迪奥科技标语
Basic knowledge of machine vision light source
Author:Administrator   Published in:2019-11-07 11:14

The basic parts of visual inspection hardware include: processor, camera, lens, light source. Through the appropriate lighting design, the target information and background information in the image can be separated optimally, which can not only greatly reduce the algorithm difficulty of image processing, but also improve the accuracy and reliability of the system. Unfortunately, there is no general machine vision lighting system that can meet different detection requirements, so for each specific case , all need to design suitable lighting devices to achieve the best effect, while inappropriate lighting will cause many problems. Machine vision light source is so important, but often ignored by many people. At present, machine vision light source mainly uses LED (light emitting diode).

201606241543275412.jpg

The ways of machine vision are as follows:

Direct light: the incident light basically comes from one direction, with a small angle. It can cast shadows of objects.

Diffuse light: the incident light comes from multiple directions, or even all directions. It does not cast obvious shadows.

Polarized light: in a plane perpendicular to the direction of propagation, the light vector vibrates only in a fixed direction.

Directional light: light with the same angle, such as sunlight. The narrower the light angle, the closer the direct light is to the parallel light.

Basis of machine vision light source:

I. freedom of shape

An LED light source is composed of many single LEDs, so compared with other light sources, it can be made into more shapes, and it is easier to design the shape and size of the light source according to the user's situation.

II. Long service life

In order to make the image processing unit get accurate and reproducible measurement results, the lighting system must ensure that it can provide stable image input for a long time. After 10000 to 30000 hours of continuous operation, the brightness of LED light source decreases, but it is far better than other types of light source. In addition, by using the control system to make it work intermittently, the heating of the light-emitting tube can be restrained, and the service life will be doubled.

III. fast response

The response time of LED is very short. The real meaning of the response time is to ensure the work switching between multiple light sources or between different areas of a light source according to the requirements. When the special controller is used to power the LED light source, the time to reach the maximum illumination is less than 10s

IV. various colors

In addition to the shape of the light source, another way to get stable image input is to choose the color of the light source. Even the same shape of light source, due to the different color of the image will be very different. In fact, how to use the technical characteristics of light source color to get the best contrast image effect is always the main direction of light source development.

V. low comprehensive operation cost

Choose low-cost products with no guarantee of performance, and the savings of initial investment will soon be offset by daily maintenance and repair costs. Other light sources not only consume 2-10 times more power than LED light sources, but also need to be replaced almost every month, which wastes a lot of valuable time for maintenance engineers. Moreover, the more light sources are put into use, the greater the cost of device replacement and labor, so it is very economical to select long-life LED light sources in the long run.

In the optical system of machine vision application design, the most concerned is the reflected light on the object surface. Because the geometry, luster and color of the object surface determine how the light reflects on the object surface. The key to machine vision application of light source comes down to how to control the light reflection of objects. Only when the reflected light is well controlled, the collected image is easy to control.

 


Copyright @ 2016 - 2019 迪奥科技 版权所有 备案号: 粤ICP备09101295号