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#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#
# https://www.apache.org/licenses/LICENSE-2.0
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"""
Adjusts the contrast of an image.
"""
from typing import Any, Dict
import cv2
from peekingduck.pipeline.nodes.abstract_node import AbstractNode
from peekingduck.pipeline.nodes.base import ThresholdCheckerMixin
[docs]class Node(ThresholdCheckerMixin, AbstractNode):
"""Adjusts the contrast of an image, by multiplying with a gain/`alpha
parameter <https://docs.opencv.org/4.x/d3/dc1/tutorial_basic_
linear_transform.html>`_.
Inputs:
|img_data|
Outputs:
|img_data|
Configs:
alpha (:obj:`float`): **[0.0, 3.0], default = 1.0**. |br|
Increasing the value of alpha increases the contrast.
"""
def __init__(self, config: Dict[str, Any] = None, **kwargs: Any) -> None:
super().__init__(config, node_path=__name__, **kwargs)
self.check_bounds("alpha", "[0.0, 3.0]")
def run(self, inputs: Dict[str, Any]) -> Dict[str, Any]:
"""Adjusts the contrast of an image frame.
Args:
inputs (Dict): Inputs dictionary with the key `img`.
Returns:
(Dict): Outputs dictionary with the key `img`.
"""
img = cv2.convertScaleAbs(inputs["img"], alpha=self.alpha, beta=0)
return {"img": img}
def _get_config_types(self) -> Dict[str, Any]:
"""Returns dictionary mapping the node's config keys to respective types."""
return {"alpha": float}