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merging algorithm explanation adjusted

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Matthias Bisping 2022-04-11 09:28:00 +02:00
parent 887b8339a2
commit 710783a2f8
1 changed files with 22 additions and 7 deletions
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29
image_prediction/stitching/merging.py
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@ -1,6 +1,6 @@
from copy import deepcopy from copy import deepcopy
from functools import reduce from functools import reduce
from typing import Iterable, Callable from typing import Iterable, Callable, List
from PIL import Image from PIL import Image
from funcy import juxt, first, rest, rcompose from funcy import juxt, first, rest, rcompose
@ -17,14 +17,29 @@ def no_new_merges(pairs1, pairs2):
return len(pairs1) == len(pairs2) return len(pairs1) == len(pairs2)
def merge_along_both_axes(pairs: Iterable[ImageMetadataPair]): def merge_along_both_axes(pairs: Iterable[ImageMetadataPair]) -> List[ImageMetadataPair]:
pairs = merge_along_axis(pairs, "x") pairs = merge_along_axis(pairs, "x")
pairs = list(merge_along_axis(pairs, "y")) pairs = list(merge_along_axis(pairs, "y"))
return pairs return pairs
def merge_along_axis(pairs: Iterable[ImageMetadataPair], axis): def merge_along_axis(pairs: Iterable[ImageMetadataPair], axis) -> Iterable[ImageMetadataPair]:
"""Partially merges image-metadata pairs of adjacent images along a given axis. Needs to be iterated with
alternating axes until no more merges happen to merge all adjacent images.
Explanation:
Merging algorithm works as follows:
A dot represents a pair, a bracket a group and a colon a merged pair.
1) Start with pairs: (........)
2) Align on lesser: ([....] [....])
3) Align on greater: ([[..] [..]] [[....]])
4) Flatten once: ([..] [..] [....])
5) Merge orthogonally: ([:] [..] [:..])
6) Flatten once: (:..:..)
"""
def group_pairs_within_groups_by_greater_coordinate(groups): def group_pairs_within_groups_by_greater_coordinate(groups):
return map(CoordGrouper(axis).group_pairs_by_greater_coordinate, groups) return map(CoordGrouper(axis).group_pairs_by_greater_coordinate, groups)
@ -35,11 +50,11 @@ def merge_along_axis(pairs: Iterable[ImageMetadataPair], axis):
return CoordGrouper(axis).group_pairs_by_lesser_coordinate(pairs) return CoordGrouper(axis).group_pairs_by_lesser_coordinate(pairs)
return rcompose( return rcompose(
group_pairs_by_lesser_coordinate, # pairs -> groups of pairs aligned on one edge group_pairs_by_lesser_coordinate,
group_pairs_within_groups_by_greater_coordinate, # -> groups of pairs fully aligned on orthogonal axis group_pairs_within_groups_by_greater_coordinate,
flatten_groups_once, # groups of groups of pairs -> groups of pairs flatten_groups_once,
merge_groups_along_orthogonal_axis, merge_groups_along_orthogonal_axis,
flatten_groups_once, # groups of pairs -> pairs flatten_groups_once,
)(pairs) )(pairs)