Table 1.

Overview on the visual attribute labels in the SUN-SEG database

ID	Name	Description
SI	Surgical Instruments	The endoscopic surgical procedures involve the positioning of instruments, such as snares, forceps, knives and electrodes
IB	Indefinable Boundaries	The foreground and background areas around the object have a similar colour
HO	Heterogeneous Object	Object regions have distinct colours
GH	Ghosting	Object has anomaly RGB-coloured boundary due to fast-moving or insufficient refresh rate
FM	Fast Motion	The average per-frame object motion, computed as the Euclidean distance of polyp centroids between consecutive frames, is larger than 20 pixels
SO	Small Object	The average ratio between the object size and the image area is smaller than 0.05
LO	Large Object	The average ratio between the object bounding-box area and the image area is larger than 0.15
OCC	Occlusion	Object becomes partially or fully occluded
OV	Out of View	Object is partially clipped by the image boundaries
SV	Scale Variation	The average area ratio among any pair of bounding boxes enclosing the target object is smaller than 0.5.

Descriptions are copied from the official Git repository https://github.com/GewelsJI/VPS