如何在opencv中计算粗糙度轮廓？

Question

在opencv中有没有一种计算粗糙度轮廓的方法？在

图像示例：https://docs.google.com/file/d/0ByS6Z5WRz-h2NDgySmJ6NnpId0U/edit?usp=sharing

更新

我的粗糙度计算代码：

周长轮廓/凸面船体周长

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]

#ROUGHNESS
perimeter = cv2.arcLength(unicocnt,True)
hull = cv2.convexHull(unicocnt,returnPoints = False)
hullperimeter = cv2.arcLength(hull,True)

print("perimeter")
print(perimeter)
print("hullperimeter")
print(hullperimeter)


roughness = perimeter/hullperimeter
print("roughness")
print(roughness)

错误：

^{pr2}$

Answer 1

错误在converxhull查找线上。在

hull = cv2.convexHull(unicocnt,returnPoints = False)

默认情况下，标志returnPoints是True。然后返回的外壳包含外壳点或轮廓点的像素坐标。它通常用于绘制船体，寻找其面积、周长等

但如果将其指定为False，则返回的值是等高线中这些坐标的索引。它通常用于查找凸性缺陷。在

所以你的代码应该如下所示：

^{pr2}$

如需更详细的示例说明，请阅读^{}.中的conversixhull部分