# ---------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License.
# ---------------------------------------------------------
import copy
import inspect
from enum import Enum
from genalog.degradation import effect
DEFAULT_METHOD_PARAM_TO_INCLUDE = "src"
[docs]class ImageState(Enum):
ORIGINAL_STATE = "ORIGINAL_STATE"
CURRENT_STATE = "CURRENT_STATE"
[docs]class Degrader:
""" An object for applying multiple degradation effects onto an image"""
def __init__(self, effects):
"""
Arguments:
effects (list) : a list of 2-element tuple (method_name, method_kwargs) where:
:method_name: the name of the degradation method (method must be defined in 'genalog.degradation.effect')
:method_kwargs: the keyword arguments of the corresponding method
Example:
::
[
("blur", {"radius": 3}),
("bleed_through", {"alpha": 0.8),
("morphology", {"operation": "open", "kernel_shape": (3,3), "kernel_type": "ones"})
]
The example above will apply degradation effects to the images
in the following sequence:
::
"blur" -> "bleed_through" -> "morphological operation (open)"
"""
Degrader.validate_effects(effects)
self.effects_to_apply = copy.deepcopy(effects)
self._add_default_method_param()
[docs] @staticmethod
def validate_effects(effects):
"""Validate the effects list
Arguments:
effects (list) : a list of 2-element tuple ``(method_name, method_kwargs)``
that defines:
1. ``method_name`` : the name of the degradation method \
(method must be defined in ``genalog.degradation.effect``)
2. ``method_kwargs`` : the keyword arguments of the corresponding method
Example:
::
[
("blur", {"radius": "3"}),
("bleed_through", {"alpha":"0.8"}),
("morphology", {"operation": "open", "kernel_shape": (3,3), "kernel_type": "ones"}),
]
Raises:
ValueError: raise this error when:
``method_name`` not defined in "genalog.degradation.effect"
``method_kwargs`` is not a valid keyword arguments in the corresponding method
"""
for effect_tuple in effects:
method_name, method_kwargs = effect_tuple
try:
# Try to find corresponding degradation method in the module
method = getattr(effect, method_name)
except AttributeError:
raise ValueError(
f"Method '{method_name}' is not defined in 'genalog.degradation.effect'"
)
# Get the method signatures
method_sign = inspect.signature(method)
# Check if method parameters are valid
for (
param_name
) in method_kwargs.keys(): # i.e. ["operation", "kernel_shape", ...]
if param_name not in method_sign.parameters:
method_args = [param for param in method_sign.parameters]
raise ValueError(
f"Invalid parameter name '{param_name}' for method 'genalog.degradation.effect.{method_name}()'. " +
f"Method parameter names are: {method_args}"
)
def _add_default_method_param(self):
"""All methods in "genalog.degradation.effect" module have a required
method parameter named "src". This parameter will be included if not provided
by the input keyword argument dictionary.
"""
for effect_tuple in self.effects_to_apply:
method_name, method_kwargs = effect_tuple
if DEFAULT_METHOD_PARAM_TO_INCLUDE not in method_kwargs:
method_kwargs[
DEFAULT_METHOD_PARAM_TO_INCLUDE
] = ImageState.CURRENT_STATE
[docs] def apply_effects(self, src):
"""Apply degradation effects in sequence
Arguments:
src (numpy.ndarray) : source image of shape (rows, cols)
Returns:
a copy of the source image {numpy.ndarray} after apply the effects
"""
self.original_state = src
self.current_state = src
# Preserve the original effect instructions
effects_to_apply = copy.deepcopy(self.effects_to_apply)
for effect_tuple in effects_to_apply:
method_name, method_kwargs = effect_tuple
method = getattr(effect, method_name)
# Replace constants (i.e. ImageState.ORIGINAL_STATE) with actual image state
method_kwargs = self.insert_image_state(method_kwargs)
# Calling the degradation method
self.current_state = method(**method_kwargs)
return self.current_state
[docs] def insert_image_state(self, kwargs):
"""Replace the enumeration (ImageState) with the actual image in
the keyword argument dictionary
Arguments:
kwargs (dict) : keyword argument dictionary
Ex: {"src": ImageState.ORIGINAL_STATE, "radius": 5}
Returns:
return keyword argument dictionary replaced with
reference to the image
"""
for keyword, argument in kwargs.items():
if argument is ImageState.ORIGINAL_STATE:
kwargs[keyword] = self.original_state.copy()
if argument is ImageState.CURRENT_STATE:
kwargs[keyword] = self.current_state.copy()
return kwargs
