For this road marking inspection application, the customer was looking for a machine vision camera system because he had already performed some tests with a consumer camera but ran into limitations here. The customer wanted to inspect road markings while driving. The camera recordings would be 8 hours per day, in a daylight environment.

Machine vision camera selection

To get the right set up, start by selecting the right industrial camera. In this road marking inspection case, we recommend an MARS-1840-63GTC camera. The customer specified in his application that he was looking for an industrial camera with at least 4k resolution (4096 × 2160 pixels) and 60 frames per second. This color 10GigE camera has these specifications and is the best option we can offer.

Another important fact was that the images will be taken when the camera is moving, in which case we recommend a global shutter camera. Further explanation of the difference between global and rolling shutter cameras is explained in this article from our knowledge center: Rolling Shutter vs Global Shutter

Lens for GMAX2518 sensor

The chosen 10GigE 18MP camera for this road marking inspection vision system has a GMAX2518 sensor, this is a 1’’ sensor. A helpful tool to determine which lens is best suited for this vision system is our Lens calculator tool.

In the application, the customer indicated that he had a relatively large field of view. He wanted to be able to see approximately between 10 and 13 meters. By using the lens calculator and its advanced options, you can calculate what your final field of view will be with the recommended focal length. As you can see, that amounts to 11229 x 10230 millimeters and that was sufficient for the customer. 
The customer also indicated in the application that he wanted to use a working distance between 3 and 6 meters. In the calculation above, you can see that we used a working distance of 6 meters. It was also important to the customer that with this set up the customer would have an opening angle of 90 - 100 degrees horizontal field of view. The combination of a camera with a 1' sensor and a 6mm lens gives an opening horizontal angle of 95 degrees, so this is sufficient.
In the next step, we will look for a suitable 6mm lens. Since the camera has a 1’ sensor, we have to look for a lens with an equal or larger sensor size. In this case, we selected the LCM-10MP-06MM-F1.8-1.1-ND1 lens.

Lighting for road marking inspection

On this particular road marking inspection project, the client indicated that they did not want to use machine vision lighting. This is because the images will only be taken in daylight. If you want to develop a similar application in the dark, it is of course advisable to use lighting for this. A good lighting solution for this would be our NIR LED spotlight, VA3-SL-110x90-IR940. This LED spotlight is suitable for the NIR range of 940NM and features 28 watts. If the horizontal opening angle of your camera and lens set up is greater than 20 degrees, we strongly recommend using at least 2 of these LED spotlights. This way, you will create more uniform lighting. 
If you would like advice on which lighting would best suit your application, please contact us.

Image processing software for road marking inspection

A machine vision application is not complete without the use of appropriate image processing software. For this road marking inspection application, the customer wanted to make recordings of about 8 hours a day, divided into 10-minute recordings. For this type of application, we generally recommend the IOI 2nd Look software. You can download a free demo version from our website.

IO Industries' 2ndLook software for Windows and Linux is a flexible, cost-effective tool designed for recording video from industrial GigE and USB3 Vision cameras in the factory or research lab. Troubleshooting a production process and recording scientific experiments are common applications for this easy-to-use video recording software. 2ndLook has been tested with an extensive list of video cameras commonly used in industrial and scientific applications.

Support for road marking inspection

Would you like to have support from one of our machine vision experts for creating your own road marking inspection vision system? We look forward to helping you in finding the right set up, please contact us via the form below!