A device for obtaining an image includes a projector configured to project light having a preset pattern to an object, a first camera configured to sense light reflected and fed back by the object to obtain a depth image, a second camera configured to obtain a color image of the object, a motion sensor configured to sense a motion of the device. The device also includes and a processor configured to obtain a color image and a plurality of depth images of the object, by changing a parameter about the projected light and the light sensed by the first camera. When the motion of the device is less than a threshold, the processor is configured to merge pieces of depth information respectively obtained from the plurality of depth images with each other, and obtain a 3D image of the object, based on the merged depth information and the color image.