Lessons from training a segmentation model

· 1 min read

What actually moved the needle when segmenting thin, rare structures — and what didn't.

  • computer vision
  • segmentation
  • deep learning

Placeholder note — edit freely.

A few things I’d tell my past self before starting a hard segmentation project:

  • Loss function beats architecture for extreme class imbalance. A combined Dice + focal loss did more than swapping backbones.
  • Augment aggressively, but realistically. Augmentations that don’t reflect real variation just add noise.
  • Post-processing is underrated. Connected-components filtering removed a lot of false positives for almost no cost.
  • Visualize predictions early and often. Metrics hide failure modes that a quick overlay makes obvious.
  • 2D vs 3D is a budget decision. 3D context helps but is memory-bound; patch it or accept slower inference.

The meta-lesson: on low-signal problems, spend your time on data, loss, and evaluation before reaching for a bigger model.