VISUAL PATTERN RECOGNITION IN ROBOTICS
Ashwin Patani, Miloni Ganatra · 2014
Visual Pattern Recognition in Robotics: Real-time pattern recognition algorithm to detect & recognize the sign-board consists of 3 steps : Color-based filtering, locating sign(s) in an image and detection of pattern of the sign. Very good results are obtained for the 2nd & 3rd steps and the first one is having tough challenges. The standard technique for detecting and recognizing road signs consists of three steps (Lalonde and Li, 1995). First, color segmentation or color thresholding is applied to emphasize possible signs in an image. Thus, restricting the search area in the image. Second, template matching is applied for shape detection. Third, specific signs are detected using template matching or neural networks. In this part, a specialized robust color filter is applied on the image to mark the red circle surrounding the sign board pattern. The algorithm has to use a broad definition of red and white colors since various intensities and saturations can occur in real images (depending on weather, day/nightlight, etc.). On the other hand, only red color on traffic signs should be detected to minimize the number of starting points for the pattern recognition algorithm. Thus, detection of red color outside a traffic sign (like on buildings, cars, etc.) should be minimized. Detection and recognition are two major steps for determining types of traffic signs. Detection refers to the task of locating the traffic signs in given images. Where recognition requires some knowledge base, or specific criteria to understand what pattern is showing. Based on that pattern, control signal will be sent to robot and robot will move in that specified direction.