中文摘要：

运用方向小波的多尺度和多方向变换，对高温镁熔液表面弱小气泡进行检测。先对原始图像进行方向小波变换重构高频，抑制背景杂质，再作帧差和迭代阈值分割处理，最后运用数学形态学检测到弱小气泡，并将结果与传统小波检测进行比较。实验结果表明方向小波变换方法是有效的，而且方向小波更符合图像的方向特点，能够较好地检测出复杂背景中的弱小气泡。

英文摘要：

The detection of the weak and dim bubble in magnesium melt based on the multi-scale and multi-di- rectional advantages of directional wavelet transform were investigated. Original images were decomposed by direc- tional wavelet transform in order to get the high frequency coefficients and suppress background. Then, iterative threshold and mathematical morphology were used to get the target. The difference between traditional and directional wavelet transform was compared. The results indicate that the proposed method is effective. Directional wavelet trans- form can meet the image direction character better, it can detect weak and dim target in complex background.