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Humphrey visual field analyser. Humphrey field analyser ( HFA) is a tool for measuring the human visual field that is commonly used by optometrists, orthoptists and ophthalmologists, particularly for detecting monocular visual field. [1] The results of the analyser identify the type of vision defect.
For a normal lens focused at infinity, the diagonal (or horizontal or vertical) field of view can be calculated as: F O V = 2 × arctan ( sensor size 2 f ) {\displaystyle \mathrm {FOV} =2\times \arctan \left({\frac {\text{sensor size}}{2f}}\right)}
Machine vision is the technology and methods used to provide imaging -based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry. Machine vision refers to many technologies, software and hardware products, integrated systems, actions, methods and expertise.
In order to determine the power of intraocular lens, several values need to be known: Eye's axial length (AL) Corneal power (K) Postoperative IOL position within the eye known as estimated lens position (ELP) The anterior chamber constant: A-constant or another lens related constant
Circle of confusion. In optics, a circle of confusion (CoC) is an optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. It is also known as disk of confusion, circle of indistinctness, blur circle, or blur spot . In photography, the circle of confusion is used to determine the depth ...
Angle of view can also be determined using FOV tables or paper or software lens calculators. [5] Log-log graphs of focal length vs crop factor vs diagonal, horizontal and vertical angles of view for film or sensors of 3:2 and 4:3 aspect ratios.
Bokeh simulator and depth of field calculator Interactive depth of field calculator with background blur simulation feature Lens Comparison: Nikon 50mm f/1.4D vs. 50mm f/1.4G Demonstration of varying apertures on Depth of Field
Vision of 6/12 corresponds to lower performance, while vision of 6/3 to better performance. Normal individuals have an acuity of 6/4 or better (depending on age and other factors). In the expression 6/x vision, the numerator (6) is the distance in metres between the subject and the chart and the denominator (x) the distance at which a person ...
Normal lens. In machine vision a normal or entrocentric lens is a lens that generates images that are generally held to have a "natural" perspective compared with lenses with longer or shorter focal lengths. Lenses of shorter focal length are called wide-angle lenses, while longer focal length lenses are called telephoto lenses. O
Snellen chart. Purpose. Snellen chart is used to estimate visual acuity (last three rows are 20/15, 20/13 and 20/10) A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen who developed the chart in 1862 as a measurement tool for the acuity formula ...