Cameras¶

Create Camera objects using instrument().

Generic Camera Interface¶

Package containing a driver module/class for each supported camera type.

class instrumental.drivers.cameras.Camera(inst=None, **kwds)¶

A generic camera device.

Camera driver internals can often be quite different; however, Instrumental defines a few basic concepts that all camera drivers should have.

There are two basic modes: finite and continuous.

In finite mode, a camera performs a capture sequence, returning one or more images all at once, when the sequence is finished.

In continuous or live mode, the camera continuously retrieves images until it is manually stopped. This mode can be used e.g. to make a GUI that looks at a live view of the camera. The process looks like this:

>>> cam.start_live_video()
>>> while not_done():
>>>     frame_ready = cam.wait_for_frame()
>>>     if frame_ready:
>>>         arr = cam.latest_frame()
>>>         do_stuff_with(arr)
>>> cam.stop_live_video()

fill_all_coords(kwds, names)¶

find_hot_pixels(stddevs=10, **kwds)¶: Generate the list of hot pixels on the camera sensor.

abstract get_captured_image(timeout='1s', copy=True)¶

Get the image array(s) from the last capture sequence.

Returns an image numpy array (or tuple of arrays for a multi-exposure sequence). The array has shape (height, width) for grayscale images, and (height, width, 3) for RGB images. Typically the dtype will be uint8, or sometimes uint16 in the case of 16-bit monochromatic cameras.

Parameters

timeout (Quantity([time]) or None, optional) – Max time to wait for wait for the image data to be ready. If None, will block forever. If timeout is exceeded, a TimeoutError will be raised.
copy (bool, optional) – Whether to copy the image memory or directly reference the underlying buffer. It is recommended to use True (the default) unless you know what you’re doing.

abstract grab_image(timeouts='1s', copy=True, **kwds)¶

Perform a capture and return the resulting image array(s).

This is essentially a convenience function that calls start_capture() then get_captured_image(). See get_captured_image() for information about the returned array(s).

Parameters

timeouts (Quantity([time]) or None, optional) – Max time to wait for wait for the image data to be ready. If None, will block forever. If timeout is exceeded, a TimeoutError will be raised.
copy (bool, optional) – Whether to copy the image memory or directly reference the underlying buffer. It is recommended to use True (the default) unless you know what you’re doing.
include (You can specify other parameters of the capture as keyword arguments. These) –
n_frames (int) – Number of exposures in the sequence
vbin (int) – Vertical binning
hbin (int) – Horizontal binning
exposure_time (Quantity([time])) – Duration of each exposure
width (int) – Width of the ROI
height (int) – Height of the ROI
cx (int) – X-axis center of the ROI
cy (int) – Y-axis center of the ROI
left (int) – Left edge of the ROI
right (int) – Right edge of the ROI
top (int) – Top edge of the ROI
bot (int) – Bottom edge of the ROI

abstract latest_frame(copy=True)¶

Get the latest image frame in live mode.

Returns the image array received on the most recent successful call to wait_for_frame().

Parameters: copy (bool, optional) – Whether to copy the image memory or directly reference the underlying buffer. It is recommended to use True (the default) unless you know what you’re doing.

save_hot_pixels(path=None)¶: Save a file listing the hot pixels.

set_defaults(**kwds)¶

abstract start_capture(**kwds)¶

Start a capture sequence and return immediately.

Depending on your camera-specific shutter/trigger settings, this will either start the exposure immediately or ready the camera to start on an explicit (hardware or software) trigger.

It can be useful to invoke start_capture() and get_captured_image() explicitly if you expect the capture sequence to take a long time and you’d like to perform some operations while you wait for the camera:

>>> cam.start_capture()
>>> do_other_useful_stuff()
>>> arr = cam.get_captured_image()

See grab_image() for the set of available kwds.

abstract start_live_video(**kwds)¶

Start live video mode.

Once live video mode has been started, images will automatically and continuously be acquired. You can check if the next frame is ready by using wait_for_frame(), and access the most recent image’s data with get_captured_image().

See grab_image() for the set of available kwds.

abstract stop_live_video()¶: Stop live video mode.

abstract wait_for_frame(timeout=None)¶

Wait until the next frame is ready (in live mode).

Blocks and returns True once the next frame is ready, False if the timeout was reached. Using a timeout of 0 simply polls to see if the next frame is ready.

Parameters: timeout (Quantity([time]), optional) – How long to wait for wait for the image data to be ready. If None (the default), will block forever.
Returns: frame_ready – True if the next frame is ready, False if the timeout was reached.
Return type: bool

DEFAULT_KWDS = {'bot': None, 'cx': None, 'cy': None, 'exposure_time': <Quantity(10, 'millisecond')>, 'fix_hotpixels': False, 'gain': 0, 'hbin': 1, 'height': None, 'left': None, 'n_frames': 1, 'right': None, 'top': None, 'vbin': 1, 'width': None}¶

abstract property height¶: Height of the camera image in pixels

abstract property max_height¶: Max settable height of the camera image, given current binning/subpixel settings

abstract property max_width¶: Max settable width of the camera image, given current binning/subpixel settings

abstract property width¶: Width of the camera image in pixels