A method of generating a hologram using redundancy of a 3D video, the method comprising: comparing a color image of a current 3D image frame and a color image of a previous 3D image frame to output an intensity difference value and comparing a depth image of the current 3D image frame and a depth image of the previous 3D image frame to output a depth difference value; determining a 3D point (721, 741) that has changed among 3D points contained in the current 3D image frame based on the intensity difference value and the depth difference value as a difference 3D point; generating an update map for indicating that the difference 3D point needs to be updated; determining a 3D point related to the difference 3D point (721, 741) among the 3D points contained in the current 3D image frame as a phantom 3D point, wherein the phantom 3D point corresponds to a 3D point causing a phantom image effect due to a 3D point blocked by the difference 3D point in depth direction; modifying the generated update map for indicating additionally that the phantom 3D point needs to be updated; and generating a hologram of the current 3D image frame based on the modified update map, wherein comparing the current 3D image frame and the previous 3D image frame comprises: calculating the intensity difference value between the color image of the current 3D image frame and the color image of the previous 3D image frame; calculating the depth difference value between the depth image of the current 3D image frame and the depth image of the previous 3D image frame; and calculating a final difference value by adding the intensity difference value and the depth difference value, and wherein determining the 3D point (721, 741) that has changed comprises determining the 3D point (721, 741) for which the final difference value exceeds a threshold value as the difference 3D point. comparing a color image of a current 3D image frame and a color image of a previous 3D image frame to output an intensity difference value and comparing a depth image of the current 3D image frame and a depth image of the previous 3D image frame to output a depth difference value; determining a 3D point (721, 741) that has changed among 3D points contained in the current 3D image frame based on the intensity difference value and the depth difference value as a difference 3D point; generating an update map for indicating that the difference 3D point needs to be updated; determining a 3D point related to the difference 3D point (721, 741) among the 3D points contained in the current 3D image frame as a phantom 3D point, wherein the phantom 3D point corresponds to a 3D point causing a phantom image effect due to a 3D point blocked by the difference 3D point in depth direction; modifying the generated update map for indicating additionally that the phantom 3D point needs to be updated; and generating a hologram of the current 3D image frame based on the modified update map, wherein comparing the current 3D image frame and the previous 3D image frame comprises: calculating the intensity difference value between the color image of the current 3D image frame and the color image of the previous 3D image frame; calculating the depth difference value between the depth image of the current 3D image frame and the depth image of the previous 3D image frame; and calculating a final difference value by adding the intensity difference value and the depth difference value, and wherein determining the 3D point (721, 741) that has changed comprises determining the 3D point (721, 741) for which the final difference value exceeds a threshold value as the difference 3D point. calculating the intensity difference value between the color image of the current 3D image frame and the color image of the previous 3D image frame; calculating the depth difference value between the depth image of the current 3D image frame and the depth image of the previous 3D image frame; and calculating a final difference value by adding the intensity difference value and the depth difference value, and wherein determining the 3D point (721, 741) that has changed comprises determining the 3D point (721, 741) for which the final difference value exceeds a threshold value as the difference 3D point.