Anatomy and Physiology of the Retina

Hildebrand, Göran Darius; Fielder, Alistair R.

doi:10.1007/978-3-642-12041-1_2

Cited by 65 publications

(69 citation statements)

References 117 publications

(202 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The vessel confidence measure calculates the similarity of a MFR to an ideal vessel profile. Receiver 1 The source of these images is not specified in [13].…”

Section: Literature Surveymentioning

confidence: 99%

“…This results in four options for representing the filter response, namely the real, imaginary, phase and magnitude components. The real component can be represented as follows: (1) where G, W , x and y are defined by the respective equations (2-5) below.…”

Section: Gabor Filter Vessel Enhancementmentioning

confidence: 99%

“…The fovea appears as a high intensity blob in the middle of the image. Effective normalization should not detect this region as a vessel as it is biologically known to have limited vasculature [1]. Segmenting the inverted image based on gray level thresholding is not viable as the blood vessels and the fundus background are both of visibly varying intensity.…”

Section: Data Setsmentioning

confidence: 99%

“…The role that the retina plays in this process is substantial as it is estimated that 80% of all sensory information in humans originates from the retina [1]. This indicates its importance in our interaction with the physical world and explains why it remains one of the most scientifically explored components of the human body.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Segmentation of retinal blood vessels using normalized Gabor filters and automatic thresholding

Gwetu¹,

Tapamo²,

Viriri³

2014

SACJ

View full text Add to dashboard Cite

Although computerized retinal image blood vessel segmentation has been extensively researched, there is still room for improvement in the quality of the segmented images. Since retinal image analysis is still widely used in the diagnosis of diabetic retinopathy, efficient and accurate image characterization techniques are required. Previous work has mainly focused on improving segmentation accuracy rates with little regard to the false positives that are produced by illumination variation. This research work presents a hybrid approach towards the segmentation of retinal blood vessels. New approaches towards the reduction of background illumination variation are proposed using normalized Gabor filtering. These are the base-offset encoding and a modified version of an existing zero-integral kernel technique. The valley emphasis automatic thresholding scheme is used to segment the Gabor response images. Experiments are conducted on the DRIVE and STARE retinal image data sets. Accuracy rates of up to 94% are achieved through the zero-integral and base offset methods. This is comparable with results from literature, where the same data sets are segmented using other classification techniques. The median-offset method is found to most effectively reduce background illumination variation.

show abstract

“…The vessel confidence measure calculates the similarity of a MFR to an ideal vessel profile. Receiver 1 The source of these images is not specified in [13].…”

Section: Literature Surveymentioning

confidence: 99%

Section: Gabor Filter Vessel Enhancementmentioning

confidence: 99%

Section: Data Setsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Segmentation of retinal blood vessels using normalized Gabor filters and automatic thresholding

Gwetu¹,

Tapamo²,

Viriri³

2014

SACJ

View full text Add to dashboard Cite

show abstract

“…Histologically, the macula is subdivided into the fovea, parafovea and perifovea from the centre to its periphery. 6 The cone density decreases as one moves from the fovea to the perifovea while the rod density increases. 7 The centre of the fovea, called the foveola, is completely devoid of both ganglion and inner nuclear cells but has the highest density of cones.…”

Section: Introductionmentioning

confidence: 99%

Repeatability of macular thickness measurements with the iVue-100 optical coherence tomographer

Rampersad

Hansraj

2018

Afr. vis. eye health

View full text Add to dashboard Cite

Optical coherence tomography is an objective, non-invasive imaging technology, 12 first introduced in 1991, and is similar to ultrasonography except that reflected light rays instead of sound waves Background: The reliability of an instrument is dependent on its accuracy and repeatability. The iVue-100 optical coherence tomographer (OCT) is a spectral domain device that has the advantage of being able to measure both the anterior and posterior segments of the eye. But its repeatability for macular thickness measurements has not been assessed and this was the primary purpose of this study. Aim:To determine the repeatability of the iVue-100 OCT for macular thickness measurements.Settings: This study was conducted at the University of KwaZulu-Natal.Methods: Repeatability (intra-observer, inter-observer and inter-session) of the iVue-100 OCT was assessed on 50 participants selected using convenience sampling. Data were statistically analysed using Bland-Altman analysis, the intra-class correlation coefficient (ICC), coefficient of variation and the paired t-test. Results:The mean age and standard deviation for the 50 participants were 23.88 ± 6.93 years (range 18-51 years). The ICCs for intra-observer repeatability ranged between 0.940 and 0.989, whereas the coefficients of variation ranged between 0.040 and 0.084. For both inter-observer and inter-session repeatability, the t-test showed no statistically significant differences (p > 0.05), and Bland-Altman analysis found the majority of the measurements to be within the 95% limits of agreement. Conclusion:Irrespective of whether repeated measurements are being taken consecutively by the same examiner, by a different observer or at a different time, the iVue-100 OCT is highly reliable in terms of repeatability which is of paramount importance in any clinical or research setting.

show abstract

Association of Diabetic Macular Nonperfusion With Outer Retinal Disruption on Optical Coherence Tomography

et al. 2015

View full text Add to dashboard Cite

Anatomy and Physiology of the Retina

Cited by 65 publications

References 117 publications

Segmentation of retinal blood vessels using normalized Gabor filters and automatic thresholding

Segmentation of retinal blood vessels using normalized Gabor filters and automatic thresholding

Repeatability of macular thickness measurements with the iVue-100 optical coherence tomographer

Association of Diabetic Macular Nonperfusion With Outer Retinal Disruption on Optical Coherence Tomography

Contact Info

Product

Resources

About