A method of operating a laundry treatment machine, the laundry treatment machine being configured to process laundry via rotation of a tub, the method comprising: sensing a first amount of the laundry in the tub; supplying water to a first water level in the tub; sensing the level of water in the tub; sensing a second amount of the laundry in the tub; and judging whether the laundry included dry laundry or wet laundry using the sensed first amount of laundry, the sensed second amount of laundry, and the sensed water level value, characterized by sensing the first amount of the laundry in the tub comprises: accelerating the tub during an acceleration section; and rotating the tub at a constant velocity during a constant velocity section; and sensing the first amount of the laundry in the tub based on a back electromotive force compensation value corresponding to average back electromotive force value during the constant velocity section and a difference between an average current command value to drive a motor that is used to rotate the tub during the acceleration section and an average current command value to drive the motor during the constant velocity section; wherein the sensed first amount of laundry increases as the difference between the average current command value to rotate the motor during the accelerated rotating section and the average current command value to rotate the motor during the constant velocity rotating section increases; and wherein as the back electromotive force compensation value increases the sensed first amount of laundry increases. sensing a first amount of the laundry in the tub; supplying water to a first water level in the tub; sensing the level of water in the tub; sensing a second amount of the laundry in the tub; and judging whether the laundry included dry laundry or wet laundry using the sensed first amount of laundry, the sensed second amount of laundry, and the sensed water level value, characterized by sensing the first amount of the laundry in the tub comprises: accelerating the tub during an acceleration section; and rotating the tub at a constant velocity during a constant velocity section; and sensing the first amount of the laundry in the tub based on a back electromotive force compensation value corresponding to average back electromotive force value during the constant velocity section and a difference between an average current command value to drive a motor that is used to rotate the tub during the acceleration section and an average current command value to drive the motor during the constant velocity section; wherein the sensed first amount of laundry increases as the difference between the average current command value to rotate the motor during the accelerated rotating section and the average current command value to rotate the motor during the constant velocity rotating section increases; and wherein as the back electromotive force compensation value increases the sensed first amount of laundry increases. accelerating the tub during an acceleration section; and rotating the tub at a constant velocity during a constant velocity section; and sensing the first amount of the laundry in the tub based on a back electromotive force compensation value corresponding to average back electromotive force value during the constant velocity section and a difference between an average current command value to drive a motor that is used to rotate the tub during the acceleration section and an average current command value to drive the motor during the constant velocity section; wherein the sensed first amount of laundry increases as the difference between the average current command value to rotate the motor during the accelerated rotating section and the average current command value to rotate the motor during the constant velocity rotating section increases; and wherein as the back electromotive force compensation value increases the sensed first amount of laundry increases.