A process and system of energy signal detection, which improves sensitivity, performance and reliability thereof and reduces false alarms by distinguishing between noise and real signals, includes the steps of receiving a plurality of data samples and generating a predetermined number of constructed sample windows of constructed samples in time, determining a control range for each of said constructed sample windows, determining whether there is an alarm pre-condition by comparing relationship between successive constructed sample windows, and generating an output signal when the alarm pre-condition is qualified, and detecting white light for preventing false alarm created by the white light.