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

Question

我一直在尝试使用OpenCV在我的网络摄像头上进行颜色检测，并且不断出现标题和下面所示的错误：

 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相关的任何问题。有什么想法吗？

Answer 1

可能的问题1：凸轮设置

• 按Windows Key，键入camera。点击Camera privacy settings。

  << img src =“ https://image.soinside.com/eyJ1cmwiOiAiaHR0cHM6Ly9pLnN0YWNrLmltZ3VyLmNvbS9zdU9vaC5wbmcifQ==” width =“ 500” alt =“宽演示图片”>

• 在打开的屏幕上，确保Allow apps to access your camera处于打开状态。

  << img src =“ https://image.soinside.com/eyJ1cmwiOiAiaHR0cHM6Ly9pLnN0YWNrLmltZ3VyLmNvbS9pampJZC5wbmcifQ==” width =“ 320” alt =“宽演示图片”>

  ] >>

现在，重试您的代码！

可能的问题2：索引错误

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))
大多数情况下，如果您使用笔记本电脑的网络摄像头，则应尝试0

：

cap = cv2.VideoCapture(0)