A system for adjusting the position and size of a picture generated by deflecting a light source in response to a deflection current and displayed in a picture area larger than the picture includes sensors for sensing the picture arranged outside the picture and within the picture area. First and second differential amplifier both have an inverting and noninverting input terminal. A deflection voltage proportional to the deflection current is applied to the noninverting input terminal of the first differential amplifier and to inverting input terminal of the second differential amplifier. A first reference voltage is applied to the inverting input terminal of the first differential amplifier to produce a positive correction pulse in accordance with the difference between the deflection voltage and the first reference voltage. A second reference voltage is applied to the noninverting input terminal of the second differential amplifier to produce a negative correction pulse in accordance with the difference between the deflection voltage and the second reference voltage. A correction signal generator is responsive to the correction pulses and provides correction signals to the deflection circuit.