<p>A touch system including a touch panel and a readout circuit is disclosed. The touch panel is integrated with a plurality of photosensitive elements within pixel elements, and capable of displaying at least touch position by at least an optical inputting. The touch panel provides a signal data when the touch panel is touched. The readout circuit is configured to receive the signal data and includes a transformation unit and a processing unit. The transformation unit generates a signal value based on the signal data and a transformation parameter. The processing unit executes a specific action when the signal value is less than a preset value.</p>
