With the rapid development of welding automation technology, weld seam tracking system has become an important topic in the welding field. The use of weld seam tracking system to achieve automation of the welding process has become inevitable in the future. Therefore, many disciplines of technology have been applied to weld seam tracking system, among which CCD camera is an indispensable part.
The main function of CCD cameras in weld seam tracking sensors is to read images. When shooting a scene with a CCD camera, the light reflected by the scene is transmitted to the CCD through the lens of the CCD camera. After CCD exposure, the photodiode is excited by light and releases charges, resulting in the electrical signal of the photosensitive element.
The CCD control chip uses the control signal circuit in the photosensitive element to control the current generated by the photodiode, which is output by the current transmission circuit. The CCD camera will collect the electrical signal generated by a single imaging and output it uniformly to the amplifier. The amplified and filtered electrical signal is sent to A/D, which converts the electrical signal (now an analog signal) into a digital signal. The magnitude of the value is directly proportional to the strength of the electrical signal, i.e. the voltage. These values are actually the data of the image.
However, relying solely on the image data obtained in the previous step cannot directly generate images, and it needs to be output to a digital signal processor (DSP). In DSP, these image data are subjected to post-processing such as color correction and white balance processing (depending on the user's settings in the CCD camera), encoded into the image format, resolution, and other data formats supported by the camera, and then stored as image files. Finally, the image file is written to the memory of the CCD camera (internal or external memory).
After storing the image, image processing is performed to obtain the deviation between the weld seam and the welding gun. Then, a control signal is sent to the PLC through the upper computer. During the debugging process, the entire system can achieve accurate weld seam tracking.