Houghtool--a software package for the use of the Hough transform. The Hough Transform (HT) is a popular method for detecting curve segments in an image. A software package, the Houghtool, is proposed to calculate the HT. Several methods for line detection are implemented in the package. These include new HT techniques such as probabilistic approaches which use random sampling of the input points. The aim of the Houghtool is to provide general tools for the design of new algorithms and to provide solutions to specific applications. The software design is flexible to allow user extension of the tools provided. A graphical user interface, the XHoughtool, is provided for the visualization of the HT calculation.