In many practical situations on the factory floor or in nature sciences, a task of the detection of circular objects is encountered. In technical reality, rolling elements are of great usability, while in nature sciences, biological objects are usually circular as they optimize the area-to-perimeter ratio. Two problems are major concern here: either the objects searched for are difficult to distinguish or the detection is to be performed in real time. The first problem is due to non-even illumination, low-contrast, noise or restricted, partial visibility of objects.