I have been trying to run a color detection on my webcam by using OpenCV, and it keeps getting the error as shown in the title, and below:
imgHsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV)
cv2.error: OpenCV(4.0.0) C:\projects\opencv-python\opencv\modules\imgproc\src\color.cpp:181: error: (-215:Assertion failed) !_src.empty() in function 'cv::cvtColor'
The code that I wanted to run is:
import cv2
import numpy as np
frameWidth = 640
frameHeight = 480
cap = cv2.VideoCapture(1)
cap.set(3, frameWidth)
cap.set(4, frameHeight)
def empty(a):
pass
cv2.namedWindow("HSV")
cv2.resizeWindow("HSV",640,240)
cv2.createTrackbar("HUE Min","HSV",0,179,empty)
cv2.createTrackbar("HUE Max","HSV",179,179,empty)
cv2.createTrackbar("SAT Min","HSV",0,255,empty)
cv2.createTrackbar("SAT Max","HSV",255,255,empty)
cv2.createTrackbar("VALUE Min","HSV",0,255,empty)
cv2.createTrackbar("VALUE Max","HSV",255,255,empty)
while True:
_, img = cap.read(0)
imgHsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV)
h_min = cv2.getTrackbarPos("HUE Min","HSV")
h_max = cv2.getTrackbarPos("HUE Max", "HSV")
s_min = cv2.getTrackbarPos("SAT Min", "HSV")
s_max = cv2.getTrackbarPos("SAT Max", "HSV")
v_min = cv2.getTrackbarPos("VALUE Min", "HSV")
v_max = cv2.getTrackbarPos("VALUE Max", "HSV")
print(h_min)
lower = np.array([h_min,s_min,v_min])
upper = np.array([h_max,s_max,v_max])
mask = cv2.inRange(imgHsv,lower,upper)
result = cv2.bitwise_and(img,img, mask = mask)
mask = cv2.cvtColor(mask, cv2.COLOR_GRAY2BGR)
hStack = np.hstack([img,mask,result])
cv2.imshow('Original', img)
cv2.imshow('HSV Color Space', imgHsv)
cv2.imshow('Mask', mask)
cv2.imshow('Result', result)
cv2.imshow('Horizontal Stacking', hStack)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows()
I am not sure whether this is the issue of OpenCV version, or anything related to the code or smth. Any ideas?
Press Windows Key
, typecamera
. Click on the Camera privacy settings
.
On the opening screen, make sure that Allow apps to access your camera
is ON.
Now, retry with your code!
Find the camera index:
max_cam_number = 10
for i in range(-1, max_cam_number):
cap = cv2.VideoCapture(i)
test, frame = cap.read()
if test:
print("i : "+str(i)+" /// result: "+str(test))
Most of the time, if you are using your laptop's webcam, you should try 0:
cap = cv2.VideoCapture(0)