BaseCameraInterface

A uniform, backend-agnostic contract for any camera driver in your photonics lab software. By subclassing the abstract base class, you can swap in different SDKs (FliSdk, Flir/spinaker, or even a test stub) without changing your acquisition pipeline.

Purpose

This module provides:

  • A uniform API across all supported camera hardware.
  • SOLID design principles to promote single-responsibility, extensibility, and decoupling.
  • Type safety through Python type hints.
  • Easy testing via dependency injection and mockability.

Key Interface: CameraInterface

CameraInterface is an abstract base class defining the essential operations expected from any camera implementation.

Core Lifecycle Methods

Method Description
__init__(**kwargs) Sets up camera SDK, applies configuration, and prepares for acquisition.
start_capture() Begins image acquisition or live streaming.
stop_capture() Halts image acquisition or live streaming.
get_image(wait=True) Retrieves the latest frame, optionally blocking until a new one is ready.
close() Releases hardware resources and shuts down the camera safely.

Camera Settings as Properties

Common camera parameters are exposed as Python properties, allowing both reading and writing through a uniform interface:

Property Type Description
exposure float Camera exposure time (in seconds).
framerate float Frame rate (in frames per second).
gain float Sensor analog gain.

These properties standardize hardware parameter control across heterogeneous devices.

Dark Frame Management

CameraInterface includes methods for managing dark-frame capture and reuse:

Method Description
take_dark(frames, save_path) Captures and averages multiple frames to generate a dark frame.
load_dark(file) Loads a previously saved dark frame from disk for subtraction or QA.

This is particularly useful for calibration routines and background subtraction workflows.

Design Considerations

  • Interface Enforcement: All camera drivers must adhere to the same method/property interface, enabling interchangeability without modification to upstream systems.
  • Extensibility: New camera types can be integrated by subclassing CameraInterface and implementing the required methods.
  • Mockability for Testing: By abstracting away hardware-specific logic, the interface enables injection of mocks and stubs in test environments.
  • Consistency: Centralized documentation and type annotations help enforce clarity and uniformity across all implementations.

Intended Usage

The module is meant to be subclassed by hardware-specific drivers. This approach enables higher-level tools (e.g. data acquisition scripts, GUIs, or analysis pipelines) to remain agnostic to the underlying camera backend.

For a practical implementation, refer to concrete subclasses such as FliCamera, which adapts the interface to the FliSdk hardware.

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BaseCameraInterface.start_capture

 BaseCameraInterface.start_capture ()

Begin image acquisition or live stream.

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BaseCameraInterface.stop_capture

 BaseCameraInterface.stop_capture ()

Halt image acquisition or live stream.

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BaseCameraInterface.exposure

 BaseCameraInterface.exposure ()

Get or set the camera exposure time in seconds.

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BaseCameraInterface.framerate

 BaseCameraInterface.framerate ()

Get or set the camera frame rate in frames per second.

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BaseCameraInterface.gain

 BaseCameraInterface.gain ()

Get or set the camera gain (e.g., sensor analog gain).

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BaseCameraInterface.get_image

 BaseCameraInterface.get_image (wait:bool=True)

Retrieve the latest image frame. :param wait: block until a new frame is available :return: 2D numpy array representing the image

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BaseCameraInterface.take_dark

 BaseCameraInterface.take_dark (frames:int=100,
                                save_path:Optional[pathlib.Path]=None)

Acquire a dark frame by averaging multiple captures. :param frames: number of frames to average :param save_path: optional file path to save the dark frame :return: dark frame array

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BaseCameraInterface.load_dark

 BaseCameraInterface.load_dark (file:Union[str,pathlib.Path])

Load a previously saved dark frame from disk.

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BaseCameraInterface.close

 BaseCameraInterface.close ()

Release all resources and shut down the camera.

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goodtimer

 goodtimer (time_ms)

*Active wait timer for precise timing control.

Unlike time.sleep(), this function actively consumes CPU cycles to ensure more precise timing at the expense of CPU usage.*

Type Details
time_ms float Time to wait in milliseconds.