motion_detector.py

import numpy as np
import cv2
from PIL import Image, ImageGrab
from rc import RCModel


class MotionDetect(object):

    def __init__(self):
        self._image_previous_rgb = None
        self._frame_count = 0

    def motion_detector(self):
        self._frame_count = 0
        previous_frame = None

        while True:
            self._frame_count += 1

            # 1. Load image; convert to RGB
            img_brg = np.array(ImageGrab.grab())
            img_rgb = cv2.cvtColor(src=img_brg, code=cv2.COLOR_BGR2RGB)

            if ((self._frame_count % 2) == 0):
                # 2. Prepare image; grayscale and blur
                prepared_frame = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)
                prepared_frame = cv2.GaussianBlur(src=prepared_frame, ksize=(5, 5), sigmaX=0)

            # 3. Set previous frame and continue if there is None
            if previous_frame is None:
                # First frame; there is no previous one yet
                previous_frame = prepared_frame
                continue

            # calculate difference and update previous frame
            diff_frame = cv2.absdiff(src1=previous_frame, src2=prepared_frame)
            previous_frame = prepared_frame

            # 4. Dilute the image a bit to make differences more seeable; more suitable for contour detection
            kernel = np.ones((5, 5))
            diff_frame = cv2.dilate(diff_frame, kernel, 1)

            # 5. Only take different areas that are different enough (>20 / 255)
            thresh_frame = cv2.threshold(src=diff_frame, thresh=20, maxval=255, type=cv2.THRESH_BINARY)[1]

            contours, _ = cv2.findContours(image=thresh_frame, mode=cv2.RETR_EXTERNAL, method=cv2.CHAIN_APPROX_SIMPLE)
            #cv2.drawContours(image=img_rgb, contours=contours, contourIdx=-1, color=(0, 255, 0), thickness=2,
            #                 lineType=cv2.LINE_AA)

            for contour in contours:
                if cv2.contourArea(contour) < 50:
                    # too small: skip!
                    continue
                (x, y, w, h) = cv2.boundingRect(contour)
                cv2.rectangle(img=img_rgb, pt1=(x, y), pt2=(x + w, y + h), color=(0, 255, 0), thickness=2)

            self.show(frame_rgb=img_rgb)
            if (cv2.waitKey(30) == 27):
                break

    def show(self, frame_rgb):
        cv2.imshow('Motion detector', frame_rgb)