Method and system for robust tilt adjustment and cropping of license plate images

A system for tilt adjustment and cropping of license plate images, said system comprising:

• a processor;
• a data bus coupled to said processor;
• and
• a computer-usable medium embodying computer program code, said computer-usable medium being coupled to said data bus, said computer program code comprising instructions executable by said processor and configured for:
• converting an image of a vehicle into a binary image, said image of said vehicle including data indicative of a license plate of said vehicle and license plate characters thereof;
• removing a long run within a binary image and applying a morphological filtering to break an unwanted connection between said license plate characters due to a license plate frame and an image noise;
• identifying and screening a connected component within said binary image based on a plurality of key metrics to remove all but the most likely candidate character connected components from said binary image;
• and
• performing a line-fit based iterative search for a tilt removal and a vertical cropping of said binary image to obtain a tight bounding box with respect to said license plate characters if a sufficient candidate character remains after performing said line-fit based iterative search, thereby removing any inherent tilt and obtaining a vertically cropped license plate image based on said image of said vehicle.

A processor-readable medium storing code representing instructions to cause a process to perform a process for tilt adjustment and cropping of license plate images, said code comprising code to:

• convert an image of a vehicle into a binary image, said image of said vehicle including data indicative of a license plate of said vehicle and license plate characters thereof;
• remove a long run within a binary image and apply a morphological filtering to break an unwanted connection between said license plate characters due to a license plate frame and an image noise;
• identify and screen a connected component within said binary image based on a plurality of key metrics to remove all but the most likely candidate character connected components from said binary image;
• and
• perform a line-fit based iterative search for a tilt removal and a vertical cropping of said binary image to obtain a tight bounding box with respect to said license plate characters if a sufficient candidate character remains after performing said line-fit based iterative search, thereby removing any inherent tilt and obtaining a vertically cropped license plate image based on said image of said vehicle.