An Enhanced Block Based Edge Detection Technique Using Hysteresis Thresholding

Abstract

Edge detection is a crucial step in various image processing systems like computer vision , pattern recognition and feature extraction. The Canny edge detection algorithm even though exhibits high accuracy, is computationally more complex compared to other edge detection techniques. A block based distributed edge detection technique is presented in this paper, which adaptively finds the thresholds for edge detection depending on block type and the distribution of gradients in each block. A novel method of computation of high threshold has been proposed in this paper. Block-based hysteresis thresholds are computed using a non uniform gradient magnitude histogram. The algorithm exhibits remarkably high edge detection accuracy, scalability and significantly reduced computational time. Pratt's Figure of Merit quantifies the accuracy of the edge detector, which showed better values than that of original Canny and distributed Canny edge detector for benchmark dataset. The method detected all visually prominent edges for diverse block size.

Smart Transport System using Automatic Number Plate Recognition

“…Based on gradient histograms threshold values can be set [13]. The distribution of gradients in each block and thresholds for the detected edges is found [14]. The contours of the vehicle can be found using Canny Algorithm [15].…”