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What is a feature map in CNNs?

Updated May 15, 2026

Short answer

A feature map is the output produced by applying a filter to an input image.

Deep explanation

Each convolution filter produces a feature map representing where a specific pattern appears in the input. Early layers detect edges, while deeper layers detect complex structures like objects.

Real-world example

Detecting road lanes in autonomous driving systems.

Common mistakes

  • Thinking feature maps are manually designed features.

Follow-up questions

  • Why do deeper layers have more abstract feature maps?
  • Can feature maps be visualized?

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