Line and streak detection on polished and textured surfaces using line integrals
M. Sezer Erkılınç, Mustafa Musa Jaber, Eli S. Saber, Robert E. Pearson · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2011
In this paper, a framework for detecting lines in a polished or textured substrate is proposed. Modules for image capture, rectification, enhancement, and line detection are included. If the surface being examined is specular (mirror-like), the image capture will be restricted, that is, the camera has to be fixed off-axis in the zenith direction. A module for image rectification and projection is included to overcome this limitation in order to yield an orthographic image. In addition, a module for image enhancement that includes high-boost is employed to improve the edge sharpness and decrease the spatial noise in the image. Finally, a line-integral technique is applied to find the confidence vectors that represent the spatial positions of the lines of interest. The Full-Width at Half-Max (FWHM) approximation is applied to determine the corresponding lines in a target image. Experimental results show that our technique has an effective performance on synthetic and real images. Print quality assessment is the main application of the proposed algorithm; however, it can be used to detect lines/ streak in prints, on substrate or any type of media where lines are visible.