Heterojunction adjustable threshold three color detectors (ATCDs) have been shown to detect the three fundamental colors of the visible spectrum under three different bias conditions. Operation has already been demonstrated under steady-state conditions and has been proven in transient conditions at video rates. We assumed that a large area array was scanned row by row and each pixel was addressed by a reading pulse during each array sweep. Between two reading pulses, the pixel is open circuit, discharging through recombination of excess carriers. The driving waveform is three fold-valued and the correct readout requires more than one sequential sweep of the array for each value of the waveform. The exact number of sequential sweeps required for correct sensing also depends on the time duration of the reading pulses, and under particular conditions, it can be reduced to two.