1. An image processing method comprising: repetitively updating image data; detecting an object satisfying predetermined conditions from the image data and find coordinates of the object; displaying a detection result indicating a region where the object is detected by overlapping the image based on the coordinates of the object; and measuring time during a continuing display of the detection result, wherein when the object cannot be detected during the display of detection result and the time of continuing display of the detection result does not reach predetermined time, the detection result is continuously displayed on the display unit based on the coordinates of the object detected before, and when the time of continuing display of the detection result reaches predetermined time, display of the detection result is erased.