Add multi-class non-maximum suppression operator.

python/paddle/v2/fluid/tests/test_bipartite_match_op.py

@@ -62,7 +62,7 @@ def batch_bipartite_match(distance, lod):
     return match_indices, match_dist
 
 
-class TestBipartiteMatchOpForWithLoD(OpTest):
+class TestBipartiteMatchOpWithLoD(OpTest):
     def setUp(self):
         self.op_type = 'bipartite_match'
         lod = [[0, 5, 11, 23]]

python/paddle/v2/fluid/tests/test_multiclass_nms_op.py

@@ -0,0 +1,199 @@
+#  Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
+#
+#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
+#limitations under the License.
+import unittest
+import numpy as np
+import copy
+from op_test import OpTest
+
+
+def iou(box_a, box_b):
+    """Apply intersection-over-union overlap between box_a and box_b
+    """
+    xmin_a = min(box_a[0], box_a[2])
+    ymin_a = min(box_a[1], box_a[3])
+    xmax_a = max(box_a[0], box_a[2])
+    ymax_a = max(box_a[1], box_a[3])
+
+    xmin_b = min(box_b[0], box_b[2])
+    ymin_b = min(box_b[1], box_b[3])
+    xmax_b = max(box_b[0], box_b[2])
+    ymax_b = max(box_b[1], box_b[3])
+
+    area_a = (ymax_a - ymin_a) * (xmax_a - xmin_a)
+    area_b = (ymax_b - ymin_b) * (xmax_b - xmin_b)
+    if area_a <= 0 and area_b <= 0:
+        return 0.0
+
+    xa = max(xmin_a, xmin_b)
+    ya = max(ymin_a, ymin_b)
+    xb = min(xmax_a, xmax_b)
+    yb = min(ymax_a, ymax_b)
+
+    inter_area = max(xb - xa, 0.0) * max(yb - ya, 0.0)
+
+    box_a_area = (box_a[2] - box_a[0]) * (box_a[3] - box_a[1])
+    box_b_area = (box_b[2] - box_b[0]) * (box_b[3] - box_b[1])
+
+    iou_ratio = inter_area / (area_a + area_b - inter_area)
+
+    return iou_ratio
+
+
+def nms(boxes, scores, score_threshold, nms_threshold, top_k=200, eta=1.0):
+    """Apply non-maximum suppression at test time to avoid detecting too many
+    overlapping bounding boxes for a given object.
+    Args:
+        boxes: (tensor) The location preds for the img, Shape: [num_priors,4].
+        scores: (tensor) The class predscores for the img, Shape:[num_priors].
+        overlap: (float) The overlap thresh for suppressing unnecessary boxes.
+        top_k: (int) The Maximum number of box preds to consider.
+    Return:
+        The indices of the kept boxes with respect to num_priors.
+    """
+    all_scores = copy.deepcopy(scores)
+    all_scores = all_scores.flatten()
+    selected_indices = np.argwhere(all_scores > score_threshold)
+    selected_indices = selected_indices.flatten()
+    all_scores = all_scores[selected_indices]
+
+    sorted_indices = np.argsort(-all_scores, axis=0)
+    sorted_scores = all_scores[sorted_indices]
+    if top_k < -1 and top_k < sorted_indices.shape[0]:
+        sorted_indices = sorted_indices[:top_k]
+        sorted_scores = sorted_scores[:top_k]
+
+    selected_indices = []
+    adaptive_threshold = nms_threshold
+    for i in range(sorted_scores.shape[0]):
+        idx = sorted_indices[i]
+        keep = True
+        for k in range(len(selected_indices)):
+            if keep:
+                kept_idx = selected_indices[k]
+                overlap = iou(boxes[idx], boxes[kept_idx])
+                keep = overlap <= adaptive_threshold
+            else:
+                break
+        if keep:
+            selected_indices.append(idx)
+        if keep and eta < 1 and adaptive_threshold > 0.5:
+            adaptive_threshold *= eta
+    return selected_indices
+
+
+def multiclass_nms(boxes, scores, background, score_threshold, nms_threshold,
+                   nms_top_k, keep_top_k):
+    class_num = scores.shape[0]
+    priorbox_num = scores.shape[1]
+
+    selected_indices = []
+    num_det = 0
+    for c in range(class_num):
+        if c == background: continue
+        indices = nms(boxes, scores[c], score_threshold, nms_threshold,
+                      nms_top_k)
+        selected_indices.append((c, indices))
+        num_det += len(indices)
+
+    if keep_top_k > -1 and num_det > keep_top_k:
+        score_index = []
+        for c, indices in selected_indices:
+            for idx in indices:
+                score_index.append((scores[c][idx], c, idx))
+
+        sorted_score_index = sorted(
+            score_index, key=lambda tup: tup[0], reverse=True)
+        sorted_score_index = sorted_score_index[:keep_top_k]
+        selected_indices = []
+        for s, c, idx in sorted_score_index:
+            selected_indices.append((c, idx))
+
+    return selected_indices
+
+
+def batched_multiclass_nms(boxes, scores, background, score_threshold,
+                           nms_threshold, nms_top_k, keep_top_k):
+    batch_size = scores.shape[0]
+
+    det_outs = []
+    lod = [0]
+    for n in range(batch_size):
+        nmsed_outs = multiclass_nms(boxes, scores[n], background,
+                                    score_threshold, nms_threshold, nms_top_k,
+                                    keep_top_k)
+        lod.append(lod[-1] + len(nmsed_outs))
+        if len(nmsed_outs) == 0: continue
+        for c, indices in nmsed_outs:
+            for idx in indices:
+                xmin, ymin, xmax, ymax = boxes[idx][:]
+                det_outs.append(
+                    (c, scores[n][c][idx], c, xmin, ymin, xmax, ymax))
+    return det_outs, lod
+
+
+class TestMulticlassNMSOp(OpTest):
+    def setUp(self):
+        self.op_type = 'multiclass_nms'
+        N = 7
+        M = 1230
+        C = 21
+        BOX_SIZE = 4
+        background = 0
+        nms_threshold = 0.3
+        nms_top_k = 400
+        keep_top_k = 200
+        score_threshold = 0.01
+
+        scores = np.random.random((N, C, M)).astype('float32')
+        boxes = np.random.random((M, BOX_SIZE)).astype('float32')
+        boxes[:, 0:2] = boxes[:, 0:2] * 0.5
+        boxes[:, 2:4] = boxes[:, 0:2] * 0.5 + 0.5
+
+        nmsed_outs, lod = batched_multiclass_nms(boxes, scores, background,
+                                                 score_threshold, nms_threshold,
+                                                 nms_top_k, keep_top_k)
+        self.inputs = {'Bboxes': boxes, 'Scores': scores}
+        self.outputs = {'Out': (nmsed_outs, [lod])}
+
+    def test_check_output(self):
+        self.check_output()
+
+
+class TestIOU(unittest.TestCase):
+    def test_iou(self):
+        box1 = np.array([4.0, 3.0, 7.0, 5.0]).astype('float32')
+        box2 = np.array([3.0, 4.0, 6.0, 8.0]).astype('float32')
+
+        expt_output = np.array([2.0 / 16.0]).astype('float32')
+        calc_output = np.array([iou(box1, box2)]).astype('float32')
+        self.assertTrue(np.allclose(calc_output, expt_output))
+
+
+if __name__ == '__main__':
+    unittest.main()
+    # N = 7
+    # M = 8
+    # C = 5
+    # BOX_SIZE = 4
+    # background = 0
+    # nms_threshold = 0.3
+    # nms_top_k = 400
+    # keep_top_k = 200
+    # score_threshold = 0.5
+
+    # scores = np.random.random((N, C, M)).astype('float32')
+    # boxes = np.random.random((M, BOX_SIZE)).astype('float32')
+    # boxes[:, 0 : 2] = boxes[:, 0 : 2] * 0.5
+    # boxes[:, 2 : 4] = boxes[:, 0 : 2] * 0.5 + 0.5
+    # print nmsed_outs, lod