Two overlapping plush items can occupy the same colour range. A useful extraction needs to distinguish the individuals rather than select every similarly coloured pixel.
Ultralytics describes instance segmentation as producing a separate mask or contour for each detected object. Ultralytics — segment.
Specify the boundary convention
Decide how the dataset treats loose pile, transparent packaging and partially hidden edges. Annotators need the same convention; otherwise, disagreement about the boundary becomes training noise.
Review the intended use
A mask suitable for a catalogue cutout may be inadequate for comparing a precise contour. Inspect thin features and contact points instead of judging only the broad body region. A model-generated boundary remains an estimate, and the original photograph should remain available for review.
Source reviewed 25 October 2026. Interpretation and original diagrams: PLUSHIP / Qunhe. Examples are illustrative.
Related reading
Semantic and Instance Segmentation Organise a Scene Differently
Hyperparameter Search Needs a Separate Performance Estimate