Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative assessment of retinal images is crucial in ocular diseases related clinical application. Pulsatile properties caused by cardiac rhythm, such as spontaneous venous pulsation (SVP) and pulsatile motion of small arterioles, can be visualized by dynamic retinal imaging techniques and provide clinical significance. In this paper, we aim at vessel pulsatile motion detection and measurement. We proposed a novel approach for pulsatile motion measurement of retinal blood vessels by applying retinal image registration, blood vessel detection and blood vessel motion detection and measurement on infrared retinal image sequences. The performance of the proposed methods was evaluated on 8 image sequences with 240 images. A preliminary result has demonstrated the good performance of the method for blood vessel pulsatile motion observation and measurement.
Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative assessment of retinal images is crucial in ocular diseases related clinical application. In this paper, we proposed approaches for improving the quality of blood vessel detection based on our initial blood vessel detection methods. A blood vessel spur pruning method has been developed for removing the blood vessel spurs both on vessel medial lines and binary vessel masks, which are caused by artifacts and side-effect of Gaussian matched vessel enhancement. A Gaussian matched filtering compensation method has been developed for removing incorrect vessel branches in the areas of low illumination. The proposed approaches were applied and tested on the color fundus images from one publicly available database and our diabetic retinopathy screening dataset. A preliminary result has demonstrated the robustness and good performance of the proposed approaches and their potential application for improving retinal blood vessel detection.
Retinal optic cup-disk-ratio (CDR) is a one of important indicators of glaucomatous neuropathy. In this paper, we
propose a novel multi-step 4-quadrant thresholding method for optic disk segmentation and a multi-step temporal-nasal segmenting method for optic cup segmentation based on blood vessel inpainted HSL lightness images and green images. The performance of the proposed methods was evaluated on a group of color fundus images and compared with the manual outlining results from two experts. Dice scores of detected disk and cup regions between the auto and manual results were computed and compared. Vertical CDRs were also compared among the three results. The preliminary experiment has demonstrated the robustness of the method for automatic optic disk and cup segmentation and its potential value for clinical application.
Retinal images are long-accepted clinical diagnostic method for ocular diseases. Of late, automated assessment of retinal
images has proven to be a useful adjunct in clinical decision support systems. In this paper, we propose a retinal image
registration method, which combine retinal image enhancement and non-rigid image registration methods, for
longitudinal retinal image alignment. A further illumination correction and gray value matching methods are applied for
the longitudinal image comparison and subtraction. The solution can enhance the assessment of longitudinal changes of
retinal images and image subtraction in a clinical application system. The performance of the proposed solution has been
tested on longitudinal retinal images. Preliminary results have demonstrated the accuracy and robustness of the solutions
and their potential application in a clinical environment.
Imaging plays a vital role in the diagnosis and recording of ophthalmic disease and pathology. Of particular interest to ophthalmologists is disease progression. Using conventional viewing techniques this is often difficult to determine. This paper discusses and demonstrates some simple Internet tools that can be used to aid in the dynamic visualization of changes in photographs of the retina and cornea.
This study was designed to determine the degree and methods of digital image compression to produce ophthalmic imags of sufficient quality for transmission and diagnosis. The photographs of 15 subjects, which inclined eyes with normal, subtle and distinct pathologies, were digitized to produce 1.54MB images and compressed to five different methods: (i) objectively by calculating the RMS error between the uncompressed and compressed images, (ii) semi-subjectively by assessing the visibility of blood vessels, and (iii) subjectively by asking a number of experienced observers to assess the images for quality and clinical interpretation. Results showed that as a function of compressed image size, wavelet compressed images produced less RMS error than JPEG compressed images. Blood vessel branching could be observed to a greater extent after Wavelet compression compared to JPEG compression produced better images then a JPEG compression for a given image size. Overall, it was shown that images had to be compressed to below 2.5 percent for JPEG and 1.7 percent for Wavelet compression before fine detail was lost, or when image quality was too poor to make a reliable diagnosis.
The aim of this study was to develop a computerized stereo- flicker chronoscopy and chronometry system to improve the technique of neuroretinal optic disc rim assessment. Digitized stereo photographs of 22 eyes of glaucoma patients were analyzed subjectively by computerized flickering of serial images, and objectively by measuring the width of the neuroretinal rim at 18 positions around the optic disc. A major source of error was identified as color changes in the images over time. Color adjustment algorithms were developed and the assessments and measurements were repeated. For chronometry after color adjustment there was improvement to most of the tests on the data: agreement (50% to 73%), specificity (45% to 84%), positive agreement (50% to 71%) and negative agreement (50% to 73%). Sensitivity remained constant at about 55%.
The scanning laser ophthalmoscope (SLO) is a modern tool which is now widely used to image the fundus of the eye, particularly for assessment of the optic nerve head. We describe a modified SLO capable of producing stereo pairs of the optic disk in real time. A pair of toggling mirrors is used to switch between entry positions of the scanned laser beam into the pupil of the eye thereby creating a stereo base for capturing the two different views required for the pair. Our laboratory prototype is constructed from reflective optics only in the bi-directional part of the beam path, including the focusing and beam shaping unit. Thus, we avoid unwanted back reflections and chromatic aberrations. Light from different laser sources (458 to 1100 nm) can be launched into the SLO, also simultaneously. Collimated beams in beam splitting locations allow for easy modifications. Imaging in fluorescence mode or polarization dependent imaging is also possible. High quality multi-wavelengths stereo pairs of both model and real optic disks were obtained. a lateral resolution of up to 6 micrometer and an axial resolution of up to 65 micrometer was established.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.