# encoding: utf-8
# ------------------------------------------------------------------------
# Copyright 2020 All Histolab Contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
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# ------------------------------------------------------------------------
import csv
import logging
import os
from abc import abstractmethod
from itertools import zip_longest
from typing import Iterable, List, Optional, Tuple, Union
import numpy as np
import PIL
from .exceptions import LevelError, TileSizeOrCoordinatesError
from .masks import BiggestTissueBoxMask, BinaryMask
from .scorer import Scorer
from .slide import Slide
from .tile import Tile
from .types import CoordinatePair
from .util import (
random_choice_true_mask2d,
rectangle_to_mask,
region_coordinates,
regions_from_binary_mask,
regions_to_binary_mask,
scale_coordinates,
)
try:
from typing import Protocol, runtime_checkable
except ImportError:
from typing_extensions import Protocol, runtime_checkable
logger = logging.getLogger("tiler")
COORDS_WITHIN_EXTRACTION_MASK_THRESHOLD = 0.8
@runtime_checkable
class Tiler(Protocol):
"""General tiler object"""
level: int
mpp: float # if provided, always takes precedence over level
tile_size: Tuple[int, int]
@abstractmethod
def extract(
self,
slide: Slide,
extraction_mask: BinaryMask = BiggestTissueBoxMask(),
log_level: str = "INFO",
) -> None:
pass # pragma: no cover
def locate_tiles(
self,
slide: Slide,
extraction_mask: BinaryMask = BiggestTissueBoxMask(),
scale_factor: int = 32,
alpha: int = 128,
outline: Union[str, Iterable[str], Iterable[Tuple[int]]] = "red",
linewidth: int = 1,
tiles: Optional[Iterable[Tile]] = None,
) -> PIL.Image.Image:
"""Draw tile box references on a rescaled version of the slide
Parameters
----------
slide : Slide
Slide reference where placing the tiles
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`
scale_factor : int, optional
Scaling factor for the returned image. Default is 32.
alpha : int, optional
The alpha level to be applied to the rescaled slide. Default is 128.
outline : Union[str, Iterable[str], Iterable[Tuple[int]]], optional
The outline color for the tile annotations. Default is 'red'.
You can provide this as a string compatible with matplotlib, or
you can provide a list of the same length as the tiles, where
each color is your assigned color for the corresponding individual
tile. This list can be a list of matplotlib-style string colors, or
a list of tuples of ints in the [0, 255] range, each of
length 3, representing the red, green and blue color for each tile.
For example, if you have two tiles that you want to be colored
yellow, you can pass this argument as any of the following ..
- 'yellow'
- ['yellow', 'yellow']
- [(255, 255, 0), (255, 255, 0)]
linewidth : int, optional
Thickness of line used to draw tiles. Default is 1.
tiles : Optional[Iterable[Tile]], optional
Tiles to visualize. Will be extracted if None. Default is None.
You may decide to provide this argument if you do not want the
tiles to be re-extracted for visualization if you already have
the tiles in hand.
Returns
-------
PIL.Image.Image
PIL Image of the rescaled slide with the extracted tiles outlined
"""
img = slide.scaled_image(scale_factor)
img.putalpha(alpha)
draw = PIL.ImageDraw.Draw(img)
if tiles is None:
tiles = (
self._tiles_generator(slide, extraction_mask)[0]
if isinstance(self, ScoreTiler)
else self._tiles_generator(slide, extraction_mask)
)
tiles_coords = (tile[1] for tile in tiles)
for coords, one_outline in self._tile_coords_and_outline_generator(
tiles_coords, outline
):
rescaled = scale_coordinates(coords, slide.dimensions, img.size)
draw.rectangle(tuple(rescaled), outline=one_outline, width=linewidth)
return img
# ------- implementation helpers -------
def _has_valid_tile_size(self, slide: Slide) -> bool:
"""Return True if the tile size is smaller or equal than the ``slide`` size.
Parameters
----------
slide : Slide
The slide to check the tile size against.
Returns
-------
bool
True if the tile size is smaller or equal than the ``slide`` size at
extraction level, False otherwise
"""
return (
self.tile_size[0] <= slide.level_dimensions(self.level)[0]
and self.tile_size[1] <= slide.level_dimensions(self.level)[1]
)
def _scale_factor(self, slide: Slide) -> float:
"""Retrieve the scale factor that maps the original tile_size to proper one.
Parameters
----------
slide : Slide
The slide to tile.
Returns
-------
float
Scale factor that maps the original self.tile_size to proper one.
"""
if self.mpp is None:
return 1.0
return self.mpp / slide.base_mpp
@staticmethod
def _tile_coords_and_outline_generator(
tiles_coords: Iterable[CoordinatePair],
outlines: Union[str, List[str], List[Tuple[int]]],
) -> Union[str, Tuple[int]]:
"""Zip tile coordinates and outlines from tile and outline iterators.
Parameters
----------
tiles_coords : Iterable[CoordinatePair]
Coordinates referring to the tiles' upper left and lower right corners.
outlines : Union[str, Iterable[str], Iterable[Tuple[int]]]
See docstring for ``locate_tiles`` for details.
Yields
-------
CoordinatePair
Coordinates referring to the tiles' upper left and lower right corners.
Union[str, Tuple[int]]
Fixed outline depending on user input to used by method ``locate_tiles``.
"""
if isinstance(outlines, str):
for coords in tiles_coords:
yield coords, outlines
elif hasattr(outlines, "__iter__"):
for coords, one_outline in zip_longest(tiles_coords, outlines):
if None in (coords, one_outline):
raise ValueError(
"There should be as many outlines as there are tiles!"
)
yield coords, one_outline
else:
raise ValueError(
"The parameter ``outline`` should be of type: "
"str, Iterable[str], or Iterable[List[int]]"
)
def _tile_filename(
self, tile_wsi_coords: CoordinatePair, tiles_counter: int
) -> str:
"""Return the tile filename according to its 0-level coordinates and a counter.
Parameters
----------
tile_wsi_coords : CoordinatePair
0-level coordinates of the slide the tile has been extracted from.
tiles_counter : int
Counter of extracted tiles.
Returns
-------
str
Tile filename, according to the format
`{prefix}tile_{tiles_counter}_level{level}_{x_ul_wsi}-{y_ul_wsi}-{x_br_wsi}"
"-{y_br_wsi}{suffix}`
"""
x_ul_wsi, y_ul_wsi, x_br_wsi, y_br_wsi = tile_wsi_coords
tile_filename = (
f"{self.prefix}tile_{tiles_counter}_level{self.level}_{x_ul_wsi}-{y_ul_wsi}"
f"-{x_br_wsi}-{y_br_wsi}{self.suffix}"
)
return tile_filename
def _tiles_generator(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> Tuple[Tile, CoordinatePair]:
pass # pragma: no cover
def _tile_size(self, slide: Slide) -> Tuple[int, int]:
"""Get the proper tile size for level or mpp requested.
Parameters
----------
slide : Slide
The slide to tile.
Returns
-------
Tuple[int, int]
Proper tile size at desired level or MPP resolution.
"""
if self.mpp is None:
return self.tile_size
return tuple(int(j * self._scale_factor(slide)) for j in self.tile_size)
def _validate_level(self, slide: Slide) -> None:
"""Validate the Tiler's level according to the Slide.
Parameters
----------
slide : Slide
Slide from which to extract the tiles
Raises
------
LevelError
If the level is not available for the slide
"""
if len(slide.levels) - abs(self.level) < 0:
raise LevelError(
f"Level {self.level} not available. Number of available levels: "
f"{len(slide.levels)}"
)
def _validate_tile_size(self, slide: Slide) -> None:
"""Validate the tile size according to the Slide.
Parameters
----------
slide : Slide
Slide from which to extract the tiles
Raises
------
TileSizeError
If the tile size is larger than the slide size
"""
if not self._has_valid_tile_size(slide):
raise TileSizeOrCoordinatesError(
f"Tile size {self.tile_size} is larger than slide size "
f"{slide.level_dimensions(self.level)} at level {self.level}"
)
[docs]class GridTiler(Tiler):
"""Extractor of tiles arranged in a grid, at the given level, with the given size.
Arguments
---------
tile_size : Tuple[int, int]
(width, height) of the extracted tiles.
level : int, optional
Level from which extract the tiles. Default is 0.
Superceded by mpp if the mpp argument is provided.
check_tissue : bool, optional
Whether to check if the tile has enough tissue to be saved. Default is True.
tissue_percent : float, optional
Number between 0.0 and 100.0 representing the minimum required percentage of
tissue over the total area of the image, default is 80.0. This is considered
only if ``check_tissue`` equals to True.
pixel_overlap : int, optional
Number of overlapping pixels (for both height and width) between two adjacent
tiles. If negative, two adjacent tiles will be strided by the absolute value of
``pixel_overlap``. Default is 0.
prefix : str, optional
Prefix to be added to the tile filename. Default is an empty string.
suffix : str, optional
Suffix to be added to the tile filename. Default is '.png'
mpp : float, optional
Micron per pixel resolution of extracted tiles. Takes precedence over level.
Default is None.
"""
def __init__(
self,
tile_size: Tuple[int, int],
level: int = 0,
check_tissue: bool = True,
tissue_percent: float = 80.0,
pixel_overlap: int = 0,
prefix: str = "",
suffix: str = ".png",
mpp: float = None,
):
self.tile_size = tile_size
self.final_tile_size = tile_size
self.level = level if mpp is None else 0
self.mpp = mpp
self.check_tissue = check_tissue
self.tissue_percent = tissue_percent
self.pixel_overlap = pixel_overlap
self.prefix = prefix
self.suffix = suffix
@property
def tile_size(self) -> Tuple[int, int]:
"""(width, height) of the extracted tiles."""
return self._valid_tile_size
@tile_size.setter
def tile_size(self, tile_size_: Tuple[int, int]):
if tile_size_[0] < 1 or tile_size_[1] < 1:
raise ValueError(f"Tile size must be greater than 0 ({tile_size_})")
self._valid_tile_size = tile_size_
# ------- implementation helpers -------
@staticmethod
def _are_coordinates_within_extraction_mask(
tile_thumb_coords: CoordinatePair,
binary_mask_region: np.ndarray,
) -> bool:
"""Chack whether the ``tile_thumb_coords`` are inside of ``binary_mask_region``.
Return True if 80% of the tile area defined by tile_thumb_coords is inside the
area of the ``binary_mask_region.
Parameters
----------
tile_thumb_coords : CoordinatePair
Coordinates of the tile at thumbnail dimension.
binary_mask_region : np.ndarray
Binary mask with True inside of the tissue region considered.
Returns
-------
bool
Whether the 80% of the tile area defined by tile_thumb_coords is inside the
area of the ``binary_mask_region.
"""
tile_thumb_mask = rectangle_to_mask(
dims=binary_mask_region.shape, vertices=tile_thumb_coords
)
tile_in_binary_mask = binary_mask_region & tile_thumb_mask
tile_area = np.count_nonzero(tile_thumb_mask)
tile_in_binary_mask_area = np.count_nonzero(tile_in_binary_mask)
return tile_area > 0 and (
tile_in_binary_mask_area / tile_area
> COORDS_WITHIN_EXTRACTION_MASK_THRESHOLD
)
def _grid_coordinates_from_bbox_coordinates(
self,
bbox_coordinates_lvl: CoordinatePair,
slide: Slide,
binary_mask_region: np.ndarray,
) -> CoordinatePair:
"""Generate Coordinates at level 0 of grid tiles within a tissue box.
Parameters
----------
bbox_coordinates_lvl : CoordinatePair
Coordinates of the tissue box from which to calculate the coordinates of the
tiles.
slide : Slide
Slide from which to calculate the coordinates.
binary_mask_region : np.ndarray
Binary mask corresponding to the connected component (region) considered.
Notes
-----
This method needs to be called for every connected component (region) within the
extraction mask.
Yields
-------
Iterator[CoordinatePair]
Iterator of tiles' CoordinatePair
"""
tile_w_lvl, tile_h_lvl = self.tile_size
n_tiles_row = self._n_tiles_row(bbox_coordinates_lvl)
n_tiles_column = self._n_tiles_column(bbox_coordinates_lvl)
for i in range(n_tiles_row):
for j in range(n_tiles_column):
x_ul_lvl = (
bbox_coordinates_lvl.x_ul + tile_w_lvl * i - self.pixel_overlap * i
)
y_ul_lvl = (
bbox_coordinates_lvl.y_ul + tile_h_lvl * j - self.pixel_overlap * j
)
x_ul_lvl = np.clip(x_ul_lvl, bbox_coordinates_lvl.x_ul, None)
y_ul_lvl = np.clip(y_ul_lvl, bbox_coordinates_lvl.y_ul, None)
x_br_lvl = x_ul_lvl + tile_w_lvl
y_br_lvl = y_ul_lvl + tile_h_lvl
tile_lvl_coords = CoordinatePair(x_ul_lvl, y_ul_lvl, x_br_lvl, y_br_lvl)
tile_thumb_coords = scale_coordinates(
reference_coords=tile_lvl_coords,
reference_size=slide.level_dimensions(level=self.level),
target_size=binary_mask_region.shape[::-1],
)
if self._are_coordinates_within_extraction_mask(
tile_thumb_coords, binary_mask_region
):
tile_wsi_coords = scale_coordinates(
reference_coords=tile_lvl_coords,
reference_size=slide.level_dimensions(level=self.level),
target_size=slide.level_dimensions(level=0),
)
yield tile_wsi_coords
def _grid_coordinates_generator(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> CoordinatePair:
"""Generate Coordinates at level 0 of grid tiles within the tissue.
Parameters
----------
slide : Slide
Slide from which to calculate the coordinates. Needed to calculate the
tissue area.
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
Yields
-------
Iterator[CoordinatePair]
Iterator of tiles' CoordinatePair
"""
binary_mask = extraction_mask(slide)
regions = regions_from_binary_mask(binary_mask)
for region in regions:
bbox_coordinates_thumb = region_coordinates(region) # coords of the bbox
bbox_coordinates_lvl = scale_coordinates(
bbox_coordinates_thumb,
binary_mask.shape[::-1],
slide.level_dimensions(self.level),
)
binary_mask_region = regions_to_binary_mask([region], binary_mask.shape)
yield from self._grid_coordinates_from_bbox_coordinates(
bbox_coordinates_lvl, slide, binary_mask_region
)
def _n_tiles_column(self, bbox_coordinates: CoordinatePair) -> int:
"""Return the number of tiles which can be extracted in a column.
Parameters
----------
bbox_coordinates : CoordinatePair
Coordinates of the tissue box
Returns
-------
int
Number of tiles which can be extracted in a column.
"""
return (bbox_coordinates.y_br - bbox_coordinates.y_ul) // (
self.tile_size[1] - self.pixel_overlap
)
def _n_tiles_row(self, bbox_coordinates: CoordinatePair) -> int:
"""Return the number of tiles which can be extracted in a row.
Parameters
----------
bbox_coordinates : CoordinatePair
Coordinates of the tissue box
Returns
-------
int
Number of tiles which can be extracted in a row.
"""
return (bbox_coordinates.x_br - bbox_coordinates.x_ul) // (
self.tile_size[0] - self.pixel_overlap
)
def _tiles_generator(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> Tuple[Tile, CoordinatePair]:
"""Generator of tiles arranged in a grid.
Parameters
----------
slide : Slide
Slide from which to extract the tiles
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
Yields
-------
Tile
Extracted tile
CoordinatePair
Coordinates of the slide at level 0 from which the tile has been extracted
"""
grid_coordinates_generator = self._grid_coordinates_generator(
slide, extraction_mask
)
for coords in grid_coordinates_generator:
try:
tile = slide.extract_tile(
coords,
tile_size=self.final_tile_size,
mpp=self.mpp,
level=self.level if self.mpp is None else None,
)
except TileSizeOrCoordinatesError:
continue
if not self.check_tissue or tile.has_enough_tissue(self.tissue_percent):
yield tile, coords
[docs]class RandomTiler(Tiler):
"""Extractor of random tiles from a Slide, at the given level, with the given size.
Arguments
---------
tile_size : Tuple[int, int]
(width, height) of the extracted tiles.
n_tiles : int
Maximum number of tiles to extract.
level : int, optional
Level from which extract the tiles. Default is 0.
Superceded by mpp if the mpp argument is provided.
seed : int, optional
Seed for RandomState. Must be convertible to 32 bit unsigned integers. Default
is 7.
check_tissue : bool, optional
Whether to check if the tile has enough tissue to be saved. Default is True.
tissue_percent : float, optional
Number between 0.0 and 100.0 representing the minimum required percentage of
tissue over the total area of the image, default is 80.0. This is considered
only if ``check_tissue`` equals to True.
prefix : str, optional
Prefix to be added to the tile filename. Default is an empty string.
suffix : str, optional
Suffix to be added to the tile filename. Default is '.png'
max_iter : int, optional
Maximum number of iterations performed when searching for eligible (if
``check_tissue=True``) tiles. Must be grater than or equal to ``n_tiles``.
mpp : float, optional
Micron per pixel resolution. If provided, takes precedence over level.
Default is None.
"""
def __init__(
self,
tile_size: Tuple[int, int],
n_tiles: int,
level: int = 0,
seed: int = 7,
check_tissue: bool = True,
tissue_percent: float = 80.0,
prefix: str = "",
suffix: str = ".png",
max_iter: int = int(1e4),
mpp: float = None,
):
self.tile_size = tile_size
self.final_tile_size = tile_size
self.n_tiles = n_tiles
self.max_iter = max_iter
self.level = level if mpp is None else 0
self.mpp = mpp
self.seed = seed
self.check_tissue = check_tissue
self.tissue_percent = tissue_percent
self.prefix = prefix
self.suffix = suffix
[docs] def extract(
self,
slide: Slide,
extraction_mask: BinaryMask = BiggestTissueBoxMask(),
log_level: str = "INFO",
) -> None:
"""Extract random tiles and save them to disk, following this filename pattern:
`{prefix}tile_{tiles_counter}_level{level}_{x_ul_wsi}-{y_ul_wsi}-{x_br_wsi}-{y_br_wsi}{suffix}`
Parameters
----------
slide : Slide
Slide from which to extract the tiles
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
log_level: str, {"DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"}
Threshold level for the log messages. Default "INFO"
Raises
------
TileSizeError
If the tile size is larger than the slide size
LevelError
If the level is not available for the slide
"""
level = logging.getLevelName(log_level)
logger.setLevel(level)
self._validate_level(slide)
self.tile_size = self._tile_size(slide)
self._validate_tile_size(slide)
random_tiles = self._tiles_generator(slide, extraction_mask)
tiles_counter = 0
for tiles_counter, (tile, tile_wsi_coords) in enumerate(random_tiles):
tile_filename = self._tile_filename(tile_wsi_coords, tiles_counter)
full_tile_path = os.path.join(slide.processed_path, tile_filename)
tile.save(full_tile_path)
logger.info(f"\t Tile {tiles_counter} saved: {tile_filename}")
logger.info(f"{tiles_counter+1} Random Tiles have been saved.")
@property
def max_iter(self) -> int:
return self._valid_max_iter
@max_iter.setter
def max_iter(self, max_iter_: int = int(1e4)):
if max_iter_ < self.n_tiles:
raise ValueError(
f"The maximum number of iterations ({max_iter_}) must be grater than or"
f" equal to the maximum number of tiles ({self.n_tiles})."
)
self._valid_max_iter = max_iter_
@property
def tile_size(self) -> Tuple[int, int]:
return self._valid_tile_size
@tile_size.setter
def tile_size(self, tile_size_: Tuple[int, int]):
if tile_size_[0] < 1 or tile_size_[1] < 1:
raise ValueError(f"Tile size must be greater than 0 ({tile_size_})")
self._valid_tile_size = tile_size_
# ------- implementation helpers -------
def _random_tile_coordinates(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> CoordinatePair:
"""Return 0-level Coordinates of a tile picked at random within the box.
Parameters
----------
slide : Slide
Slide from which calculate the coordinates. Needed to calculate the box.
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
Returns
-------
CoordinatePair
Random tile Coordinates at level 0
"""
binary_mask = extraction_mask(slide)
tile_w_lvl, tile_h_lvl = self.tile_size
x_ul_lvl, y_ul_lvl = random_choice_true_mask2d(binary_mask)
# Scale tile dimensions to extraction mask dimensions
tile_w_thumb = (
tile_w_lvl * binary_mask.shape[1] / slide.level_dimensions(self.level)[0]
)
tile_h_thumb = (
tile_h_lvl * binary_mask.shape[0] / slide.level_dimensions(self.level)[1]
)
x_br_lvl = x_ul_lvl + tile_w_thumb
y_br_lvl = y_ul_lvl + tile_h_thumb
tile_wsi_coords = scale_coordinates(
reference_coords=CoordinatePair(x_ul_lvl, y_ul_lvl, x_br_lvl, y_br_lvl),
reference_size=binary_mask.shape[::-1],
target_size=slide.dimensions,
)
return tile_wsi_coords
def _tiles_generator(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> Tuple[Tile, CoordinatePair]:
"""Generate Random Tiles within a slide box.
Stops if:
* the number of extracted tiles is equal to ``n_tiles`` OR
* the maximum number of iterations ``max_iter`` is reached
Parameters
----------
slide : Slide
The Whole Slide Image from which to extract the tiles.
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
Yields
------
tile : Tile
The extracted Tile
coords : CoordinatePair
The level-0 coordinates of the extracted tile
"""
np.random.seed(self.seed)
iteration = valid_tile_counter = 0
while True:
tile_wsi_coords = self._random_tile_coordinates(slide, extraction_mask)
try:
tile = slide.extract_tile(
tile_wsi_coords,
tile_size=self.final_tile_size,
mpp=self.mpp,
level=self.level if self.mpp is None else None,
)
except TileSizeOrCoordinatesError:
iteration -= 1
continue
if not self.check_tissue or tile.has_enough_tissue(self.tissue_percent):
yield tile, tile_wsi_coords
valid_tile_counter += 1
iteration += 1
if self.max_iter and iteration >= self.max_iter:
break
if valid_tile_counter >= self.n_tiles:
break
[docs]class ScoreTiler(GridTiler):
"""Extractor of tiles arranged in a grid according to a scoring function.
The extraction procedure is the same as the ``GridTiler`` extractor, but only the
first ``n_tiles`` tiles with the highest score are saved.
Arguments
---------
scorer : Scorer
Scoring function used to score the tiles.
tile_size : Tuple[int, int]
(width, height) of the extracted tiles.
n_tiles : int, optional
The number of tiles to be saved. Default is 0, which means that all the tiles
will be saved (same exact behaviour of a GridTiler). Cannot be negative.
level : int, optional
Level from which extract the tiles. Default is 0.
Superceded by mpp if the mpp argument is provided.
check_tissue : bool, optional
Whether to check if the tile has enough tissue to be saved. Default is True.
tissue_percent : float, optional
Number between 0.0 and 100.0 representing the minimum required percentage of
tissue over the total area of the image, default is 80.0. This is considered
only if ``check_tissue`` equals to True.
pixel_overlap : int, optional
Number of overlapping pixels (for both height and width) between two adjacent
tiles. If negative, two adjacent tiles will be strided by the absolute value of
``pixel_overlap``. Default is 0.
prefix : str, optional
Prefix to be added to the tile filename. Default is an empty string.
suffix : str, optional
Suffix to be added to the tile filename. Default is '.png'
mpp : float, optional.
Micron per pixel resolution. If provided, takes precedence over level.
Default is None.
"""
def __init__(
self,
scorer: Scorer,
tile_size: Tuple[int, int],
n_tiles: int = 0,
level: int = 0,
check_tissue: bool = True,
tissue_percent: float = 80.0,
pixel_overlap: int = 0,
prefix: str = "",
suffix: str = ".png",
mpp: float = None,
):
self.scorer = scorer
self.n_tiles = n_tiles
super().__init__(
tile_size,
level,
check_tissue,
tissue_percent,
pixel_overlap,
prefix,
suffix,
mpp=mpp,
)
# ------- implementation helpers -------
def _tiles_generator(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> Tuple[List[Tuple[float, CoordinatePair]], List[Tuple[float, CoordinatePair]]]:
r"""Calculate the tiles with the highest scores and their extraction coordinates
Parameters
----------
slide : Slide
The slide to extract the tiles from.
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
Returns
-------
Tuple[List[Tuple[float, CoordinatePair]], List[Tuple[float, CoordinatePair]]]
List of tuples containing the scores and the extraction coordinates
for the tiles with the highest scores. If scaled=True, each score `s_i` of
the i-th tile is normalized as
.. math::
s_{\hat{i}}=\frac{s_i-\min_{j\in T}{s_j}}{\max_{j\in T}{s_j}-\min_{j\in T}{s_j}}
where `T` is the set of all the retrieved tiles. Notice that the normalized
scores range between 0 and 1. This could be useful to have a more intuitive
comparison between the scores. Each tuple represents a tile.
Raises
------
ValueError
If ``n_tiles`` is negative.
""" # noqa
all_scores = self._scores(slide, extraction_mask)
scaled_scores = self._scale_scores(all_scores)
sorted_tiles_by_score = sorted(all_scores, key=lambda x: x[0], reverse=True)
sorted_tiles_by_scaled_score = sorted(
scaled_scores, key=lambda x: x[0], reverse=True
)
if self.n_tiles < 0:
raise ValueError(f"'n_tiles' cannot be negative ({self.n_tiles})")
if self.n_tiles > 0:
highest_score_tiles = sorted_tiles_by_score[: self.n_tiles]
highest_scaled_score_tiles = sorted_tiles_by_scaled_score[: self.n_tiles]
else:
highest_score_tiles = sorted_tiles_by_score
highest_scaled_score_tiles = sorted_tiles_by_scaled_score
return highest_score_tiles, highest_scaled_score_tiles
@staticmethod
def _save_report(
report_path: str,
highest_score_tiles: List[Tuple[float, CoordinatePair]],
highest_scaled_score_tiles: List[Tuple[float, CoordinatePair]],
filenames: List[str],
) -> None:
"""Save to ``filename`` the report of the saved tiles with the associated score.
The CSV file
Parameters
----------
report_path : str
Path to the report
highest_score_tiles : List[Tuple[float, CoordinatePair]]
List of tuples containing the score and the extraction coordinates for the
tiles with the highest score. Each tuple represents a tile.
highest_scaled_score_tiles : List[Tuple[float, CoordinatePair]]
List of tuples containing the scaled score between 0 and 1 and the
extraction coordinates for the tiles with the highest score. Each tuple
represents a tile.
filenames : List[str]
List of the tiles' filename
"""
header = ["filename", "score", "scaled_score"]
rows = [
dict(zip(header, values))
for values in zip(
filenames,
np.array(highest_score_tiles, dtype=object)[:, 0],
np.array(highest_scaled_score_tiles, dtype=object)[:, 0],
)
]
with open(report_path, "w+", newline="") as filename:
writer = csv.DictWriter(
filename, fieldnames=header, lineterminator=os.linesep
)
writer.writeheader()
writer.writerows(rows)
@staticmethod
def _scale_scores(
scores: List[Tuple[float, CoordinatePair]]
) -> List[Tuple[float, CoordinatePair]]:
"""Scale scores between 0 and 1.
Parameters
----------
scores : List[Tuple[float, CoordinatePair]]
Scores to be scaled
Returns
-------
List[Tuple[float, CoordinatePair]])
Scaled scores
"""
scores_ = np.array(scores, dtype=object)[:, 0]
coords = np.array(scores, dtype=object)[:, 1]
scores_scaled = (scores_ - np.min(scores_)) / (
np.max(scores_) - np.min(scores_)
)
return list(zip(scores_scaled, coords))
def _scores(
self, slide: Slide, extraction_mask: BinaryMask = BiggestTissueBoxMask()
) -> List[Tuple[float, CoordinatePair]]:
"""Calculate the scores for all the tiles extracted from the ``slide``.
Parameters
----------
slide : Slide
The slide to extract the tiles from.
extraction_mask : BinaryMask, optional
BinaryMask object defining how to compute a binary mask from a Slide.
Default `BiggestTissueBoxMask`.
Returns
-------
List[Tuple[float, CoordinatePair]]
List of tuples containing the score and the extraction coordinates for each
tile. Each tuple represents a tile.
"""
if next(super()._tiles_generator(slide, extraction_mask), None) is None:
raise RuntimeError(
"No tiles have been generated. This could happen if `check_tissue=True`"
)
grid_tiles = super()._tiles_generator(slide, extraction_mask)
scores = []
for tile, tile_wsi_coords in grid_tiles:
score = self.scorer(tile)
scores.append((score, tile_wsi_coords))
return scores