Straight line extraction in binary drawings using morphological operations

In the analysis of grayscale images, straight line segments are usually extracted by using the Hough Transform method. Straight line detection using Hough Transform has the disadvantage that detecting peaks in the accumulator array is not always a reliable process. Thus, a significant amount of error may result. In this paper, we propose to extract straight line segments from binary images using binary morphological operations. In addition to the endpoint coordinates, the width of a line segment can also be reliably computed in the process. In the proposed approach, a set of line-shaped fixed-length structuring elements with orientation ranging from 0 to 180 degrees is used to extract line segments of all orientations. The algorithm is flexible for different applications. Line segments of different thickness, length, and orientation can be extracted with high precision. Experiment results we obtained on engineering map drawings demonstrate the good performance of the algorithm.