title: Continuous evaluation of AI Platform gives a `data_json_key` error
body: <p>With continuous evaluation of AI Platform, <code>data_json_key</code> error occurs. </p>
  
  <p><strong>Evaluation Job Inputs</strong></p>
  
  <ul>
  <li>Model objective: Image object detection (box)</li>
  <li>IoU (Intersection over Union): 0.1</li>
  <li>Data key: b64</li>
  <li>Prediction label key: detection_classes</li>
  <li>Prediction score key: detection_scores</li>
  <li>Bounding box key: detection_boxes</li>
  <li>Labeling Service: No</li>
  <li>Daily sample percentage: 100%</li>
  <li>Daily sample limit: 100</li>
  </ul>
  
  <p><strong>Error log</strong></p>
  
  <pre><code>Partial Failures: [{"code":5,"message":"Can not find the image data under the data_json_key: image_bytes/b64"},{"code":5,"message":"Can not find the image data under the data_json_key: image_bytes/b64"},{"code":5,"message":"Can not find the image data under the data_json_key: image_bytes/b64"},{"message":"Found incorrect number of labeled dataset when preparing evaluation for dataset_id: 5ee3023a_0000_25e5_a9d2_94eb2c19321a"}]
  </code></pre>
  
  <p>I have <code>data_json_key</code> set to <code>b64</code> and I think this is the correct predictive key for the model. However, the job returns an error as if it were expecting <code>image_bytes/b64</code>.</p>
  
  <p><strong>Supplement</strong></p>
  
  <p>The model is made by transfer learning <code>ssd_mobilenetv2_oidv4</code>*1 with TensorFlow Object Detection API according to this method*2.</p>
  
  <p>1.<a href="https://github.com/tensorflow/models/blob/master/research/object_detection/g3doc/detection_model_zoo.md" rel="nofollow noreferrer">https://github.com/tensorflow/models/blob/master/research/object_detection/g3doc/detection_model_zoo.md</a></p>
  
  <p>2.<a href="https://cloud.google.com/blog/products/gcp/performing-prediction-with-tensorflow-object-detection-models-on-google-cloud-machine-learning-engine" rel="nofollow noreferrer">https://cloud.google.com/blog/products/gcp/performing-prediction-with-tensorflow-object-detection-models-on-google-cloud-machine-learning-engine</a></p>