  In this paper, a bridge member damage cause estimation framework is proposed
by calculating the image position using Structure from Motion (SfM) and
acquiring its information via Visual Question Answering (VQA). For this, a VQA
model was developed that uses bridge images for dataset creation and outputs
the damage or member name and its existence based on the images and questions.
In the developed model, the correct answer rate for questions requiring the
member's name and the damage's name were 67.4% and 68.9%, respectively. The
correct answer rate for questions requiring a yes/no answer was 99.1%. Based on
the developed model, a damage cause estimation method was proposed. In the
proposed method, the damage causes are narrowed down by inputting new questions
to the VQA model, which are determined based on the surrounding images obtained
via SfM and the results of the VQA model. Subsequently, the proposed method was
then applied to an actual bridge and shown to be capable of determining damage
and estimating its cause. The proposed method could be used to prevent damage
causes from being overlooked, and practitioners could determine inspection
focus areas, which could contribute to the improvement of maintenance
techniques. In the future, it is expected to contribute to infrastructure
diagnosis automation.
