1. An anomalous shadow detection system comprising anomalous shadow detecting means for detecting a suspected anomalous shadow from image data descriptive of an inputted image according to a prescribed detection process, and image output means for outputting information including at least information identifying the detected suspected anomalous shadow, wherein the image output means further outputs value(s) of one or more standard parameters concerning the suspected anomalous shadow together with the information including at least the information identifying the suspected anomalous shadow.