1. An image correction method comprising: computing, from a feature value of an input image, a plurality of scene belonging rates each of which prescribes a probability with which the input image belongs to each category scene; computing a combined correction parameter that is a weighted average of by-scene correction parameters using the plurality of scene belonging rates and an unknown scene belonging rate that prescribes a probability with which the input image belongs to an unknown scene; and performing image correction processing for the input image using the combined correction parameter; wherein said computing a combined correction parameter computation includes computing the combined correction parameter by further using a by-scene erroneous class cation weight value.