Add max size assert in DETRdemo (#171)

notebooks/detr_demo.ipynb

@@ -597,6 +597,11 @@
         "    # mean-std normalize the input image (batch-size: 1)\n",
         "    img = transform(im).unsqueeze(0)\n",
         "\n",
+        "    # demo model only support by default images with aspect ratio between 0.5 and 2\n",
+        "    # if you want to use images with an aspect ratio outside this range\n",
+        "    # rescale your image so that the maximum size is at most 1333 for best results\n",
+        "    assert img.shape[-2] <= 1600 and img.shape[-1] <= 1600, 'demo model only supports images up to 1600 pixels on each side'\n",
+        "\n",
         "    # propagate through the model\n",
         "    outputs = model(img)\n",
         "\n",
@@ -698,4 +703,4 @@
       ]
     }
   ]
-}
+}