from config import EyeTrackConfig from enum import Enum import threading import queue import cv2 WAIT_TIME = 0.1 class CameraState(Enum): CONNECTING = 0 CONNECTED = 1 DISCONNECTED = 2 class Camera: def __init__( self, config: EyeTrackConfig, camera_index: int, cancellation_event: "threading.Event", capture_event: "threading.Event", camera_status_outgoing: "queue.Queue[CameraState]", camera_output_outgoing: "queue.Queue", ): self.camera_status = CameraState.CONNECTING self.config = config self.camera_index = camera_index self.camera_address = config.capture_source self.camera_status_outgoing = camera_status_outgoing self.camera_output_outgoing = camera_output_outgoing self.capture_event = capture_event self.cancellation_event = cancellation_event self.current_capture_source = config.capture_source self.wired_camera: "cv2.VideoCapture" = None self.error_message = "\033[93m[WARN] Capture source {} not found, retrying...\033[0m" def set_output_queue(self, camera_output_outgoing: "queue.Queue"): self.camera_output_outgoing = camera_output_outgoing def run(self): while True: if self.cancellation_event.is_set(): print("\033[94m[INFO] Exiting capture thread\033[0m") return should_push = True # If things aren't open, retry until they are. Don't let read requests come in any earlier # than this, otherwise we can deadlock ourselves. if ( self.config.capture_source != None and self.config.capture_source != "" ): if ( self.wired_camera is None or not self.wired_camera.isOpened() or self.camera_status == CameraState.DISCONNECTED or self.config.capture_source != self.current_capture_source ): print(self.error_message.format(self.config.capture_source)) # This requires a wait, otherwise we can error and possible screw up the camera # firmware. Fickle things. if self.cancellation_event.wait(WAIT_TIME): return self.current_capture_source = self.config.capture_source self.wired_camera = cv2.VideoCapture(self.current_capture_source) should_push = False else: # We don't have a capture source to try yet, wait for one to show up in the GUI. if self.cancellation_event.wait(WAIT_TIME): self.camera_status = CameraState.DISCONNECTED return # Assuming we can access our capture source, wait for another thread to request a capture. # Cycle every so often to see if our cancellation token has fired. This basically uses a # python event as a contextless, resettable one-shot channel. if should_push and not self.capture_event.wait(timeout=0.02): continue self.get_wired_camera_picture(should_push) if not should_push: # if we get all the way down here, consider ourselves connected self.camera_status = CameraState.CONNECTED def get_wired_camera_picture(self, should_push): try: ret, image = self.wired_camera.read() if not ret: self.wired_camera.set(cv2.CAP_PROP_POS_FRAMES, 0) raise RuntimeError("Problem while getting frame") frame_number = self.wired_camera.get(cv2.CAP_PROP_POS_FRAMES) fps = self.wired_camera.get(cv2.CAP_PROP_FPS) if should_push: self.push_image_to_queue(image, frame_number, fps) except: print( "Capture source problem, assuming camera disconnected, waiting for reconnect." ) self.camera_status = CameraState.DISCONNECTED pass def push_image_to_queue(self, image, frame_number, fps): # If there's backpressure, just yell. We really shouldn't have this unless we start getting # some sort of capture event conflict though. qsize = self.camera_output_outgoing.qsize() if qsize > 1: print( f"CAPTURE QUEUE BACKPRESSURE OF {qsize}. CHECK FOR CRASH OR TIMING ISSUES IN ALGORITHM." ) self.camera_output_outgoing.put((image, frame_number, fps)) self.capture_event.clear()