From 3b74c7991956b26a01175361848eebb29c7b03e8 Mon Sep 17 00:00:00 2001
From: Blake Blackshear <blakeb@blakeshome.com>
Date: Sun, 4 Jun 2023 08:27:55 -0500
Subject: [PATCH] implement and use cnt bgsub

---
 frigate/motion/cnt_motion.py | 117 +++++++++++++++++++++++++++++++++++
 frigate/video.py             |   4 +-
 2 files changed, 119 insertions(+), 2 deletions(-)
 create mode 100644 frigate/motion/cnt_motion.py

diff --git a/frigate/motion/cnt_motion.py b/frigate/motion/cnt_motion.py
new file mode 100644
index 000000000..dc3eba537
--- /dev/null
+++ b/frigate/motion/cnt_motion.py
@@ -0,0 +1,117 @@
+from typing import Tuple
+
+import cv2
+import imutils
+import numpy as np
+
+from frigate.config import MotionConfig
+from frigate.motion import MotionDetector
+
+
+class CNTMotionDetector(MotionDetector):
+    def __init__(
+        self,
+        frame_shape: Tuple[int, int, int],
+        config: MotionConfig,
+        improve_contrast,
+        threshold,
+        contour_area,
+    ):
+        self.frame_shape = frame_shape
+        self.threshold = threshold
+        self.contour_area = contour_area
+        self.improve_contrast = improve_contrast
+        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],
+        )
+        resized_mask = cv2.resize(
+            config.mask,
+            dsize=(self.motion_frame_size[1], self.motion_frame_size[0]),
+            interpolation=cv2.INTER_LINEAR,
+        )
+        self.blur_kernel = (
+            3,  # int(0.05 * self.motion_frame_size[0]),
+            3,  # int(0.05 * self.motion_frame_size[0]),
+        )
+
+        self.mask = np.where(resized_mask == [0])
+        # createBackgroundSubtractorCNT(int minPixelStability = 15,
+        #                       bool useHistory = true,
+        #                       int maxPixelStability = 15*60,
+        #                       bool isParallel = true);
+        self.bg_subtractor = cv2.bgsegm.createBackgroundSubtractorCNT()
+        self.save_images = False
+        self.frame_counter = 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=cv2.INTER_LINEAR,
+        )
+        if self.improve_contrast.value:
+            resized_frame = cv2.equalizeHist(resized_frame)
+        blurred_frame = cv2.GaussianBlur(
+            resized_frame, self.blur_kernel, cv2.BORDER_DEFAULT
+        )
+        # mask frame
+        blurred_frame[self.mask] = [255]
+        fg = self.bg_subtractor.apply(blurred_frame)
+        thresh = cv2.threshold(fg, self.threshold.value, 255, cv2.THRESH_BINARY)[1]
+
+        # dilate the thresholded image to fill in holes, then find contours
+        # on thresholded image
+        cnts = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
+        cnts = imutils.grab_contours(cnts)
+
+        # loop over the contours
+        for c in cnts:
+            # if the contour is big enough, count it as motion
+            contour_area = cv2.contourArea(c)
+            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),
+                    )
+                )
+
+        if self.save_images:
+            self.frame_counter += 1
+            # print("--------")
+            # print(self.frame_counter)
+            thresh_boxes = cv2.cvtColor(fg, cv2.COLOR_GRAY2BGR)
+            for c in cnts:
+                contour_area = cv2.contourArea(c)
+                if contour_area > self.contour_area.value:
+                    x, y, w, h = cv2.boundingRect(c)
+                    cv2.rectangle(
+                        thresh_boxes,
+                        (x, y),
+                        (x + w, y + h),
+                        (0, 0, 255),
+                        2,
+                    )
+            # print("--------")
+            image_row_1 = cv2.hconcat(
+                [
+                    cv2.cvtColor(fg, cv2.COLOR_GRAY2BGR),
+                    cv2.cvtColor(
+                        self.bg_subtractor.getBackgroundImage(), cv2.COLOR_GRAY2BGR
+                    ),
+                ]
+            )
+            image_row_2 = cv2.hconcat(
+                [cv2.cvtColor(thresh, cv2.COLOR_GRAY2BGR), thresh_boxes]
+            )
+            combined_image = cv2.vconcat([image_row_1, image_row_2])
+            cv2.imwrite(f"debug/frames/motion-{self.frame_counter}.jpg", combined_image)
+        return motion_boxes
diff --git a/frigate/video.py b/frigate/video.py
index 2e4edd220..35b24a609 100755
--- a/frigate/video.py
+++ b/frigate/video.py
@@ -18,7 +18,7 @@ from frigate.config import CameraConfig, DetectConfig, PixelFormatEnum
 from frigate.const import CACHE_DIR
 from frigate.log import LogPipe
 from frigate.motion import MotionDetector
-from frigate.motion.frigate_motion import FrigateMotionDetector
+from frigate.motion.cnt_motion import CNTMotionDetector
 from frigate.object_detection import RemoteObjectDetector
 from frigate.track import ObjectTracker
 from frigate.track.norfair_tracker import NorfairTracker
@@ -463,7 +463,7 @@ def track_camera(
     objects_to_track = config.objects.track
     object_filters = config.objects.filters
 
-    motion_detector = FrigateMotionDetector(
+    motion_detector = CNTMotionDetector(
         frame_shape,
         config.motion,
         improve_contrast_enabled,