--- /dev/null
+# --------------------------------------------------------
+# Faster R-CNN
+# Copyright (c) 2015 Microsoft
+# Licensed under The MIT License [see LICENSE for details]
+# Written by Ross Girshick and Xinlei Chen
+# --------------------------------------------------------
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import os
+from libs.configs import cfgs
+import numpy as np
+import numpy.random as npr
+from libs.box_utils.cython_utils.cython_bbox import bbox_overlaps
+from libs.box_utils import encode_and_decode
+
+
+def anchor_target_layer(
+ gt_boxes, img_shape, all_anchors, is_restrict_bg=False):
+ """Same as the anchor target layer in original Fast/er RCNN """
+
+ total_anchors = all_anchors.shape[0]
+ img_h, img_w = img_shape[1], img_shape[2]
+ gt_boxes = gt_boxes[:, :-1] # remove class label
+
+
+ # allow boxes to sit over the edge by a small amount
+ _allowed_border = 0
+
+ # only keep anchors inside the image
+ if cfgs.IS_FILTER_OUTSIDE_BOXES:
+ inds_inside = np.where(
+ (all_anchors[:, 0] >= -_allowed_border) &
+ (all_anchors[:, 1] >= -_allowed_border) &
+ (all_anchors[:, 2] < img_w + _allowed_border) & # width
+ (all_anchors[:, 3] < img_h + _allowed_border) # height
+ )[0]
+ else:
+ inds_inside = range(all_anchors.shape[0])
+
+ anchors = all_anchors[inds_inside, :]
+
+ # label: 1 is positive, 0 is negative, -1 is dont care
+ labels = np.empty((len(inds_inside),), dtype=np.float32)
+ labels.fill(-1)
+
+ # overlaps between the anchors and the gt boxes
+ overlaps = bbox_overlaps(
+ np.ascontiguousarray(anchors, dtype=np.float),
+ np.ascontiguousarray(gt_boxes, dtype=np.float))
+
+ argmax_overlaps = overlaps.argmax(axis=1)
+ max_overlaps = overlaps[np.arange(len(inds_inside)), argmax_overlaps]
+ gt_argmax_overlaps = overlaps.argmax(axis=0)
+ gt_max_overlaps = overlaps[
+ gt_argmax_overlaps, np.arange(overlaps.shape[1])]
+ gt_argmax_overlaps = np.where(overlaps == gt_max_overlaps)[0]
+
+ if not cfgs.TRAIN_RPN_CLOOBER_POSITIVES:
+ labels[max_overlaps < cfgs.RPN_IOU_NEGATIVE_THRESHOLD] = 0
+
+ labels[gt_argmax_overlaps] = 1
+ labels[max_overlaps >= cfgs.RPN_IOU_POSITIVE_THRESHOLD] = 1
+
+ if cfgs.TRAIN_RPN_CLOOBER_POSITIVES:
+ labels[max_overlaps < cfgs.RPN_IOU_NEGATIVE_THRESHOLD] = 0
+
+ num_fg = int(cfgs.RPN_MINIBATCH_SIZE * cfgs.RPN_POSITIVE_RATE)
+ fg_inds = np.where(labels == 1)[0]
+ if len(fg_inds) > num_fg:
+ disable_inds = npr.choice(
+ fg_inds, size=(len(fg_inds) - num_fg), replace=False)
+ labels[disable_inds] = -1
+
+ num_bg = cfgs.RPN_MINIBATCH_SIZE - np.sum(labels == 1)
+ if is_restrict_bg:
+ num_bg = max(num_bg, num_fg * 1.5)
+ bg_inds = np.where(labels == 0)[0]
+ if len(bg_inds) > num_bg:
+ disable_inds = npr.choice(
+ bg_inds, size=(len(bg_inds) - num_bg), replace=False)
+ labels[disable_inds] = -1
+
+ bbox_targets = _compute_targets(anchors, gt_boxes[argmax_overlaps, :])
+
+ # map up to original set of anchors
+ labels = _unmap(labels, total_anchors, inds_inside, fill=-1)
+ bbox_targets = _unmap(bbox_targets, total_anchors, inds_inside, fill=0)
+
+ # labels = labels.reshape((1, height, width, A))
+ rpn_labels = labels.reshape((-1, 1))
+
+ # bbox_targets
+ bbox_targets = bbox_targets.reshape((-1, 4))
+ rpn_bbox_targets = bbox_targets
+
+ return rpn_labels, rpn_bbox_targets
+
+
+def _unmap(data, count, inds, fill=0):
+ """ Unmap a subset of item (data) back to the original set of items (of
+ size count) """
+ if len(data.shape) == 1:
+ ret = np.empty((count,), dtype=np.float32)
+ ret.fill(fill)
+ ret[inds] = data
+ else:
+ ret = np.empty((count,) + data.shape[1:], dtype=np.float32)
+ ret.fill(fill)
+ ret[inds, :] = data
+ return ret
+
+
+def _compute_targets(ex_rois, gt_rois):
+ """Compute bounding-box regression targets for an image."""
+ # targets = bbox_transform(ex_rois, gt_rois[:, :4]).astype(
+ # np.float32, copy=False)
+ targets = encode_and_decode.encode_boxes(unencode_boxes=gt_rois,
+ reference_boxes=ex_rois,
+ scale_factors=cfgs.ANCHOR_SCALE_FACTORS)
+ # targets = encode_and_decode.encode_boxes(ex_rois=ex_rois,
+ # gt_rois=gt_rois,
+ # scale_factor=None)
+ return targets