cap.read()

    # Flip the image(frame)
    img = cv2.flip(img, 1)

    # Convert BGR image to RGB image
    imgRGB = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)

    # Process the RGB image
    results = hands.process(imgRGB)

    # If hands are present in image(frame)
    if results.multi_hand_landmarks:

        # Both Hands are present in image(frame)
        if len(results.multi_handedness) == 2:
                # Display 'Both Hands' on the image
            cv2.putText(img, 'Both Hands', (250, 50),
                        cv2.FONT_HERSHEY_COMPLEX,
                        0.9, (0, 255, 0), 2)

        # If any hand present
        else:
            for i in results.multi_handedness:
                
                # Return whether it is Right or Left Hand
                label = MessageToDict(i)
                ['classification'][0]['label']

                if label == 'Left':
                    
                    # Display 'Left Hand' on
                    # left side of window
                    cv2.putText(img, label+' Hand',
                                (20, 50),
                                cv2.FONT_HERSHEY_COMPLEX,
                                0.9, (0, 255, 0), 2)

                if label == 'Right':
                    
                    # Display 'Left Hand'
                    # on left side of window
                    cv2.putText(img, label+' Hand', (460, 50),
                                cv2.FONT_HERSHEY_COMPLEX,
                                0.9, (0, 255, 0), 2)

    # Display Video and when 'q'
    # is entered, destroy the window
    cv2.imshow('Image', img)
    if cv2.waitKey(1) & 0xff == ord('q'):
        break

and i got this error :

Traceback (most recent call last):
  File "C:\Users\'\Desktop\Projects\Rafan\Python\Face detection in opencv.py", line 28, in <module>
    imgRGB = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
cv2.error: OpenCV(4.7.0) D:\a\opencv-python\opencv-python\opencv\modules\imgproc\src\color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'

can anyone help to find the error out.

Answer 1

This errors basically occurs when your webcam is not connected or for some reason openCV is unable to connect with your webcam. You can also try replacing the 0 in cap = cv2.VideoCapture(0) to 1 or 2.