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Narrow gap submerged arc welding process requires arc always kept, so in order to meet this requirement, the introduction of automatic seam tracking system. The current seam tracking system there are many, respectively, based on different sensors, vision sensors than other sensors but has obvious advantages, so the development of vision-based sensor for seam tracking system is necessary. Image acquisition system is based on the vision sensor seam tracking system is an important component, its function is to receive the camera input image data, buffering and preprocessing, the last valid output to the computer. The computer for further image processing, the arc of the feedback signal to the mechanism control section, in order to achieve automatic seam tracking. It can be said image acquisition accuracy, clarity and speed are critical seam tracking. Image acquisition system consists of two major components, namely, optical structure and frame grabbers. In a light source and a visual sensor angle, distance, constituting the optical path structure installed. Image acquisition card based on the actual choice of a complete application development and design. The entire system is designed to focus the image acquisition card, since the image acquisition card dedicated to the narrow gap SAW, so the design mainly in the narrow gap welding and submerged arc welding process is characterized as the basis. Frame grabber to FPGA logic control and image pre-processing algorithm to achieve the core of the device, not only the entire design with high flexibility, and make the circuit simple and efficient. In connection with the camera issue, widely used on the market as a camera link frame grabber input interface, improved versatility acquisition card, the data transfer rate and noise immunity. The PCI bus as the output interface frame grabber, image acquisition card data transmission between computers, to achieve data transmission speed and precision. The first part is the optical path of the image acquisition system design, discusses in detail the options for the light source and the actual installation, as well as its vision sensor and image acquisition to achieve the principles of the weld. The second part is the image acquisition card design, but also the focus of the work of the project, including the frame grabber hardware circuit design and software programming design. Finally, the image acquisition card on the computer test case, and according to the weld image features, image preprocessing methods do research. For the arc welding process, splash, dust and other effects, respectively, using the image enhancement, filtering and binarization pretreatment method was finally obtained the weld features, seam image small amount of data.
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