如何使用 opencv 从图像中改进矩形？

Question

我有一个如下所示的输入图像：

]

我做了一些处理，并从我的输入图像中得到线条，如下 Lined Image :

我想要像这样检测到单元格的输出：输出图像

我尝试使用 findContours 和 connectedComponentsWithStats 方法找到单元格边界框，但它们没有给我令人满意的结果。

我的代码：

对于轮廓：

contours, hierarchy = cv2.findContours(img, cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

for contour in contours[2:]:
    (x,y,w,h) = cv2.boundingRect(contour)
    cv2.rectangle(img, (x,y), (x+w,y+h),(0, 255, 0),2)

对于 connectedComponentsWithStats:

_, labels, stats,_ = cv2.connectedComponentsWithStats(img, connectivity=4, ltype=cv2.CV_32S)
for x,y,w,h,area in stats[2:]:
    cv2.rectangle(img,(x,y),(x+w,y+h),(0,255,0),2)

感谢任何帮助。

Answer 1

# 
import cv2

image = cv2.imread('JoWnj.jpg')
result = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY_INV, 51, 9)

# Fill rectangular contours
# CHECK OTHER CONTOUR SETTINGS ? TO EXLCUDE OUTER ?
# https://docs.opencv.org/master/d9/d8b/tutorial_py_contours_hierarchy.html
# https://medium.com/analytics-vidhya/opencv-findcontours-detailed-guide-692ee19eeb18
# cnts = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cv2.findContours(thresh, cv2.RETR_CCOMP, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
for c in cnts:
    cv2.drawContours(thresh, [c], -1, (255, 255, 255), -1)
    cv2.drawContours(thresh, [c], -1, (0, 0, 0), 1)

# Morph open
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (7, 4))
opening = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=4)
# opening = cv2.morphologyEx(thresh, cv2.MORPH_CLOSE, kernel, iterations=4)

# Draw rectangles
# cnts = cv2.findContours(opening, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cv2.findContours(opening, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
for c in cnts:
    x, y, w, h = cv2.boundingRect(c)
    cv2.rectangle(image, (x, y-3), (x + w, y + h-3), (36, 255, 12), 1)
    # filled
    # cv2.rectangle(image, (x, y), (x + w, y + h), (36,255,12), -1)

cv2.imwrite('sunday.jpg', image)

result image that You want: 参考：

如何使用 opencv 从图像中改进矩形？

How to improve rectangles from image using opencv?

python

opencv

contour

computer-vision

python-3.x