Measuring Steel Tensile Deformation Of Optical Imaging System Research

Traditionally, the measurement is carried out by the way of contacting, where the sensors are attached on the steel ropes. During the process of stretching steel ropes, sensors are inevitably broken and the measurement precision is declined, because of strong frication force between sensitive device of the sensor and coarse surface of the steel. What is worse, the sensor will be badly destroyed at the same time that steel rope is cracked.In order to solve some problems on measuring the steel tensile deformation of traditional real-time system, a real-time, high-accuracy, non-contacting optoelectronic sensing system for the steel rope tensile deformation is demonstrated. Tensile deformation of steel rope is detected in real-time using a linear CCD. The photoelectric test system includes light source, tention sensor system, CCD camera, DAQ card and software processing system. The light source system provides original light intensity, which of optical power, stability will be mainly considered. The tension sensing system provides force for tensile deformation of steels. CCD imaging system meets the demand of getting clear image, so will include the enough number of pixels and the suitable rate of driving. For the demand of real time, data acquisition system will consider the influence of noise, filtering, amplification, the acquisition bits and rate. Software processing system calls software development kits for secondary development, controls hardware to work efficiently and conveniently, completes the algorithm and provides a friendly user interface.For high-accuracy measurement, asymmetric floating threshold method is used to binarize and distinguish the difference between testing objects and background. By using the linear fitting, absolute error below0.054mm and relative error below1.4%at tensile deformation range from0to10mm is realized. During the dual-optical test, absolute error below0.429mm and relative error below1.77%at tensile deformation range from0to80mm is realized. Some improvements for increasing the precision of the measurement are proposed. With the help of friendly user interface (UI), created by C, C++, MFC based on Windows XP and Visual C++6.0, it is convinent to control the testing system for clients.