To detect a car trailer its very hard. There're a lot of car trailers that has the same license plate as the car itself. To detect if its a trailer I need to search in a area around the license plate. I already are making a detector for the license plate with Viola and Jones. Only to detect if there is a triangle you don't see very clearly on the image. The images coming from section control so a lot of different thresholds in the day time.
For the privacy I have to delete the license plate details
So my question are there special ways of image processing that would be help full. I thought about: - canny - adapting threshold - Image Gradients
But big difficulty is that the application needs to be real-time.