Annotation tool

We carefully designed the UX of the annotation tool from the ground-up to make annotating as simple and efficient as possible.

Remo currently supports three types of annotations:

  • Image level annotation for image classification tasks
  • Bounding boxes for object detection tasks
  • Polygons for segmentations tasks


Regardless of the annotation task selected, you can add tags to an image from the corresponding menu.

Tags are designed to give total flexibility in categorising images, and allows full control to index and search images at second stage.

Annotation status

To facilitate managing the annotation process, you can assign an annotation status to your images. Annotation status can be either:

  • Done indicated by a green mark
  • On Hold indicated by a yellow mark
  • To do not marked in any way

This is extremely useful to organise the annotation process, as you might want to go back to annotate some difficult pictures at a later stage (just use the sort by button).

Deep Zoom

Remo supports zooming in and out of an image quickly via the mouse wheel. It also features a zoom menu, with the ability to fit zoom level to an image width or height.

Under the hood, Remo decomposes big images in tiles, allowing to serve high resolution portions of a picture only when needed.

This allows Remo to support very big images - this was tested with images in the order of 200,000 pixels per dimension and up to 2GB for a single image.

Xclick for Object Detection

Following the approach defined in the paper Extreme click for efficient object detection, we implemented the efficient annotation method "xclick", which should yield a speedup of up to 5x compared to the traditional "draw a box" annotation.

Annotation shortcuts

To facilitate annotation, the annotation tool features a number of shortcuts to the most common functionalities.

Key What it does
Hold Space Bar Grab tool
Mouse Wheel Zoom in / out
E Explore tool
B Draw a box (once and return to previous tool)
D xclick (once and return to previous tool)
P Draw a polygon (once and return to previous tool)
Backspace Delete selected object (no confirmation needed)
Numbers and other letters Select a class to annotate or visualise annotations


If you have any suggestions on the Annotation tool, accessibility issues or new features that you would like included, we are all ears. The best way to get in touch is to write on the forum.