Aspherical lenses and large depth of field technology: influence industrial camera imaging effect of two major technical indicators
In recent years, machine vision with its performance, the advantages of the imaging by industrial production and scientific research of many industries.
And machine vision clear and accurate imaging effect of natural and industrial camera imaging techniques are inseparable.
Learned, factors affecting the effect of lens imaging culvert is lens, aperture, the depth of field, several main parameters, such as the current concern more is basically spherical lens and large depth of field technical indicators, and the Chinese machine vision mall, emphatically analyse the two technical indicators for machine vision camera imaging effect.
A, aspheric lens technical indicators for the lens, the definition of the picture is the most important indicators, emphasized here is the whole picture.
Camera lens with spherical and aspherical two kinds commonly, spherical lens because of its inherent spherical aberration and astigmatism, field, makes the picture resolution is not high, especially the picture edge can appear even falsified.
Aspherical lenses, by contrast, to improve the image of spherical lens caused by the inherent limitations, effectively improve the image definition of the edge, to a large extent by fuzzy phenomena are avoided.
Aspherical lenses clear imaging effect is understandable, but relatively the cost also is higher, and this is what led to the industrial application of aspheric also cannot achieve the main reason for the popularity.
However, due to using aspheric lens is able to obtain a good image, so there are still a lot of customers in the use, rather than a spherical lens market also is still the effect of lens imaging effect important technical indicators.
Second, the large depth of field technical indicators depth of field refers to the camera can clear imaging distance range, that is to say, want to get a clear picture, you need to lens have good depth of field, the greater the depth of field, clear picture of the greater range, after image magnification, distant scenery can still see clearly.
Large lens depth of field can enhance the picture clarity, enlarged picture clear area, is a large enough to influence the effect of lens imaging technology index.
So, when we choose a big depth of field lens, imaging can be used after the definition of the zoom in to.
The parameters of the depth of field is not an independent existence, it goes with the focal length and aperture, taken from the parameters such as have a certain relationship.
For example: aperture is inversely proportional to the depth of field is, large aperture, small depth of field;
Small aperture, the depth of field.
Long focal length and also is inversely proportional to the depth of field, lens focal length, depth of field,
Short focal length, depth of field.
The distance is proportional to the depth of field is taken, was taken from far, large depth of field;
Taken from the close, small depth of field.
Three, other technical indicators are in addition to the above two specifications, there are some factors are affecting the imaging lens.
For example, large aperture contrast has had great influence on the image, under low light conditions, if the aperture is not big enough, picture will look bleak, noise adding, picture quality could be greatly decreased.