The objective of region-of-interest (ROI) detection is to identify portions of an image that contain targets. It is an important procedure for reducing data volume without losing important target information. The proposed algorithm aims at generating accurate representations of the ROIs such that each ROI covers one complete target. In addition, computation of the proposed algorithm is reduced by making use of information such as image resolution and approximate size of the targets. For this purpose, a multiscale, hierarchical architecture is developed. Results of the ROI detection in low-quality aerial imagery are provided to illustrate the effectiveness of the proposed algorithm.