scistag.mediastag.camera_cv2.CameraCv2¶

class CameraCv2(source)[source]¶

Bases: VideoSourceCamera

A camera source wrapping OpenCV’s camera access capabilities

Initializer

Parameters: source (int | str) – The camera source. When a number is passed it will be interpreted as “web cam” index, e.g. 0,

otherwise it will be handled as gstreamer pipeline definition.

Methods

`add_redirect`	Redirects the camera's data into a local or remote DataStag storage
`continue_video`	Pauses the video
`get_camera_name`	Returns the global name of a local camera
`get_image`	Returns the current image as np array
`get_local_camera`	Returns a unique name for a local camera at given source IF the camera is also registered and is usable
`get_local_camera_exists`	Returns if a camera with given source was registered
`get_local_camera_name`	Returns a unique name for a local camera at given source
`handle_fetch`	Tries to fetch data from the camera
`handle_initialize_camera`	Initializes the camera. Could be executed in another thread, lock data
`handle_redirections`	Forwards the new camera image into callback functions and/or database targets
`pause`	Pauses the video
`redirect_to_vault`	Redirects the camera's stream into the vault :type index: `int` :param index: The internal index
`seek`	Seeks to given video position :type position_s: `float` :param position_s: The new desired position :rtype: `float` :return: The real new position
`set_filter`	Assigns a filter which is assigned to every image received from the original video source.
`set_image`	Updates the current image
`start`	Starts the camera
`stop`	Stops the camera thread
`update_progress`	Tries to update the videos' progress

Attributes

`LOCAL_CAMERA_STREAM_IDENTIFIER`	Local camera, e.g.
`LOCAL_CAMERA_STREAM_IDENTIFIER_TYPE`	Name definition of the local camera's type
`__dict__`
`__doc__`
`__module__`
`__weakref__`	list of weak references to the object (if defined)
`source`	The camera's source as unique identifier

_get_image_int(timestamp=None)¶

Returns the most recent image and it’s time stamp

Parameters: timestamp (float | None) – If provided and the image was not modified no image will be returned.
Return type: tuple[float, Image | None]
Returns: The newest image if one is available and timestamp does not match the previous time stamp.

add_redirect(target, timeout_s=5.0)¶

Redirects the camera’s data into a local or remote DataStag storage

Parameters

target (str | Callable[[float, Image], None]) – If a string this is interpreted as a DataStag target identifier, otherwise a function to be
timeout_s – The timeout in seconds for how long the local camera streams shall be kept in the vault

called.

continue_video()¶: Pauses the video

classmethod get_camera_name(index)¶

Returns the global name of a local camera

Parameters: index (int) – The camera’s index
Return type: str
Returns: The identifier under which the camera can be stored in the local DataStag vault

get_image(timestamp=None, wait=False, timeout_s=2.0)¶

Returns the current image as np array

Parameters

timestamp (float | None) – The timestamp of the last image received
wait (bool) – If set the function will wait for the next valid image
timeout_s (float) – The timeout in seconds before a TimeoutError exception will be raised. 2 seconds by default. If set to -1 the function will wait forever.

Return type

tuple[float, Image | None]

Returns

Updated timestamp, the image

classmethod get_local_camera(source)¶

Returns a unique name for a local camera at given source IF the camera is also registered and is usable

Parameters: source (int | str) – The camera’s index or other unique identifier
Return type: str | None
Returns: The unique identifier if the camera does exist. Otherwise None

classmethod get_local_camera_exists(source)¶

Returns if a camera with given source was registered

Parameters: source (int | str) – The camera’s source name, class specific. Should be globally unique
Return type: bool
Returns: True if the camera was found

classmethod get_local_camera_name(source)¶

Returns a unique name for a local camera at given source

Parameters: source (int | str) – The camera’s index or other unique identifier
Return type: str
Returns: The unique identifier

handle_fetch()[source]¶

Tries to fetch data from the camera

Return type: tuple[float, Image | None]
Returns: The new image on success. None if no new image was available.

handle_initialize_camera()[source]¶

Initializes the camera. Could be executed in another thread, lock data: accordingly.

Overwrite this with your initialization code.

handle_redirections()¶: Forwards the new camera image into callback functions and/or database targets

pause()¶: Pauses the video

redirect_to_vault(index)¶: Redirects the camera’s stream into the vault :type index: int :param index: The internal index

seek(position_s)¶: Seeks to given video position :type position_s: float :param position_s: The new desired position :rtype: float :return: The real new position

set_filter(image_filter)¶

Assigns a filter which is assigned to every image received from the original video source. For example call set_filter(Grayscale()) to convert the camera or video to grayscale. You can also assign an ImageFilterPipeline to combine multiple filters. :type image_filter: ImageFilter | None :param image_filter: The filter to assign or None to disable it

Return type: None

set_image(timestamp, image)¶

Updates the current image

Parameters

timestamp (float) – The timestamp
image (Image) – The newest image

Return type

None

start()¶

Starts the camera

Return type: VideoSourceCamera
Returns: The camera object

stop()¶

Stops the camera thread

Return type: VideoSourceCamera
Returns: The camera object

update_progress()¶

Tries to update the videos’ progress

Return type: bool
Returns: True if the progress was updated

LOCAL_CAMERA_STREAM_IDENTIFIER = 'streams.cameras.camera_'¶: Local camera, e.g. a webcam connected to the hosting PC directly

LOCAL_CAMERA_STREAM_IDENTIFIER_TYPE = '.type'¶: Name definition of the local camera’s type

_lock¶: Access lock

_remote_thread¶: The remote thread

auto_progress¶: If defined the get_image function is also allowed to update the video’s progress. Otherwise the managing control, e.g. the VideoPlayer is responsible to do so

duration¶: The video’s overall duration in seconds. 0 if a stream

fps¶: The videos frame per second count

image_filter: ImageFilter | None¶: A filter which shall be applied to every image received from the video before it’s returned

is_stream¶: Defines if the source is a continuous stream

last_raw_image: Image | None¶: The last raw image received internal

last_raw_image_timestamp: float¶: The last raw image’s time stamp

last_returned_image: Image | None¶: The last returned image (after applying filters etc.)

last_update_timestamp¶: Timestamp of the last update

position¶: The current position (in seconds)

recent_image: Image | None¶: The most recent image

recent_timestamp: float¶: The most recent image’s time stamp

redirections¶: Targets the camera image shall be redirected to

repeat¶: The movie’s repeat mode

source: int | str¶: The camera’s source as unique identifier

speed¶: The movie’s playback speed. 1.0 = 100%

start_timestamp¶: Timestamp when the playback started or continued

started¶: Defines if the remote thread was started

time_per_frame¶: The amount of seconds per frame (1/fps)

valid¶: Defines if there is a valid source

video_resolution¶: The video’s size in pixels