vault backup: 2025-03-04 11:17:00

20.01. Programming/Python/opencv.md

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+### 將camera包裝成class
+```python
+class CameraCv(object):
+    def __init__(self, videoSource=0):
+        self.videoSource = videoSource
+        self.camera = None
+        self.cameraWidth = 0
+        self.cameraHeight = 0
+        self.cameraPreviewThreadHandle = None
+        self.cameraPreviewThreadStopEvent = threading.Event()
+        self.lastframeRGB = None
+        self.latestFrame = None
+
+    def start(self):
+        print("Open Camera")
+        self.camera = cv2.VideoCapture(self.videoSource, cv2.CAP_DSHOW)
+        if not self.camera.isOpened():
+            raise ValueError("Unable to open video source {}".format(self.videoSource))
+
+        # Get video source width and height
+        self.cameraWidth  = self.camera.get(cv2.CAP_PROP_FRAME_WIDTH)
+        self.cameraHeight = self.camera.get(cv2.CAP_PROP_FRAME_HEIGHT)
+
+        self.cameraPreviewThreadStopEvent.clear()
+        self.cameraPreviewThreadHandle = threading.Thread(target=self.collectFrame, daemon=True, args=())
+        self.cameraPreviewThreadHandle.start()
+
+    def stop(self):
+        print("Close Camera")
+        self.cameraPreviewThreadStopEvent.set()
+        if self.camera.isOpened():
+            self.camera.release()
+            cv2.destroyAllWindows()
+
+    def collectFrame(self):
+        while True:
+            ret, frame = self.camera.read()
+            if ret:
+                # Return a boolean success flag and the current frame converted to BGR
+                self.lastframeRGB = frame
+                self.latestFrame = ImageTk.PhotoImage(image=Image.fromarray(cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)))
+
+            if self.cameraPreviewThreadStopEvent.is_set():
+                break
+
+            time.sleep(0.016)
+
+    def draw(self, container):
+        if self.latestFrame is not None:
+            container.imgtk = self.latestFrame
+            container.configure(image=self.latestFrame)
+
+    def read(self):
+        return self.camera.read()
+
+    def getLastFrameRgb(self):
+        return self.lastframeRGB
+
+    def saveFrame(self, filepath):
+        cv2.imwrite(filepath, self.getLastFrameRgb())
+```