Marrugo A.G.2020-03-262020-03-2620142014 3rd International Congress of Engineering Mechatronics and Automation, CIIMA 2014 - Conference Proceedings9781479979325https://hdl.handle.net/20.500.12585/9053Retinal photography is important for the assessment of eye diseases. The task of fine focusing the image is demanding and lack of focus is often the cause of suboptimal photographs. The advent of digital cameras has provided the opportunity to automate the focusing process. In this work, we propose an auto-focus system for non-mydriatic retinal imaging. The core of the system is based on a robust image-based focus measure. The measure is basically a quantification of image anisotropy computed by means of the normalized discrete cosine transform. Additionally, we optimize the autofocusing method by evaluating different focus search strategies. Encouraging experimental results reveal that the method is able to identify the best focus reliably with optimal speed. © 2014 IEEE.Recurso electrónicoapplication/pdfenghttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/conferenceObject10.1109/CIIMA.2014.6983425AutofocusImage processingNon-mydriaticRetinal imagingAlgorithmsDiscrete cosine transformsImage processingOphthalmologyPhotographyAuto-focusAuto-focus systemAuto-focusingFocusing algorithmImage anisotropiesNon-mydriaticRetinal imagingSearch strategiesFocusinginfo:eu-repo/semantics/restrictedAccessAtribución-NoComercial 4.0 InternacionalUniversidad Tecnológica de BolívarRepositorio UTB2432983930072014663996603209063