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Universal Image Quality Index

Module Interface

class torchmetrics.UniversalImageQualityIndex(kernel_size=(11, 11), sigma=(1.5, 1.5), reduction='elementwise_mean', data_range=None, **kwargs)[source]

Computes Universal Image Quality Index (UniversalImageQualityIndex).

Parameters
  • kernel_size (Sequence[int]) – size of the gaussian kernel

  • sigma (Sequence[float]) – Standard deviation of the gaussian kernel

  • reduction (Literal[‘elementwise_mean’, ‘sum’, ‘none’, None]) –

    a method to reduce metric score over labels.

    • 'elementwise_mean': takes the mean (default)

    • 'sum': takes the sum

    • 'none' or None: no reduction will be applied

  • data_range (Optional[float]) – Range of the image. If None, it is determined from the image (max - min)

  • kwargs (Any) – Additional keyword arguments, see Advanced metric settings for more info.

Returns

Tensor with UniversalImageQualityIndex score

Example

>>> import torch
>>> from torchmetrics import UniversalImageQualityIndex
>>> preds = torch.rand([16, 1, 16, 16])
>>> target = preds * 0.75
>>> uqi = UniversalImageQualityIndex()
>>> uqi(preds, target)
tensor(0.9216)

Initializes internal Module state, shared by both nn.Module and ScriptModule.

compute()[source]

Computes explained variance over state.

Return type

Tensor

update(preds, target)[source]

Update state with predictions and targets.

Parameters
  • preds (Tensor) – Predictions from model

  • target (Tensor) – Ground truth values

Return type

None

Functional Interface

torchmetrics.functional.universal_image_quality_index(preds, target, kernel_size=(11, 11), sigma=(1.5, 1.5), reduction='elementwise_mean', data_range=None)[source]

Universal Image Quality Index.

Parameters
  • preds (Tensor) – estimated image

  • target (Tensor) – ground truth image

  • kernel_size (Sequence[int]) – size of the gaussian kernel

  • sigma (Sequence[float]) – Standard deviation of the gaussian kernel

  • reduction (Optional[Literal[‘elementwise_mean’, ‘sum’, ‘none’]]) –

    a method to reduce metric score over labels.

    • 'elementwise_mean': takes the mean (default)

    • 'sum': takes the sum

    • 'none' or None: no reduction will be applied

  • data_range (Optional[float]) – Range of the image. If None, it is determined from the image (max - min)

Return type

Tensor

Returns

Tensor with UniversalImageQualityIndex score

Raises
  • TypeError – If preds and target don’t have the same data type.

  • ValueError – If preds and target don’t have BxCxHxW shape.

  • ValueError – If the length of kernel_size or sigma is not 2.

  • ValueError – If one of the elements of kernel_size is not an odd positive number.

  • ValueError – If one of the elements of sigma is not a positive number.

Example

>>> from torchmetrics.functional import universal_image_quality_index
>>> preds = torch.rand([16, 1, 16, 16])
>>> target = preds * 0.75
>>> universal_image_quality_index(preds, target)
tensor(0.9216)

References

[1] Zhou Wang and A. C. Bovik, “A universal image quality index,” in IEEE Signal Processing Letters, vol. 9, no. 3, pp. 81-84, March 2002, doi: 10.1109/97.995823.

[2] Zhou Wang, A. C. Bovik, H. R. Sheikh and E. P. Simoncelli, “Image quality assessment: from error visibility to structural similarity,” in IEEE Transactions on Image Processing, vol. 13, no. 4, pp. 600-612, April 2004, doi: 10.1109/TIP.2003.819861.