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import torch |
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import lpips |
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from .image import rgb2ycbcr_pt |
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from .common import frozen_module |
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def calculate_psnr_pt(img, img2, crop_border, test_y_channel=False): |
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"""Calculate PSNR (Peak Signal-to-Noise Ratio) (PyTorch version). |
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Reference: https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio |
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Args: |
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img (Tensor): Images with range [0, 1], shape (n, 3/1, h, w). |
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img2 (Tensor): Images with range [0, 1], shape (n, 3/1, h, w). |
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crop_border (int): Cropped pixels in each edge of an image. These pixels are not involved in the calculation. |
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test_y_channel (bool): Test on Y channel of YCbCr. Default: False. |
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Returns: |
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float: PSNR result. |
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""" |
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assert img.shape == img2.shape, (f'Image shapes are different: {img.shape}, {img2.shape}.') |
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if crop_border != 0: |
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img = img[:, :, crop_border:-crop_border, crop_border:-crop_border] |
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img2 = img2[:, :, crop_border:-crop_border, crop_border:-crop_border] |
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if test_y_channel: |
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img = rgb2ycbcr_pt(img, y_only=True) |
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img2 = rgb2ycbcr_pt(img2, y_only=True) |
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img = img.to(torch.float64) |
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img2 = img2.to(torch.float64) |
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mse = torch.mean((img - img2)**2, dim=[1, 2, 3]) |
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return 10. * torch.log10(1. / (mse + 1e-8)) |
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class LPIPS: |
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def __init__(self, net: str) -> None: |
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self.model = lpips.LPIPS(net=net) |
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frozen_module(self.model) |
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@torch.no_grad() |
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def __call__(self, img1: torch.Tensor, img2: torch.Tensor, normalize: bool) -> torch.Tensor: |
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""" |
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Compute LPIPS. |
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Args: |
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img1 (torch.Tensor): The first image (NCHW, RGB, [-1, 1]). Specify `normalize` if input |
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image is range in [0, 1]. |
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img2 (torch.Tensor): The second image (NCHW, RGB, [-1, 1]). Specify `normalize` if input |
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image is range in [0, 1]. |
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normalize (bool): If specified, the input images will be normalized from [0, 1] to [-1, 1]. |
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Returns: |
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lpips_values (torch.Tensor): The lpips scores of this batch. |
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""" |
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return self.model(img1, img2, normalize=normalize) |
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def to(self, device: str) -> "LPIPS": |
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self.model.to(device) |
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return self |
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