imgHsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV) cv2.error: OpenCV(4.0.0)

Question

我一直在尝试使用 OpenCV 运行在我的网络摄像头上进行颜色检测，但它不断出现如标题和下方所示的错误：

 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'

我想要运行的代码是：

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()

我不确定这是OpenCV版本的问题，还是与代码或smth有关的任何问题。有什么想法吗？

Answer 1

可能的问题 #1：摄像头设置

按Windows Key，键入camera。点击 Camera privacy settings.
在打开屏幕上，确保 Allow apps to access your camera 已打开。

现在，使用您的代码重试！

可能的问题 #2：错误的索引

查找相机索引：

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))

大多数时候，如果您使用笔记本电脑的网络摄像头，您应该尝试 0:

cap = cv2.VideoCapture(0)

imgHsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV) cv2.error: OpenCV(4.0.0)

imgHsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV) cv2.error: OpenCV(4.0.0)

python

opencv

colors

detection

可能的问题 #1：摄像头设置

可能的问题 #2：错误的索引