Python从图像opencv中提取多个对象 [英] Python extract multiple objects from image opencv
问题描述
我正在尝试使用OpenCV使用颜色从图像中提取对象,我尝试通过反阈值和灰度与cv2.findContours()
结合使用,但是无法递归使用它.此外,我无法弄清楚如何从原始图像中切出"匹配并将其保存到单个文件中.
I am trying to extract object from an image using the color using OpenCV, I have tried by inverse thresholding and grayscale combined with cv2.findContours()
but I am unable to use it recursively. Furthermore I can't figure out how to "cut out" the match from the original image and save it to a single file.
~
import cv2
import numpy as np
# load the images
empty = cv2.imread("empty.jpg")
full = cv2.imread("test.jpg")
# save color copy for visualization
full_c = full.copy()
# convert to grayscale
empty_g = cv2.cvtColor(empty, cv2.COLOR_BGR2GRAY)
full_g = cv2.cvtColor(full, cv2.COLOR_BGR2GRAY)
empty_g = cv2.GaussianBlur(empty_g, (51, 51), 0)
full_g = cv2.GaussianBlur(full_g, (51, 51), 0)
diff = full_g - empty_g
# thresholding
diff_th =
cv2.adaptiveThreshold(full_g,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
cv2.THRESH_BINARY,11,2)
# combine the difference image and the inverse threshold
zone = cv2.bitwise_and(diff, diff_th, None)
# threshold to get the mask instead of gray pixels
_, zone = cv2.threshold(bag, 100, 255, 0)
# dilate to account for the blurring in the beginning
kernel = np.ones((15, 15), np.uint8)
bag = cv2.dilate(bag, kernel, iterations=1)
# find contours, sort and draw the biggest one
contours, _ = cv2.findContours(bag, cv2.RETR_TREE,
cv2.CHAIN_APPROX_SIMPLE)
contours = sorted(contours, key=cv2.contourArea, reverse=True)[:3]
i = 0
while i < len(contours):
x, y, width, height = cv2.boundingRect(contours[i])
roi = full_c[y:y+height, x:x+width]
cv2.imwrite("piece"+str(i)+".png", roi)
i += 1
空白处是一张上面的一张,尺寸为1500 * 1000的白色图像,而测试是上面的一张.
Where empty is just a white image size 1500 * 1000 as the one above and test is the one above.
这是我想出的,只是缺点,我有第三张图像,而不是只有2张图像现在显示阴影区域...
This is what I came up with, only downside, I have a third image instead of only the 2 expected showing a shadow zone now...
推荐答案
这是一种简单的方法:
- 将图像转换为灰度和高斯模糊图像
- 执行Canny边缘检测
- 将图像放大以形成更大的轮廓
- 遍历轮廓并找到边界框
- 提取投资回报率并保存图像
Canny边缘检测
检测到的投资回报率
要提取ROI,您可以使用cv2.boundingRect()
找到边界框坐标,裁剪所需区域,然后保存图像
To extract the ROI, you can find the bounding box coordinates using cv2.boundingRect()
, crop the desired region, then save the image
x,y,w,h = cv2.boundingRect(c)
ROI = original[y:y+h, x:x+w]
第一个对象
第二个对象
import cv2
import numpy as np
image = cv2.imread('1.jpg')
original = image.copy()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
blurred = cv2.GaussianBlur(gray, (3, 3), 0)
canny = cv2.Canny(blurred, 120, 255, 1)
kernel = np.ones((5,5),np.uint8)
dilate = cv2.dilate(canny, kernel, iterations=1)
# Find contours
cnts = cv2.findContours(dilate, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
# Iterate thorugh contours and filter for ROI
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), 2)
ROI = original[y:y+h, x:x+w]
cv2.imwrite("ROI_{}.png".format(image_number), ROI)
image_number += 1
cv2.imshow('canny', canny)
cv2.imshow('image', image)
cv2.waitKey(0)
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