The image format is structured as follows:
- The images contain one traffic sign each.
- Images contain a border of 10 % around the actual traffic sign (at least 5 pixels) to allow for edge-based approaches.
- Images are stored in PPM format – Portable, Pixmap, and P6 (http://en.wikipedia.org/wiki/Netpbm_format).
- Image sizes vary between 15 x 15 and 250 x 250 pixels.
- Images are not necessarily squared.
- The actual traffic sign is not necessarily centered within the image. This is true for images that were close to the image border in the full camera image.
- The bounding box of the traffic sign is a part of the annotations, which we will see in the following section.
The following are examples of a few classes:
- ( 0, b'Speed limit (20 km/h)') ( 1, b'Speed limit (30 km/h)')
- ( 2, b'Speed limit (50 km/h)') ( 3, b'Speed limit (60 km/h)')
- ( 4, b'Speed limit (70 km/h)') ( 5, b'Speed limit (80 km/h)')
- ( 6, b'End of...
