Image processing apparatus and image processing method as well as image processing system

An image processing method for processing a right viewpoint image and a left viewpoint image, or multi-viewpoint images, with parallax, comprising:

• displaying an image on a monitor based on the right viewpoint image and left viewpoint image, or multi-viewpoint images, with the displayed image being used by a user for specifying an indispensable output area which the user wants to be included in a 3D image synthesized by merging the right viewpoint image and left viewpoint image, or multi-viewpoint images, together, and outputted;
• inputting through an input device information on the indispensable output area as specified by the user referring to the image as displayed on the monitor;
• causing, by a control unit, the indispensable output area to be indicated in the image as displayed on the monitor;
• and
• outputting the right viewpoint image and left viewpoint image, or multi-viewpoint images, and the information on the indispensable output area from an output device.