The spatial resolution performance of a fibre-optic reflectometric technique for the automatic detection and measurement of surface cracks

摘要: We present an analysis of the spatial resolution achievable with a new fibre-optic reflectometric technique, contrived by authors for automatic detection cracks in inner sides steam generator tubes small diameter (20 mm). An analytical expression modulation transfer function (MTF) our measurement system is obtained, from which limit technique defined. Experimental values MTF, measured first laboratory prototype, are compared theoretical predictions and range validity expressions discussed. Also, some results obtained second-generation prototype presented, it being demonstrated that parallel spacing 50 µm between adjacent edges can be resolved practical inspection tasks.