slmsuite.hardware.cameras.camera.Camera

class Camera(width, height, bitdepth=8, dx_um=None, dy_um=None, rot='0', fliplr=False, flipud=False, name='camera')[source]

Bases: object

Abstract class for cameras. Comes with transformations and helper functions like autoexpose.

name

Camera identifier.

Type: str

shape

Stores (height, width) of the camera in pixels, the same convention as numpy.shape().

Type: (int, int)

bitdepth

Depth of a camera pixel well in bits.

Type: int

bitresolution

Stores 2**bitdepth.

Type: int

dx_um

\(x\) pixel pitch in microns. Defaults to None. Potential future features will use this.

Type: float or None

dy_um

\(y\) pixel pitch in microns. See dx_um.

Type: float or None

exposure_bounds_s

Shortest and longest allowable integration in seconds.

Type: (float, float) OR None

woi

WOI (window of interest) in (x, width, y, height) form.

Type: tuple

default_shape

Default shape of the camera before any WOI changes are made.

Type: tuple

transform

Flip and/or rotation operator specified by the user in __init__(). The user is expected to apply this transform to the matrix returned in get_image(). Note that WOI changes are applied on the camera hardware before this transformation.

Type: lambda

Methods

`autoexposure`	Sets the exposure of the camera such that the maximum value is at `set_fraction` of the dynamic range.
`autofocus`	Uses an FFT contrast metric to find optimal focus when scanning over some variable `z`.
`close`	Abstract method to close the camera and delete related objects.
`flush`	Abstract method to cycle the image buffer (if any) such that all new `get_image()` calls yield fresh frames.
`get_exposure`	Abstract method to get the integration time in seconds.
`get_image`	Abstract method to pull an image from the camera and return.
`get_images`	Grab `image_count` images in succession.
`info`	Abstract method to load display information.
`reset`	Abstract method to reset the camera to a default state.
`set_exposure`	Abstract method to set the integration time in seconds.
`set_woi`	Abstract method to narrow the imaging region to a 'window of interest' for faster framerates.

__init__(width, height, bitdepth=8, dx_um=None, dy_um=None, rot='0', fliplr=False, flipud=False, name='camera')[source]

Initializes a camera.

In addition to the other class attributes, accepts the following parameters to set transform. See get_orientation_transformation().

Parameters

width – See shape.
height – See shape.
bitdepth – See bitdepth.
dx_um – See dx_um.
dy_um – See dy_um.
rot (str or int) – Rotates returned image by the corresponding degrees in ["90", "180", "270"] or numpy.rot90() code in [1, 2, 3]. Defaults to no rotation. Used to determine shape and transform.
fliplr (bool) – Flips returned image left right. Used to determine transform.
flipud (bool) – Flips returned image up down. Used to determine transform.
name (str) – Defaults to "camera".

close()[source]: Abstract method to close the camera and delete related objects.

static info(verbose=True)[source]

Abstract method to load display information.

Parameters: verbose (bool) – Whether or not to print display information.
Returns: An empty list.
Return type: list

reset()[source]: Abstract method to reset the camera to a default state.

get_exposure()[source]

Abstract method to get the integration time in seconds. Used in autoexposure().

Returns: Integration time in seconds.
Return type: float

set_exposure(exposure_s)[source]

Abstract method to set the integration time in seconds. Used in autoexposure().

Parameters: exposure_s (float) – The integration time in seconds.

set_woi(woi=None)[source]

Abstract method to narrow the imaging region to a ‘window of interest’ for faster framerates.

Parameters: woi (list, None) – See woi. If None, defaults to largest possible.
Returns: woi – woi.
Return type: list

flush(timeout_s=1)[source]

Abstract method to cycle the image buffer (if any) such that all new get_image() calls yield fresh frames.

Parameters: timeout_s (float) – The time in seconds to wait for frames to catch up with triggers.

get_image(timeout_s=1)[source]

Abstract method to pull an image from the camera and return.

Parameters: timeout_s (float) – The time in seconds to wait for the frame to be fetched.
Returns: Array of shape shape.
Return type: numpy.ndarray

get_images(image_count, flush=False)[source]

Grab image_count images in succession. Overwrite this implementation if a camera supports faster batch acquisition.

Parameters

image_count (int) – Number of images to grab.
flush (bool) – Whether to flush before grabbing.

Returns

Array of shape (image_count, height, width).

Return type

numpy.ndarray

autoexposure(set_fraction=0.5, tol=0.05, exposure_bounds_s=None, window=None, average_count=5, timeout_s=5, verbose=True)[source]

Sets the exposure of the camera such that the maximum value is at set_fraction of the dynamic range. Useful for mitigating deleterious over- or under- exposure.

Parameters

set_fraction (float) – Fraction of camera dynamic range to target image maximum.
tol (float) – Fractional tolerance for exposure adjustment.
exposure_bounds_s ((float, float) OR None) – Shortest and longest allowable integration in seconds. If None, defaults to exposure_bounds_s. If this attribute was not set (or not availible on a particular camera), then None instead defaults to unbounded.
window (array_like or None) – See window. If None, the full camera frame will be used.
average_count (int) – Number of frames to average intensity over for noise reduction.
timeout_s (float) – Stop attempting to autoexpose after timeout_s seconds.
verbose (bool) – Whether to print exposure updates.

Returns

Resulting exposure in seconds.

Return type

float

autofocus(z_get, z_set, z_list=None, plot=False)[source]

Uses an FFT contrast metric to find optimal focus when scanning over some variable z. This z often takes the form of a vertical stage to position a sample precisely at the plane of imaging of a lens or objective. The contrast metric works particularly well when combined with a projected spot array hologram.

Parameters

z_get (lambda) – Gets the current position of the focusing stage. Should return a float.
z_set (lambda) – Sets the position of the focusing stage to a given float.
z_list (array_like or None) – z values to sweep over during search. Defaults (when None) to numpy.linspace(-4,4,16).
plot (bool) – Whether to provide illustrative plots.