Let's start with a brief discussion leading up to just what we mean when we say facial expression classification.
In Chapter 7, Deep Learning Using TensorFlow on the IBM Cloud, we used IBM Watson Studio to perform object detection within random images. In that use case, we asked our project's model to find or detect common or known objects that might be pictured within an image. For example, we submitted an image of an animal and the solution correctly detected and identified a pinto horse, although no further information about the detected object was produced, such as whether the horse was angry or frightened.