We have developed methods which allow us to analyze images obtained with high resolution scanning laser ophthalmoscope (SLO). Registered retinal vessels can be extracted and quantified using image processing methods. Obtained data can be further analyzed for calculations of vessel morphological parameters.
We have developed a high resolution scanning laser ophthalmoscope optimized for imaging the morphology and dynamics of the retinal vessels. The system has flexible control over the imaging field of view allowing for easy navigation on the retina and selection of the desired vessel for high magnification imaging. We have also developed image processing methods that allow for extraction and quantification of vessel walls and lumen that serve for calculation of various morphological parameters.
We present a novel platform for eye tracking showing high speed and accuracy in a wide range of realizable visual tasks. The optical setup consists of the scanning laser ophthalmoscope, the actual tracker (the FreezEye Tracker), and a visual projector for task presentation. The MEMS-based tracker scans the retina with a framerate of 1.24 kHz, providing high angular and temporal resolution. Advanced algorithms allow for precise reconstruction of the eye trajectory covering the range of movements from small microsaccades to high amplitude saccades. The high quality of the generated data provides an abundance of data potentially useful for diagnostic purposes.
Neurodegenerative diseases, such as multiple sclerosis (MS), negatively impact the aging global population. MS damage various parts of the central nervous system, leading to various eye-movement abnormalities. We have built a retinal FreezEye Tracker (FET) to measure a wide dynamic range of eye movements of up to 10 degrees with an ultrahigh temporal and spatial resolution during visual tasks, including fixations, experiments with saccades, and smooth pursuit. To compare, we performed the same experiments with pupil tracker EyeLink 1000. The amplitudes of detected saccades are similar in both devices, but FET provides high-resolution details on eye trajectory during fixation periods.
Constructing an image acquired by a non-uniform scanning pattern is a difficult task. The main challenges are:(1) resampling technique (2) discrepancy between demanded (dictated by control signal) and actually performed, empirical scanning path. Here, we show how to calibrate the scanning path of MEMS scanner using Galvanometric Scanner and to what extent the time of acquisition impacts the resulting image.
The eye motion is broadly considered as a valuable source of information in the fields related to psychology, neuroscience and neurology. Therefore, quantitative characterization of eye tracker data is an important task. Saccades are sigmoidal, ballistic movements that in particular deserve more attention due to their complex shape and natural diversity. We have developed the high accuracy model of saccades and microsaccades of mean absolute error equal to 0.0104 degree on average. We present the methodology for extraction of saccadic features using this model and show the potential of the method in biometric experiments.
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