blakeblackshear.frigate/frigate/motion/improved_motion.py

import cv2
import imutils
import numpy as np
from scipy.ndimage import gaussian_filter

from frigate.config import MotionConfig
from frigate.motion import MotionDetector


class ImprovedMotionDetector(MotionDetector):
    def __init__(
        self,
        frame_shape,
        config: MotionConfig,
        fps: int,
        improve_contrast,
        threshold,
        contour_area,
        name="improved",
        blur_radius=1,
        interpolation=cv2.INTER_NEAREST,
        contrast_frame_history=50,
    ):
        self.name = name
        self.config = config
        self.frame_shape = frame_shape
        self.resize_factor = frame_shape[0] / config.frame_height
        self.motion_frame_size = (
            config.frame_height,
            config.frame_height * frame_shape[1] // frame_shape[0],
        )
        self.avg_frame = np.zeros(self.motion_frame_size, np.float32)
        self.motion_frame_count = 0
        self.frame_counter = 0
        resized_mask = cv2.resize(
            config.mask,
            dsize=(self.motion_frame_size[1], self.motion_frame_size[0]),
            interpolation=cv2.INTER_AREA,
        )
        self.mask = np.where(resized_mask == [0])
        self.save_images = False
        self.calibrating = True
        self.improve_contrast = improve_contrast
        self.threshold = threshold
        self.contour_area = contour_area
        self.blur_radius = blur_radius
        self.interpolation = interpolation
        self.contrast_values = np.zeros((contrast_frame_history, 2), np.uint8)
        self.contrast_values[:, 1:2] = 255
        self.contrast_values_index = 0

    def detect(self, frame):
        motion_boxes = []

        gray = frame[0 : self.frame_shape[0], 0 : self.frame_shape[1]]

        # resize frame
        resized_frame = cv2.resize(
            gray,
            dsize=(self.motion_frame_size[1], self.motion_frame_size[0]),
            interpolation=self.interpolation,
        )

        if self.save_images:
            resized_saved = resized_frame.copy()

        # Improve contrast
        if self.improve_contrast.value:
            # TODO tracking moving average of min/max to avoid sudden contrast changes
            minval = np.percentile(resized_frame, 4).astype(np.uint8)
            maxval = np.percentile(resized_frame, 96).astype(np.uint8)
            # skip contrast calcs if the image is a single color
            if minval < maxval:
                # keep track of the last 50 contrast values
                self.contrast_values[self.contrast_values_index] = [minval, maxval]
                self.contrast_values_index += 1
                if self.contrast_values_index == len(self.contrast_values):
                    self.contrast_values_index = 0

                avg_min, avg_max = np.mean(self.contrast_values, axis=0)

                resized_frame = np.clip(resized_frame, avg_min, avg_max)
                resized_frame = (
                    ((resized_frame - avg_min) / (avg_max - avg_min)) * 255
                ).astype(np.uint8)

        if self.save_images:
            contrasted_saved = resized_frame.copy()

        # mask frame
        # this has to come after contrast improvement
        resized_frame[self.mask] = [255]

        resized_frame = gaussian_filter(resized_frame, sigma=1, radius=self.blur_radius)

        if self.save_images:
            blurred_saved = resized_frame.copy()

        if self.save_images or self.calibrating:
            self.frame_counter += 1
        # compare to average
        frameDelta = cv2.absdiff(resized_frame, cv2.convertScaleAbs(self.avg_frame))

        # compute the threshold image for the current frame
        thresh = cv2.threshold(
            frameDelta, self.threshold.value, 255, cv2.THRESH_BINARY
        )[1]

        # dilate the thresholded image to fill in holes, then find contours
        # on thresholded image
        thresh_dilated = cv2.dilate(thresh, None, iterations=1)
        cnts = cv2.findContours(
            thresh_dilated, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE
        )
        cnts = imutils.grab_contours(cnts)

        # loop over the contours
        total_contour_area = 0
        for c in cnts:
            # if the contour is big enough, count it as motion
            contour_area = cv2.contourArea(c)
            total_contour_area += contour_area
            if contour_area > self.contour_area.value:
                x, y, w, h = cv2.boundingRect(c)
                motion_boxes.append(
                    (
                        int(x * self.resize_factor),
                        int(y * self.resize_factor),
                        int((x + w) * self.resize_factor),
                        int((y + h) * self.resize_factor),
                    )
                )

        pct_motion = total_contour_area / (
            self.motion_frame_size[0] * self.motion_frame_size[1]
        )

        # once the motion drops to less than 1% for the first time, assume its calibrated
        if pct_motion < 0.01:
            self.calibrating = False

        # if calibrating or the motion contours are > 80% of the image area (lightning, ir, ptz) recalibrate
        if self.calibrating or pct_motion > self.config.lightning_threshold:
            motion_boxes = []
            self.calibrating = True

        if self.save_images:
            thresh_dilated = cv2.cvtColor(thresh_dilated, cv2.COLOR_GRAY2BGR)
            for b in motion_boxes:
                cv2.rectangle(
                    thresh_dilated,
                    (int(b[0] / self.resize_factor), int(b[1] / self.resize_factor)),
                    (int(b[2] / self.resize_factor), int(b[3] / self.resize_factor)),
                    (0, 0, 255),
                    2,
                )
            frames = [
                cv2.cvtColor(resized_saved, cv2.COLOR_GRAY2BGR),
                cv2.cvtColor(contrasted_saved, cv2.COLOR_GRAY2BGR),
                cv2.cvtColor(blurred_saved, cv2.COLOR_GRAY2BGR),
                cv2.cvtColor(frameDelta, cv2.COLOR_GRAY2BGR),
                cv2.cvtColor(thresh, cv2.COLOR_GRAY2BGR),
                thresh_dilated,
            ]
            cv2.imwrite(
                f"debug/frames/{self.name}-{self.frame_counter}.jpg",
                cv2.hconcat(frames)
                if self.frame_shape[0] > self.frame_shape[1]
                else cv2.vconcat(frames),
            )

        if len(motion_boxes) > 0:
            self.motion_frame_count += 1
            if self.motion_frame_count >= 10:
                # only average in the current frame if the difference persists for a bit
                cv2.accumulateWeighted(
                    resized_frame,
                    self.avg_frame,
                    0.2 if self.calibrating else self.config.frame_alpha,
                )
        else:
            # when no motion, just keep averaging the frames together
            cv2.accumulateWeighted(
                resized_frame,
                self.avg_frame,
                0.2 if self.calibrating else self.config.frame_alpha,
            )
            self.motion_frame_count = 0

        return motion_boxes