这里有一种简单的方法:
- 将图像转换为灰度
- 阈值处理以获得二进制图像
- 执行形态学操作以平滑图像
- 查找轮廓并提取ROI
将图像转换为灰度后,我们进行阈值处理以获取二值图像。
image = cv2.imread('1.png')
original = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 120, 255, cv2.THRESH_BINARY)[1]
接下来我们创建一个内核并对图像进行形态学操作以使其更加平滑。这一步通过侵蚀图像“断开”连接三个矩形的关节。
点击此处查看形态学操作的详细信息。
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (25,25))
opening = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=3)
从这里我们使用 numpy 切片找到轮廓并提取 ROI。所需矩形的边界框绘制在原始图像上。
cnts = cv2.findContours(opening, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
image_number = 0
for c in cnts:
x,y,w,h = cv2.boundingRect(c)
cv2.rectangle(image, (x, y), (x + w, y + h), (36,255,12), 3)
ROI = original[y:y+h, x:x+w]
cv2.imwrite("ROI_{}.png".format(image_number), ROI)
image_number += 1
这是每个单独保存的ROI。
完整代码
import cv2
image = cv2.imread('1.png')
original = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 120, 255, cv2.THRESH_BINARY)[1]
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (25,25))
opening = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=3)
cnts = cv2.findContours(opening, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
image_number = 0
for c in cnts:
x,y,w,h = cv2.boundingRect(c)
cv2.rectangle(image, (x, y), (x + w, y + h), (36,255,12), 3)
ROI = original[y:y+h, x:x+w]
cv2.imwrite("ROI_{}.png".format(image_number), ROI)
image_number += 1
cv2.imshow('opening', opening)
cv2.imshow('thresh', thresh)
cv2.imshow('image', image)
cv2.waitKey()