Pascal VOC

Format specification
supported annotations:
- Rectangles (detection and layout tasks)
- Tags (action- and classification tasks)
- Polygons (segmentation task)
supported attributes:
- occluded (both UI option and a separate attribute)
- truncated and difficult (should be defined for labels as checkbox -es)
- action attributes (import only, should be defined as checkbox -es)
- arbitrary attributes (in the attributes section of XML files)

Pascal VOC export

Downloaded file: a zip archive of the following structure:

taskname.zip/
├── JPEGImages/
│   ├── <image_name1>.jpg
│   ├── <image_name2>.jpg
│   └── <image_nameN>.jpg
├── Annotations/
│   ├── <image_name1>.xml
│   ├── <image_name2>.xml
│   └── <image_nameN>.xml
├── ImageSets/
│   └── Main/
│       └── default.txt
└── labelmap.txt

# labelmap.txt
# label : color_rgb : 'body' parts : actions
background:::
aeroplane:::
bicycle:::
bird:::

Pascal VOC import

Uploaded file: a zip archive of the structure declared above or the following:

taskname.zip/
├── <image_name1>.xml
├── <image_name2>.xml
└── <image_nameN>.xml

It must be possible for CVAT to match the frame name and file name from annotation .xml file (the filename tag, e. g. <filename>2008_004457.jpg</filename> ).

There are 2 options:

full match between frame name and file name from annotation .xml (in cases when task was created from images or image archive).
match by frame number. File name should be <number>.jpg or frame_000000.jpg. It should be used when task was created from video.

Segmentation mask export

Downloaded file: a zip archive of the following structure:

taskname.zip/
├── labelmap.txt # optional, required for non-VOC labels
├── ImageSets/
│   └── Segmentation/
│       └── default.txt # list of image names without extension
├── SegmentationClass/ # merged class masks
│   ├── image1.png
│   └── image2.png
└── SegmentationObject/ # merged instance masks
    ├── image1.png
    └── image2.png

# labelmap.txt
# label : color (RGB) : 'body' parts : actions
background:0,128,0::
aeroplane:10,10,128::
bicycle:10,128,0::
bird:0,108,128::
boat:108,0,100::
bottle:18,0,8::
bus:12,28,0::

Mask is a png image with 1 or 3 channels where each pixel has own color which corresponds to a label. Colors are generated following to Pascal VOC algorithm. (0, 0, 0) is used for background by default.

supported shapes: Rectangles, Polygons

Segmentation mask import

Uploaded file: a zip archive of the following structure:

  taskname.zip/
  ├── labelmap.txt # optional, required for non-VOC labels
  ├── ImageSets/
  │   └── Segmentation/
  │       └── <any_subset_name>.txt
  ├── SegmentationClass/
  │   ├── image1.png
  │   └── image2.png
  └── SegmentationObject/
      ├── image1.png
      └── image2.png

It is also possible to import grayscale (1-channel) PNG masks. For grayscale masks provide a list of labels with the number of lines equal to the maximum color index on images. The lines must be in the right order so that line index is equal to the color index. Lines can have arbitrary, but different, colors. If there are gaps in the used color indices in the annotations, they must be filled with arbitrary dummy labels. Example:

q:0,128,0:: # color index 0
aeroplane:10,10,128:: # color index 1
_dummy2:2,2,2:: # filler for color index 2
_dummy3:3,3,3:: # filler for color index 3
boat:108,0,100:: # color index 3
...
_dummy198:198,198,198:: # filler for color index 198
_dummy199:199,199,199:: # filler for color index 199
...
the last label:12,28,0:: # color index 200

supported shapes: Polygons

How to create a task from Pascal VOC dataset

Download the Pascal Voc dataset (Can be downloaded from the PASCAL VOC website)
Create a CVAT task with the following labels:
```
aeroplane bicycle bird boat bottle bus car cat chair cow diningtable
dog horse motorbike person pottedplant sheep sofa train tvmonitor
```
You can add ~checkbox=difficult:false ~checkbox=truncated:false attributes for each label if you want to use them.

Select interesting image files (See Creating an annotation task guide for details)
zip the corresponding annotation files
click Upload annotation button, choose Pascal VOC ZIP 1.1

and select the zip file with annotations from previous step. It may take some time.