A wind turbine blade has at least one lightning receptor, wherein at least part of a surface of the wind turbine blade close to the lightning receptor is covered by a protective layer having electrical and thermal insulating material. In the invention, on the top signal layer and power path of the bottom solder layer for layout of the main bridge chip and on the power ring, the decoupling capacitors are connected in between the ground bonding padssolder balls and the power bonding padssolder balls of the power paths and power rings, so as to provide a stable power supply for the operation of the main bridge chip. A combiner combines the control signal with a drive signal for the generator motor and supplies the combined signal through a power controller to the generator motor. Grown regions are counted as indicating mitotic figures by thresholding region number, area and luminance.