Object Instance Annotation Guidelines

Annotation Guidelines

• Try to be consistent but precise with labels.
  • Example: don’t label something as just a ‘seat’, try to label it as a ‘chair’ or ‘sofa’
• Try to label/paint object instances different color (e.g. two chairs should be painted as two colors). Some turkers will paint all instances of the same category the same color.
  • It’s sometimes unclear what constitutes ‘one instance’. For instance, what is one wall, one cabinet, one bookshelf? Use your intuition and the below point. ** An object instance should be (mostly) connected and compact, and if movable, typically moved as one object
• Try to get close to 100% coverage (shown on lower left) but don’t spend an inordinate amount of time labeling small items / junk geometry. At least 90% should be done for each room.
• Check the bounding box around each segment to confirm no extraneous parts are added to the segment

Category specific guidelines

• Floating geometry that shouldn’t be there: label as REMOVE
• Make sure walls, floors, ceilings don’t have extraneous parts associated with them
• Chairs - please try to annotate individual chairs as separate instances by using different colors!
• Walls - label each continuous flat wall plane with one color (each flat plane = one wall).
• Painting/mirrors on walls - try to separate out from the wall
• Ceilings - please label the ceilings, and try to label lights on the ceilings as well
• Rugs on floors - try to label separately (okay if hard to separate out, and rug is marked as floor)
• Windows: Label window panes (if reconstructed - often they will be missing) as “window” and the frame around as “window frame” (the frame is typically reconstructed well.
• Doors: Label door surfaces as “door”. Also label the door frame that is embedded in the wall as “door frame”.
• Plants in pots: If big enough, label pot and plant separately.
• Bookshelves/cabinets - Do not label individual shelves of a bookshelf. Try to identify and mark separate bookshelves. Cabinet instances are sometimes hard to differentiate, try to mark disconnected cabinets as separate cabinets (at least when it looks like they can be moved separately).
• Stairs - please label the steps as stairs (all steps in a staircase together is desirable) and the staircase railing separately
• Showers - please label wall and floor of showers as “shower wall” and “shower floor” and separate from the main wall and floor.
• Pillows - try to label individually
• Small objects / hard to identify objects - Segment and try to label as accurately as possible (if unrecognizable - label as “object”).
• Hard to paint objects - okay to skip labeling
• External walls / objects - For meshes that represent one room, there may be walls/parts outside of the room. For these, label as normal but add “/other room” to the label (e.g. “wall /other room”).

Things to look out for in verification pass

• Semantic labels are correct and "full" (i.e. a chair label refers to a chair, includes as much of the chair geometry as possible, and does not include other geometry)
• No duplicate instance labels (e.g., two partial chair labels for same chair geometry)
• No prominent missing objects (e.g., all obvious chair instances are annotated)