Dep. Computación, Universidade da Coruña, Spain.
Comput Methods Programs Biomed. 2011 Apr;102(1):1-16. doi: 10.1016/j.cmpb.2010.12.001. Epub 2011 Jan 26.
Fluorescein angiography is an established technique for examining the functional integrity of the retinal microcirculation for early detection of changes due to retinopathy. This paper describes a new method for the registration of large Scanning Laser Ophthalmoscope sequences (SLO), where the patient has been injected with a fluorescent dye. This allows the measurement of parameters such as the arteriovenous passage time. Due to the long time needed to acquire these sequences, there will inevitably be eye movement, which must be corrected prior to the application of quantitative analysis. The algorithm described here combines mutual information-based registration and landmark-based registration. The former will allow the alignment of the darkest frames of the sequence, where the dye has not still arrived to the retina, because of its ability to work with images without a preprocessing or segmentation, while the latter uses relevant features (the vessels) extracted by means of a robust creaseness operator, to get a very fast and accurate registration. The algorithm only detects rigid transformations but proves to be robust against the slight alterations derived from the eye location perspective during acquisition. Results were validated by expert clinicians.
荧光素血管造影术是一种用于检查视网膜微循环功能完整性的成熟技术，可用于早期发现视网膜病变引起的变化。本文描述了一种新的方法，用于对已注射荧光染料的大扫描激光检眼镜（SLO）序列进行配准。这允许测量诸如动静脉通过时间等参数。由于获取这些序列需要很长时间，因此不可避免地会出现眼球运动，在进行定量分析之前必须对其进行校正。这里描述的算法结合了基于互信息的配准和基于地标配准。前者可以对准序列中最暗的帧，因为这些帧中的染料尚未到达视网膜，这是因为它能够在无需预处理或分割的情况下处理图像；而后者则使用通过稳健的脊线算子提取的相关特征（血管），实现非常快速和准确的配准。该算法仅检测刚体变换，但证明对采集过程中源自眼球位置的细微变化具有鲁棒性。结果由专家临床医生进行了验证。
