With over 15 years of experience and 500+ unique optical systems designed, Optics for Hire specializes in advanced optical engineering. If it uses light, we've worked on it.

mtf是什么意思

The formula for MTF in an ideal optical system where MTF is defined by the diffraction limit. It is show below as a formula and plotted on an MTF chart in the second image

调制传递函数

Polarization, in Physics, is defined as a phenomenon caused due to the wave nature of electromagnetic radiation. Sunlight travels through the vacuum to reach the Earth, which is an example of an electromagnetic wave. These waves are called electromagnetic waves because they form when an electric field interacts with a magnetic field. In this article, you will learn about two types of waves, transverse waves and longitudinal waves. You will also learn about polarization and plane polarised light.

The electric field of light follows an elliptical propagation. The amplitude and phase difference between the two linear components are not equal.

modulation transfer function中文

Residual aberration deviates wave fronts going from the object when compared with ideal system. However there is criteria when real optical system can be regarded as ideal. It is similar to tolerance which provides that. This criteria names as Rayleigh λ/4. It means that absolute value of wavefront deviation in optical system has to be not exceed quarter (fourth) of wavelength value. In this example ideal MTF in black, real in blue.

When optical system posses big residual aberrations then calculation of MTF is loosing accuracy. Reasonable limit is wavefront deviation in 1 lambda.

LensMTF

Light is the interaction of electric and magnetic fields travelling through space. The electric and magnetic vibrations of a light wave occur perpendicularly to each other. The electric field moves in one direction and the magnetic field in another ‘perpendicular to each other. So, we have one plane occupied by an electric field, another plane of the magnetic field perpendicular to it, and the direction of travel is perpendicular to both. These electric and magnetic vibrations can occur in numerous planes. A light wave that is vibrating in more than one plane is known as unpolarized light. The light emitted by the sun, by a lamp or a tube light are all unpolarised light sources. As you can see in the image below, the direction of propagation is constant, but the planes on which the amplitude occurs are changing.

In real system the difference can be bigger because of residual aberrations. One of the biggest influences is astigmatism.

In image below, the upper half is a sinusoidal test object and the lower half is an object imaged by a real optical systems. The upper half has perfect contrast the lower half is contract is reduced because of diffraction.

There are two linear components in the electric field of light that are perpendicular to each other such that their amplitudes are equal, but the phase difference is π/2. The propagation of the occurring electric field will be in a circular motion.

MTF

Usually MTF chart includes two plots for selected off axis points of field of view. There is a very small difference because of different apture value from Meridional and sagittal apertures., this come from tilt and other geometrical issues.

But it has slightly lower resolution because of residual aberration which depends on optical performances, number of lens elements and types of glasses.

mtf群体

Below are examples of MTF plot from Zemax, on the left image the x axis is spatial in units of line pair per mm and the Y axis is amplitude which also can be called contrast. The different color lines are different fields of view. The black line is plot for ideal system.

Understanding the purpose of an MTF chart and how to read and MTF chart is an essential skill for anyone involved in the development of products that use optics.

Modulation transfer function

In this post we will review the definitions, show example charts, impact of sensor, abberrations, Meridional and sagittal plots and diffraction limited optical systems.

mtf光学

An ‘Ideal’ optical system is one which transfers optical wave fronts from an object without any deviations. But in any real optical system there is a limit to apeture and and apeture creates diffraction which reduces MTF. As the diffraction spacial frequency grows, the MTF of a system is reduces. An analog in electronics is where devices filter temporary frequencies. MTF of ideal system has formula.

With over 20 years of experience and 800+ unique optical systems designed, Optics for Hire specializes in advanced optical engineering. If it uses light, we've worked on it.

Transverse waves are waves, in which the movement of the particles in the wave is perpendicular to the direction of motion of the wave.

The other kind of wave is a polarized wave. Polarized waves are light waves in which the vibrations occur in a single plane. Plane polarized light consists of waves in which the direction of vibration is the same for all waves. In the image above, you can see that a plane polarized light vibrates on only one plane. The process of transforming unpolarized light into polarized light is known as polarization. The devices like the polarizers you see are used for the polarization of light.

MTF stands for modulation transfer function, this means the transferring of differing optical spatial frequencies through an optical systems.