RectLabel

An offline image annotation tool for object detection and segmentation.

To download RectLabel apps.

Post the problem to our Github issues.

Have questions? Send an email to support@rectlabel.com.

Thank you.

Open images folder and annotations folder

You can drag & drop each images folder and annotations folder to the open table.
“Label format” is to change the label format to read/write in the PASCAL VOC xml format or YOLO text format.
“Sort images” is to sort images by Alphabetic, Numeric, and Last modified.
“Read images folder recursively” is to read all images from the root folder. You can search sub folder names in searching image name feature.
After opening images, we recommend to use File menu -> Remove EXIF orientation flags.
Image file names which include “_pixels” or “_depth” are skipped.
To copy the current image file name, click on the image file name shown at the top-left corner.

├── images
│   ├── 0.jpg
│   └── 1.jpg
└── annotations
    ├── 0.xml or 0.txt
    └── 1.xml or 1.txt

Once opened images and annotations folders, from the second launch, you can use command line arguments to RectLabel which image files should be opened.

open -a RectLabel --args -images 000000000872.jpg,000000010363.jpg
open -a RectLabel\ Pro --args -images 000000000872.jpg,000000010363.jpg

open_table

Open images folder

For the annotations folder, RectLabel uses “images/annotations” folder.

└── images
    ├── annotations
    ├── 0.jpg
    └── 1.jpg

Open a folder which includes a yaml file

You can open the YOLOv5/YOLOv8 folder exported from Roboflow.

└── exported_YOLOv5_YOLOv8_folder
    ├── data.yaml
    ├── train
    │   ├── images
    │   └── labels
    ├── valid
    │   ├── images
    │   └── labels
    └── test
        ├── images
        └── labels

Convert video to image frames

For “Video file”, open a video file.
For “Output folder”, open a folder to save the image frames.
For “Image size”, both width and height would be less than or equal to the size.
For “Frames per second”, to reduce the number of frames to be exported.
For “Frame suffix”, you can select “frame1” or “frame001”.

video_to_frames

Remove EXIF orientation flags

On RectLabel, according to the Exif orientation flags, each image is rotated and shown in the front orientation.
You can remove the EXIF orientation flags from images and convert images to the front orientation.
If necessary, you can rotate the image using Edit menu -> Rotate the image right/left.

Resize images

You can resize images and annotations.
For “Image size”, both width and height would be less than or equal to the size.
If “Image size” is empty, images are not resized but annotations are resized to the same size as images.

Next image and Prev image

To show the next image, press the right arrow key.
To show the previous image, press the left arrow key.
Pressing the command key, the step size becomes 10.
You can use Trackpad gestures and Magic Mouse gestures.

Jump to image number

You can specify the image number to show.

Move images

You can move all images or random fraction of total to another folder.
Searching images, you can move searched images to another folder.

Copy images

You can copy all images or random fraction of total to another folder.
Searching images, you can copy searched images to another folder.

Save

The annotation file is saved as {image_file_name}.xml in the PASCAL VOC xml format or {image_file_name}.txt in the YOLO text format.

Close folder

You can close current images and annotations folders.