小波梯度域重建融合法应用于龋齿太赫兹成像

Terahertz Imaging of Caries Wavelet Gradient Domain Reconstruction Fusion

龋病是发病率最高的口腔疾病,也是全世界最流行的疾病之一。太赫兹光谱成像技术因具有宽频带光谱分析能力强、空间分辨率高、电离辐射低等优势,有望成为龋病诊断的新技术手段。本文以含牙本质龋的牙齿切片为研究对象,进行反射式太赫兹光谱扫描,以频域幅值为参数对样品的光谱数据做二维重构成像,获得多幅不同频率下的龋齿太赫兹光谱图像。为了解决单一参数所得的龋齿太赫兹图像动态范围小、对比度低,边缘和细节位置模糊不清的问题,采用小波梯度域重建的融合方法,将多幅图像中梯度幅值较大的部分集中于一幅图像上,得到了一幅细节特征更加清晰完整的新图像。实验结果表明,融合后的图像相较于融合前的图像在信息熵、平均梯度以及对比度上均有所提高,不同组织之间的区分效果更加显著。

Caries is one of the most prevalent oral diseases worldwide.Terahertz spectral imaging technology has the advantages of strong broadband spectral analysis ability,high spatial resolution,and low ionizing radiation and is expected to be a new technical means for caries diagnosis.In this study,tooth slices containing dentin caries were used as the research object,and reflective terahertz spectral scanning was performed.The spectral data of the samples were reconstructed using two-dimensional imaging with the frequency-domain amplitude as the parameter,and several terahertz spectral images of caries were obtained at different frequencies.To solve the problems of small dynamic range,low contrast,and ambiguous edges,the detailed position of the terahertz image was obtained using a single parameter.Using the fusion method of wavelet gradient domain reconstruction,the larger gradient amplitudes of several images are concentrated in one image,and a new image with clearer and more complete detailed features is obtained.The experimental results show that the information entropy,average gradient,and contrast of the fused images are improved compared with those of the pre-fused images,and the discrimination effect between different tissues is more significant.