CS5720 - Week 4
Slide 75 of 80

Fully Connected Layers in CNNs

What are FC Layers in CNNs?

Fully Connected (FC) layers in CNNs are traditional neural network layers where every neuron connects to every neuron in the previous layer. They typically appear at the end of the network for final classification or regression.
Key Characteristics:

• Each neuron receives all features from previous layer
• No spatial structure preservation
• High parameter count
• Excellent for decision making
💡 Key Insight
FC layers act as the "brain" that makes final decisions based on features extracted by convolutional layers.

Why Use FC Layers?

  • 🎯
    Final Classification
    Convert feature maps to class probabilities
  • 🔗
    Feature Combination
    Combine spatial features for global understanding
  • 📐
    Dimensionality Reduction
    Reduce feature dimensions to output size
  • 📈
    Complex Patterns
    Learn complex non-linear relationships

CNN Architecture with FC Layers

Conv Layers
Feature Extraction
32×32×64
Pool Layers
Downsampling
16×16×64
Flatten
Reshape
16384 × 1
FC Layer 1
Dense
512 neurons
FC Layer 2
Output
10 classes
Click on any layer to learn more about its role in the CNN!
Prepared by Dr. Gorkem Kar