fix off by one error in mask rcnn (#801)

utils/open_model_zoo/mask_rcnn_inception_resnet_v2_atrous_coco/interp.py

@@ -1,5 +1,6 @@
 import numpy as np
 import cv2
+from skimage.measure import approximate_polygon, find_contours
 
 
 MASK_THRESHOLD = .5
@@ -43,22 +44,21 @@ def segm_postprocess(box: list, raw_cls_mask, im_h, im_w, threshold):
  y = box[4] * height
  right = box[5] * width
  bottom = box[6] * height
- mask = masks[index][label]
+ mask = masks[index][label - 1]
 
  mask = segm_postprocess((x, y, right, bottom),
  mask,
  height,
  width,
  MASK_THRESHOLD)
 
- contour, _ = cv2.findContours(mask,
- cv2.RETR_EXTERNAL,
- cv2.CHAIN_APPROX_TC89_KCOS)
+ contours = find_contours(mask, MASK_THRESHOLD)
+ contour = contours[0]
+ contour = np.flip(contour, axis=1)
+ contour = approximate_polygon(contour, tolerance=2.5)
+ segmentation = contour.tolist()
 
- contour = contour[0]
- contour = contour.tolist()
- contour = [x[0] for x in contour]
 
  # NOTE: if you want to see the boxes, uncomment next line
  # results.add_box(x, y, right, bottom, label, frame_number)
- results.add_polygon(contour, label, frame_number)
+ results.add_polygon(segmentation, label, frame_number)