#!/usr/bin/env python
# vim: set fileencoding=utf-8 :
# @author: Manuel Guenther <Manuel.Guenther@idiap.ch>
# @date: Thu May 24 10:41:42 CEST 2012
#
# Copyright (C) 2011-2012 Idiap Research Institute, Martigny, Switzerland
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import bob.ip.base
import numpy
from .Base import Base
from bob.bio.base.preprocessor import Preprocessor
class FaceCrop (Base):
"""Crops the face according to the given annotations.
This class is designed to perform a geometric normalization of the face based on the eye locations, using :py:class:`bob.ip.base.FaceEyesNorm`.
Usually, when executing the :py:meth:`crop_face` function, the image and the eye locations have to be specified.
There, the given image will be transformed such that the eye locations will be placed at specific locations in the resulting image.
These locations, as well as the size of the cropped image, need to be specified in the constructor of this class, as ``cropped_positions`` and ``cropped_image_size``.
Some image databases do not provide eye locations, but rather bounding boxes.
This is not a problem at all.
Simply define the coordinates, where you want your ``cropped_positions`` to be in the cropped image, by specifying the same keys in the dictionary that will be given as ``annotations`` to the :py:meth:`crop_face` function.
.. note;::
These locations can even be outside of the cropped image boundary, i.e., when the crop should be smaller than the annotated bounding boxes.
Sometimes, databases provide pre-cropped faces, where the eyes are located at (almost) the same position in all images.
Usually, the cropping does not conform with the cropping that you like (i.e., image resolution is wrong, or too much background information).
However, the database does not provide eye locations (since they are almost identical for all images).
In that case, you can specify the ``fixed_positions`` in the constructor, which will be taken instead of the ``annotations`` inside the :py:meth:`crop_face` function (in which case the ``annotations`` are ignored).
Sometimes, the crop of the face is outside of the original image boundaries.
Usually, these pixels will simply be left black, resulting in sharp edges in the image.
However, some feature extractors do not like these sharp edges.
In this case, you can set the ``mask_sigma`` to copy pixels from the valid border of the image and add random noise (see :py:func:`bob.ip.base.extrapolate_mask`).
**Parameters:**
cropped_image_size : (int, int)
The size of the resulting cropped images.
cropped_positions : dict
The coordinates in the cropped image, where the annotated points should be put to.
This parameter is a dictionary with usually two elements, e.g., ``{'reye':(RIGHT_EYE_Y, RIGHT_EYE_X) , 'leye':(LEFT_EYE_Y, LEFT_EYE_X)}``.
However, also other parameters, such as ``{'topleft' : ..., 'bottomright' : ...}`` are supported, as long as the ``annotations`` in the `__call__` function are present.
fixed_positions : dict or None
If specified, ignore the annotations from the database and use these fixed positions throughout.
mask_sigma : float or None
Fill the area outside of image boundaries with random pixels from the border, by adding noise to the pixel values.
To disable extrapolation, set this value to ``None``.
To disable adding random noise, set it to a negative value or 0.
mask_neighbors : int
The number of neighbors used during mask extrapolation.
See :py:func:`bob.ip.base.extrapolate_mask` for details.
mask_seed : int or None
The random seed to apply for mask extrapolation.
.. warning::
When run in parallel, the same random seed will be applied to all parallel processes.
Hence, results of parallel execution will differ from the results in serial execution.
kwargs
Remaining keyword parameters passed to the :py:class:`Base` constructor, such as ``color_channel`` or ``dtype``.
"""
def __init__(
self,
cropped_image_size, # resolution of the cropped image, in order (HEIGHT,WIDTH); if not given, no face cropping will be performed
cropped_positions, # dictionary of the cropped positions, usually: {'reye':(RIGHT_EYE_Y, RIGHT_EYE_X) , 'leye':(LEFT_EYE_Y, LEFT_EYE_X)}
fixed_positions = None, # dictionary of FIXED positions in the original image; if specified, annotations from the database will be ignored
mask_sigma = None, # The sigma for random values areas outside image
mask_neighbors = 5, # The number of neighbors to consider while extrapolating
mask_seed = None, # The seed for generating random values during extrapolation
**kwargs # parameters to be written in the __str__ method
):
Base.__init__(self, **kwargs)
# call base class constructor
Preprocessor.__init__(
self,
cropped_image_size = cropped_image_size,
cropped_positions = cropped_positions,
fixed_positions = fixed_positions,
mask_sigma = mask_sigma,
mask_neighbors = mask_neighbors,
mask_seed = mask_seed
)
# check parameters
assert len(cropped_positions) == 2
if fixed_positions:
assert len(fixed_positions) == 2
# copy parameters
self.cropped_image_size = cropped_image_size
self.cropped_positions = cropped_positions
self.cropped_keys = sorted(cropped_positions.keys())
self.fixed_positions = fixed_positions
self.mask_sigma = mask_sigma
self.mask_neighbors = mask_neighbors
self.mask_rng = bob.core.random.mt19937(mask_seed) if mask_seed is not None else bob.core.random.mt19937()
# create objects required for face cropping
self.cropper = bob.ip.base.FaceEyesNorm(crop_size=cropped_image_size, right_eye=cropped_positions[self.cropped_keys[0]], left_eye=cropped_positions[self.cropped_keys[1]])
self.cropped_mask = numpy.ndarray(cropped_image_size, numpy.bool)
[docs] def crop_face(self, image, annotations = None):
"""crop_face(image, annotations = None) -> face
Executes the face cropping on the given image and returns the cropped version of it.
**Parameters:**
image : 2D :py:class:`numpy.ndarray`
The face image to be processed.
annotations : dict or ``None``
The annotations that fit to the given image.
``None`` is only accepted, when ``fixed_positions`` were specified in the constructor.
**Returns:**
face : 2D :py:class:`numpy.ndarray` (float)
The cropped face.
"""
if self.fixed_positions is not None:
annotations = self.fixed_positions
if annotations is None:
raise ValueError("Cannot perform image cropping since annotations are not given, and no fixed annotations are specified.")
assert isinstance(annotations, dict)
if not all(k in annotations for k in self.cropped_keys):
raise ValueError("At least one of the expected annotations '%s' are not given in '%s'." % (self.cropped_keys, annotations.keys()))
# create output
mask = numpy.ones(image.shape[-2:], dtype=numpy.bool)
shape = self.cropped_image_size if image.ndim == 2 else [image.shape[0]] + list(self.cropped_image_size)
cropped_image = numpy.zeros(shape)
self.cropped_mask[:] = False
# perform the cropping
self.cropper(
image, # input image
mask, # full input mask
cropped_image, # cropped image
self.cropped_mask, # cropped mask
right_eye = annotations[self.cropped_keys[0]], # position of first annotation, usually right eye
left_eye = annotations[self.cropped_keys[1]] # position of second annotation, usually left eye
)
if self.mask_sigma is not None:
# extrapolate the mask so that pixels outside of the image original image region are filled with border pixels
if cropped_image.ndim == 2:
bob.ip.base.extrapolate_mask(self.cropped_mask, cropped_image, self.mask_sigma, self.mask_neighbors, self.mask_rng)
else:
[bob.ip.base.extrapolate_mask(self.cropped_mask, cropped_image_channel, self.mask_sigma, self.mask_neighbors, self.mask_rng) for cropped_image_channel in cropped_image]
return cropped_image
def __call__(self, image, annotations = None):
"""__call__(image, annotations = None) -> face
Aligns the given image according to the given annotations.
First, the desired color channel is extracted from the given image.
Afterward, the face is cropped, according to the given ``annotations`` (or to ``fixed_positions``, see :py:meth:`crop_face`).
Finally, the resulting face is converted to the desired data type.
**Parameters:**
image : 2D or 3D :py:class:`numpy.ndarray`
The face image to be processed.
annotations : dict or ``None``
The annotations that fit to the given image.
**Returns:**
face : 2D :py:class:`numpy.ndarray`
The cropped face.
"""
# convert to the desired color channel
image = self.color_channel(image)
# crop face
image = self.crop_face(image, annotations)
# convert data type
return self.data_type(image)