Enhanced detection of normal retinal nerve-fiber striations using a charge-coupled device and digital filtering.
We used a 1024 x 1024 pixel, 15-microns, 16-bit-encoding, multi-pin-phase charge-coupled device (CCD) to obtain images of the normal human retinal nerve fiber layer. This device, which operates at room temperature, offers significantly better signal-to-noise ratio, linearity, and dynamic range than do photographic film, video imaging techniques, or commercially available CCDs. We demonstrate the use of a nonlinear digital filter, together with filter windows, that enhances fine detail of NFL striations, while suppressing noise, in limited areas of the CCD images. High-sensitivity imaging of this type, together with appropriate digital processing, may prove useful in diagnosing and following nerve-fiber-layer damage due to glaucoma.
Richards
D W
DW
Department of Ophthalmology, University of South Florida College of Medicine, Tampa.
Janesick
J R
JR
Elliot
S T
ST
Dingizian
A
A
Velthuizen
R
R
Wei
Q
Q
Clarke
L P
LP
D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009412:Nerve Fibers / Q000502:physiology; D009900:Optic Nerve / Q000166:cytology* / Q000502:physiology; D012160:Retina / Q000166:cytology* / Q000502:physiology; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted