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Understanding Spherical Lenses and Imaging Comparison with Aspheric Lenses

The optical lens is an optical component used by movie cameras, projectors, cameras, and cameras to generate images, and consists of multiple lenses. It is an indispensable component in the machine vision system, which directly affects the quality of the imaging, and affects the realization and effect of the algorithm. Optical lenses can be divided into short-focus lenses, medium-focus lenses, and telephoto lenses in terms of focal length; wide-angle, standard, and telephoto lenses in terms of field of view; fixed-aperture fixed-focus lenses and manual aperture fixed-focus lenses in terms of structure. Auto-iris fixed-focus lenses, manual zoom lenses, auto-zoom lenses, auto-iris electric zoom lenses, electric three-variable (aperture, focal length, and focus) lenses, etc. So what is a spherical lens?

1. What is a spherical lens?

The convex or concave surface of the lens is shaped like a section cut from a sphere, which is a spherical lens. The convex or concave mirror for myopia or hyperopia has only one radius of curvature, the convex surface of the inner TC lens for astigmatism has one radius of curvature, and the concave surface has two perpendicularly intersecting radii of curvature. A mirror whose reflective surface is part of a sphere is called a spherical mirror (a part of a spherical shell—a spherical cap). A lens whose lenses are all composed of spherical lenses is a spherical lens. Spherical lenses are more common in the low-end market. Its advantage is low cost.

2. Types of spherical lenses

Spherical lenses are divided into convex mirrors and concave mirrors. 1. Concave mirror: A spherical mirror that uses the inner side of the sphere as the reflecting surface is called a concave mirror. 2. Convex mirror: A spherical mirror that uses the outside of the spherical surface as the reflecting surface is called a convex mirror.

3. Imaging comparison between spherical lens and aspheric lens

Spherical lens means that both the inner and outer sides of the lens are spherical, or one side is a spherical lens and the other half is a flat lens. The surface shape of the aspheric lens is determined by the multi-image high-order equation, and the radii of each point on the surface shape are different. When the general spherical lens is used for imaging, it cannot ideally focus the object object to a point, and various aberrations will appear. Therefore, its image quality is generally relatively poor. In order to improve the imaging quality, different types of concave and convex lenses are generally used to cancel out the aberrations; while using aspheric lenses, the aspheric surface can effectively improve the imaging quality of the lens.

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