title: Evaluation on Coco-type data set returns error
body: <p>I am using the Faster R-CNN model available from <a href="https://github.com/facebookresearch/maskrcnn-benchmark" rel="nofollow noreferrer">https://github.com/facebookresearch/maskrcnn-benchmark</a>.  I am trying to evaluate the results of a trained model on the KITTI data set, after converting it to Coco Format (2D object detection).</p>
  
  <p>The results are 0 or -1 and sometimes it throws an error in the CocoApi toolkit at g["area"]. </p>
  
  <blockquote>
    <p>pycoco if g['ignore'] or (g['area']aRng[1]):
    "KeyError: 'area'"</p>
  </blockquote>
  
  <p>From what I found while researching the problem, "area" is used for segmentation and I do not have that kind of annotation in my data set.</p>
  
  <p>An small example of how my converted annotation file looks:</p>
  
  <pre><code>{
      "images": [
          {
              "file_name": "007292.png",
              "id": 1,
              "width": 1392,
              "height": 512
          },
          {
              "file_name": "000603.png",
              "id": 2,
              "width": 1392,
              "height": 512
          },
          {
              "file_name": "004313.png",
              "id": 3,
              "width": 1392,
              "height": 512
          },
          {
              "file_name": "006401.png",
              "id": 4,
              "width": 1392,
              "height": 512
          },
          {
              "file_name": "005442.png",
              "id": 5,
              "width": 1392,
              "height": 512
          }
      ],
      "annotations": [
          {
              "image_id": 1,
              "id": 1,
              "category_id": 1,
              "bbox": [
                  589.08,
                  176.53,
                  26.719999999999914,
                  26.409999999999997
              ],
              "iscrowd": 0
          },
          {
              "image_id": 1,
              "id": 2,
              "category_id": 1,
              "bbox": [
                  235.9,
                  190.63,
                  115.16,
                  57.78
              ],
              "iscrowd": 0
          },
          {
              "image_id": 1,
              "id": 3,
              "category_id": 1,
              "bbox": [
                  426.57,
                  184.2,
                  42.0,
                  26.700000000000017
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 4,
              "category_id": 1,
              "bbox": [
                  1211.2,
                  182.65,
                  11.799999999999955,
                  186.35
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 5,
              "category_id": 1,
              "bbox": [
                  386.94,
                  180.98,
                  57.80000000000001,
                  30.55000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 6,
              "category_id": 1,
              "bbox": [
                  736.21,
                  173.49,
                  113.90999999999997,
                  96.44999999999999
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 7,
              "category_id": 1,
              "bbox": [
                  701.98,
                  174.7,
                  91.55999999999995,
                  66.01000000000002
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 8,
              "category_id": 1,
              "bbox": [
                  682.42,
                  176.25,
                  58.200000000000045,
                  47.53
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 9,
              "category_id": 1,
              "bbox": [
                  667.8,
                  175.85,
                  51.190000000000055,
                  39.24000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 2,
              "id": 10,
              "category_id": 1,
              "bbox": [
                  654.6,
                  176.88,
                  31.110000000000014,
                  26.49000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 3,
              "id": 11,
              "category_id": 1,
              "bbox": [
                  267.69,
                  179.7,
                  101.13,
                  33.120000000000005
              ],
              "iscrowd": 0
          },
          {
              "image_id": 3,
              "id": 12,
              "category_id": 1,
              "bbox": [
                  461.31,
                  176.05,
                  72.38000000000005,
                  28.73999999999998
              ],
              "iscrowd": 0
          },
          {
              "image_id": 3,
              "id": 13,
              "category_id": 1,
              "bbox": [
                  600.36,
                  177.08,
                  52.360000000000014,
                  23.299999999999983
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 14,
              "category_id": 1,
              "bbox": [
                  1061.94,
                  96.68,
                  179.05999999999995,
                  277.32
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 15,
              "category_id": 1,
              "bbox": [
                  280.52,
                  184.02,
                  148.01,
                  96.92999999999998
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 16,
              "category_id": 1,
              "bbox": [
                  143.54,
                  179.75,
                  350.11,
                  194.25
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 17,
              "category_id": 1,
              "bbox": [
                  861.45,
                  139.2,
                  178.20000000000005,
                  64.58000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 18,
              "category_id": 1,
              "bbox": [
                  1018.27,
                  144.44,
                  88.04999999999995,
                  43.25
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 19,
              "category_id": 1,
              "bbox": [
                  1061.23,
                  147.01,
                  100.31999999999994,
                  39.27000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 20,
              "category_id": 1,
              "bbox": [
                  439.12,
                  184.57,
                  66.10000000000002,
                  43.43000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 21,
              "category_id": 1,
              "bbox": [
                  381.68,
                  184.81,
                  98.5,
                  63.59
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 22,
              "category_id": 1,
              "bbox": [
                  673.9,
                  172.28,
                  52.389999999999986,
                  36.53999999999999
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 23,
              "category_id": 1,
              "bbox": [
                  473.3,
                  180.94,
                  49.079999999999984,
                  36.900000000000006
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 24,
              "category_id": 1,
              "bbox": [
                  609.73,
                  179.26,
                  35.860000000000014,
                  27.670000000000016
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 25,
              "category_id": 1,
              "bbox": [
                  668.0,
                  173.81,
                  88.37,
                  31.150000000000006
              ],
              "iscrowd": 0
          },
          {
              "image_id": 4,
              "id": 26,
              "category_id": 1,
              "bbox": [
                  585.17,
                  172.42,
                  40.520000000000095,
                  15.630000000000024
              ],
              "iscrowd": 0
          },
          {
              "image_id": 5,
              "id": 27,
              "category_id": 1,
              "bbox": [
                  192.88,
                  178.88,
                  74.23000000000002,
                  33.49000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 5,
              "id": 28,
              "category_id": 1,
              "bbox": [
                  250.68,
                  179.92,
                  65.70999999999998,
                  26.27000000000001
              ],
              "iscrowd": 0
          },
          {
              "image_id": 5,
              "id": 29,
              "category_id": 1,
              "bbox": [
                  306.54,
                  178.95,
                  55.48999999999995,
                  22.670000000000016
              ],
              "iscrowd": 0
          }
      ],
      "categories": [
          {
              "name": "Car",
              "id": 1
          }
      ]
  }
  </code></pre>
  
  <p>EDIT: I have added the area property to the labels, computed as bbox[2]*bbox[3], there is no error anymore, but the results are 0.</p>
  
  <p>Any help would be gladly appreciated! </p>