Psychology of Convolutional Neural Network

Understanding Network behind the Object Recognition as a Brain

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Every moment our sensory system is collecting a myriad of information and sending them to our brain in a format that it can understand. In a split second of looking at a scene, we can identify individual objects within our view. Even in the crowd, we can tell between people and trees, moreover, we can quickly spot faces that are familiar to us. How do we do this? Moreover, can a machine see the way we see?

Mechanism of Human Vision

The basic mechanism of our vision is as follows: lights from the external visual field enter our eyes. These lights are projected to the receptive field of photoreceptive cells where the light projection is converted into electrical signals. These signals from both eyes meet at a hub called the optic chiasm. Here, signals are separated into either side of the hemispheres based on their original visual field.

These separated signals go through different routes before arriving at the cortex. One of the main routes detects spatial information (the tectopulvinar pathway), and another path is responsible for processing patterns and colors (the geniculostriate pathway).

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So now our brain has successfully composed the light signals into patterns, colors, orientation, location, etc. The primary visual cortex at the back of our brain receives these signals and distributes them deeper into our brain. One of the primary paths is through the inferior temporal cortex. As the signals move through our inferior temporal cortex, they converge and become more and more complex. Now the brain is able to infer what the combination of these signals is based on the knowledge we already have stored in our brain. This is roughly a known process our brain goes through to recognize and identify an object.

One of the key insights here comes from the 1981 Nobel Prize winners in Physiology or Medicine, David H. Hubel, and Torsten N. Wiesel. Hubel and Wiesel discovered that the receptive fields that elicit response signals at each layer of…