An active pixel comprises a sensor circuit for collecting radiation induced charges and transducing them to a measurement signal corresponding to the amount of charge collected, and a capacitor element with two nodes, where the measurement signal is present on a node of the capacitor element. The memory circuit is clocked, i.e. driven by a pulsed signal. The pulse on the memory circuit will rise the reset level at the output, which is lowered due to threshold voltage losses in the active pixel circuit, thus restoring a large signal swing. Arrays of the pixels are described, as well as a method for reading out such a pixel.