NONCONTACT LASER INSPECTION FOR THE INNER WALL SURFACE OF A PIPE

A non-contact laser sensor based on the ring optical cutting image met hod to measure the size and profile of the inner wall of a pipe is dev eloped. The sensor consists of a laser diode light source, an optical ring pattern generator and a CCD camera. The optical ring pattern from the optical ring pattern generator is projected onto the inner wall o f the pipe, which is then viewed by the CCD camera. Reasonable paramet ers according to the theory of light scattering and reflection are cho sen to simulate and optimize the measurement system. The adaptive weig hted average value filter and the subpixel technique on several-step c omputing and half Gaussian fitting are deployed to obtain the edge and the centre of the ring image in order to filter the noise of the imag e and raise the resolution of the measurement system. The experimental results show that the principle is correct and the techniques are rea lizable.