# Download the example dataset: BSDS300
wget https://www.eecs.berkeley.edu/Research/Projects/CS/vision/bsds/BSDS300-images.tgz

# Extract the images and create image list
tar xvf BSDS300-images.tgz
find BSDS300/ | grep jpg > image.lst

Specify the labels and lst_path. You may also want to adjust the image_rows and image_cols.

python qtlabel.py

After start the program, you will see the following UI. There are 3 parts in the UI: top/middle/bottom.

In this example, the label list contains: animal, flower and human, which are specified in label.cfg After choosing a label from the list, you can start labeling.

TIPS: Press F1~F12 to select the first ~ twelfth label.

The are 3 different background colors for each image:

1. Green: this image is unlabelled
2. Blue: this image is a positive sample for the selected label
3. Red: this image is a negative sample for the selected label

Operations related to Image Browser:

1. Click an image to open image viewer, which allows you view the large images.
2. Click the image viewer to close it.
3. Right click an image to change its label. Everytime you right click an image, the label will be written to the database.

The are three buttons at the bottom:

1. Pos & Next(Q)(HotKey: Q): mark all the Green images to Blue, then move to the next page.
2. Neg & Next(W)(HotKey: W): mark all the Green images to Red, then move to the next page.
3. Prev(E) (HotKey: E): move to the previous page.
4. Next(R) (HotKey: R): move to the next page.

The label information will be stored in a sqlite3 database, which can be accessed via standard sqlite3 browser, e.g.

1. sqlitebrowser
2. SQLite Manager

You may also get the labels from command line like this:

sqlite3 label.sqlite "select * from labels"

The above command will print a table of labels. The following command prints the schema of the table:

sqlite3 label.sqlite ".schema labels"

Positive samples will be marked as 1, negative samples will be marked as -1, unlabelled samples will be marked as 0.