annotation tool for object detection

edit

Try Labelbox (www.labelbox.io).

Labelbox is a cloud based tool to easily label data.

Labelbox makes it really easy to do basic image classification or segmentation tasks. Simply upload a CSV file pointing to the location of your data and choose an image classification or segmentation labeling template to get started.

In addition, It supports any kind of data such as text, images, maps, videos and even point clouds or medical DICOM. One can create a custom labeling interface with HTML and javascript and can be as simple as 30 lines of code. You can see their template code here: https://github.com/Labelbox/Labelbox

Additional feature includes project management, team management and performance metrics.

If it's related to documents, then Transkribus is quite good: https://transkribus.eu/Transkribus/

If you are using Mac OS X, you can use RectLabel.

An image annotation tool to label images for bounding box object detection and segmentation.

https://rectlabel.com

Key features:

• Drawing bounding box, polygon, and cubic bezier
• Export index color mask image and separated mask images
• 1-click buttons make your labeling work faster
• Customize the label dialog to combine with attributes
• Settings for objects, attributes, hotkeys, and labeling fast
• Layer order for overlapped boxes
• Quick zoom to existing boxes
• Support the PASCAL VOC format

you can use annotation.cpp

A PR has been added for both 2.4 and master branch to get a universal OpenCV based annotation tool included in the repository.

Of course it'll vary based on your use case, but you can check out:

http://labelme.csail.mit.edu/Release3.0/