add a method to draw bboxes and labels

mmcv/visualization/__init__.py

 from .color import Color, color_val
-from .image import imshow, imshow_bboxes
+from .image import imshow, imshow_bboxes, imshow_det_bboxes
 from .optflow import flowshow, flow2rgb, make_color_wheel
 
 __all__ = [
-    'Color', 'color_val', 'imshow', 'imshow_bboxes', 'flowshow', 'flow2rgb',
-    'make_color_wheel'
+    'Color', 'color_val', 'imshow', 'imshow_bboxes', 'imshow_det_bboxes',
+    'flowshow', 'flow2rgb', 'make_color_wheel'
 ]

mmcv/visualization/image.py

@@ -64,3 +64,68 @@ def imshow_bboxes(img,
         imshow(img, win_name, wait_time)
     if out_file is not None:
         imwrite(img, out_file)
+
+
+def imshow_det_bboxes(img,
+                      bboxes,
+                      labels,
+                      class_names=None,
+                      score_thr=0,
+                      bbox_color='green',
+                      text_color='green',
+                      thickness=1,
+                      font_scale=0.5,
+                      show=True,
+                      win_name='',
+                      wait_time=0,
+                      out_file=None):
+    """Draw bboxes and class labels (with scores) on an image.
+
+    Args:
+        img (str or ndarray): The image to be displayed.
+        bboxes (ndarray): Bounding boxes (with scores), shaped (n, 4) or (n, 5).
+        labels (ndarray): Labels of bboxes.
+        class_names (list[str]): Names of each classes.
+        score_thr (float): Minimum score of bboxes to be shown.
+        bbox_color (str or tuple or :obj:`Color`): Color of bbox lines.
+        text_color (str or tuple or :obj:`Color`): Color of texts.
+        thickness (int): Thickness of lines.
+        font_scale (float): Font scales of texts.
+        show (bool): Whether to show the image.
+        win_name (str): The window name.
+        wait_time (int): Value of waitKey param.
+        out_file (str or None): The filename to write the image.
+    """
+    assert bboxes.ndim == 2
+    assert labels.ndim == 1
+    assert bboxes.shape[0] == labels.shape[0]
+    assert bboxes.shape[1] == 4 or bboxes.shape[1] == 5
+    img = imread(img)
+
+    if score_thr > 0:
+        assert bboxes.shape[1] == 5
+        scores = bboxes[:, -1]
+        inds = scores > score_thr
+        bboxes = bboxes[inds, :]
+        labels = labels[inds, :]
+
+    bbox_color = color_val(bbox_color)
+    text_color = color_val(text_color)
+
+    for bbox, label in zip(bboxes, labels):
+        bbox_int = bbox.astype(np.int32)
+        left_top = (bbox_int[0], bbox_int[1])
+        right_bottom = (bbox_int[2], bbox_int[3])
+        cv2.rectangle(
+            img, left_top, right_bottom, bbox_color, thickness=thickness)
+        label_text = class_names[
+            label] if class_names is not None else 'cls {}'.format(label)
+        if bbox.shape[1] > 4:
+            label_text += '|{:.02f}'.format(bbox[-1])
+        cv2.putText(img, label_text, (bbox_int[0], bbox_int[1] - 2),
+                    cv2.FONT_HERSHEY_COMPLEX, font_scale, text_color)
+
+    if show:
+        imshow(img, win_name, wait_time)
+    if out_file is not None:
+        imwrite(img, out_file)