1. An apparatus for processing moving image data so as to obtain stationary image data representative of a desired image picture and suitable for display on a display device, said apparatus comprising: means for designating a first region in an image picture; motion detecting means for detecting motion in the designated first region in accordance with at least one motion detection coefficient, in which each said motion detection coefficient is setable by an operator to a desired value; interpolating means for interpolating the image data in accordance with the motion detection results by use of a predetermined interpolation technique; means for causing the interpolated image data to be outputted for display on the display device for observation by the operator; and means, operative when the operator determines that the display is unacceptable, for performing one of (i) designating a second region in the image picture, detecting motion in the second designated region in accordance with the at least one motion detection coefficient, interpolating the image data in accordance with the motion detecting results of the second designated region and causing the latest interpolated image data to be outputted for display on the display device for observation by the operator and (ii) resetting at least one said motion detection coefficient, detecting motion in the first designated region in accordance with the at least one reset motion detection coefficient, interpolating the image data in accordance with the latest motion detecting results of the first designated region and causing the latest interpolated image data to be outputted for display on the display device for observation by the operator.