diff --git a/deep_sort/iou_matching.py b/deep_sort/iou_matching.py
index c4dd0b88..9efeb947 100644
--- a/deep_sort/iou_matching.py
+++ b/deep_sort/iou_matching.py
@@ -23,7 +23,7 @@ def iou(bbox, candidates):
         occluded by the candidate.
 
     """
-    bbox_tl, bbox_br = bbox[:2], bbox[:2] + bbox[2:]
+    bbox_tl, bbox_br = bbox[:2], bbox[:2] + bbox[2:] - 1
     candidates_tl = candidates[:, :2]
     candidates_br = candidates[:, :2] + candidates[:, 2:]
 
diff --git a/tools/generate_detections.py b/tools/generate_detections.py
index c7192c26..2eea81e6 100644
--- a/tools/generate_detections.py
+++ b/tools/generate_detections.py
@@ -53,8 +53,13 @@ def extract_image_patch(image, bbox, patch_shape):
         bbox[0] -= (new_width - bbox[2]) / 2
         bbox[2] = new_width
 
-    # convert to top left, bottom right
-    bbox[2:] += bbox[:2]
+    # convert to top left, bottom right,
+    # box is (x, y, width, height). In order
+    # to get right bottom corner we need to
+    #  add width and height to x and y
+    # correspondingly and subtract 1
+    # as on line 67 for images rects
+    bbox[2:] += bbox[:2] - 1
     bbox = bbox.astype(np.int)
 
     # clip at image boundaries