picamera motion detection - super hacky!

detect_motion.py

from picamera import PiCamera, PiCameraCircularIO, PiVideoFrameType
from picamera.array import PiRGBArray
from time import sleep
import io
import cv2

def diff_image(t0, t1, t2):
    d1 = cv2.absdiff(t2, t1)
    d2 = cv2.absdiff(t1, t0)
    return cv2.bitwise_and(d1, d2)

def detect_motion():
    for frame in stream.frames:
        print(frame)
    #print(stream.frames[0])

def write_video(stream):
    print("writing")
    with stream.lock:
        # Find the first header frame in the video
        for frame in stream.frames:
            if frame.frame_type == PiVideoFrameType.sps_header:
                stream.seek(frame.position)
                break
        # Write the rest of the stream to disk
        with io.open('video.h264', 'wb') as output:
            output.write(stream.read())

with PiCamera(resolution="1056x768") as cam:
    capture_stream = PiRGBArray(cam)
    stream = PiCameraCircularIO(cam, seconds=30)
    images = []
    try:
        cam.start_preview(alpha = 192)
        cam.framerate = 10
        cam.start_recording(stream, format="h264")
        cam.color_effects = (128,128)
        print("recording")
        while True:
            cam.capture(capture_stream, format='bgr')
            images.append(cv2.cvtColor(capture_stream.array, cv2.COLOR_RGB2GRAY))
            capture_stream.truncate(0)
            if len(images) == 3:
                #print("diff")
                diff = diff_image(images[0], images[1], images[2])
                #for i in range(len(images)):
                #    cv2.imwrite("image{}.png".format(i), images[i])
                #cv2.imwrite("diff.png", diff)
                if cv2.countNonZero(diff) > 300000:
                    print("motion")
                #print(cv2.countNonZero(diff))
                images.pop(0)
            
            #cam.wait_recording(0.1)
        #input("press enter")
        #write_video(stream)
    finally:
        cam.stop_recording()
        cam.stop_preview()
 
print("finished")