Recently, robots utilizing UAV (Unmanned Aerial Vehicle) or the like for next generation social infrastructure are developed, and acquisition of images for inspection of concrete structures is becoming more efficient. It is also expected to develop an effective image processing system against large amount of data, to maintain and manage an enormous number of structures efficiently. In this paper, we propose an image processing method for reliable evaluation, and it realizes efficient visual

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... ection of concrete structures. At first, we propose a semi-automatic crack extraction method in which an operator roughly specifies the position of cracks on the image. We also propose applying super-resolution and an evaluation method of crack width using a crack scale. Furthermore, we propose an image synthesis method that corrects lens distortion aberration using only the straight line on the image and interpolates occlusion using multiple images from different viewpoints. Experimental results show that cracks can be extracted with high accuracy by the semi-automatic processing even in low spatial-resolution and low contrast images. And it also suppresses the calculation cost and the photographing cost, compared to the conventional method.