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# Copyright (c) OpenMMLab. All rights reserved.
import numpy as np
import torch
from mmcv.ops import RoIAlignRotated
from .utils import (euclidean_distance_matrix, feature_embedding,
normalize_adjacent_matrix)
class LocalGraphs:
"""Generate local graphs for GCN to classify the neighbors of a pivot for
DRRG: Deep Relational Reasoning Graph Network for Arbitrary Shape Text
Detection.
[https://arxiv.org/abs/2003.07493]. This code was partially adapted from
https://github.com/GXYM/DRRG licensed under the MIT license.
Args:
k_at_hops (tuple(int)): The number of i-hop neighbors, i = 1, 2.
num_adjacent_linkages (int): The number of linkages when constructing
adjacent matrix.
node_geo_feat_len (int): The length of embedded geometric feature
vector of a text component.
pooling_scale (float): The spatial scale of rotated RoI-Align.
pooling_output_size (tuple(int)): The output size of rotated RoI-Align.
local_graph_thr(float): The threshold for filtering out identical local
graphs.
"""
def __init__(self, k_at_hops, num_adjacent_linkages, node_geo_feat_len,
pooling_scale, pooling_output_size, local_graph_thr):
assert len(k_at_hops) == 2
assert all(isinstance(n, int) for n in k_at_hops)
assert isinstance(num_adjacent_linkages, int)
assert isinstance(node_geo_feat_len, int)
assert isinstance(pooling_scale, float)
assert all(isinstance(n, int) for n in pooling_output_size)
assert isinstance(local_graph_thr, float)
self.k_at_hops = k_at_hops
self.num_adjacent_linkages = num_adjacent_linkages
self.node_geo_feat_dim = node_geo_feat_len
self.pooling = RoIAlignRotated(pooling_output_size, pooling_scale)
self.local_graph_thr = local_graph_thr
def generate_local_graphs(self, sorted_dist_inds, gt_comp_labels):
"""Generate local graphs for GCN to predict which instance a text
component belongs to.
Args:
sorted_dist_inds (ndarray): The complete graph node indices, which
is sorted according to the Euclidean distance.
gt_comp_labels(ndarray): The ground truth labels define the
instance to which the text components (nodes in graphs) belong.
Returns:
pivot_local_graphs(list[list[int]]): The list of local graph
neighbor indices of pivots.
pivot_knns(list[list[int]]): The list of k-nearest neighbor indices
of pivots.
"""
assert sorted_dist_inds.ndim == 2
assert (sorted_dist_inds.shape[0] == sorted_dist_inds.shape[1] ==
gt_comp_labels.shape[0])
knn_graph = sorted_dist_inds[:, 1:self.k_at_hops[0] + 1]
pivot_local_graphs = []
pivot_knns = []
for pivot_ind, knn in enumerate(knn_graph):
local_graph_neighbors = set(knn)
for neighbor_ind in knn:
local_graph_neighbors.update(
set(sorted_dist_inds[neighbor_ind,
1:self.k_at_hops[1] + 1]))
local_graph_neighbors.discard(pivot_ind)
pivot_local_graph = list(local_graph_neighbors)
pivot_local_graph.insert(0, pivot_ind)
pivot_knn = [pivot_ind] + list(knn)
if pivot_ind < 1:
pivot_local_graphs.append(pivot_local_graph)
pivot_knns.append(pivot_knn)
else:
add_flag = True
for graph_ind, added_knn in enumerate(pivot_knns):
added_pivot_ind = added_knn[0]
added_local_graph = pivot_local_graphs[graph_ind]
union = len(
set(pivot_local_graph[1:]).union(
set(added_local_graph[1:])))
intersect = len(
set(pivot_local_graph[1:]).intersection(
set(added_local_graph[1:])))
local_graph_iou = intersect / (union + 1e-8)
if (local_graph_iou > self.local_graph_thr
and pivot_ind in added_knn
and gt_comp_labels[added_pivot_ind]
== gt_comp_labels[pivot_ind]
and gt_comp_labels[pivot_ind] != 0):
add_flag = False
break
if add_flag:
pivot_local_graphs.append(pivot_local_graph)
pivot_knns.append(pivot_knn)
return pivot_local_graphs, pivot_knns
def generate_gcn_input(self, node_feat_batch, node_label_batch,
local_graph_batch, knn_batch,
sorted_dist_ind_batch):
"""Generate graph convolution network input data.
Args:
node_feat_batch (List[Tensor]): The batched graph node features.
node_label_batch (List[ndarray]): The batched text component
labels.
local_graph_batch (List[List[list[int]]]): The local graph node
indices of image batch.
knn_batch (List[List[list[int]]]): The knn graph node indices of
image batch.
sorted_dist_ind_batch (list[ndarray]): The node indices sorted
according to the Euclidean distance.
Returns:
local_graphs_node_feat (Tensor): The node features of graph.
adjacent_matrices (Tensor): The adjacent matrices of local graphs.
pivots_knn_inds (Tensor): The k-nearest neighbor indices in
local graph.
gt_linkage (Tensor): The surpervision signal of GCN for linkage
prediction.
"""
assert isinstance(node_feat_batch, list)
assert isinstance(node_label_batch, list)
assert isinstance(local_graph_batch, list)
assert isinstance(knn_batch, list)
assert isinstance(sorted_dist_ind_batch, list)
num_max_nodes = max([
len(pivot_local_graph) for pivot_local_graphs in local_graph_batch
for pivot_local_graph in pivot_local_graphs
])
local_graphs_node_feat = []
adjacent_matrices = []
pivots_knn_inds = []
pivots_gt_linkage = []
for batch_ind, sorted_dist_inds in enumerate(sorted_dist_ind_batch):
node_feats = node_feat_batch[batch_ind]
pivot_local_graphs = local_graph_batch[batch_ind]
pivot_knns = knn_batch[batch_ind]
node_labels = node_label_batch[batch_ind]
device = node_feats.device
for graph_ind, pivot_knn in enumerate(pivot_knns):
pivot_local_graph = pivot_local_graphs[graph_ind]
num_nodes = len(pivot_local_graph)
pivot_ind = pivot_local_graph[0]
node2ind_map = {j: i for i, j in enumerate(pivot_local_graph)}
knn_inds = torch.tensor(
[node2ind_map[i] for i in pivot_knn[1:]])
pivot_feats = node_feats[pivot_ind]
normalized_feats = node_feats[pivot_local_graph] - pivot_feats
adjacent_matrix = np.zeros((num_nodes, num_nodes),
dtype=np.float32)
for node in pivot_local_graph:
neighbors = sorted_dist_inds[node,
1:self.num_adjacent_linkages +
1]
for neighbor in neighbors:
if neighbor in pivot_local_graph:
adjacent_matrix[node2ind_map[node],
node2ind_map[neighbor]] = 1
adjacent_matrix[node2ind_map[neighbor],
node2ind_map[node]] = 1
adjacent_matrix = normalize_adjacent_matrix(adjacent_matrix)
pad_adjacent_matrix = torch.zeros(
(num_max_nodes, num_max_nodes),
dtype=torch.float,
device=device)
pad_adjacent_matrix[:num_nodes, :num_nodes] = torch.from_numpy(
adjacent_matrix)
pad_normalized_feats = torch.cat([
normalized_feats,
torch.zeros(
(num_max_nodes - num_nodes, normalized_feats.shape[1]),
dtype=torch.float,
device=device)
],
dim=0)
local_graph_labels = node_labels[pivot_local_graph]
knn_labels = local_graph_labels[knn_inds]
link_labels = ((node_labels[pivot_ind] == knn_labels) &
(node_labels[pivot_ind] > 0)).astype(np.int64)
link_labels = torch.from_numpy(link_labels)
local_graphs_node_feat.append(pad_normalized_feats)
adjacent_matrices.append(pad_adjacent_matrix)
pivots_knn_inds.append(knn_inds)
pivots_gt_linkage.append(link_labels)
local_graphs_node_feat = torch.stack(local_graphs_node_feat, 0)
adjacent_matrices = torch.stack(adjacent_matrices, 0)
pivots_knn_inds = torch.stack(pivots_knn_inds, 0)
pivots_gt_linkage = torch.stack(pivots_gt_linkage, 0)
return (local_graphs_node_feat, adjacent_matrices, pivots_knn_inds,
pivots_gt_linkage)
def __call__(self, feat_maps, comp_attribs):
"""Generate local graphs as GCN input.
Args:
feat_maps (Tensor): The feature maps to extract the content
features of text components.
comp_attribs (ndarray): The text component attributes.
Returns:
local_graphs_node_feat (Tensor): The node features of graph.
adjacent_matrices (Tensor): The adjacent matrices of local graphs.
pivots_knn_inds (Tensor): The k-nearest neighbor indices in local
graph.
gt_linkage (Tensor): The surpervision signal of GCN for linkage
prediction.
"""
assert isinstance(feat_maps, torch.Tensor)
assert comp_attribs.ndim == 3
assert comp_attribs.shape[2] == 8
sorted_dist_inds_batch = []
local_graph_batch = []
knn_batch = []
node_feat_batch = []
node_label_batch = []
device = feat_maps.device
for batch_ind in range(comp_attribs.shape[0]):
num_comps = int(comp_attribs[batch_ind, 0, 0])
comp_geo_attribs = comp_attribs[batch_ind, :num_comps, 1:7]
node_labels = comp_attribs[batch_ind, :num_comps,
7].astype(np.int32)
comp_centers = comp_geo_attribs[:, 0:2]
distance_matrix = euclidean_distance_matrix(
comp_centers, comp_centers)
batch_id = np.zeros(
(comp_geo_attribs.shape[0], 1), dtype=np.float32) * batch_ind
comp_geo_attribs[:, -2] = np.clip(comp_geo_attribs[:, -2], -1, 1)
angle = np.arccos(comp_geo_attribs[:, -2]) * np.sign(
comp_geo_attribs[:, -1])
angle = angle.reshape((-1, 1))
rotated_rois = np.hstack(
[batch_id, comp_geo_attribs[:, :-2], angle])
rois = torch.from_numpy(rotated_rois).to(device)
content_feats = self.pooling(feat_maps[batch_ind].unsqueeze(0),
rois)
content_feats = content_feats.view(content_feats.shape[0],
-1).to(feat_maps.device)
geo_feats = feature_embedding(comp_geo_attribs,
self.node_geo_feat_dim)
geo_feats = torch.from_numpy(geo_feats).to(device)
node_feats = torch.cat([content_feats, geo_feats], dim=-1)
sorted_dist_inds = np.argsort(distance_matrix, axis=1)
pivot_local_graphs, pivot_knns = self.generate_local_graphs(
sorted_dist_inds, node_labels)
node_feat_batch.append(node_feats)
node_label_batch.append(node_labels)
local_graph_batch.append(pivot_local_graphs)
knn_batch.append(pivot_knns)
sorted_dist_inds_batch.append(sorted_dist_inds)
(node_feats, adjacent_matrices, knn_inds, gt_linkage) = \
self.generate_gcn_input(node_feat_batch,
node_label_batch,
local_graph_batch,
knn_batch,
sorted_dist_inds_batch)
return node_feats, adjacent_matrices, knn_inds, gt_linkage