Add data anchor sampling for face detection. (#3450)

* add CropImageWithDataAnchorSampling
* Refine bbox sampling code
* Update comments
* fix import and variable problem

ppdet/data/transform/op_helper.py

@@ -18,6 +18,9 @@ from __future__ import division
 from __future__ import print_function
 
 import numpy as np
+import random
+import math
+import cv2
 
 
 def meet_emit_constraint(src_bbox, sample_bbox):
@@ -40,20 +43,35 @@ def clip_bbox(src_bbox):
 
 
 def bbox_area(src_bbox):
+    if src_bbox[2] < src_bbox[0] or src_bbox[3] < src_bbox[1]:
+        return 0.
+    else:
         width = src_bbox[2] - src_bbox[0]
         height = src_bbox[3] - src_bbox[1]
         return width * height
 
 
+def is_overlap(object_bbox, sample_bbox):
+    if object_bbox[0] >= sample_bbox[2] or \
+       object_bbox[2] <= sample_bbox[0] or \
+       object_bbox[1] >= sample_bbox[3] or \
+       object_bbox[3] <= sample_bbox[1]:
+        return False
+    else:
+        return True
+
+
 def filter_and_process(sample_bbox, bboxes, labels, scores=None):
     new_bboxes = []
     new_labels = []
     new_scores = []
-    for i in range(len(labels)):
+    for i in range(len(bboxes)):
         new_bbox = [0, 0, 0, 0]
         obj_bbox = [bboxes[i][0], bboxes[i][1], bboxes[i][2], bboxes[i][3]]
         if not meet_emit_constraint(obj_bbox, sample_bbox):
             continue
+        if not is_overlap(obj_bbox, sample_bbox):
+            continue
         sample_width = sample_bbox[2] - sample_bbox[0]
         sample_height = sample_bbox[3] - sample_bbox[1]
         new_bbox[0] = (obj_bbox[0] - sample_bbox[0]) / sample_width
@@ -72,6 +90,25 @@ def filter_and_process(sample_bbox, bboxes, labels, scores=None):
     return bboxes, labels, scores
 
 
+def bbox_area_sampling(bboxes, labels, scores, target_size, min_size):
+    new_bboxes = []
+    new_labels = []
+    new_scores = []
+    for i, bbox in enumerate(bboxes):
+        w = float((bbox[2] - bbox[0]) * target_size)
+        h = float((bbox[3] - bbox[1]) * target_size)
+        if w * h < float(min_size * min_size):
+            continue
+        else:
+            new_bboxes.append(bbox)
+            new_labels.append(labels[i])
+            new_scores.append(scores[i])
+    bboxes = np.array(new_bboxes)
+    labels = np.array(new_labels)
+    scores = np.array(new_scores)
+    return bboxes, labels, scores
+
+
 def generate_sample_bbox(sampler):
     scale = np.random.uniform(sampler[2], sampler[3])
     aspect_ratio = np.random.uniform(sampler[4], sampler[5])
@@ -89,6 +126,112 @@ def generate_sample_bbox(sampler):
     return sampled_bbox
 
 
+def generate_sample_bbox_square(sampler, image_width, image_height):
+    scale = np.random.uniform(sampler[2], sampler[3])
+    aspect_ratio = np.random.uniform(sampler[4], sampler[5])
+    aspect_ratio = max(aspect_ratio, (scale**2.0))
+    aspect_ratio = min(aspect_ratio, 1 / (scale**2.0))
+    bbox_width = scale * (aspect_ratio**0.5)
+    bbox_height = scale / (aspect_ratio**0.5)
+    if image_height < image_width:
+        bbox_width = bbox_height * image_height / image_width
+    else:
+        bbox_height = bbox_width * image_width / image_height
+    xmin_bound = 1 - bbox_width
+    ymin_bound = 1 - bbox_height
+    xmin = np.random.uniform(0, xmin_bound)
+    ymin = np.random.uniform(0, ymin_bound)
+    xmax = xmin + bbox_width
+    ymax = ymin + bbox_height
+    sampled_bbox = [xmin, ymin, xmax, ymax]
+    return sampled_bbox
+
+
+def data_anchor_sampling(bbox_labels, image_width, image_height, scale_array,
+                         resize_width):
+    num_gt = len(bbox_labels)
+    # np.random.randint range: [low, high)
+    rand_idx = np.random.randint(0, num_gt) if num_gt != 0 else 0
+
+    if num_gt != 0:
+        norm_xmin = bbox_labels[rand_idx][0]
+        norm_ymin = bbox_labels[rand_idx][1]
+        norm_xmax = bbox_labels[rand_idx][2]
+        norm_ymax = bbox_labels[rand_idx][3]
+
+        xmin = norm_xmin * image_width
+        ymin = norm_ymin * image_height
+        wid = image_width * (norm_xmax - norm_xmin)
+        hei = image_height * (norm_ymax - norm_ymin)
+        range_size = 0
+
+        area = wid * hei
+        for scale_ind in range(0, len(scale_array) - 1):
+            if area > scale_array[scale_ind] ** 2 and area < \
+                    scale_array[scale_ind + 1] ** 2:
+                range_size = scale_ind + 1
+                break
+
+        if area > scale_array[len(scale_array) - 2]**2:
+            range_size = len(scale_array) - 2
+
+        scale_choose = 0.0
+        if range_size == 0:
+            rand_idx_size = 0
+        else:
+            # np.random.randint range: [low, high)
+            rng_rand_size = np.random.randint(0, range_size + 1)
+            rand_idx_size = rng_rand_size % (range_size + 1)
+
+        if rand_idx_size == range_size:
+            min_resize_val = scale_array[rand_idx_size] / 2.0
+            max_resize_val = min(2.0 * scale_array[rand_idx_size],
+                                 2 * math.sqrt(wid * hei))
+            scale_choose = random.uniform(min_resize_val, max_resize_val)
+        else:
+            min_resize_val = scale_array[rand_idx_size] / 2.0
+            max_resize_val = 2.0 * scale_array[rand_idx_size]
+            scale_choose = random.uniform(min_resize_val, max_resize_val)
+
+        sample_bbox_size = wid * resize_width / scale_choose
+
+        w_off_orig = 0.0
+        h_off_orig = 0.0
+        if sample_bbox_size < max(image_height, image_width):
+            if wid <= sample_bbox_size:
+                w_off_orig = np.random.uniform(xmin + wid - sample_bbox_size,
+                                               xmin)
+            else:
+                w_off_orig = np.random.uniform(xmin,
+                                               xmin + wid - sample_bbox_size)
+
+            if hei <= sample_bbox_size:
+                h_off_orig = np.random.uniform(ymin + hei - sample_bbox_size,
+                                               ymin)
+            else:
+                h_off_orig = np.random.uniform(ymin,
+                                               ymin + hei - sample_bbox_size)
+
+        else:
+            w_off_orig = np.random.uniform(image_width - sample_bbox_size, 0.0)
+            h_off_orig = np.random.uniform(image_height - sample_bbox_size, 0.0)
+
+        w_off_orig = math.floor(w_off_orig)
+        h_off_orig = math.floor(h_off_orig)
+
+        # Figure out top left coordinates.
+        w_off = float(w_off_orig / image_width)
+        h_off = float(h_off_orig / image_height)
+
+        sampled_bbox = [
+            w_off, h_off, w_off + float(sample_bbox_size / image_width),
+            h_off + float(sample_bbox_size / image_height)
+        ]
+        return sampled_bbox
+    else:
+        return 0
+
+
 def jaccard_overlap(sample_bbox, object_bbox):
     if sample_bbox[0] >= object_bbox[2] or \
         sample_bbox[2] <= object_bbox[0] or \
@@ -108,6 +251,29 @@ def jaccard_overlap(sample_bbox, object_bbox):
     return overlap
 
 
+def intersect_bbox(bbox1, bbox2):
+    if bbox2[0] > bbox1[2] or bbox2[2] < bbox1[0] or \
+        bbox2[1] > bbox1[3] or bbox2[3] < bbox1[1]:
+        intersection_box = [0.0, 0.0, 0.0, 0.0]
+    else:
+        intersection_box = [
+            max(bbox1[0], bbox2[0]), max(bbox1[1], bbox2[1]),
+            min(bbox1[2], bbox2[2]), min(bbox1[3], bbox2[3])
+        ]
+    return intersection_box
+
+
+def bbox_coverage(bbox1, bbox2):
+    inter_box = intersect_bbox(bbox1, bbox2)
+    intersect_size = bbox_area(inter_box)
+
+    if intersect_size > 0:
+        bbox1_size = bbox_area(bbox1)
+        return intersect_size / bbox1_size
+    else:
+        return 0.
+
+
 def satisfy_sample_constraint(sampler,
                               sample_bbox,
                               gt_bboxes,
@@ -136,3 +302,87 @@ def satisfy_sample_constraint(sampler,
         return np.all(satisfied)
     else:
         return False
+
+
+def satisfy_sample_constraint_coverage(sampler, sample_bbox, gt_bboxes):
+    if sampler[6] == 0 and sampler[7] == 0:
+        has_jaccard_overlap = False
+    else:
+        has_jaccard_overlap = True
+    if sampler[8] == 0 and sampler[9] == 0:
+        has_object_coverage = False
+    else:
+        has_object_coverage = True
+
+    if not has_jaccard_overlap and not has_object_coverage:
+        return True
+    found = False
+    for i in range(len(gt_bboxes)):
+        object_bbox = [
+            gt_bboxes[i][0], gt_bboxes[i][1], gt_bboxes[i][2], gt_bboxes[i][3]
+        ]
+        if has_jaccard_overlap:
+            overlap = jaccard_overlap(sample_bbox, object_bbox)
+            if sampler[6] != 0 and \
+                    overlap < sampler[6]:
+                continue
+            if sampler[7] != 0 and \
+                    overlap > sampler[7]:
+                continue
+            found = True
+        if has_object_coverage:
+            object_coverage = bbox_coverage(object_bbox, sample_bbox)
+            if sampler[8] != 0 and \
+                    object_coverage < sampler[8]:
+                continue
+            if sampler[9] != 0 and \
+                    object_coverage > sampler[9]:
+                continue
+            found = True
+        if found:
+            return True
+    return found
+
+
+def crop_image_sampling(img, sample_bbox, image_width, image_height,
+                        target_size):
+    # no clipping here
+    xmin = int(sample_bbox[0] * image_width)
+    xmax = int(sample_bbox[2] * image_width)
+    ymin = int(sample_bbox[1] * image_height)
+    ymax = int(sample_bbox[3] * image_height)
+
+    w_off = xmin
+    h_off = ymin
+    width = xmax - xmin
+    height = ymax - ymin
+    cross_xmin = max(0.0, float(w_off))
+    cross_ymin = max(0.0, float(h_off))
+    cross_xmax = min(float(w_off + width - 1.0), float(image_width))
+    cross_ymax = min(float(h_off + height - 1.0), float(image_height))
+    cross_width = cross_xmax - cross_xmin
+    cross_height = cross_ymax - cross_ymin
+
+    roi_xmin = 0 if w_off >= 0 else abs(w_off)
+    roi_ymin = 0 if h_off >= 0 else abs(h_off)
+    roi_width = cross_width
+    roi_height = cross_height
+
+    roi_y1 = int(roi_ymin)
+    roi_y2 = int(roi_ymin + roi_height)
+    roi_x1 = int(roi_xmin)
+    roi_x2 = int(roi_xmin + roi_width)
+
+    cross_y1 = int(cross_ymin)
+    cross_y2 = int(cross_ymin + cross_height)
+    cross_x1 = int(cross_xmin)
+    cross_x2 = int(cross_xmin + cross_width)
+
+    sample_img = np.zeros((height, width, 3))
+    sample_img[roi_y1: roi_y2, roi_x1: roi_x2] = \
+        img[cross_y1: cross_y2, cross_x1: cross_x2]
+
+    sample_img = cv2.resize(
+        sample_img, (target_size, target_size), interpolation=cv2.INTER_AREA)
+
+    return sample_img

ppdet/data/transform/operators.py

@@ -31,7 +31,9 @@ from PIL import Image, ImageEnhance
 from ppdet.core.workspace import serializable
 
 from .op_helper import (satisfy_sample_constraint, filter_and_process,
-                        generate_sample_bbox, clip_bbox)
+                        generate_sample_bbox, clip_bbox, data_anchor_sampling,
+                        satisfy_sample_constraint_coverage, crop_image_sampling,
+                        generate_sample_bbox_square, bbox_area_sampling)
 
 logger = logging.getLogger(__name__)
 
@@ -526,8 +528,6 @@ class CropImage(BaseOperator):
             batch_sampler (list): Multiple sets of different
                                   parameters for cropping.
             satisfy_all (bool): whether all boxes must satisfy.
-            avoid_no_bbox (bool): whether to to avoid the 
-                                  situation where the box does not appear.
             e.g.[[1, 1, 1.0, 1.0, 1.0, 1.0, 0.0, 1.0],
                  [1, 50, 0.3, 1.0, 0.5, 2.0, 0.1, 1.0],
                  [1, 50, 0.3, 1.0, 0.5, 2.0, 0.3, 1.0],
@@ -538,6 +538,8 @@ class CropImage(BaseOperator):
            [max sample, max trial, min scale, max scale,
             min aspect ratio, max aspect ratio,
             min overlap, max overlap]
+            avoid_no_bbox (bool): whether to to avoid the 
+                                  situation where the box does not appear.
         """
         super(CropImage, self).__init__()
         self.batch_sampler = batch_sampler
@@ -599,6 +601,151 @@ class CropImage(BaseOperator):
         return sample
 
 
+@register_op
+class CropImageWithDataAchorSampling(BaseOperator):
+    def __init__(self,
+                 batch_sampler,
+                 anchor_sampler=None,
+                 target_size=None,
+                 das_anchor_scales=[16, 32, 64, 128],
+                 sampling_prob=0.5,
+                 min_size=8.,
+                 avoid_no_bbox=True):
+        """
+        Args:
+            anchor_sampler (list): anchor_sampling sets of different
+                                  parameters for cropping.
+            batch_sampler (list): Multiple sets of different
+                                  parameters for cropping.
+              e.g.[[1, 10, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.2, 0.0]]
+                  [[1, 50, 1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0],
+                   [1, 50, 0.3, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0],
+                   [1, 50, 0.3, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0],
+                   [1, 50, 0.3, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0],
+                   [1, 50, 0.3, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0]]
+              [max sample, max trial, min scale, max scale,
+               min aspect ratio, max aspect ratio,
+               min overlap, max overlap, min coverage, max coverage]
+            target_size (bool): target image size.
+            das_anchor_scales (list[float]): a list of anchor scales in data
+                anchor smapling.
+            min_size (float): minimum size of sampled bbox.
+            avoid_no_bbox (bool): whether to to avoid the
+                                  situation where the box does not appear.
+        """
+        super(CropImageWithDataAchorSampling, self).__init__()
+        self.anchor_sampler = anchor_sampler
+        self.batch_sampler = batch_sampler
+        self.target_size = target_size
+        self.sampling_prob = sampling_prob
+        self.min_size = min_size
+        self.avoid_no_bbox = avoid_no_bbox
+        self.scale_array = np.array(das_anchor_scales)
+
+    def __call__(self, sample, context):
+        """
+        Crop the image and modify bounding box.
+        Operators:
+            1. Scale the image weight and height.
+            2. Crop the image according to a radom sample.
+            3. Rescale the bounding box.
+            4. Determine if the new bbox is satisfied in the new image.
+        Returns:
+            sample: the image, bounding box are replaced.
+        """
+        assert 'image' in sample, "image data not found"
+        im = sample['image']
+        gt_bbox = sample['gt_bbox']
+        gt_class = sample['gt_class']
+        image_width = sample['w']
+        image_height = sample['h']
+        gt_score = None
+        if 'gt_score' in sample:
+            gt_score = sample['gt_score']
+        sampled_bbox = []
+        gt_bbox = gt_bbox.tolist()
+
+        prob = np.random.uniform(0., 1.)
+        if prob > self.sampling_prob:  # anchor sampling
+            assert self.anchor_sampler
+            for sampler in self.anchor_sampler:
+                found = 0
+                for i in range(sampler[1]):
+                    if found >= sampler[0]:
+                        break
+                    sample_bbox = data_anchor_sampling(
+                        gt_bbox, image_width, image_height, self.scale_array,
+                        self.target_size)
+                    if sample_bbox == 0:
+                        break
+                    if satisfy_sample_constraint_coverage(sampler, sample_bbox,
+                                                          gt_bbox):
+                        sampled_bbox.append(sample_bbox)
+                        found = found + 1
+            im = np.array(im)
+            while sampled_bbox:
+                idx = int(np.random.uniform(0, len(sampled_bbox)))
+                sample_bbox = sampled_bbox.pop(idx)
+
+                crop_bbox, crop_class, crop_score = filter_and_process(
+                    sample_bbox, gt_bbox, gt_class, gt_score)
+                crop_bbox, crop_class, crop_score = bbox_area_sampling(
+                    crop_bbox, crop_class, crop_score, self.target_size,
+                    self.min_size)
+
+                if self.avoid_no_bbox:
+                    if len(crop_bbox) < 1:
+                        continue
+                im = crop_image_sampling(im, sample_bbox, image_width,
+                                         image_height, self.target_size)
+                sample['image'] = im
+                sample['gt_bbox'] = crop_bbox
+                sample['gt_class'] = crop_class
+                sample['gt_score'] = crop_score
+                return sample
+            return sample
+
+        else:
+            for sampler in self.batch_sampler:
+                found = 0
+                for i in range(sampler[1]):
+                    if found >= sampler[0]:
+                        break
+                    sample_bbox = generate_sample_bbox_square(
+                        sampler, image_width, image_height)
+                    if satisfy_sample_constraint_coverage(sampler, sample_bbox,
+                                                          gt_bbox):
+                        sampled_bbox.append(sample_bbox)
+                        found = found + 1
+            im = np.array(im)
+            while sampled_bbox:
+                idx = int(np.random.uniform(0, len(sampled_bbox)))
+                sample_bbox = sampled_bbox.pop(idx)
+                sample_bbox = clip_bbox(sample_bbox)
+
+                crop_bbox, crop_class, crop_score = filter_and_process(
+                    sample_bbox, gt_bbox, gt_class, gt_score)
+                # sampling bbox according the bbox area
+                crop_bbox, crop_class, crop_score = bbox_area_sampling(
+                    crop_bbox, crop_class, crop_score, self.target_size,
+                    self.min_size)
+
+                if self.avoid_no_bbox:
+                    if len(crop_bbox) < 1:
+                        continue
+                xmin = int(sample_bbox[0] * image_width)
+                xmax = int(sample_bbox[2] * image_width)
+                ymin = int(sample_bbox[1] * image_height)
+                ymax = int(sample_bbox[3] * image_height)
+                im = im[ymin:ymax, xmin:xmax]
+                sample['image'] = im
+                sample['gt_bbox'] = crop_bbox
+                sample['gt_class'] = crop_class
+                sample['gt_score'] = crop_score
+                return sample
+            return sample
+
+
 @register_op
 class NormalizeBox(BaseOperator):
     """Transform the bounding box's coornidates to [0,1]."""