PROBLEM TO BE SOLVED: To determine whether or not a specific plant exists even in a situation that soil appears as well as a tree in one part. SOLUTION: The method includes: a step (A) of calculating a first degree of similarity between spectral data of a checking target and a reference spectral data of the tree regarding a region including at least a first region out of a visible light region, where a feature of the tree appears; a step (B) of calculating a second degree of similarity between a spectral data of a checking target and a reference spectral data of the tree regarding a region including at least a second region out of a near infrared light region, where a feature of the tree appears; a step (C) of calculating a third degree of similarity by weighting and adding the first degree of similarity and the second degree of similarity; and a step (D) of comparing the third degree of similarity with a predetermined threshold. The weight of the first degree of similarity is larger than the weight of the second degree of similarity. COPYRIGHT: (C)2013,JPO&INPIT
