If you means the traffic warning sign recognition, here is an example on MathWorks website:

http://www.mathworks.com/help/vision/examples/traffic-warning-sign-recognition.html

I hope it helps.

https://www.mathworks.com/help/gpucoder/examples/code-generation-for-traffic-sign-detection-and-recognition-networks.html

Prerequisites

• CUDA enabled NVIDIA® GPU with compute capability 3.2 or higher.
• NVIDIA CUDA toolkit and driver.
• NVIDIA cuDNN library v7 or higher.
• Environment variables for the compilers and libraries. For more information, see Environment Variables.
• Deep Learning Toolbox™ to use a SeriesNetwork object.
• Image Processing Toolbox™ for reading and displaying images.
• Computer Vision Toolbox™ for the video reader, viewer, and Non-Maximal Suppression (NMS) used in the example.

I don understand what you nedd. The sign function?