Defocus

Description

Apply defocus blur to the input image.

    This transform simulates the effect of an out-of-focus camera by applying a defocus blur
    to the image. It uses a combination of disc kernels and Gaussian blur to create a realistic
    defocus effect.

    Args:
        radius (tuple[int, int] | int): Range for the radius of the defocus blur.
            If a single int is provided, the range will be [1, radius].
            Larger values create a stronger blur effect.
            Default: (3, 10)

        alias_blur (tuple[float, float] | float): Range for the standard deviation of the Gaussian blur
            applied after the main defocus blur. This helps to reduce aliasing artifacts.
            If a single float is provided, the range will be (0, alias_blur).
            Larger values create a smoother, more aliased effect.
            Default: (0.1, 0.5)

        p (float): Probability of applying the transform. Should be in the range [0, 1].
            Default: 0.5

    Targets:
        image

    Image types:
        uint8, float32

    Note:
        - The defocus effect is created using a disc kernel, which simulates the shape of a camera's aperture.
        - The additional Gaussian blur (alias_blur) helps to soften the edges of the disc kernel, creating a
          more natural-looking defocus effect.
        - Larger radius values will create a stronger, more noticeable defocus effect.
        - The alias_blur parameter can be used to fine-tune the appearance of the defocus, with larger values
          creating a smoother, potentially more realistic effect.

    Example:
        >>> import numpy as np
        >>> import albumentations as A
        >>> image = np.random.randint(0, 256, (100, 100, 3), dtype=np.uint8)
        >>> transform = A.Defocus(radius=(4, 8), alias_blur=(0.2, 0.4), always_apply=True)
        >>> result = transform(image=image)
        >>> defocused_image = result['image']

    References:
        - https://en.wikipedia.org/wiki/Defocus_aberration
        - https://www.researchgate.net/publication/261311609_Realistic_Defocus_Blur_for_Multiplane_Computer-Generated_Holography
    

Parameters

• p: float (default: 0.5)
• radius: int | tuple[int, int] | float | tuple[float, float] (default: (3, 10))
• alias_blur: int | tuple[int, int] | float | tuple[float, float] (default: (0.1, 0.5))

Targets

• Image

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