Study On The Visual Detection System Of Inner Wall Of Small-diameter Workpiece

With the development of science and technology,precise workpieces characterized by small holes have been widely developed and used in all fields of production and life and play an important role.Miniaturization has become the development trend of modern equipment.But the surface detection of small-diameter workpiece is very difficult.In particular,the detection method of the inner wall has always been a problem due to small measurement space and poor lighting condition.The study of high precision detection method for small-diameter workpiece is of great significance to the development of precision measurement technologyOn the basis of the analysis of current detection technology for small-diameter workpiece,this paper proposes a visual inspection method based on the principle of optical reflection.The method uses a special composite reflector to reflect the image of inner wall to the camera for digital processing under the condition of sufficient illumination.This method realizes the application of machine vison technology in the detection of the inner wall of small-diameter workpiece.This paper introduces the method of imaging acquisition and processing based on the establishment of the imaging model and completes the structure design of the system.The function of lighting source in visual inspection is emphatically analyzed,and the light source model,lighting mode and working distance suitable for the system are determined through theoretical calculation and experimental simulation.The paper also studies the problems of coaxial alignment and continuous camera shooting and designs related treatment methods.Finally a pixel equivalent calibration method is proposed and the corresponding relationship between the camera image pixel and the actual physical size of the workpiece is built by the calibration of the detection system.This topic constructs the detection system combining with the rotating platform and lifting platform,realizing the visual inspection of inner wall of small workpiece with a 2-5mm hole.The complete unfolding image can be obtained and the resolution is better than 10μm.The establishment of the system verifies the feasibility of the solution and solves the problem of inner wall detection of small-diameter workpiece.