1. In a digital medium environment including an image processing application that performs object segmentation on an input image, an improved object segmentation method implemented by the image processing application, the method comprising: receiving an input image that includes an object region to be segmented; processing the input image to provide a first segmentation that defines the object region, said processing comprising: parsing the input image to provide a probability mask which classifies individual pixels in the input image; determining, from a database, multiple images which have layouts at least similar to a layout of the input image, wherein the multiple images include respective masks; processing the respective masks to provide a weighted average mask; and combining the probability mask and the weighted average mask to provide the first segmentation; and processing the first segmentation to provide a second segmentation that provides pixel-wise label assignments for the object region.