SignalNoiseRatio

class mmeval.metrics.SignalNoiseRatio(crop_border: int = 0, input_order: str = 'CHW', convert_to: Optional[str] = None, channel_order: str = 'rgb', **kwargs)

Signal-to-Noise Ratio.

Ref: https://en.wikipedia.org/wiki/Signal-to-noise_ratio

参数

• crop_border (int) – Cropped pixels in each edges of an image. These pixels are not involved in the PeakSignalNoiseRatio calculation. Defaults to 0.

• input_order (str) – Whether the input order is ‘HWC’ or ‘CHW’. Defaults to ‘HWC’.

• convert_to (str, optional) – Whether to convert the images to other color models. If None, the images are not altered. When computing for ‘Y’, the images are assumed to be in BGR order. Options are ‘Y’ and None. Defaults to None.

• channel_order (str) – The channel order of image. Choices are ‘rgb’ and ‘bgr’. Defaults to ‘rgb’.

• **kwargs – Keyword parameters passed to BaseMetric.

实际案例

>>> from mmeval import SignalNoiseRatio
>>> import numpy as np
>>>
>>> snr = SignalNoiseRatio(crop_border=1, input_order='CHW',
...                        convert_to='Y', channel_order='rgb')
>>> gts = np.random.randint(0, 255, size=(3, 32, 32))
>>> preds = np.random.randint(0, 255, size=(3, 32, 32))
>>> snr(preds, gts)  
{'snr': ...}

Calculate SignalNoiseRatio between 2 images:

>>> gts = np.ones((3, 32, 32)) * 2
>>> preds = np.ones((3, 32, 32))
>>> SignalNoiseRatio.compute_snr(preds, gts)
6.020599913279624

add(predictions: Sequence[numpy.ndarray], groundtruths: Sequence[numpy.ndarray], channel_order: Optional[str] = None) → None

Add SignalNoiseRatio score of batch to self._results

参数

• predictions (Sequence[np.ndarray]) – Predictions of the model.

• groundtruths (Sequence[np.ndarray]) – The ground truth images.

• channel_order (Optional[str]) – The channel order of the input samples. If not passed, will set as self.channel_order. Defaults to None.

compute_metric(results: List[numpy.float64]) → Dict[str, float]

Compute the SignalNoiseRatio metric.

This method would be invoked in BaseMetric.compute after distributed synchronization.

参数

results (List[np.float64]) – A list that consisting the SignalNoiseRatio score. This list has already been synced across all ranks.

返回

The computed SignalNoiseRatio metric.

返回类型

Dict[str, float]

static compute_snr(prediction: numpy.ndarray, groundtruth: numpy.ndarray) → numpy.float64

Calculate SignalNoiseRatio (Signal-to-Noise Ratio).

Ref: https://en.wikipedia.org/wiki/Signal-to-noise_ratio

参数

• prediction (np.ndarray) – Images with range [0, 255].

• groundtruth (np.ndarray) – Images with range [0, 255].

返回

SignalNoiseRatio result.

返回类型

np.float64