1. A method implemented by one or more computing devices, the method comprising: receiving an indication of a user-defined region in at least one of a plurality of stereoscopic images of an image scene, the receiving including detecting user interaction with a smoothness tool in a user interface that is used to display the at least one of the plurality of stereoscopic images; and calculating stereo correspondence of image data of the plurality of stereoscopic images of the image scene, the calculating performed based at least in part on the user-defined region as indicating a smoothness in disparities to be calculated for pixels in the user-defined region.