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Frequently Asked Questions

Why are most machine vision light sources of red color?
The image sensors used in machine vision cameras are most sensitive to light of red color. Additionally, red LEDs have a longer lifetime than LEDs of any other color.

If red LEDs last so long, why use other colors?
Though many inspections use black & white image sensors, the choice of light color is still important. Increasing Contrast with Colored Light is the process of using light color to either isolate or diminish colored portions of an object by using like or opposite colors.

Why use RGB?
Red, green and blue LEDs, when combined together in equal parts, create a while light approximately twice as bright as the white LEDs currently available. The advantage of the RGB combination is that the individual colors can be adjusted to create any hue in the cisible spectrum. The ability to fine tune color can significantly increase the efficiency of an inspection.

Why strobe?... and what is "Turbo Charging" an LED?
In fast moving inspections, using a strobe stops action in order for the camera to capture a clear image. When synchonized with the camera shutter, the strobed light will provide maximum intensity when the shutter is opened widest. Strobing becomes Turbo Changing when short bursts of high current are forced through an LED, increasing intensity. An added benefit of strobing is extending the life of the LEDs.

Red LEDs 660nm Green LEDs 520nm Blue LEDs 470nm

DC Current __________ Strobed ------------------

How useful are filters in an inspection?
Among other things, filters remove unwanted light, isolate specific colors, or decrease glare in an inspection. Band Pass filters allow only a narrow range of light through to the camera. In settings where ambient light creates an inconsistent variable, the band pass filter removes all but a specific range of light, eliminating the need for a shroud around the inspection area. Band Pass filters can also help isolate a color or range of colors within an inspection. Cut Off filters allow light above or below a specific wavelength to be visible to the camera. Polarizing filters help regulate the amount of glare from many specular objects.

How is color related to Camera Sensitivity?
Image sensors come in a range of spectral sensitivities and can be specifically matched to light color in order to optimize the light - the greater the intensity range available to the camera, the greater the ability to control the light with either shutter speed or by adjusting the aperture.