83 lines
2.3 KiB
Python
83 lines
2.3 KiB
Python
import cv2, time
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from threading import RLock
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from sharedLogging import SlaveLogger
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from auxilary import freeBusyPath
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class Camera:
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def __init__(self, queue):
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self._lock = RLock()
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self._index = 0
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self._logger = SlaveLogger(__name__, 'DEBUG', queue)
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freeBusyPath('/dev/video{}'.format(self._index), self._logger)
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# NOTE: we use 0-255 on forms instead of floats because they look nicer
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logitechProperties = {
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'FPS': 25, # integer from 10 to 30 in multiples of 5
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'BRIGHTNESS': 127/255, # float from 0 to 1
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'CONTRAST': 32/255, # float from 0 to 1
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'SATURATION': 32/255, # float from 0 to 1
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'GAIN': 64/255, # float from 0 to 1
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}
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self._properties = {}
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self.setProps(**logitechProperties)
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def getProps(self, *args):
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return {prop: self._video.get(getattr(cv2, 'CAP_PROP_' + prop)) for prop in args}
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def setProps(self, *args, **kwargs):
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# silly hack, need to reset the videoCapture object every time
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# we change settings (they can only be changed once apparently)
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self._lock.acquire()
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try:
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if hasattr(self, '_video'):
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self._video.release()
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self._video = cv2.VideoCapture(self._index)
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for prop, val in kwargs.items():
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self._properties[prop] = val
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self._video.set(getattr(cv2, 'CAP_PROP_' + prop), val)
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self._logger.debug('set %s to %s', prop, val)
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finally:
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self._lock.release()
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# the reset code here could be put in seperate thread to accellarate
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def getFrame(self):
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frame = None
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self._lock.acquire()
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try:
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# will try 3 attempts to grab frame, will reset on failure
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i = 3
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while i > 0:
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if self._video.isOpened():
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success, image = self._video.read()
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ret, jpeg = cv2.imencode('.jpg', image)
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frame = jpeg.tobytes()
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break
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else:
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time.sleep(5)
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self.reset()
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i -= 1
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# after 3 fails return the dummy frame
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if not frame:
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with open('noimage.jpg', 'rb') as f:
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time.sleep(1)
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frame = f.read()
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finally:
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self._lock.release()
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return frame
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def reset(self):
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self.setProps(**self._properties)
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self._logger.debug('camera reset')
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def __del__(self):
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try:
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self._video.release()
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self._logger.debug('Release camera at index %s', self._index)
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except AttributeError:
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self._logger.debug('Failed to release camera at index %s', self._index)
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