EyeTrackVR/EyeTrackApp/camera.py
2022-11-03 18:28:25 +02:00

109 lines
4.5 KiB
Python

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 = "Capture source {} not found, retrying"
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("Exiting capture thread")
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()