In industrial times lens selection 'on this issue, to be familiar with the changing times lens to say is very simple, but for people who are not familiar with changing times lens, must according to the change times lens selection step and method to choose an appropriate variable times lens.
, of course, the simplest method is only need to tell to change times lens manufacturers, you can use the industrial camera model, the size of the object to be tested, working distance, such as requirement, then become times lens manufacturers will provide you with the appropriate variable times.
First of all to understand several important parameters of the lens, specific to the parameters of the reference is as follows: parameters: the focal length.
Distance from the center of the lens to show the distance between the focus of clear image, the focal length is an important performance indexes of machine vision camera, its length determines the size of the image, the size of the Angle and the size of the depth of field.
The shorter the focal length, Angle, the greater the can observation are also more scope;
On the other hand, the focal length, the more often, the smaller the Angle, also can observe the scope of the smaller.
In order to better realize the collection of image, the lens is divided into two types: a fixed focus and zoom.
Parameter 2: aperture.
Aperture is change the middle hole size in the lens of a mechanical device, its size, determined by the focal length and the ratio of clear aperture.
The smaller the ratio, the larger the aperture, the amount of light in a unit time also is larger;
On the other hand, the bigger the ratio, the smaller the aperture is, the optical quantity will follow.
Three parameters: shooting distance.
As the name implies, lens face to the distance of the object to be tested is called the shooting distance.
Four parameters: the depth of field.
Machine vision lens clear scope of the object to be tested is a limit, and the depth of field is refers to the objects in the foreground is focused on the clear after, before and after the objects within a certain distance, can clearly show the range.
The depth of field and aperture, focal length, closely related to the shooting range.
The smaller the aperture, the greater the depth of field;
The smaller the aperture, the greater the depth of field.
2 the longer the focal length, depth of field is smaller;
The shorter the focal length, the greater the depth of field;
The greater the shot distance, depth of field;
The nearer the distance, the smaller the depth of field.
In addition to the above four main parameters influence each other, machine vision camera parameters include the size of the CCD, and the interface of the camera, resolution, field of vision, optical magnification, and so on.
It is the influence parameters in the machine vision camera can play its role, when choosing a lens, must be based on principles of suitable for testing, therefore, essential to the understanding of its parameters.
Industrial change times lens selection strategy determine the scope of the changing times: change times lens have three times than series: 6.
5 x variable times than (
5 x, WD: 90毫米)
0 x variable times than (
0 x, WD: 84毫米)
5 x variable times than (
5 x, WD: 84毫米)
Determine the main lens type, and additional features the main variable times lens has a continuous variable, fixed times, electric and rate feedback lens four types.
Additional features fine-tuning (
And collocation of coaxial light.
Determine the TV ADAPTER, and other accessories used by 1, view camera SENSOR size, such as: the FOV view (1/2, and need
Generally measured workpiece slightly larger than)
2, according to the ratio, WD, preliminary confirmed that TV ADAPTER and additional mirror, and see if FOV table can meet the requirements.