An electrostatic chuck includes a chuck body having a chucking surface and a back surface, an electrode within the chuck body and at least one conduit for providing fluid communication between the back surface and a chucking surface. A pixel value at each pixel position is determined as a value proportional to an absolute value of the amplitude of the magnetization vector detected for each of the pixel positions. The key landmarks may be detected using discriminative joint contexts representing combinations of multiple key landmarks. In some embodiments, the pressure vessel communicates with one or more cylinder devices to exchange air and liquid with the cylinder chamber thereof. voltage pulses, has a pulse period T in a range from about 3 to about 60 seconds, and each pulse period T includes a positive pulse duration of T from about 0. Furthermore, a drive generates is provided for generating an operating motion of the soil contact element, and an energy store is provided for storing electrical energy.