用于焊缝检测的比色图像偏心算法

提出了基于焊接比色图像偏心的概念并给出计算公式.从比色图像信号强度与焊接区域发射率、光谱辐射强度等的关系、比色值与焊接温度场及比色系统波长的关系以及比色图像偏心计算公式出发,分析了比色图像比色值分布对称性,推导并建立了焊接比色图像偏心与焊接区温度的函数值、焊缝中心与电弧中心偏差间关系模型.研究了以比色图像偏心作为检测对象的优异特性,给出了模型在某一焊接工艺参数条件下的数值解,发现模型的输出与输入有很好的线性关系.仿真试验证明以比色图像偏心可以代替焊缝中心偏差,为进一步研究比色图像偏心算法的实际应用打下理论基础.

A new approach to detect weld seam based on offset-distance arithmetic of welding colorimetry image

A new method to detect the weld seam centerline by calculating the offset-distance based on welding colorimetry image was proposed.The concept of offset-distance was defined and the offset-distance arithmetic that analyzes the welding colorimetry image was applied to obtain the deviation between the weld seam centerline and the arc column center.Based on the offset-distance formula,the relationship of some factors such as the signal intensity of CCD,welding temperature field,center wavelength of a narrow-band filter,emissivity of welding region,weld seam and the radiant intensity was obtained.Model giving the relation between the offset-distance of welding colorimetry image and the discrete numerical welding temperature field and the deviation between the weld seam centerline and the arc column center had been established.The numerical solution of the model had been presented and the relation curve had been shown.The conclusion indicates that the output parameter of the model which is the offset-distance of the welding colorimetry image and the input parameter which is the weld seam centerline has a good linear relation.Therefore the deviation between the weld seam centerline and the weld arc column center which is hardly detected directly from the welding visual image can be calculated by the offset-distance which is easily obtained from the welding colorimetry image.The factors influenced the accuracy of the model have been analyzed.The model makes the application of the offset-distance of welding colorimetry image for detecting the actual weld seam centerline more practical and simpler.