Edge detection and mathematic fitting for corneal surface with Matlab software
Journal Title: International Journal of Ophthalmology - Year 2017, Vol 10, Issue 3
Abstract
"AIM: To select the optimal edge detection methods to identify the corneal surface, and compare three fitting curve equations with Matlab software. METHODS: Fifteen subjects were recruited. The corneal images from optical coherence tomography (OCT) were imported into Matlab software. Five edge detection methods (Canny, Log, Prewitt, Roberts, Sobel) were used to identify the corneal surface. Then two manual identifying methods (ginput and getpts) were applied to identify the edge coordinates respectively. The differences among these methods were compared. Binomial curve (y=Ax2+Bx+C), Polynomial curve [p(x)=p1xn+p2xn-1 +....+pnx+pn+1] and Conic section (Ax2+Bxy+Cy2+Dx+Ey+F=0) were used for curve fitting the corneal surface respectively. The relative merits among three fitting curves were analyzed. Finally, the eccentricity (e) obtained by corneal topography and conic section were compared with paired t-test. RESULTS: Five edge detection algorithms all had continuous coordinates which indicated the edge of the corneal surface. The ordinates of manual identifying were close to the inside of the actual edges. Binomial curve was greatly affected by tilt angle. Polynomial curve was lack of geometrical properties and unstable. Conic section could calculate the tilted symmetry axis, eccentricity, circle center, etc. There were no significant differences between ‘e’ values by corneal topography and conic section (t=0.9143, P=0.3760 >0.05). CONCLUSION: It is feasible to simulate the corneal surface with mathematical curve with Matlab software. Edge detection has better repeatability and higher efficiency. The manual identifying approach is an indispensable complement for detection. Polynomial and conic section are both the alternative methods for corneal curve fitting. Conic curve was the optimal choice based on the specific geometrical properties."
Authors and Affiliations
Tong Qiao
Keywords
Related Articles
- EP ID EP610046
- DOI 10.18240/ijo.2017.03.02
- Views 63
- Downloads 0
MMP-2 Rs24386 (C-->T) gene polymorphism and the phenotype of age-related macular degeneration
"AIM: To examine the MMP-2 (-1306 C/T) gene polymorphism and the phenotype characterized by soft and hard drusen of early age-related macular degeneration (AMD) and geographic atrophy of late AMD form. METHODS: The study...
High speed small gauge anterior vitrectomy cutter for scleral fixated intraocular lens implantation
"AIM: To report the outcomes of anterior vitrectomy using high speed cutter for scleral fixated intraocular lens (SFIOL) implantation in patients with posterior capsular rupture . METHODS: Medical records of 51 patients...
Clinical outcomes at one year following keratoconus treatment with accelerated transepithelial cross-linking
This study evaluated the clinical outcomes in keratoconus corneas following accelerated transepithelial corneal collagen cross-linking (CXL) (Avedro KXL® system, Waltham, MA, USA) over one year of follow-up. The mean dep...
Role of vasoactive intestinal peptide in Aspergillus fumigatus-infected cornea
"AIM: To investigate the anti-inflammatory role of vasoactive intestinal peptide (VIP) in Aspergillus fumigatus (A. fumigatus) ketatitis. METHODS: Expression of VIP was tested by polymerase chain reaction (PCR) in C57BL/...
Comparative study of the efficacy and safety of bromfenac, nepafenac and diclofenac sodium for the prevention of cystoid macular edema after phacoemulsification
"AIM: To compare the efficacy, tolerability and safety of bromfenac 0.09%, nepafenac 0.1% or diclofenac 0.1% for the prophylaxis of the cystoid macular edema (CME) after phacoemulsification. METHODS: Group sequential obs...