Depth imaging device and driving method thereof

A depth imaging device, comprising:

• a first camera;
• a second camera, wherein the first camera and the second camera form a first depth imaging system;
• a projection element, wherein the projection element and the second camera form a second depth imaging system, wherein a distance between the projection element and the second camera is not equal to a distance between the first camera and the second camera;
• and
• a control unit, electrically connected to the first camera, the second camera and the projection element, wherein the control unit is configured to instruct one of the first depth imaging system and the second depth imaging system to acquire a depth map and a confidence map corresponding to the depth map, and determine whether each of confidence values in the confidence map is smaller than a confidence threshold value, if each of the confidence values is smaller than the confidence threshold value, the control unit turns on the other one of the first depth imaging system and the second depth imaging system, if at least one of the confidence values is not smaller than the confidence threshold value, the control unit determines whether a closest distance in the depth map falls within a predetermined range, if the closest distance falls within the predetermined range, the control unit does not turn on the other one of the first depth imaging system and the second depth imaging system, and if the closest distance is not within the predetermined range, the control unit turns on the other one of the first depth imaging system and the second depth imaging system.