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from collections.abc import Sequence |
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from typing import Any, List, Optional, Union |
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from torch import Tensor |
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from typing_extensions import Literal |
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from torchmetrics.functional.image.ergas import _ergas_compute, _ergas_update |
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from torchmetrics.metric import Metric |
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from torchmetrics.utilities import rank_zero_warn |
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from torchmetrics.utilities.data import dim_zero_cat |
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from torchmetrics.utilities.imports import _MATPLOTLIB_AVAILABLE |
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from torchmetrics.utilities.plot import _AX_TYPE, _PLOT_OUT_TYPE |
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if not _MATPLOTLIB_AVAILABLE: |
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__doctest_skip__ = ["ErrorRelativeGlobalDimensionlessSynthesis.plot"] |
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class ErrorRelativeGlobalDimensionlessSynthesis(Metric): |
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r"""Calculate the `Error relative global dimensionless synthesis`_ (ERGAS) metric. |
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This metric is used to calculate the accuracy of Pan sharpened image considering normalized average error of each |
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band of the result image. It is defined as: |
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.. math:: |
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ERGAS = \frac{100}{r} \cdot \sqrt{\frac{1}{N} \sum_{k=1}^{N} \frac{RMSE(B_k)^2}{\mu_k^2}} |
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where :math:`r=h/l` denote the ratio in spatial resolution (pixel size) between the high and low resolution images. |
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:math:`N` is the number of spectral bands, :math:`RMSE(B_k)` is the root mean square error of the k-th band between |
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low and high resolution images, and :math:`\\mu_k` is the mean value of the k-th band of the reference image. |
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As input to ``forward`` and ``update`` the metric accepts the following input |
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- ``preds`` (:class:`~torch.Tensor`): Predictions from model |
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- ``target`` (:class:`~torch.Tensor`): Ground truth values |
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As output of `forward` and `compute` the metric returns the following output |
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- ``ergas`` (:class:`~torch.Tensor`): if ``reduction!='none'`` returns float scalar tensor with average ERGAS |
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value over sample else returns tensor of shape ``(N,)`` with ERGAS values per sample |
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Args: |
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ratio: ratio of high resolution to low resolution. |
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reduction: a method to reduce metric score over labels. |
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- ``'elementwise_mean'``: takes the mean (default) |
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- ``'sum'``: takes the sum |
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- ``'none'`` or ``None``: no reduction will be applied |
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kwargs: Additional keyword arguments, see :ref:`Metric kwargs` for more info. |
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Example: |
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>>> from torch import rand |
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>>> from torchmetrics.image import ErrorRelativeGlobalDimensionlessSynthesis |
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>>> preds = rand([16, 1, 16, 16]) |
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>>> target = preds * 0.75 |
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>>> ergas = ErrorRelativeGlobalDimensionlessSynthesis() |
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>>> ergas(preds, target).round() |
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tensor(10.) |
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""" |
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higher_is_better: bool = False |
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is_differentiable: bool = True |
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full_state_update: bool = False |
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plot_lower_bound: float = 0.0 |
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preds: List[Tensor] |
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target: List[Tensor] |
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def __init__( |
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self, |
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ratio: float = 4, |
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reduction: Literal["elementwise_mean", "sum", "none", None] = "elementwise_mean", |
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**kwargs: Any, |
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) -> None: |
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super().__init__(**kwargs) |
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rank_zero_warn( |
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"Metric `UniversalImageQualityIndex` will save all targets and" |
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" predictions in buffer. For large datasets this may lead" |
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" to large memory footprint." |
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) |
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self.add_state("preds", default=[], dist_reduce_fx="cat") |
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self.add_state("target", default=[], dist_reduce_fx="cat") |
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self.ratio = ratio |
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self.reduction = reduction |
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def update(self, preds: Tensor, target: Tensor) -> None: |
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"""Update state with predictions and targets.""" |
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preds, target = _ergas_update(preds, target) |
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self.preds.append(preds) |
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self.target.append(target) |
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def compute(self) -> Tensor: |
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"""Compute explained variance over state.""" |
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preds = dim_zero_cat(self.preds) |
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target = dim_zero_cat(self.target) |
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return _ergas_compute(preds, target, self.ratio, self.reduction) |
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def plot( |
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self, val: Optional[Union[Tensor, Sequence[Tensor]]] = None, ax: Optional[_AX_TYPE] = None |
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) -> _PLOT_OUT_TYPE: |
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"""Plot a single or multiple values from the metric. |
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Args: |
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val: Either a single result from calling `metric.forward` or `metric.compute` or a list of these results. |
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If no value is provided, will automatically call `metric.compute` and plot that result. |
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ax: An matplotlib axis object. If provided will add plot to that axis |
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Returns: |
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Figure and Axes object |
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Raises: |
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ModuleNotFoundError: |
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If `matplotlib` is not installed |
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.. plot:: |
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:scale: 75 |
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>>> # Example plotting a single value |
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>>> from torch import rand |
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>>> from torchmetrics.image import ErrorRelativeGlobalDimensionlessSynthesis |
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>>> preds = rand([16, 1, 16, 16]) |
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>>> target = preds * 0.75 |
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>>> metric = ErrorRelativeGlobalDimensionlessSynthesis() |
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>>> metric.update(preds, target) |
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>>> fig_, ax_ = metric.plot() |
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.. plot:: |
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:scale: 75 |
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>>> # Example plotting multiple values |
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>>> from torch import rand |
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>>> from torchmetrics.image import ErrorRelativeGlobalDimensionlessSynthesis |
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>>> preds = rand([16, 1, 16, 16]) |
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>>> target = preds * 0.75 |
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>>> metric = ErrorRelativeGlobalDimensionlessSynthesis() |
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>>> values = [ ] |
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>>> for _ in range(10): |
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... values.append(metric(preds, target)) |
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>>> fig_, ax_ = metric.plot(values) |
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""" |
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return self._plot(val, ax) |
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