我试图检测图像中红色物体上的轮廓，但在使用openCv时不断出现错误。findContour函数

Question

我试图获得图像的一部分轮廓，但调用cv时不断出现错误。找到你的形象。为了在图像中找到物体，我首先尝试提取物体的颜色，它是红色的，然后我尝试在检测到的物体上找到轮廓。

import cv2 as cv
import numpy as np


def main():

    image_find_goal = "image.jpg"
    kernel = np.ones((5,5),np.uint8)
    #findGoal(image_find_goal)
    img1 = cv.imread(image_find_goal)
    img = cv.resize(img1,(700,700))
    hsv = cv.cvtColor(img,cv.COLOR_BGR2HSV)

    #range for red color
    lower_r = np.array([160,100,100])
    upper_r = np.array([179,255,255])
    mask = cv.inRange(hsv,lower_r,upper_r)
    res = cv.bitwise_and(img,img,mask=mask)
    _,thresh = cv.threshold(res,125,255,cv.THRESH_BINARY)
    dilate =  cv.dilate(thresh,None,iterations=1)

    contours, hierarchy = cv.findContours(dilate,cv.RETR_TREE,cv.CHAIN_APPROX_NONE)
    for cnt in contours:
        epsilon = 0.1*cv.arcLength(cnt,True)
        approx = cv.approxPolyDP(cnt,epsilon,True)
        if len(approx) == 4:
            cv.drawContours(img,cnt,-1,(60,255,255),4)

    cv.imshow('OBSTACLES',img)
    cv.waitKey(0)
    cv.destroyWindow(img)

我得到的错误是：

轮廓，层次=cv。找到的容器（扩张，cv.翻新树，cv.链约无）cv2。错误：OpenCV（4.4.0）/tmp/pip-req-build-sw_3pm_8/OpenCV/modules/imgproc/src/contours。cpp:195:错误：（-210:不支持的格式或格式组合）[Start]FindContours在模式下仅支持CV_8UC1图像！=CV_RETR_FLOODFILL仅在函数“cvStartFindContours_Impl”中支持CV_32SC1图像

Answer 1

Ciao，

我认为这个片段解决了你的问题。因为你对轮廓感兴趣，我会在扩张前应用Canny边缘检测。此操作还将修复您得到的CV类型错误

import cv2 as cv
import numpy as np

image_find_goal = "image.jpg"
#findGoal(image_find_goal)
img1 = cv.imread(image_find_goal)
img = cv.resize(img1,(700,700))
hsv = cv.cvtColor(img,cv.COLOR_BGR2HSV)

#range for red color
lower_r = np.array([160,100,100])
upper_r = np.array([179,255,255])
mask = cv.inRange(hsv,lower_r,upper_r)
res = cv.bitwise_and(img,img,mask=mask)
_,thresh = cv.threshold(res,125,255,cv.THRESH_BINARY)

# check which are the best canny threshold values for your image
imgCanny = cv.Canny(thresh, 180, 180)
dilate = cv.dilate(imgCanny, None, iterations = 1)
# cv.imshow("dilate", dilate)
# cv.waitKey()

contours, hierarchy = cv.findContours(dilate,cv.RETR_TREE,cv.CHAIN_APPROX_NONE)
for cnt in contours:
    epsilon = 0.1*cv.arcLength(cnt,True)
    approx = cv.approxPolyDP(cnt,epsilon,True)
    if len(approx) == 4:
        cv.drawContours(img,cnt,-1,(60,255,255),4)

cv.imshow('OBSTACLES',img)
cv.waitKey(0)
cv.destroyAllWindows()

祝你愉快，
安东尼诺