If you have access to ground truth of masked objects (some can be found online), then one way to quantify the performance is to retrieve objects after doing superpixel segmentation and apply the Intersection over Union (IoU) method.
You can refer to this article: "Comparison and evaluation of methods for liver segmentation from CT datasets"
Five measures are described: Volumetric Overlap Error, Relative Volume Difference, Average Symmetric Surface Distance, Root Mean Square Symmetric Surface Distance and Maximum Symmetric Surface Distance. Other popular measures include DICE and Hausdorff Distance .