Annotation types


Below you will find a table with all the annotation answer types that are currently supported on Grand Challenge.

Answer type Description Stored as Caveats
Point single point 3D location of the point (json) -
Multiple points multiple points array of points (json) -
Distance measurement single line drawn on a single plane 3D locations of the start and end positions of the line (json) -
Multiple distance measurements multiple lines, each drawn on a single plane array of lines (json) -
2D Bounding Box rectangle drawn on a single plane 3D locations of the four corners of the rectangle (json) -
Multiple 2D Bounding Boxes multiple rectangles, each drawn on a single plane array of rectangles (json) -
Polygon shape drawn on a single plane array of 3D locations of the seed points of the polygon (json) size limitation, see below
Multiple polygons multiple shapes, each drawn on a single plane array of polygons (json) size limitation, see below
Polygon (saved as mask) shape drawn on a single plane mha file no edit option, will be deprecated
Multiple polygons (saved as mask) multiple shapes, each drawn on a single plane mha file no edit option, will be deprecated
Mask multiple shapes, each drawn on a single plane mha file -

For (Multiple) polygons answer types, it is possible to create a large (number of) polygon(s) for a single question. This can lead to issues when saving these answers to Grand Challenge, as the answer becomes very big. For this reason the "saved as mask" option was introduced. With this answer type, the user can create an annotation using the polygon editor, with extended options like snapping and contouring. When saving the answer, the polygon is converted to a mask and the resulting image is sent to Grand Challenge. It solved the issue with saving large answers, while still offering all the polygon tools. However, it does have the limitation that once saved, it is not possible to edit the answer. Since then, the Mask answer type has been added. With the recently introduced switching of editor feature, it offers all the polygon tool options but also allows for mask editing. The "saved as mask" option will therefor be deprecated in a future release.

💡Use Mask answer type if you expect a high number of annotations for a single question or you if prefer your answer in image format

💡Use Polygon or Multiple polygons answer type if you don't expect a high number of annotations for a single question and you prefer the answers in a json format

⚠️ The "saved as mask" option will be deprecated in a future release.