mmagic.evaluation.metrics.snr

Module Contents

Classes

SNR	Signal-to-Noise Ratio.

Functions

snr(gt, pred[, crop_border, input_order, convert_to, ...])

Calculate PSNR (Peak Signal-to-Noise Ratio).

class mmagic.evaluation.metrics.snr.SNR(gt_key: str = 'gt_img', pred_key: str = 'pred_img', collect_device: str = 'cpu', prefix: Optional[str] = None, crop_border=0, input_order='CHW', convert_to=None)

Bases: mmagic.evaluation.metrics.base_sample_wise_metric.BaseSampleWiseMetric

Signal-to-Noise Ratio.

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

Parameters

• gt_key (str) – Key of ground-truth. Default: ‘gt_img’

• pred_key (str) – Key of prediction. Default: ‘pred_img’

• collect_device (str) – Device name used for collecting results from different ranks during distributed training. Must be ‘cpu’ or ‘gpu’. Defaults to ‘cpu’.

• prefix (str, optional) – The prefix that will be added in the metric names to disambiguate homonymous metrics of different evaluators. If prefix is not provided in the argument, self.default_prefix will be used instead. Default: None

• crop_border (int) – Cropped pixels in each edges of an image. These pixels are not involved in the SNR calculation. Default: 0.

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

• convert_to (str) – 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. Default: None.

Metrics:

• SNR (float): Signal-to-Noise Ratio

metric = SNR

process_image(gt, pred, mask)

Process an image.

Parameters

• gt (Torch | np.ndarray) – GT image.

• pred (Torch | np.ndarray) – Pred image.

• mask (Torch | np.ndarray) – Mask of evaluation.

Returns

SNR result.

Return type

np.ndarray

mmagic.evaluation.metrics.snr.snr(gt, pred, crop_border=0, input_order='HWC', convert_to=None, channel_order='rgb')

Calculate PSNR (Peak Signal-to-Noise Ratio).

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

Parameters

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

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

• crop_border (int) – Cropped pixels in each edges of an image. These pixels are not involved in the PSNR calculation. Default: 0.

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

• convert_to (str) – 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. Default: None.

• channel_order (str) – The channel order of image. Default: ‘rgb’.

Returns

SNR result.

Return type

float