background extraction with opencv

bg_extract.py

import cv2

import copy


class Copyable:
    __slots__ = 'a', '__dict__'

    def __init__(self, a, b):
        self.a, self.b = a, b

    def __copy__(self):
        return type(self)(self.a, self.b)

    def __deepcopy__(self, memo):  # memo is a dict of id's to copies
        id_self = id(self)  # memoization avoids unnecesary recursion
        _copy = memo.get(id_self)
        if _copy is None:
            _copy = type(self)(
                copy.deepcopy(self.a, memo),
                copy.deepcopy(self.b, memo))
            memo[id_self] = _copy
        return _copy


def rescale_by_height(image, target_height, method=cv2.INTER_LANCZOS4):
    """Rescale `image` to `target_height` (preserving aspect ratio)."""
    w = int(round(target_height * image.shape[1] / image.shape[0]))
    return cv2.resize(image, (w, target_height), interpolation=method)


def rescale_by_width(image, target_width, method=cv2.INTER_LANCZOS4):
    """Rescale `image` to `target_width` (preserving aspect ratio)."""
    h = int(round(target_width * image.shape[0] / image.shape[1]))
    return cv2.resize(image, (target_width, h), interpolation=method)


def apply_mask(frame, mask):
    """Apply binary mask to frame, return masked image.
    """
    return cv2.bitwise_and(frame, frame, mask=mask)


def main():
    cap = cv2.VideoCapture(0)
    history = 10

    first_sub = cv2.createBackgroundSubtractorMOG2(history=history, varThreshold=50, detectShadows=False)

    # learning
    while True:
        _, frame = cap.read()
        frame_blurred = cv2.blur(frame, (10, 10))

        mask = first_sub.apply(frame_blurred)
        cv2.imshow("Frame", rescale_by_height(frame, 240))
        cv2.imshow("Mask", rescale_by_height(mask, 240))
        cv2.imshow("Masked Frame", rescale_by_height(apply_mask(frame, mask), 240))
        cv2.imshow('BG', rescale_by_height(first_sub.getBackgroundImage(), 240))

        key = cv2.waitKey(30)
        if key == 27:
            break

    cap.release()
    cv2.destroyAllWindows()


if __name__ == '__main__':
    main()