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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 ...
Telecentric lens. Bi-telecentric lens with 208 mm diameter front element and a C-mount camera interface. A telecentric lens is a special optical lens (often an objective lens or a camera lens) that has its entrance or exit pupil, or both, at infinity. The size of images produced by a telecentric lens is insensitive to either the distance ...
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.
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
A lenticular lens is an array of lenses, designed so that when viewed from slightly different angles, different parts of the image underneath are shown. [1] [2] [ failed verification – see discussion ] The most common example is the lenses used in lenticular printing , where the technology is used to give an illusion of depth, or to make ...
Computer stereo vision is the extraction of 3D information from digital images, such as those obtained by a CCD camera. By comparing information about a scene from two vantage points, 3D information can be extracted by examining the relative positions of objects in the two panels. This is similar to the biological process of stereopsis .