System and method for recognizing speed limit sign using front camera

A system for recognizing a speed limit sign, comprising:

• an image acquisition unit for acquiring a front image using a front camera;
• a traffic sign detector for detecting a traffic sign from the acquired front image using a Haar-Feature based Viola-Jones Adaptive Boosting (Adaboost) algorithm, which is used for object detection;
• a recognition unit for recognizing an internal numeral in the detected traffic sign;
• a tracking unit for tracking a traffic sign continuously appearing in the front image, and eliminating a temporarily misrecognized object;
• and
• a decision unit for determining a result of speed limit recognition on the recognized traffic sign,
• wherein the traffic sign detector comprises a horizontal detector and a vertical detector, and
• wherein a region of overlap of the horizontal detector and the vertical detector comprises an actual traffic sign region.

A system for recognizing a speed limit sign, comprising:

• an image acquisition unit for acquiring a front image using a front camera;
• a traffic sign detector for training with a traffic sign image (positive sample), which is an object to be actually recognized, and a non-traffic sign image (negative sample) with respect to the acquired front image using a Haar-Feature based Viola-Jones Adaptive Boosting (Adaboost) algorithm, and determining whether a sub-window, which is received using a scan-window search scheme with respect to a region of interest (ROI) of the front image, corresponds to an actual traffic sign or a non-traffic sign;
• a recognition unit for recognizing an internal numeral using a support vector machine (SVM) with respect to a region which is determined as a traffic sign region in a detection result of the traffic sign detector, and calculating an actual limit speed;
• a tracking unit for tracking a traffic sign continuously appearing in the front image and eliminating a temporarily misrecognized object, wherein the tracking unit tracks the traffic sign according to template matching, sets the inside of a traffic sign recognized in an image of time “t” as a template, limits a region of interest (ROI) in an image of time “t+1” on the basis of a moving speed of a corresponding vehicle, updates tracking contents when a traffic sign exists in the limited region of interest, and maintains a previous state when a traffic sign does not exists in the limited region of interest;
• and
• a decision unit for determining the traffic sign being currently recognized to have passed and terminating tracking when the traffic sign has not been tracked during three or more frames, accumulating probability values of the respective traffic signs which are outputted as the results of an SVM with respect to tracking-terminated objects, and determining a traffic sign having the greatest probability value as a final result.