中文摘要：

镁熔液表面第一气泡的识别是镁熔液含氢量快速现场检测的关键技术。由于温度和振动的影响使镁熔液图像的信噪比和对比度都较低,而且气泡目标像素少。先利用9/7提升小波进行变换,提取高频部分;再利用高频部分进行重构;然后对重构后的图像进行帧差法相减,最后进行自适应阀值处理,检测出弱目标。实验结果表明该算法能够有效地检测出复杂背景下的第一气泡。

英文摘要：

Recognition for the first bubble of the surface in magnesium alloy melt plays an important part in the fast field detection of hydrogen content.The target＇s SNR（Signal Noise Ratio） and contrast are very low because of the influence of temperature and vibration.And the pixels of the target are few.We get the high frequency coefficient after 9/7 lifting wavelet transform.And then we used the high frequency coefficient for 9/7 lifting wavelet reconstruct.Third,the frame difference was used for the reconstructed images.At last,we can detect the weak target using adaptive gray-level threshold for image filter.The result of experiment showed that satisfactory results could be achieved through the above mentioned method under the complex bachground.