Image measuring instrument of the light source should be how to choose?
Light source is a key link of image measuring instrument, good light source is helpful to measure more accurate numerical, have very important influence on the measured results, so choose the appropriate light source, also need to consider many aspects mainly include the following: 1, the light source is the most important task that need to be observed the characteristics and needs to be ignored of maximum contrast between image characteristics, and characteristics of easy to distinguish, ensure that the characteristics of the need to detect outstanding from other background.
2, and the choice of two kinds of light source, the best choice is to choose the brighter one.
When the light is not enough light, there may be three bad things will appear.
First, the SNR of the camera is not enough;
Because of the brightness of the light source is not enough, image contrast is not enough, the possibility of noise on image also increases immediately.
Second, the brightness of the light source is not enough, must increase the aperture, thus reduced the depth of field.
In addition, when the brightness of the light source is not enough natural light and random light will be the biggest influence on system.
3, another test method is to see if the light source the good light sensitivity to the position of the parts is minimal.
When the light source is placed in different areas of the camera view or different point of view, the image should not be changed.
Directional strong light source, increase the possibility to highlight areas of specular reflection occurs, it is not conducive to the back of the feature extraction.
Good light source need to be able to make you need to find the characteristics of the obvious, but a camera to take to the parts, can produce enough contrast, brightness and biggest change is not sensitive to the position of the parts.
Light source selection, image measuring instrument will be more accurate measurement results, improve the production efficiency.