Department of Physics, Ajou University, Suwon, Republic of Korea.
Sci Rep. 2022 Jul 13;12(1):11892. doi: 10.1038/s41598-022-16232-0.
Hyperspectral endoscopy has shown its potential to improve disease diagnosis in gastrointestinal tracts. Recent approaches in developing hyperspectral endoscopy are mainly focusing on enhancing image speed and quality of spectral information under a clinical environment, but there are many issues in obtaining consistent spectral information due to complicated imaging conditions, including imaging angle, non-uniform illumination, working distance, and low reflected signal. We quantitatively investigated the effect of imaging angle on the distortion of spectral information by exploiting a bifurcated fiber, spectrometer, and tissue-mimicking phantom. Spectral distortion becomes severe as increasing the angle of the imaging fiber or shortening camera exposure time for fast image acquisition. Moreover, spectral ranges from 450 to 550 nm are more susceptible to the angle-dependent spectral distortion than longer spectral ranges. Therefore, imaging angles close to normal and longer target spectral ranges with enough detector exposure time could minimize spectral distortion in hyperspectral endoscopy. These findings will help implement clinical HSI endoscopy for the robust and accurate measurement of spectral information from patients in vivo.
光谱内窥镜在胃肠道疾病诊断方面显示出了其应用潜力。目前，发展光谱内窥镜的主要方法集中在提高光谱信息的临床环境下的成像速度和质量，但由于成像角度、非均匀照明、工作距离和低反射信号等复杂的成像条件，获取一致的光谱信息存在许多问题。我们利用分叉光纤、光谱仪和组织模拟体对成像角度对光谱信息失真的影响进行了定量研究。随着成像光纤角度的增加或为了快速获取图像而缩短相机曝光时间，光谱失真会变得更加严重。此外，与较长的光谱范围相比，450 到 550nm 的光谱范围更容易受到角度相关的光谱失真的影响。因此，接近正常的成像角度和具有足够探测器曝光时间的更长目标光谱范围可以最大限度地减少光谱内窥镜中的光谱失真。这些发现将有助于实现临床 HSI 内窥镜，以便从体内患者中稳健、准确地测量光谱信息。
