o
    oi                     @   s8   d dl Z d dlmZ de jde jdede jfddZdS )	    N)mse_lossimagetargetmax_valreturnc              	   C   s   t | tjstdt|  dt |tjs tdt| d| j|jkr2td| j d|j dt|d t| |dd  S )	a  Create a function that calculates the PSNR between 2 images.

    PSNR is Peek Signal to Noise Ratio, which is similar to mean squared error.
    Given an m x n image, the PSNR is:

    .. math::

        \text{PSNR} = 10 \log_{10} \bigg(\frac{\text{MAX}_I^2}{MSE(I,T)}\bigg)

    where

    .. math::

        \text{MSE}(I,T) = \frac{1}{mn}\sum_{i=0}^{m-1}\sum_{j=0}^{n-1} [I(i,j) - T(i,j)]^2

    and :math:`\text{MAX}_I` is the maximum possible input value
    (e.g for floating point images :math:`\text{MAX}_I=1`).

    Args:
        image: the input image with arbitrary shape :math:`(*)`.
        target: the labels image with arbitrary shape :math:`(*)`.
        max_val: The maximum value in the input tensor.

    Return:
        the computed loss as a scalar.

    Examples:
        >>> ones = torch.ones(1)
        >>> psnr(ones, 1.2 * ones, 2.) # 10 * log(4/((1.2-1)**2)) / log(10)
        tensor(20.0000)

    Reference:
        https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio#Definition

    zExpected torch.Tensor but got .z*Expected tensors of equal shapes, but got z and g      $@   mean)	reduction)
isinstancetorchTensor	TypeErrortypeshapelog10mse)r   r   r    r   G/home/ubuntu/.local/lib/python3.10/site-packages/kornia/metrics/psnr.pypsnr   s   $ r   )r   torch.nn.functionalr   r   r   floatr   r   r   r   r   <module>   s   $