焊缝X射线数字化图像中像素宽度不超过3个像素的细长线缺陷, 其对比度低, 常有间断, 常规的X射线焊缝缺陷检出算法难以有效检出。针对此类缺陷, 提出了在滤波降噪的基础上, 采用逐列自适应阈值法对图像中细长线缺陷进行初步分割, 然后应用改进的局部霍夫变换剔除初步分割结果中的大量噪点, 准确分割出细长线缺陷。试验结果表明, 所提出的方法能够适应不同灰度范围的X射线图像、克服噪声及缺陷间断的影响, 有效检测出低对比度细长线缺陷。

The slim line defect whose average width is not more than three pixels in X-ray weld images is usually weak and interrupted. Normal X-ray defects detection algorithm can not detect it effectively. A new method is proposed to detect this kind of defects. After filter the original X-ray image to reduce the noise, the self-adaptive threshold value is adopted line by line to segment the slim line defects in the image preliminarily, and the improved partial Hough Transform is used to eliminate the noise and segment the line defect. The experimental results show that the proposed method can adapt to X-ray digitized images of different grey range and avoid the influence of much noise and interruption, and is effective to detect the low-contrast slim line defects.