Study on the extraction method of small pipes inner surface

To study the inspection technology of small pipes inner surface,a method for extracting inner surface section was proposed based on the inner surface image analysis.Firstly,the effective image zone was extracted in terms of geometry characteristic of the light ring.Then the radius of each point on the inner surface was achieved taking the image point which has maximum gray value along the ring radial direction as the section point.The corresponding inner section was inspected based on the method.Experiments show that the measurement accuracy of the inspection method is ±0.1mm.So,the inner surface of small pipes can be inspected with this method.