Method for advanced and low cost cross traffic alert, related processing system, cross traffic alert system and vehicle

A method for Cross Traffic Alert, comprising:

• receiving a sequence of image frames from a camera mounted on a vehicle;
• processing said sequence of image frames in order to generate Optical Flow data for each image frame comprising Motion Vectors indicating the motion of features in a current image frame compared with same features in a previous image frame;
• filtering said Optical Flow data, as a function of an orientation of each Motion Vector, to generate a reduced set of Optical Flow data comprising Motion Vectors for only the features which are lying in a road;
• calculating a Vanishing Point which is a mean point of intersections of straight lines passing through the Motion Vectors of the reduced set of Optical Flow data;
• calculating a Horizontal Filter subset by:
• receiving a Bound Box list of a previous image frame;
• checking the Bound Box list of the previous image frame and maintaining in an Optical Flow data subset the Motion Vectors of the Bound Box list of the previous image frame;
• and
• performing a Horizontal Check wherein the Motion Vectors outside the Bound Box list of the previous image frame are checked to identify horizontal Motion Vectors to be maintained in the Optical Flow data subset, wherein the Motion Vector is considered horizontal, when the following two conditions are both satisfied:
• an orientation of the Motion Vector lies within a certain degree range of a horizontal orientation;
• and
• an orientation difference between the orientation of the Motion Vector and an orientation of the Motion Vector translated on the calculated Vanishing Point exceeds a threshold;
• clustering the Horizontal Filter subset to generate the Bound Box list for a current image frame which includes transversally approaching moving objects;
• and
• outputting said Bound Box list for the current image frame to an Alert Generation device.