ToSepia

Description

Apply a sepia filter to the input image.

    This transform converts a color image to a sepia tone, giving it a warm, brownish tint
    that is reminiscent of old photographs. The sepia effect is achieved by applying a
    specific color transformation matrix to the RGB channels of the input image.

    Args:
        p (float): Probability of applying the transform. Default: 0.5.

    Targets:
        image

    Image types:
        uint8, float32

    Number of channels:
        3

    Note:
        - This transform only works with RGB images (3 channels).
        - The sepia effect is created using a fixed color transformation matrix:
          [[0.393, 0.769, 0.189],
           [0.349, 0.686, 0.168],
           [0.272, 0.534, 0.131]]
        - The output image will have the same data type as the input image.
        - For float32 images, ensure the input values are in the range [0, 1].

    Raises:
        TypeError: If the input image is not a 3-channel RGB image.

    Examples:
        >>> import numpy as np
        >>> import albumentations as A
        >>>
        # Apply sepia effect to a uint8 image
        >>> image = np.random.randint(0, 256, (100, 100, 3), dtype=np.uint8)
        >>> transform = A.ToSepia(p=1.0)
        >>> sepia_image = transform(image=image)['image']
        >>> assert sepia_image.shape == image.shape
        >>> assert sepia_image.dtype == np.uint8
        >>>
        # Apply sepia effect to a float32 image
        >>> image = np.random.rand(100, 100, 3).astype(np.float32)
        >>> transform = A.ToSepia(p=1.0)
        >>> sepia_image = transform(image=image)['image']
        >>> assert sepia_image.shape == image.shape
        >>> assert sepia_image.dtype == np.float32
        >>> assert 0 <= sepia_image.min() <= sepia_image.max() <= 1.0

    Mathematical Formulation:
        Given an input pixel [R, G, B], the sepia tone is calculated as:
        R_sepia = 0.393*R + 0.769*G + 0.189*B
        G_sepia = 0.349*R + 0.686*G + 0.168*B
        B_sepia = 0.272*R + 0.534*G + 0.131*B

        The output values are then clipped to the valid range for the image's data type.

    See Also:
        ToGray: For converting images to grayscale instead of sepia.
    

Parameters

• p: float (default: 0.5)

Targets

• Image