Automated image interpretability assessment by edge profile analysis of natural targets

초록

While ground sampling distance has been misleadingly used as the most popular measure of image quality among image providers, satellite manufacturers and general public, user community may be keen to the interpretability of remotely sensed imagery. As one measure of image interpretability, the NIIRS (National Imagery Interpretability Rating Scale) has been used. Currently, this measure is included in the metadata of some high resolution satellite images. Traditionally, the NIIRS is estimated by deploying specially made tarps of uniform reflectance. Due to this, estimating NIIRS is costly and not carried out often. Our previous study evaluated the possibility of using natural targets available in the image for NIIRS estimation. The purpose of this study is to automate the NIIRS estimation by extracting and analyzing edge profiles of natural targets automatically. First we apply simple edge selection criteria for finding good candidates for edge profile analysis. Then we scan through perpendicular to edge directions around the candidate point for constructing edge profiles. From edge profiles, parameters for the GIQE and NIIRS are calculated. We compared the NIIRS values obtained through automated edge analysis with the values from human operators and with the NIIRS values provided in the image metadata. The results showed that automated NIIRS estimation provided comparable results to the NIIRS from manual edge selection. This indicates that NIIRS values can be estimated for all images without special arrangement. The contribution of this study is that we provided the feasibility of the automated edge analysis method for calculating NIIRS values so that the value of NIIRS is systematically calculated at satellite ground stations