python - OpenCV - 如何检测两个矩形之间的交叉点?
问题描述
我正在用 OpenCV 实现一种报警系统。我需要在“安全区域”内跟踪一个人,并检测并通知他是否越界。
我已经实现了运动跟踪。现在我需要定义一个 ROI(地板上的安全区域矩形;摄像头在天花板上)并检测它与人的边界矩形之间的交集。
类似的东西。
我有以下内容:
while True:
# Grab frame from webcam
ret, color_frame = vid.read()
# resize the frame, convert it to grayscale, and blur it
color_frame = imutils.resize(color_frame, width=500)
gray = cv2.cvtColor(color_frame, cv2.COLOR_BGR2GRAY)
gray = cv2.GaussianBlur(gray, (21, 21), 0)
# MOTION TRACKING #
# Defining safe zone area on the floor.
roi = cv2.rectangle(color_frame, (50, 50), (500, 500), (0, 0, 0), 2)
# First frame to compare motion
if firstFrame is None:
firstFrame = gray
continue
# Absolute difference to detect changes.
frameDelta = cv2.absdiff(firstFrame, gray)
thresh = cv2.threshold(frameDelta, 25, 255, cv2.THRESH_BINARY)[1]
# Finding contours
thresh = cv2.dilate(thresh, None, iterations=2)
contours = cv2.findContours(thresh.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
contours = imutils.grab_contours(contours)
# Filtering contours
for c in contours:
# if the contour is too small, ignore it
if cv2.contourArea(c) < 5000:
continue
# Bounding Rect for the person which we are tracking
(x, y, w, h) = cv2.boundingRect(c)
boudingRect = cv2.rectangle(color_frame, (x, y), (x + w, y + h), (0, 255, 0), 2)
正如我所说,这个人在 ROI 区域内,现在我需要检测他是否超出范围。最后的想法是通过声音警报通知,但我主要是在那个循环内的交叉点检测上苦苦挣扎。
解决方案
这将帮助您了解如何实现两个矩形之间的交集,cv2.pointPolygonTest
有关更多信息,您可以在此处pointPolygonTest
找到它
import cv2
import numpy as np
def check_intersection(polygon1, polygon2):
intersection = False
for point in polygon2:
result = cv2.pointPolygonTest(polygon1, tuple(point), measureDist=False)
# if point inside return 1
# if point outside return -1
# if point on the contour return 0
if result == 1:
intersection = True
return intersection
image1 = np.zeros((300, 300), dtype=np.uint8)
image2 = np.zeros((300, 300), dtype=np.uint8)
# take 4 points of
rectangle1_cordinates = np.array([[50, 50], [50, 100], [100, 100], [100, 50]])
rectangle2_cordinates = np.array([[75, 75], [75, 125], [125, 125], [125, 75]])
rectangle3_cordinates = np.array([[110, 110], [110, 160], [160, 160], [160, 110]])
result_1_and_2 = check_intersection(rectangle1_cordinates, rectangle2_cordinates)
result_1_and_3 = check_intersection(rectangle1_cordinates, rectangle3_cordinates)
cv2.putText(image1, str(result_1_and_2), (20, 20), cv2.FONT_HERSHEY_COMPLEX, 0.8, 255, 1)
cv2.drawContours(image1, [rectangle1_cordinates], -1, 255, 2)
cv2.drawContours(image1, [rectangle2_cordinates], -1, 255, 2)
cv2.putText(image2, str(result_1_and_3), (20, 20), cv2.FONT_HERSHEY_COMPLEX, 0.8, 255, 1)
cv2.drawContours(image2, [rectangle1_cordinates], -1, 255, 2)
cv2.drawContours(image2, [rectangle3_cordinates], -1, 255, 2)
cv2.imshow("image1", image1)
cv2.imshow("image2", image2)
cv2.waitKey(0)
cv2.destroyAllWindows()
输出:
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