Video Input Processing in Thread ausgelagert

projectmood/WebcamVideoStream.py

+from threading import Thread
+import cv2
+
+class WebcamVideoStream:
+    def __init__(self, src=0):
+        # initialize the video camera stream and read the first frame
+        # from the stream
+        self.stream = cv2.VideoCapture(src)
+        (self.grabbed, self.frame) = self.stream.read()
+
+        # initialize the variable used to indicate if the thread should
+        # be stopped
+        self.stopped = False
+
+    def start(self):
+        # start the thread to read frames from the video stream
+        Thread(target=self.update, args=()).start()
+        return self
+
+    def update(self):
+        # keep looping infinitely until the thread is stopped
+        while True:
+            # if the thread indicator variable is set, stop the thread
+            if self.stopped:
+                return
+
+            # otherwise, read the next frame from the stream
+            (self.grabbed, self.frame) = self.stream.read()
+
+    def read(self):
+        # return the frame most recently read
+        return self.frame
+
+    def stop(self):
+        # indicate that the thread should be stopped
+        self.stopped = True
\ No newline at end of file

projectmood/webcam.py

@@ -8,7 +8,7 @@ from cv2 import WINDOW_NORMAL
 
 import cv2
 
-
+from WebcamVideoStream import WebcamVideoStream
 from face_detect import find_faces
 from image_commons import nparray_as_image, draw_with_alpha
 
@@ -36,26 +36,23 @@ def show_webcam_and_run(model, emoticons, window_size=(800, 800), window_name='M
         width, height = window_size
         cv2.resizeWindow(window_name, width, height)
 
-    vc = cv2.VideoCapture(0)
-    if vc.isOpened():
-        read_value, webcam_image = vc.read()
-    else:
-        print("Webcam nicht gefunden")
-        return
+    vc = WebcamVideoStream(src=0).start()
+    frame = vc.read()
 
-    while read_value:
-        for normalized_face, (x, y, w, h) in find_faces(webcam_image):
+    while True:
+        for normalized_face, (x, y, w, h) in find_faces(frame):
             prediction = model.predict(normalized_face)  # do prediction
 
             image_to_draw = emoticons[(prediction[0])]
             if x - 150 > 0 and y - 50 > 0 and w - 150 > 0 and h - 150 > 0:
-                draw_with_alpha(webcam_image, image_to_draw, (x-150, y-50, w-150, h-150))
+                draw_with_alpha(frame, image_to_draw, (x-150, y-50, w-150, h-150))
 
-        cv2.imshow(window_name, webcam_image)
-        read_value, webcam_image = vc.read()
+        cv2.imshow(window_name, frame)
+        frame = vc.read()
         key = cv2.waitKey(update_time)
 
         if key == 27:  # exit on ESC
+            vc.stop()
             break
 
     cv2.destroyWindow(window_name)