1. An image data processing apparatus, comprising: processing circuitry configured to: receive image data that is representative of a fetus; display a plurality of options relative to color to a user; determine one standard color based on a selected option from the plurality of options by the user; and render, using the determined standard color, an image of at least part of the fetus from the image data, wherein the processing circuitry is configured to display each option representative of respective different human skin colors and determine the standard color based on the selection of one of the displayed plurality of options.