The invention provides a method for improving efficiency of a filter bank. In the method, at least first data is determined, which is at least one of the following: the power input in the actuator, the crushing force, the particle distribution of the crushed material produced by the crusher, or the quantity of crushed material produced by the crusher. A 90 degree gear box driven by the engine is mounted below the plate and drives the pump of which the axis of rotation is horizontal. The optically anisotropic layer contains a discotic compound having a discotic plane. The control and capture unit sends a signal to each of the cameras to execute the preset in the order queued in order to capture an image taken by the camera at each of said preset. A backing reflector transverse to said first plane.