basic motion detection

chapter8/basic_motion_detection.py

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+import cv2
+import numpy as np
+
+camera = cv2.VideoCapture(0)
+
+es = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (10,10))
+kernel = np.ones((5,5),np.uint8)
+background = None
+
+while (True):
+  ret, frame = camera.read()
+  if background is None:
+    background = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
+    background = cv2.GaussianBlur(background, (21, 21), 0)
+    continue
+
+  gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
+  gray_frame = cv2.GaussianBlur(gray_frame, (21, 21), 0)
+
+  diff = cv2.absdiff(background, gray_frame)
+  diff = cv2.threshold(diff, 25, 255, cv2.THRESH_BINARY)[1]
+  diff = cv2.dilate(diff, es, iterations = 2)
+
+  image, cnts, hierarchy = cv2.findContours(diff.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
+
+  for c in cnts:
+    if cv2.contourArea(c) < 1500:
+      continue
+    (x, y, w, h) = cv2.boundingRect(c)
+    cv2.rectangle(frame, (x, y), (x + w, y + h), (255, 255, 0), 2)
+
+  cv2.imshow("contours", frame)
+  cv2.imshow("dif", diff)
+  if cv2.waitKey(1000 / 12) & 0xff == ord("q"):
+      break
+
+cv2.destroyAllWindows()
+camera.release()