主要研究基于表面等离子共振(SPR)技术的纳米级金属膜厚在线测量系统中的视频信号处理问题。由于CCD在动态连续采集图像的过程中会受到环境以及工作台旋转的影响,从而会随机地产生高斯白噪声和图像的扭曲现象,造成视频图像的模糊或者扭曲失效。通过对视频图像进行滑动平均滤波、小波分析以及动态补偿时域滤波的处理,消除了高斯白噪声和避免图像扭曲的发生,确保了CCD获取视频图像的有效性与清晰度,从而提高了从图像中获取的共振角度变化量的准确性,并进一步提高了金属薄膜厚度的测量精确度与可靠性。

Research on the video signal processing of the nanoscale metal thickness online measurement system based on surface plasmon resonance (SPR) was carried out. As the CCD will be affected by environment as well as table rotation during the dynamic continuous process of collecting images, Gaussian white noise and image distortions will be generated randomly, which then causes fuzzy or distorted video image. To overcome these defects, video image was processed by the methods of sliding average filtering, wavelet analysis and motion compensation for the time-domain filtering, in order to eliminate the white Gaussian noise and avoid the occurrence of image distortion, thus ensuring the effectiveness and resolution of the obtained video image by CCD. In this way, the accuracy of the amount of change of the resonance angle obtained from the image was improved, and the accuracy and reliability of the measurement of the thickness of the metal thin film was also improved.