1. An image processing apparatus comprising: a processor comprising a plurality of cores, each having different specifications; a first estimator that estimates a processing capability of each of the plurality of cores; a second estimator that estimates, based on the processing capability of each of the plurality of cores, a required time for each of the plurality of cores to perform a specific process; and a controller, wherein the plurality of cores comprises one or more candidate cores, the required time for each of the one or more candidate cores is equal to or less than a threshold, the controller controls one of the one or more candidate cores to perform the specific process, and the required time of the candidate core that performs the specific process is the longest among the one or more candidate cores.