利用归一化互相关算法去除吸收强度涨落调制血管造影图像模糊

Angiogram Deblurring in Absorption Intensity Fluctuation Modulation Imaging Using a Normalized Cross-correlation Algorithm

吸收强度涨落调制成像(AIFM)方法是基于血红细胞和背景组织对低相干光照明的吸收差异,通过在频域分离动态的血红细胞信号和静态的背景信号,实现对近透明活体生物样本全场无标记的光学血管造影成像.但此成像方法需采集较长的原始图像序列,系统漂移或生物抖动会造成图像模糊,难以实现对某些特定区域的血管造影成像.本文提出一种结合AIFM成像和归一化互相关算法的新方法来提升血管造影图像的质量:原始的图像序列被分成若干短时序列,每个短时序列先利用AIFM成像算法重构得到全场的血管造影图像;再利用归一化的互相关算法将所有的短时重构图像与第一帧重构图像相匹配,并融合得到最终的血管造影片.我们以活体鸡蛋胚胎为样品,通过实验验证了利用短时归一化互相关AIFM成像方法,能够消除鸡胚胎心跳引起的图像模糊,从而获得高分辨率和信噪比的心血管造影片,对研究活体动物心脑血管疾病具有重要应用价值.

Full-field label-free optical angiography is a powerful imaging technique that aids study of cardiovascular diseases in live animal models.Here,we presented a novel method that combined absorption intensity fluctuation modulation imaging with subpixel matching based on a normalized cross-correlation algorithm to eliminate blurring of angiograms caused by system drift or biological jitter.Raw images showing absorption difference between red blood cells and background tissue under illumination with low-coherence light were captured and divided into several short image sequences.These sequences were then used for image reconstruction using absorption intensity fluctuation modulation imaging to achieve full-field angiography by isolating dynamic red blood cell signals from the background signal in the frequency domain.All the reconstructed images were then matched with the first reconstructed image using the normalized cross-correlation algorithm and subsequently fused.In vivo angiography near chicken embryo heart was performed to demonstrate the efficacy of our method,and it produced clear,blur-free angiograms with high spatial resolution and signal-to-noise ratio.