A circuit controller for controlling a pixel circuit, the pixel circuit comprising: a first capacitor having a first capacitor terminal and a second capacitor terminal, a first switch for electrically coupling, when switched-on, the first capacitor terminal to a voltage source for generating a reference voltage (Vref), a photo diode for accumulating charge carriers upon exposure to incident light, the photo diode having a cathode and an anode, the anode being electrically coupled to the second capacitor terminal, a second switch for electrically coupling, when switched-on, the cathode to the first capacitor terminal, a sampling circuit having an input electrically coupled to the first capacitor terminal for sampling a voltage value at the first capacitor terminal, the circuit controller being configured for switching on the first switch and the second switch for a first reset time period, after the first reset time period, switching off the second switch for accumulating the charge carriers in the photo diode for an accumulation time period, during the accumulation time period, switching off the first switch, and controlling the sampling circuit to sample a first reference voltage value (Vref1), after the accumulation time period, switching on for a selected transfer time period the second switch for transferring the charge carriers to the first capacitor, after the selected transfer time period, switching off the second switch and controlling the sampling circuit to sample a first signal voltage value, wherein the circuit controller is configured for controlling the sampling circuit to sample a second signal voltage value during the selected transfer time period, after sampling the first signal voltage value, switching on the first switch and the second switch for a second reset time period, after the second reset time period, switching off the first switch, and controlling the sampling circuit to sample a second reference voltage value (Vref2) while the second switch is on. a first capacitor having a first capacitor terminal and a second capacitor terminal, a first switch for electrically coupling, when switched-on, the first capacitor terminal to a voltage source for generating a reference voltage (Vref), a photo diode for accumulating charge carriers upon exposure to incident light, the photo diode having a cathode and an anode, the anode being electrically coupled to the second capacitor terminal, a second switch for electrically coupling, when switched-on, the cathode to the first capacitor terminal, a sampling circuit having an input electrically coupled to the first capacitor terminal for sampling a voltage value at the first capacitor terminal, the circuit controller being configured for switching on the first switch and the second switch for a first reset time period, after the first reset time period, switching off the second switch for accumulating the charge carriers in the photo diode for an accumulation time period, during the accumulation time period, switching off the first switch, and controlling the sampling circuit to sample a first reference voltage value (Vref1), after the accumulation time period, switching on for a selected transfer time period the second switch for transferring the charge carriers to the first capacitor, after the selected transfer time period, switching off the second switch and controlling the sampling circuit to sample a first signal voltage value, wherein the circuit controller is configured for controlling the sampling circuit to sample a second signal voltage value during the selected transfer time period, after sampling the first signal voltage value, switching on the first switch and the second switch for a second reset time period, after the second reset time period, switching off the first switch, and controlling the sampling circuit to sample a second reference voltage value (Vref2) while the second switch is on.