Raspberry Pi Streaming Camera

Raspberry Pi camera implementation of the PiCameraStreamer class.

NOTES:

Still port used for image capture. Preview port reserved for onboard GPU preview.

Video port:

• Splitter port 0: Image capture (if use_video_port == True)
• Splitter port 1: Streaming frames
• Splitter port 2: Video capture
• Splitter port 3: [Currently unused]

PiCameraStreamer streams at video_resolution

Camera capture resolution set to stream_resolution in frames()

Video port uses that resolution for everything. If a different resolution is specified for video capture, this is handled by the resizer.

Still capture (if use_video_port == False) uses pause_stream to temporarily increase the capture resolution.

class openflexure_microscope.camera.pi.PiCameraStreamer

Raspberry Pi camera implementation of PiCameraStreamer.

camera = None

Picamera object

Type:picamerax.PiCamera

image_resolution = None

Resolution for image captures

Type:tuple

stream_resolution = None

Resolution for stream and video captures

Type:tuple

numpy_resolution = None

Resolution for numpy array captures

Type:tuple

jpeg_quality = None

JPEG quality

Type:int

mjpeg_quality = None

MJPEG quality

Type:int

picamera_lst_path = None

Path of .npy lens shading table file

Type:str

configuration

The current camera configuration.

state

The current read-only camera state.

initialisation()

Run any initialisation code when the frame iterator starts.

close()

Close the Raspberry Pi PiCameraStreamer.

read_settings() → dict

Return config dictionary of the PiCameraStreamer.

update_settings(config: dict)

Write a config dictionary to the PiCameraStreamer config.

The passed dictionary may contain other parameters not relevant to camera config. Eg. Passing a general config file will work fine.

Parameters:config (dict) – Dictionary of config parameters.

apply_picamera_settings(settings_dict: dict, pause_for_effect: bool = True)

Parameters:

• settings_dict (dict) – Dictionary of properties to apply to the picamerax.PiCamera: object
• pause_for_effect (bool) – Pause tactically to reduce risk of timing issues

set_zoom(zoom_value: float = 1.0) → None

Change the camera zoom, handling re-centering and scaling.

start_preview(fullscreen=True, window=None)

Start the on board GPU camera preview.

stop_preview()

Stop the on board GPU camera preview.

start_recording(output, fmt: str = 'h264', quality: int = 15)

Start recording.

Start a new video recording, writing to a output object.

Parameters:

• output – String or file-like object to write capture data to
• fmt (str) – Format of the capture.
• quality (int) – Video recording quality.

Returns:

Target object.

Return type:

output_object (str/BytesIO)

stop_recording()

Stop the last started video recording on splitter port 2.

stop_stream_recording(splitter_port: int = 1, **kwargs) → None

Sets the camera resolution to the still-image resolution, and stops recording if the stream is active.

Parameters:splitter_port (int) – Splitter port to stop recording on

start_stream_recording(splitter_port: int = 1, **kwargs) → None

Sets the camera resolution to the video/stream resolution, and starts recording if the stream should be active.

Parameters:splitter_port (int) – Splitter port to start recording on

capture(output, fmt: str = 'jpeg', use_video_port: bool = False, resize: Tuple[int, int] = None, bayer: bool = True, thumbnail: tuple = None)

Capture a still image to a StreamObject.

Defaults to JPEG format. Target object can be overridden for development purposes.

Parameters:

• output – String or file-like object to write capture data to
• fmt (str) – Format of the capture.
• use_video_port (bool) – Capture from the video port used for streaming. Lower resolution, faster.
• resize ((int, int)) – Resize the captured image.
• bayer (bool) – Store raw bayer data in capture

Returns:

Target object.

Return type:

output_object (str/BytesIO)

array(use_video_port=True) → numpy.ndarray

Capture an uncompressed still RGB image to a Numpy array.

Parameters:

• use_video_port (bool) – Capture from the video port used for streaming. Lower resolution, faster.
• resize ((int, int)) – Resize the captured image.

Returns:

Output array of capture

Return type:

output_array (np.ndarray)

wait_for_camera(timeout=5)

Wait for camera object, with 5 second timeout.

frames()

Create generator that returns frames from the camera.

Records video from port 1 to a byte stream, and iterates sequential frames.