python - 我怎么知道在opencv中轮廓是打开还是关闭？

Question

我如何知道从“查找轮廓”功能获取的轮廓在 opencv 中是打开还是关闭？

更新

我尝试将 isContourConvex 应用于此图像：https ://docs.google.com/file/d/0ByS6Z5WRz-h2RXdzVGtXUTlPSGc/edit?usp=sharing

i 提取面积最大的轮廓并返回 false。我改变，也许，轮廓提取，扩张？

nomeimg = 'Riscalate2/JPEG/e (5).jpg'

img = cv2.imread(nomeimg)

gray = cv2.imread(nomeimg,0)#convert grayscale adn binarize

element = cv2.getStructuringElement(cv2.MORPH_CROSS,(6,6)) 
graydilate = cv2.erode(gray, element) #imgbnbin

cv2.imshow('image',graydilate)
cv2.waitKey(0)

ret,thresh = cv2.threshold(graydilate,127,255,cv2.THRESH_BINARY_INV)   # binarize

imgbnbin = thresh
cv2.imshow('bn',thresh)
cv2.waitKey()

#element = cv2.getStructuringElement(cv2.MORPH_CROSS,(2,2))
#element = np.ones((11,11),'uint8')


contours, hierarchy = cv2.findContours(imgbnbin, cv2.RETR_TREE ,cv2.CHAIN_APPROX_SIMPLE)
print(len(contours))


# Take only biggest contour basing on area
Areacontours = list()
calcarea = 0.0
unicocnt = 0.0
for i in range (0, len(contours)):
    area = cv2.contourArea(contours[i])
    #print("area")
    #print(area)
    if (area > 90 ):  #con 90 trova i segni e togli puntini
        if (calcarea<area):
            calcarea = area
            unicocnt = contours[i]


convex = cv2.isContourConvex(unicocnt)
print("convex")
print(convex)

Answer 1

您正在寻找术语凹（如 C）与凸（如 O）轮廓。

猜猜看，有一种方法可以检查凸性：

cv2.isContourConvex(contour)