1. An image processing apparatus comprising: a storage configured for storing image data comprising data of a first model; and a processor configured for determining a final model parameter set and a final inlier scale of the first model by iteratively performing a model estimation process and an inlier scale estimation process, wherein the model estimation process determines a model parameter set from the image data by using an initial inlier scale, and the inlier scale estimation process determines an inlier scale by using the model parameter set, wherein when the model estimation process is repeated, and in the repeated model estimation process, a new model parameter set is determined by using a previously determined inlier scale which was determined during an immediately previously determined inlier scale estimation process, wherein in the inlier scale estimation process, a new inlier scale is determined using a model parameter set determined according to an immediately previously performed model estimation process, wherein the image data comprises data of multiple models including the first model and a second model, wherein the processor is further configured for: performing an inlier removal process whereby first inlier data indicating inliers located within the final inlier scale of the first model is removed from the image data based on the final model parameter set and the final inlier scale of the first model, and performing a final determination process whereby a final model parameter set and a final inlier scale of the second model are determined by iteratively performing the model estimation process and the inlier scale estimation process on the image data from which the first inlier data has been removed, wherein the model estimation process is performed using Maximum Feasible Subsystem (MaxFS) as a deterministic method, and wherein the inlier scale estimation process is performed using Iterative Kth Ordered Scale Estimator (IKOSE).