title: ERROR Error: Uncaught (in promise): Error: The input to the tensor constructor must be a non-null value
body: <p>Added object detection model to angular, followed all the steps to predict the object.</p>
  <pre><code> let tensor = tf.browser.fromPixels(img)
   const tensor1 = tensor.toInt().expandDims()
   const predictions =  this.model.executeAsync(tensor1)
  </code></pre>
  <p>getting Error: The input to the tensor constructor must be a non-null value.</p>
  <p>Please help</p>