System for preventing drunk driving and method for controlling the same

A drunk driving prevention system comprising:

• a camera configured to capture images of a face of a driver seated in a driver's seat of a vehicle;
• a sensor module configured to, during breath-checking of the driver of the vehicle, measure alcohol content in the driver's exhaled breath;
• and
• a control module configured to:
• perform, based on the image captured by the camera, the breath-checking;
• determine whether the breath-checking is completed,
• determine, based on the measured alcohol content, whether the driver is intoxicated;
• and
• determine, based on the determining whether the driver is intoxicated, whether or not to block starting of an engine of the vehicle;
• wherein the control module is configured to:
• calculate a first estimated breathing period from a change to a shape of the driver's mouth in the image captured during the breath-checking;
• and
• check whether a breath in the captured image matches a breath pulled into the sensor module based on a comparison between the first estimated breathing period and a second estimated breathing period determined from a change to a breath volume pulled in the sensor module to complete the breath-checking.